To determine the accuracy of bibliographic citation in the anesthesia literature, we reviewed all 1988 volumes of ANESTHESIOLOGY, Anesthesia and Analgesia, British Journal of Anaesthesia, and Canadian Journal of Anaesthesia and sequentially numbered all references appearing in that year (n = 22,748). One hundred references from each of the four journals were randomly selected. After citations to nonjournal articles (i.e., books or book chapters) were excluded, the remaining 348 citations were analyzed in detail. Six standard bibliographic elements--authors' names, article title, journal title, volume number, page numbers, and year--were examined in each selected reference. Primary sources were reviewed, unless our institution did not own the source or could not obtain it through interlibrary loan, in which case standard indexes, abstracting services, and computerized databases were consulted. Each element was checked for accuracy, and references were classified as either correct or incorrect. A reference was correct if each element of the citation was identical to its source. Of the examined references, more than half (50.3%) contained an error in at least one element. The elements most likely to be inaccurate were, in descending order, article title, author, page numbers, journal title, volume number, and year. No significant differences (P = 0.283) existed in the error rates of the four journals; the percentage of citations containing at least one error ranged from 44% (Anesthesia and Analgesia) to 56% (British Journal of Anaesthesia). The citation error rate of anesthesia journals is similar to that reported in other specialties, where error rates ranging from 38% to 54% have been documented.
Simple criteria were used to evaluate the statistical analyses in 243 articles from two American anesthesia journals published in the latter six months of 1981 and 1983. Eighty-two percent of the articles reported the use of control measures and 37% reported randomization of treatment, where they were possible. Data were classified as nominal, ordinal, or interval; as independent or related samples; as two-sample or more-than-two-sample cases. The descriptive, inferential, and correlative tests used were evaluated for appropriate application and primary errors were identified. Nine percent of the 722 descriptive statistics had major errors, most of which were a description of ordinal data as though they were interval. The incidence of erroneous applications of 394 inferential statistical tests was 78%. Nearly three-quarters of the 308 primary inferential statistical errors involved either use of a test for independent samples on related data (and vice versa) or multiple applications of an uncorrected test to the same data. Only 4% of the 113 statistics of association were considered erroneous, most because the method was not identified. No differences were detected in the incidence of errors in either experimental design or statistical analysis across time or across the two anesthesia journals. Fifteen percent of the 243 articles in both journals at both times were without major errors in statistical analysis. Recognition of potential sources of error should make it easier for investigators to use experimental designs and statistical analyses appropriate to their needs.
* Developed by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia: Joy L. Hawkins, M.D. (Chair), Denver, Colorado; James F. Arens, M.D., Houston, Texas; Brenda A Bucklin, M.D., Denver, Colorado; Richard T. Connis, Ph.D., Woodinville, Washington; Patricia A. Dailey, M.D., Hillsborough, California; David R. Gambling, M.B.B.S., San Diego, California; David G. Nickinovich, Ph.D., Bellevue, Washington; Linda S. Polley, M.D., Ann Arbor, Michigan; Lawrence C. Tsen, M.D., Boston, Massachusetts; David J. Wlody, M.D., Brooklyn, New York; and Kathryn J. Zuspan, M.D., Stillwater, Minnesota.PRACTICE guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, practice guidelines are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert opinion, open forum commentary, and clinical feasibility data.This update includes data published since the “Practice Guidelines for Obstetrical Anesthesia” were adopted by the American Society of Anesthesiologists in 1998; it also includes data and recommendations for a wider range of techniques than was previously addressed.For the purposes of these Guidelines, obstetric anesthesia refers to peripartum anesthetic and analgesic activities performed during labor and vaginal delivery, cesarean delivery, removal of retained placenta, and postpartum tubal ligation.The purposes of these Guidelines are to enhance the quality of anesthetic care for obstetric patients, improve patient safety by reducing the incidence and severity of anesthesia-related complications, and increase patient satisfaction.These Guidelines focus on the anesthetic management of pregnant patients during labor, nonoperative delivery, operative delivery, and selected aspects of postpartum care and analgesia (i.e. , neuraxial opioids for postpartum analgesia after neuraxial anesthesia for cesarean delivery). The intended patient population includes, but is not limited to, intrapartum and postpartum patients with uncomplicated pregnancies or with common obstetric problems. The Guidelines do not apply to patients undergoing surgery during pregnancy, gynecologic patients, or parturients with chronic medical disease (e.g. , severe cardiac, renal, or neurologic disease). In addition, these Guidelines do not address (1) postpartum analgesia for vaginal delivery, (2) analgesia after tubal ligation, or (3) postoperative analgesia after general anesthesia (GA) for cesarean delivery.These Guidelines are intended for use by anesthesiologists. They also may serve as a resource for other anesthesia providers and healthcare professionals who advise or care for patients who will receive anesthetic care during labor, delivery, and the immediate postpartum period.The American Society of Anesthesiologists (ASA) appointed a Task Force of 11 members to (1) review the published evidence, (2) obtain the opinion of a panel of consultants including anesthesiologists and nonanesthesiologist physicians concerned with obstetric anesthesia and analgesia, and (3) obtain opinions from practitioners likely to be affected by the Guidelines. The Task Force included anesthesiologists in both private and academic practices from various geographic areas of the United States and two consulting methodologists from the ASA Committee on Standards and Practice Parameters.The Task Force developed the Guidelines by means of a seven-step process. First, they reached consensus on the criteria for evidence. Second, original published research studies from peer-reviewed journals relevant to obstetric anesthesia were reviewed. Third, the panel of expert consultants was asked to (1) participate in opinion surveys on the effectiveness of various peripartum management strategies and (2) review and comment on a draft of the Guidelines developed by the Task Force. Fourth, opinions about the Guideline recommendations were solicited from active members of the ASA who provide obstetric anesthesia. Fifth, the Task Force held open forums at two major national meetings†to solicit input on its draft recommendations. Sixth, the consultants were surveyed to assess their opinions on the feasibility of implementing the Guidelines. Seventh, all available information was used to build consensus within the Task Force to finalize the Guidelines (appendix 1).Preparation of these Guidelines followed a rigorous methodologic process (appendix 2). To convey the findings in a concise and easy-to-understand fashion, these Guidelines use several descriptive terms. When sufficient numbers of studies are available for evaluation, the following terms describe the strength of the findings.The lack of scientific evidence in the literature is described by the following terms.Formal survey information is collected from consultants and members of the ASA. The following terms describe survey responses for any specified issue. Responses are solicited on a five-point scale ranging from 1 (strongly disagree) to 5 (strongly agree), with a score of 3 being equivocal. Survey responses are summarized based on median values as follows:Although comparative studies are insufficient to evaluate the peripartum impact of conducting a focused history (e.g. , reviewing medical records) or a physical examination, the literature reports certain patient or clinical characteristics that may be associated with obstetric complications. These characteristics include, but are not limited to, preeclampsia, pregnancy-related hypertensive disorders, HELLP syndrome, obesity, and diabetes.The consultants and ASA members both strongly agree that a directed history and physical examination, as well as communication between anesthetic and obstetric providers, reduces maternal, fetal, and neonatal complications.The anesthesiologist should conduct a focused history and physical examination before providing anesthesia care. This should include, but is not limited to, a maternal health and anesthetic history, a relevant obstetric history, a baseline blood pressure measurement, and an airway, heart, and lung examination, consistent with the ASA “Practice Advisory for Preanesthesia Evaluation.”§When a neuraxial anesthetic is planned or placed, the patient's back should be examined.Recognition of significant anesthetic or obstetric risk factors should encourage consultation between the obstetrician and the anesthesiologist. A communication system should be in place to encourage early and ongoing contact between obstetric providers, anesthesiologists, and other members of the multidisciplinary team.The literature is insufficient to assess whether a routine platelet count can predict anesthesia-related complications in uncomplicated parturients. The literature suggests that a platelet count is clinically useful for parturients with suspected pregnancy-related hypertensive disorders, such as preeclampsia or HELLP syndrome, and for other disorders associated with coagulopathy.The ASA members are equivocal, but the consultants agree that obtaining a routine intrapartum platelet count does not maternal anesthetic complications. the consultants and ASA members agree for patients with suspected preeclampsia, a platelet count reduces maternal anesthetic complications. The consultants strongly agree and the ASA members agree that a platelet count reduces maternal anesthetic complications for patients with suspected specific platelet count of neuraxial anesthetic complications not The to or a platelet count should be and based on a patient's history, physical examination, and clinical A routine platelet count is not in the literature is insufficient to whether obtaining a blood and is associated with maternal anesthetic complications. In addition, the literature is insufficient to whether a blood is for and uncomplicated parturients. The consultants and ASA members agree that an intrapartum blood should be to the blood for all routine blood is not for and uncomplicated parturients for vaginal or operative The whether to or a blood and or should be based on maternal history, complications (e.g. , in a patient with and and local institutional literature suggests that anesthetic and analgesic may the is insufficient literature to that of the or neonatal complications. the consultants and ASA members that of the reduces and neonatal complications.The should be by a before and after of neuraxial analgesia for The Task Force that of the may not be in clinical and may not be during of neuraxial is insufficient published evidence to about the between for and the risk of or during The consultants and ASA members both agree that of during labor maternal and the ASA members are equivocal, the consultants agree that of during labor does not increase maternal complications.The of of may be for uncomplicated The uncomplicated patient undergoing cesarean may of to before of anesthesia. of include, but are not limited to, and of is than the of in the patients with risk factors for (e.g. , obesity, or patients at risk for operative (e.g. , may of on a specific for that is of maternal anesthetic complications not is insufficient published evidence to address the safety of any for in obstetric The consultants and ASA members both agree that the of during labor maternal complications. They both strongly agree that patients undergoing cesarean or postpartum tubal should a of on the of (e.g. , Task Force that in patients the of is with a before is not should be in The patient undergoing surgery (e.g. , cesarean or postpartum tubal should a for of on the of (e.g. , literature does not the between and the of or in obstetric patients who evidence the of (e.g. , in during the peripartum the literature is insufficient to the impact of on The literature suggests that are in in obstetric patients and the of in reducing peripartum and The consultants and ASA members agree that the of a before operative reduces maternal (i.e. , cesarean delivery, postpartum tubal practitioners should the of for all anesthetic care during labor or who for labor delivery, are analgesic techniques sufficient for In addition, maternal medical and obstetric may the of neuraxial techniques to improve maternal and neonatal of analgesic on the medical of the of labor, and at the When sufficient (e.g. , anesthesia and are neuraxial techniques should be of the analgesic The of a specific neuraxial should be and based on anesthetic risk obstetric risk patient of labor, and at the neuraxial techniques are used for analgesia during labor or vaginal delivery, the is to provide maternal analgesia with (e.g. , with the of local at with or a neuraxial is for the of complications (e.g. , should be an is for complications (e.g. , should be should be before the of neuraxial analgesia or anesthesia and the of the neuraxial analgesic or of a of is not before neuraxial analgesia is of the literature that the of neuraxial analgesia does not the of cesarean The literature also suggests that other (i.e. , or are also The consultants strongly agree and the ASA members agree that early of analgesia (i.e. , at of than 5 to or than 5 They both that or maternal, fetal, or neonatal are by early in early labor (i.e. , 5 should be the of neuraxial analgesia is analgesia should not be on the of an and should be on an may be that the use of neuraxial analgesia does not increase the incidence of cesarean comparative studies that analgesia may be used in a of labor for cesarean patients the incidence of vaginal of other anesthetic techniques were not The consultants and ASA members agree that neuraxial techniques improve the of vaginal for patients vaginal after cesarean techniques should be to patients vaginal after cesarean these patients, it is also to early of a neuraxial that can be used for labor analgesia, or for anesthesia in the of operative literature is insufficient to assess for the the early of a or with of analgesia, maternal or neonatal The consultants and ASA members agree that early of a or for parturients reduces maternal of a or for obstetric (e.g. , or or anesthetic (e.g. , or should be to the for an In these the of a or may the of labor or a patient's for labor literature suggests that the use of local with or opioids quality of analgesia with (i.e. , or The consultants and ASA members strongly agree that local with or opioids provide analgesia with of the literature that is a of labor, with an of for the and a of vaginal local are with of the literature that are in the of cesarean the consultants ASA members agree that local with opioids (1) increase the of labor, (2) the of delivery, (3) increase maternal or increase and neonatal is insufficient literature to assess the analgesic of local with or opioids to opioids with or local The consultants are equivocal, but the ASA members agree that local improve analgesia with both the consultants and ASA members are the of The consultants are equivocal, but the ASA members that the use of with opioids the of They both that local with or opioids to opioids with or local the of or maternal, fetal, or neonatal literature the of analgesia local with opioids with of local opioids for quality and of The consultants strongly agree and the ASA members agree that the of opioids to local they both that or neonatal are The consultants but the ASA members are whether the of opioids maternal literature is insufficient to whether of analgesia local with opioids with of local opioids quality or of The consultants and ASA members are analgesia, and they both that maternal, fetal, or neonatal are of local with of analgesia , the literature suggests that are in the analgesic of of local with opioids with of local The Task Force that the of an to a local anesthetic an of local anesthetic for providing the literature is insufficient to whether a of than or to with an or analgesia with a than an of the literature that of local with opioids with of local opioids are associated with in the of labor, of delivery, or neonatal are local with opioids are with local The literature is insufficient to the of local with opioids on other maternal (e.g. , consultants and ASA members both agree that of analgesia of local with opioids analgesia with of local The consultants but the ASA members are the of of local with opioids are The consultants strongly agree and the ASA members agree that is They agree that maternal are with They are both a in and neonatal selected should patient needs and practitioner or and available The may be used for analgesia for labor and When a of local anesthetic is an may be to the of local improve the quality of analgesia, and analgesia for uncomplicated labor and should be with the of as as by of local with The of local anesthetic that maternal analgesia and should be an than is for labor analgesia in literature suggests that opioids with or local provide analgesia during labor the incidence of neonatal complications. is insufficient literature to opioids with is also insufficient literature to opioids with local opioids local consultants strongly agree and the ASA members agree that opioids provide analgesia with They both with opioids increase the of labor, the of delivery, or increase and neonatal The consultants are equivocal, but the ASA members that maternal are with with opioids local the consultants and ASA members both agree that opioids with local provide They both that the of is and that and neonatal are They are both an increase in maternal they both agree that is local are to the consultants but the ASA members are an increase in the of opioids with or local may be used to provide analgesia for labor vaginal is labor is to than the analgesic of the or is a of operative delivery, a of a should be A local anesthetic may be to a to increase and improve quality of The Task Force that the of analgesia by techniques may be for selected patients (e.g. , in literature the use of with to the of The consultants and ASA members both strongly agree that the use of reduces maternal should be used of to the risk of literature a and analgesia with local with opioids local with The literature is the impact of local with opioids on maternal with analgesia, of delivery, and of the literature that the of is with consultants and ASA members both agree that local with opioids provide early analgesia with local with They are the impact of with opioids on analgesic of labor, and The consultants and ASA members both that the risk of or neonatal The consultants but the ASA members are whether the incidence of maternal techniques may be used to provide and of analgesia for literature the of analgesia in providing analgesia with of the literature that the of labor is with with for the (e.g. , an of but not the of of the literature also that of delivery, of and are is with The literature analgesic for with a with a of the literature also in the of or of The consultants and ASA members agree that with analgesia and reduces the for anesthetic they also agree that maternal The consultants and ASA members are a in an of delivery, or a in maternal with with They both agree that with a analgesia, maternal and reduces the for anesthetic The ASA members are equivocal, but the consultants that a the of or maternal The consultants and ASA members are the of a on the incidence of analgesia may be used to provide an and for the of labor The Task Force that the use of may be to for providing anesthetic and of local may be used with or a literature is insufficient to assess whether a of anesthetic is than for removal of retained The consultants strongly agree and the ASA members agree a is in place and the patient is anesthesia is the for the removal of retained The consultants and ASA members both agree in major maternal is neuraxial Task Force in is anesthetic for removal of retained an is in place and the patient is anesthesia is should be before neuraxial anesthesia. should be should be to the of and during the immediate postpartum In major maternal with an may be to neuraxial literature suggests that is for during the removal of retained The consultants and ASA members both agree that the of for in a retained may be used as an to or general anesthesia with for during removal of retained with of or (i.e. , may the complications (e.g. , literature is insufficient to evaluate the of providing and in the labor and to that available in the The consultants and ASA members strongly agree that the available and should be and available in the labor and should be to available in the for the of complications (e.g. , analgesia, should also be available in the labor and and should be available to care for obstetric patients from major neuraxial anesthesia or literature suggests that for are with or anesthesia and that a of maternal may be associated with or of the literature that at 1 and 5 are for with anesthesia and suggests that are for anesthesia. The literature is in values is with or consultants and ASA members agree that reduces the to with or they also agree that maternal complications. The consultants are and the ASA members agree that and neonatal complications. The consultants and ASA members both agree that anesthesia the to and the quality of anesthesia with anesthesia. They both that anesthesia maternal anesthesia is with of the literature that are for anesthesia. The literature is and The consultants and ASA members agree that anesthesia to and reduces the quality of anesthesia with anesthesia. They both that anesthesia maternal is with of the literature in the of or in the literature is insufficient to evaluate associated with the use of with anesthesia. The consultants and ASA members agree that anesthesia anesthesia and reduces to with anesthesia. The ASA members are equivocal, but the consultants that maternal are The consultants and ASA members both that anesthesia with anesthesia. The ASA members are equivocal, but the consultants that maternal are The consultants strongly agree and the ASA members agree that with anesthesia of and they both agree that the to is to use a anesthetic for cesarean should be based on several These or risk factors (e.g. , the of the and the of the anesthesiologist. techniques are to for cesarean may provide of anesthesia with of anesthesia for cesarean anesthesia is should be used of may be the in (e.g. , severe severe should be of the anesthetic literature and the consultants and ASA members agree that for anesthesia reduces the of maternal with may be used to the of maternal after anesthesia for cesarean reduces the of maternal of anesthesia should not be to a of literature the of and suggests that is in reducing maternal during neuraxial anesthesia for cesarean The literature is the of patients with of are with values are after The consultants agree and the ASA members strongly agree that is for during neuraxial anesthesia. The consultants strongly agree and the ASA members agree that is an for the of and are both for during neuraxial anesthesia. In the of maternal may be of in uncomplicated postoperative analgesia after cesarean during the literature the use of opioids with of or a of was with The literature is insufficient to evaluate the impact of opioids with In addition, the literature is insufficient to evaluate opioids with The consultants strongly agree and the ASA members agree that neuraxial opioids for postoperative analgesia improve analgesia and maternal postoperative analgesia after neuraxial anesthesia for cesarean delivery, neuraxial opioids are of is insufficient literature to evaluate the of neuraxial anesthesia with for postpartum tubal In addition, the literature is insufficient to evaluate the impact of the of a postpartum tubal on maternal outcome. The consultants and ASA members both agree that neuraxial anesthesia for postpartum tubal reduces complications with The ASA members are but the consultants agree that a postpartum tubal within of does not increase maternal postpartum tubal ligation, the patient should of within of the on the of (e.g. , should be the of the and the to use a anesthetic (i.e. , neuraxial should be based on anesthetic risk obstetric risk factors (e.g. , blood and patient neuraxial techniques are to for postpartum tubal The anesthesiologist should be that will be in patients who opioids during labor, and that an for labor may be likely to with a postpartum tubal is to be performed before the patient is from the the should not be at a it other aspects of patient care on the labor and studies and reports that the of for may be associated with maternal complications. The consultants and ASA members both strongly agree that the of for reduces maternal providing obstetric care should available to In an the use of or blood is In of blood is not available or the patient should be is insufficient literature to whether is associated with maternal, fetal, or neonatal in patients with pregnancy-related hypertensive The literature is the management of obstetric patients with The consultants and ASA members agree that the routine use of or does not maternal complications in to should be and based on clinical that the patient's medical history and risk The Task Force that not all practitioners to for use of or in obstetric reports that the of for the management of may be associated with maternal, fetal, and neonatal complications. The consultants and ASA members both strongly agree that the immediate of for the management of reduces maternal, fetal, and neonatal and should and available to to a and consistent with the ASA Practice Guidelines for of the management should be available during the of neuraxial analgesia 2). In addition, for management should be available in the operative of labor and The anesthesiologist should a for of the When with and or with a or (e.g. , should be for an and the it is not to or the an should be literature is insufficient to evaluate the of in the obstetric patient during labor and In of the American that is the will to whether the can be by and of the may improve of the by The American that for to in the of the than 5 after the This that the the about after consultants and ASA members both strongly agree that the immediate of basic and in the labor and reduces maternal, fetal, and neonatal and should be available in the operative of labor and during labor and delivery, should be In addition, should be maternal is not within cesarean should be performed by the team.The scientific of these Guidelines was based on evidence or between clinical and The were to assess their impact on a of to obstetric evidence was from research literature, and evidence was from open and other activities (e.g. , purposes of literature relevant clinical studies were and of the The and a from than were a of that to the evidence review of the studies not provide evidence and were A of in a was as an evidence a or equivocal. The were summarized to obtain a for evidence before conducting a to 11 evidence studies with and information sufficient for These were (1) (2) of local with or opioids (3) of analgesia local with opioids of local of of of local with opioids of local local with opioids local with general anesthesia anesthesia for cesarean delivery, anesthesia anesthesia for cesarean delivery, use of or reduces maternal during neuraxial and neuraxial opioids opioids for postoperative analgesia after neuraxial anesthesia for cesarean or were for and were for were used as (1) the values based on of the values from the and (2) the providing of the studies by of the by the of the based on the for was used with was at for of the studies were to the were significant was To for a was for studies was and for research were are in To be as significant agree with both of data are In the of findings from both the and agree with other to be as Task Force members and two methodologists was by a for were as (1) of (2) of (3) evidence and literature for values were (1) (2) of (3) and literature These values to of was from including (1) survey opinion from consultants who were selected based on their or in obstetric anesthesia or maternal and (2) survey opinions solicited from active members of the (3) from of held open forums at two national anesthesia commentary, and Task Force opinion and The survey of was of for the and surveys were from active ASA of the surveys are in 5 and in the of the consultants were asked to of the evidence their clinical practices the Guidelines were The of was The of consultants associated with were as anesthetic care for labor and removal of retained anesthetic for cesarean postpartum tubal and management of of the that the Guidelines on the of on a that be an increase of 5 in the of on a with the of these Guidelines.
PRACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.This update includes data published since the Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration were adopted by the ASA in 1998 and published in 1999.*For these Guidelines, preoperative fasting is defined as a prescribed period of time before a procedure when patients are not allowed the oral intake of liquids or solids. Perioperative pulmonary aspiration is defined as aspiration of gastric contents occurring after induction of anesthesia, during a procedure, or in the immediate period after surgery.The purposes of these Guidelines are to (1) enhance the quality and efficiency of anesthesia care, (2) stimulate evaluation of clinical practices, and (3) reduce the severity of complications related to perioperative pulmonary aspiration of gastric contents.Enhancements in the quality and efficiency of anesthesia care include, but are not limited to, the cost-effective use of perioperative preventive medication, increased patient satisfaction, avoidance of delays and cancellations, decreased risk of dehydration or hypoglycemia from prolonged fasting, and the minimization of perioperative morbidity.Clinical practices include, but are not limited to, withholding solids and liquids for specified time periods before surgery, and prescribing pharmacologic agents to reduce gastric volume and acidity.Complications of aspiration include, but are not limited to, aspiration pneumonia, respiratory disabilities, and related morbidities.These Guidelines focus on preoperative fasting recommendations, as well as recommendations regarding the administration of pharmacologic agents to modify the volume and acidity of gastric contents during procedures in which upper airway protective reflexes may be impaired. Prevention of perioperative pulmonary aspiration is part of the larger process of preoperative evaluation and preparation of the patient.Airway management techniques that are intended to reduce the occurrence of pulmonary aspiration are not the focus of these Guidelines. For example, a rapid-sequence induction/tracheal intubation technique or an awake tracheal intubation technique may be useful to prevent this problem during the delivery of anesthesia care. In addition, these Guidelines do not address the selection of anesthetic technique.The intended patient population for these Guidelines is limited to healthy patients of all ages undergoing elective procedures. These Guidelines do not apply to patients who undergo procedures with no anesthesia or only local anesthesia when upper airway protective reflexes are not impaired, and when no risk factors for pulmonary aspiration are apparent. These Guidelines are also not intended for women in labor.These Guidelines may not apply to, or may need to be modified for (1) patients with coexisting diseases or conditions that can affect gastric emptying or fluid volume (e.g. , pregnancy, obesity, diabetes, hiatal hernia, gastroesophageal reflux disease, ileus or bowel obstruction, emergency care, enteral tube feeding) and (2) patients in whom airway management might be difficult. Anesthesiologists and other anesthesia providers should recognize that these conditions can increase the likelihood of regurgitation and pulmonary aspiration. Additional or alternative preventive strategies may be appropriate for such patients.These Guidelines are intended for use by anesthesiologists and other anesthesia providers. They also may serve as a resource for other health care professionals who advise or care for patients who receive anesthesia care during procedures. Anesthesia care during procedures refers to general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). Throughout these Guidelines, preoperative should be considered synonymous with preprocedural, as the latter term is often used to describe procedures that are not considered operations.The original Guidelines were developed by a Task Force of 10 members, including anesthesiologists in both private and academic practice from various geographic areas of North America, and a consulting methodologist from the ASA Committee on Standards and Practice Parameters.The Task Force developed the original Guidelines by means of a six-step process. First, they reached consensus on the criteria for evidence. Second, original published research studies from peer-reviewed journals relevant to preoperative fasting were reviewed and evaluated. Third, expert consultants were asked (1) to participate in opinion surveys on the effectiveness of various preoperative fasting management recommendations and (2) to review and comment on a draft of the Guidelines. Fourth, the Task Force held open forums at a national meeting†to solicit input on the draft recommendations. Fifth, expert consultants were surveyed to assess their opinions on the feasibility of implementing the Guidelines. Sixth, all available information was used to build consensus within the Task Force to finalize the Guideline recommendations (appendix 1).In 2009, the ASA Committee on Standards and Practice Parameters requested that scientific evidence for these Guidelines be updated. This update consists of an evaluation of literature that includes new studies obtained after publication of the original Guidelines, new surveys of expert consultants, and a survey of a randomly selected sample of active ASA members.Preparation of this update used the same methodologic process as was used in the original Guidelines to obtain new evidence from two principal sources: scientific evidence and opinion-based evidence (appendix 2). The protocol for reporting each source of evidence is described below.Study findings from published scientific literature were aggregated and are reported in summary form by evidence category, as described below. All literature (e.g. , randomized controlled trials, observational studies, case reports) relevant to each topic was considered when evaluating the findings. However, for reporting purposes in this document, only the highest level of evidence (i.e. , level 1, 2, or 3 within category A, B, or C) is included in the summary.Randomized controlled trials report statistically significant (P < 0.01) differences between clinical interventions for a specified clinical outcome.Level 1. The literature contains multiple randomized controlled trials. Aggregated findings are supported by meta-analysis.‡Level 2. The literature contains multiple randomized controlled trials, but there is an insufficient number of studies to conduct a viable meta-analysis for the purpose of these Guidelines.Level 3. The literature contains a single randomized controlled trial.Information from observational studies permits inference of beneficial or harmful relationships among clinical interventions and clinical outcomes.Level 1. The literature contains observational comparisons (e.g. , cohort, case-control research designs) of clinical interventions or conditions and indicates statistically significant differences between clinical interventions for a specified clinical outcome.Level 2. The literature contains noncomparative observational studies with associative (e.g. , relative risk, correlation) or descriptive statistics.Level 3. The literature contains case reports.The literature cannot determine whether there are beneficial or harmful relationships among clinical interventions and clinical outcomes.Level 1. Meta-analysis did not find significant differences among groups or conditions.Level 2. The number of studies is insufficient to conduct meta-analysis, and (1) randomized controlled trials have not found significant differences among groups or conditions, or (2) randomized controlled trials report inconsistent findings.Level 3. Observational studies report inconsistent findings or do not permit inference of beneficial or harmful relationships.The lack of scientific evidence in the literature is described using the terms defined below.Silent. No identified studies address the specified relationships among interventions and outcomes.Inadequate. The available literature cannot be used to assess relationships among clinical interventions and clinical outcomes. The literature either does not meet the criteria for content as defined in the “Focus” of the Guidelines or does not permit a clear interpretation of findings due to methodological concerns (e.g. , confounding in study design or implementation).All opinion-based evidence relevant to each topic (e.g. , survey data, open-forum testimony, Internet-based comments, letters, editorials) was considered in the development of the original Guidelines. New opinion surveys were developed to address each clinical intervention identified in the document, and identical surveys were distributed to both expert consultants and a random sample of active ASA members.Survey responses from Task Force–appointed expert consultants are reported in summary form in the text. A complete listing of consultant survey responses reported in a table in appendix 2.Survey responses from active ASA members are reported in summary form in the text. A complete listing of ASA member survey responses reported in appendix 2.Survey responses are recorded using a 5-point scale and summarized based on median values.§Strongly Agree. Median score of 5 (at least 50% of responses are 5).Agree. Median score of 4 (at least 50% of responses are 4 [or 4 and 5]).Equivocal. Median score of 3 (at least 50% of responses are 3—or no other response category or combination of similar categories contain at least 50% of responses).Disagree. Median score of 2 (at least 50% of responses are 2 [or 1 and 2]).Strongly Disagree. Median score of 1 (at least 50% of responses are 1).Open-forum testimony, Internet-based comments, letters, and editorials were all informally evaluated and discussed during the development of the original Guideline recommendations.No controlled trials were found that address the impact of conducting a preoperative assessment (e.g. , history, physical examination, survey/interview) on the frequency or severity of pulmonary aspiration of gastric contents during the perioperative period (Category D evidence ). Studies with observational findings suggest that certain predisposing conditions (e.g. , age, comorbid disease) may be associated with the risk of perioperative aspiration (Category B2 evidence ).1,2The consultants and ASA members strongly agree that a review of pertinent medical records, a physical examination, and patient survey or interview should be performed as part of preoperative evaluation. They also strongly agree that patients should be informed of fasting requirements, and the reasons for them, sufficiently in advance of their procedures. In addition, both the consultants and ASA members strongly agree that verification of patient compliance with fasting requirements should be assessed at the time of the procedure.A review of pertinent medical records, a physical examination, and patient survey or interview should be performed as part of preoperative evaluation. The history, examination, and interview should include pertinent assessment of gastroesophageal reflux disease, dysphagia symptoms, or other gastrointestinal motility disorders, potential for difficult airway management, and metabolic disorders (e.g. , diabetes mellitus) that may increase the risk of regurgitation and pulmonary aspiration. Patients should be informed of fasting requirements, and the reasons for them, sufficiently in advance of their procedures. Verification of patient compliance with fasting requirements should be assessed at the time of the procedures. When the fasting recommendations in these Guidelines are not followed, the practitioner should compare the risks and benefits of proceeding, with consideration given to the amount and type of liquids or solids ingested.Meta-analysis of randomized controlled trials3–10comparing fasting times of 2–4 4 report gastric and gastric in patients given clear liquids 2–4 before a procedure (Category evidence findings for gastric are (Category evidence of randomized controlled gastric (Category evidence and findings regarding differences in gastric volume for given clear liquids 2–4 before a procedure fasting for 4 before a procedure (Category evidence of clear liquids in the studies from to for and 2 to for clinical evidence is insufficient to address the between fasting times for clear liquids and the risk of or pulmonary aspiration (Category D evidence the consultants and ASA members strongly agree that for healthy 2 and fasting from the intake of clear liquids at least 2 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of clear liquids at least 2 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). of clear liquids include, but are not limited to, clear and These liquids should not include The volume of is the type of with observational findings are regarding the impact of 4 before a procedure on the risk of or of gastric contents during a procedure (Category evidence literature is insufficient to the of the of of and the perioperative of or pulmonary aspiration (Category D evidence consultants agree and the ASA members strongly agree that for healthy and fasting from the intake of at least 4 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of at least 4 before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia study with observational findings is regarding the impact of 4 before a procedure on the risk of or of gastric contents during a procedure (Category evidence literature is insufficient to the of the of of and the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members agree that for and fasting from the intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be The consultants agree and the ASA members strongly agree that for fasting from the intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of at least before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia randomized controlled a an of 4 before a procedure with fasting findings regarding gastric volume and for (Category evidence with findings for given 4 or before a procedure who for 4 report gastric (Category B2 evidence and gastric (Category evidence study with observational findings that fasting for may be associated with hypoglycemia in (Category B2 evidence literature is insufficient to the of the of of solids and and the perioperative of or pulmonary aspiration (Category D evidence consultants agree and the ASA members strongly agree that fasting from the intake of a (e.g. , and a clear or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be the consultants and ASA members strongly agree that fasting from the intake of a that includes or or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be the consultants and ASA members agree that for fasting from the intake of or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be The consultants agree and the ASA members strongly agree that for and fasting from the intake of or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia should be is appropriate to from intake of a or or before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia care). The Task Force that intake of or or may gastric emptying Additional fasting time (e.g. , or may be in these the amount and type of be considered when an appropriate fasting is similar to solids in gastric emptying the amount be considered when an appropriate fasting of randomized the of to reduce gastric volume (Category evidence is regarding the of on gastric acidity (Category evidence the perioperative The literature is insufficient to the of gastrointestinal on the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members that gastrointestinal should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of gastrointestinal to the risk of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not Meta-analysis of randomized trials the of to reduce gastric the perioperative period (Category evidence ). Meta-analysis of randomized the of to reduce gastric volume and acidity during the perioperative period (Category evidence ). trials that is in gastric volume and acidity (Category evidence controlled trials the of in gastric volume and acidity (Category evidence similar findings reported for (Category evidence literature is insufficient to the of either or on the perioperative of or pulmonary aspiration (Category D evidence the consultants and ASA members that should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary aspiration. The ASA members and the consultants strongly that should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of that gastric to the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not controlled trials that preoperative (e.g. , increase gastric during the perioperative period (Category evidence findings regarding gastric volume (Category evidence ). The literature does not sufficiently the between gastric acidity and the frequency of pulmonary aspiration or in does the literature sufficiently whether gastric acidity or volume is associated with decreased or in patients given preoperative who have gastric contents (Category D evidence consultants and ASA members both that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary aspiration. The consultants and ASA members both strongly agree that only should be used when are for selected preoperative use of to the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not should be used when are for selected patients for purposes other the risk of pulmonary controlled trials that the preoperative administration of in and during the period after (Category evidence ). The literature does not sufficiently the between the preoperative use of and the frequency of pulmonary aspiration (Category D evidence consultants and ASA members both that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no increased risk for pulmonary preoperative use of to reduce the risks of pulmonary aspiration in patients who have no increased risk for pulmonary aspiration is not trials are regarding the of reduce gastric volume or acidity (Category evidence ASA members and the consultants strongly that preoperative should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia to the risk of pulmonary use of to the risks of pulmonary aspiration is not controlled trials when (i.e. , are with gastrointestinal (i.e. , the of the two is in both gastric volume and acidity (Category evidence when with gastrointestinal are to in gastric acidity are when the are to gastrointestinal as the findings for gastric volume are controlled trials other single report inconsistent findings regarding gastric volume and (Category evidence ASA members and the consultants strongly that preoperative multiple agents should be before elective procedures general anesthesia, regional anesthesia, or sedation/analgesia (i.e. , monitored anesthesia in patients who have no risk for pulmonary preoperative use of multiple agents in patients who have no increased risk for pulmonary aspiration is not Fasting liquids 2 4 recommendations apply to healthy patients who are undergoing elective procedures. They are not intended for women in the Guidelines does not guarantee complete gastric The fasting periods apply to patients of all of clear liquids include clear and is similar to solids in gastric emptying the amount be considered when an appropriate fasting consists of and clear that include or or may gastric emptying Additional fasting time (e.g. , or may be in these the amount and type of be considered when an appropriate fasting recommendations are by type with In addition, of the are not for No No No No No No No No No No No No No No these Guidelines, a literature review is used in combination with opinions obtained from expert consultants and other (e.g. , American Society of Anesthesiologists members, open the literature review and opinion data are based on evidence or regarding potential relationships between clinical interventions and outcomes. The interventions were to assess their impact on pulmonary aspiration and other outcomes. for the interventions include, but are not limited to, pulmonary volume and acidity of gastric (e.g. , (e.g. , and other (e.g. , of in the literature relevant clinical studies were identified and of the For the original Guidelines, and a period from The literature for this update the period from and included review of that related to the evidence review of the studies did not provide evidence and were A of findings related to at least of the evidence No evidence literature with and information to conduct an analysis of aggregated studies (i.e. , A complete used to these Guidelines, by is available as 2, literature is according to the or of the to the an a study should either a or methodological (e.g. , for For these Guidelines, the of are pulmonary aspiration and these Guidelines focus on the between a preoperative intervention and the frequency of pulmonary and the between a preoperative intervention and the frequency or severity of an associated with aspiration (e.g. , However, the literature is insufficient to such The literature of relationships between preoperative interventions and of These of relationships are to as or a either between an intervention (e.g. , and a clinical or between two (e.g. , gastric volume and In the studies reviewed with the between of the identified interventions in the Guidelines and the of pulmonary aspiration was not a between an intervention of and pulmonary aspiration cannot be (e.g. , gastric were considered by the to be of a risk of pulmonary of such comparisons are not to provide 2 4 comparisons that for an outcome. For example, to the effectiveness of a on pulmonary the of the on gastric content as well as the occurrence of be content and are between the intervention and pulmonary aspiration. This be considered a 2 a in which or between the intervention and the of However, level 2 relationships do not the between an intervention of and the occurrence of pulmonary 3 contains of to the Guidelines (i.e. , 4 contains the other of to the Guidelines (i.e. , between an intervention and clinical from pulmonary that related to preoperative fasting and the administration of pharmacologic agents were insufficient to relationships that the interventions of in these Guidelines with the occurrence of pulmonary aspiration or the clinical from pulmonary the literature was not for assessment related to pulmonary findings for each intervention of regarding is each pertinent reported in a study is as an evidence a or These are summarized to obtain a assessment for each evidence before conducting a The literature to evidence studies with and information to conduct These evidence (1) preoperative fasting of liquids between 2 and 4 for (2) preoperative fasting of liquids between 2 and 4 for (3) preoperative preoperative and preoperative Meta-analysis was limited to gastric volume and acidity or are obtained for are obtained for are used as (1) the based on of the reported from the studies, and (2) the of the studies by each of the by the of the procedure based on the for study using 2 2 is used with frequency level is at a of for of the studies are to among study are obtained when significant is found (P < for potential a is No for studies was no for research were be as significant agree with both of data are In the of findings from the and agree with each other to be considered statistically the original Guidelines, among Task Force members and two was by using a for are as (1) type of study (2) type of (3) evidence and literature for (1) (2) (3) literature These to of was obtained from multiple (1) survey opinion from consultants who were selected based on their or in preoperative fasting and of pulmonary (2) survey opinions from active members of the American Society of (3) from of a held open forum for the original Guidelines held at a national anesthesia commentary, and Task Force opinion and The survey of was of for the consultants responses were from active American Society of Anesthesiologists members the original Guidelines, an survey was to the consultants to of the evidence their clinical practices the Guidelines were The of consultants no associated with each were as preoperative preoperative fasting of preoperative fasting of preoperative fasting of gastrointestinal pharmacologic of gastric and multiple of that the Guidelines have no on the amount of time on a For all the increase in the amount of time on a case was reported that the Guidelines increase the amount of time The time increase for these two was 5 and
In a comprehensive review on monitoring anesthesia, Stanski (1) concluded that both specific defined stimuli and specific responses are needed to assess anesthetic depth. He stated that no unifying clinical measure of anesthetic depth spans all classes of anesthetic drugs and that clinical measures that appear relevant for a single drug may not be relevant if the drug is used in a combination. This conclusion is consistent with the view that the spectrum of effects that constitutes the state of general anesthesia should not be regarded as several components of anesthesia resulting from one anesthetic action, but represents separate pharmacological actions, even if the anesthesia is produced by one drug (2). As a result, the diversity of pharmacological actions that, in combination, provide anesthesia makes it impossible to determine the potency of different actions with one measure. Several studies support this view, some of which concern the molecular mechanisms of anesthetic actions. A difference in anesthetic potency between the optical isomers of isoflurane (3–5) and between isomers of etomidate (6) has been reported. In addition, several studies using site-directed mutagenesis showed that mutation of single critical amino acid residue within the gamma-aminobutyric acidA receptor can abolish the effects of enflurane (7) and etomidate (8). These results represent strong evidence that general anesthetics can act via specific molecular mechanisms. There are also new indications that different molecular mechanisms underlie different components of general anesthesia. Quinlan et al. (9) demonstrated that, in genetically engineered mice, the lack of the β subunit of gamma-aminobutyric acidA receptor results in a significant difference in the potency of enflurane and halothane for blockade of motor response to noxious stimulation but not for the hypnotic effect. These results correlate well with the results obtained in the studies by Rampil et al. (10), Rampil (11), and Antognini and Schwartz (12) that suggest that another inhaled anesthetic, isoflurane, provides one of the basic components of anesthesia-blockade of movement response to noxious stimulation by acting primarily on the spinal cord; this occurs when unconsciousness is achieved by the action of isoflurane on the brain. The difference in the anatomic substrate suggests that different physiologic mechanisms are involved in these two actions of isoflurane. The discussion on disparate mechanisms for different components of anesthesia attracts attention to this problem (13–16). The view that the search for a reliable index of anesthetic depth should be transformed into a search for separate indices of different components of anesthesia has been addressed in a number of articles (17–19). The common conclusion was that a monitor of anesthesia may measure only one of the components of general anesthesia, such as loss of consciousness, obtunding motor response, or hemodynamic response to noxious stimulation (19). Components of anesthesia that could be combined to achieve variable goals of anesthesia may not necessarily reach the level of central nervous system (CNS) depression that results in unconsciousness. For example, neuroleptanalgesia and conscious sedation provide sedation (psychological detachment), analgesia, and amnesia. These diverse components may reach different degrees of expression with various anesthetic combinations. Even with such seemingly similar components as sedation (alertness/sedation scale) and unconsciousness profoundly different outcomes are possible with the same drug combination. For example, benzodiazepine-opioid combinations result in a striking synergism for unconsciousness (20) but only an additive effect for sedation (alert-sleepy self-rating) (21). The same kind of difference in benzodiazepine-opioid interactions for hypnotic (loss of the righting reflex) and sedative (locomotor activity) effects was observed in rats (22). Is it feasible to measure the degrees of the separate specific effects with one common index? When anesthesia was produced by one drug with relatively low specificity of action, the depth of anesthesia was actually equated with the depth of CNS depression. Therefore, a single index reflecting CNS depression in general could be used as a measure of anesthesia. With the introduction of drugs with more specific anesthetic actions (especially ketamine), the wide use of opioids, and the use of light anesthesia, it became obvious that one index cannot be used successfully to reflect all components of anesthesia. If the term depth of anesthesia became irrelevant for major components of general anesthesia taken together, it could still be relevant for each of the components measured separately. One of the most important components of anesthesia is unconsciousness, which represents an all-or-none (quantal) response to an anesthetic. One can construct a dose-response curve by using quantal data (probability of response curve), but it does not reflect the depth of the inhibitory effect. A quantal response represents only a single point in a continuum of the relationship between the dose of a drug and the effect of a function (23). Different strengths of stimuli that produce arousal could be used to quantify the depth of the effect, as was done in one of the studies with the use of behavioral arousal for measuring the depth of anesthesia (24). In this study, the depth was rank ordered along the scale; however, it was not an interval scale. With such ranking, it is impossible to say how the difference between the levels of response to weak stimulus and response to strong stimulus compares with the difference between the levels of response to strong stimulus and no response (25). Unconsciousness, like anesthesia in general, also has many components: perception, attention, memory, orientation, emotion, instinct, thought, and volition (26). With full consciousness, all these components are working in concert. Many of these components have quite dissimilar underlying mechanisms. Unconsciousness produced by drugs with low specificity of action could be regarded as a relatively simple all-or-none response; however, with some of the drugs, especially when used in borderline doses, hypnotic effect could be as complicated as anesthetic effect in general. Awareness (a state of being aware, i.e., conscious) is one of the major causes of patient complaints (18). The reported incidence of intraoperative recall (conscious or explicit memory) varies from 0.2% to 2% (1,18). However, the incidence of awareness during surgery without recall is probably much higher. The incidence of movement response to command during anesthesia with use of the isolated forearm technique has been reported as up to 8%. However, some investigators have not been able to correlate other clinical signs of light anesthesia or postoperative recall to the isolated forearm movement response (17,27). Prevention of intraoperative recall is one of the most important goals of monitoring anesthesia adequacy. Bispectral Index Introduction of the bispectral index (BIS) for anesthesia monitoring (28,29) makes it important to analyze how the new method addresses the old problem of assessment of anesthetic depth. Todd (30) recently indicated that, in the last several years, up to 50 articles concerning the BIS have appeared in mainstream, peer-reviewed anesthesia journals. He also indicated that some of the articles and reports on the BIS that appeared in the lay media are misleading. The BIS is based on bispectral processing that determines the harmonic and phase relations among the various electroencephalogram (EEG) frequencies (31,32). The BIS is a variable computed from the bispectrum (28,29); it is defined as a proprietary nonlinear single variable that is based on a large volume of clinical data correlating behavioral and EEG assessments. Different versions of the BIS have different algorithms. There are several aspects of the use of the BIS in anesthesia monitoring that should be discussed separately. Is the BIS a Universal Index for All Components of Anesthesia? Is the BIS a measure of the depth of anesthesia? As we indicated above, different components of anesthesia have different underlying mechanisms; therefore, it is difficult to expect that a single index can be used successfully for measuring the depth of anesthesia in general. The opinion of investigators familiar with the BIS is very certain. Glass et al. (19) state that “individual anesthetics each produce a unique spectrum of pharmacologic actions, so the concept of a common depth of anesthesia may need to be revisited to reflect the separate clinical components of the ideal anesthetic state. Consequently, a monitor of depth of anesthesia may measure only one of these components.” Does the BIS Predict Immobility? Initially, the BIS was evaluated “as a measure of adequate anesthesia defined by patient movement in response to skin incision,” and the conclusion was that it “may be a sensitive and specific measure” for this (33,34). Later on, the authors of a multicenter study on the BIS concluded that the index is a significant predictor of patient response to incision, but the utility of the BIS depends on the anesthetic technique being used. When opioid analgesics are used as adjuncts before incision, the correlation to patient movement becomes much less significant, so that patients with apparently “light” EEG profiles may not move at incision (35). In the most recent study on the BIS (version 3.2), the conclusion was that when sevoflurane was administered alone, the BIS (and 95% spectral edge frequency or median power frequency) did not predict movement after skin incision better than chance alone (36). However, one should keep in mind that every version of BIS 2 or higher has not been derived to predict movement (C. Roscow, written communication, October 25, 1999). Is the BIS an Index for Unconsciousness? It appears that for another component of anesthesia, unconsciousness, the predictive value of the BIS is much better than for motor response to incision (27,37,38). One of the most important questions on the accuracy of predictions of unconsciousness with the BIS is whether it is drug specific, especially whether the accuracy is altered with the addition of opioids or nitrous oxide. The tendency for such alterations was reported with the addition of alfentanil to propofol (37) and nitrous oxide to propofol (38). The changes in the predictive value of the BIS in these studies did not reach statistical significance, probably because of relatively small decreases in the propofol plasma concentration required to prevent a response in 50% of the patients caused by the additions of a second drug. However, in another recent study, the BIS values for unresponsiveness to verbal command were significantly higher in a propofol-fentanyl combination than with propofol alone (39). Most important for the notion that the BIS might be drug specific are the reports on the absence of a correlation between the BIS values and unconsciousness with ketamine alone (40) or in combination with propofol (41). The predictive value of the BIS for unconsciousness might be significantly influenced by potentially arousing intraoperative stimulation. In volunteers moderately sedated with propofol, a painful stimulus caused a small increase in the BIS value (37). It was reported that the changes in the BIS values in physiological sleep are similar to those in general anesthesia (42). However, the authors have found that in several subjects, the minimal BIS was very low (in the 20s), and that each time the subject awoke briefly, the BIS abruptly increased (usually > 96). The authors concluded that the BIS value may not reliably quantify how easily the patient may be aroused by intraoperative stimuli. The view that the BIS by itself does not actually “predict” but simply gives a measure of the current state based on the last 15–30 seconds of EEG data corresponds well with the above observation. There is an indication that, in some cases, the BIS may be patient specific. Unreasonably low BIS values in a volunteer with a low-voltage EEG signal was reported recently (43). The reported results of BIS trials indicate that BIS may be a valuable monitor for loss of consciousness for thiopental, propofol, midazolam, or isoflurane (when given alone) (27,19,38). Flaishon et al. (27), who used the isolated forearm technique with a single injection of either thiopental or propofol, concluded that the probability of recovery of consciousness can be predicted by using the BIS. However, they caution that it is unknown whether the measured endpoint has a similar mean BIS value for other drugs and that the effect of a surgical stimulus on the BIS value should be elucidated. We indicated that the incidence of intraoperative recall may be as low as 0.2%. Therefore, an extremely large number of patients would have to be studied to determine whether use of the BIS monitor can prevent awareness even with a single anesthetic. Katz (44) has recently posed the question of whether anesthesiologists purchasing the BIS monitor would be able to judge for themselves the value of the information provided by the system. Such a possibility with regard to prevention of awareness is questionable, not only as a result of the necessity of having a large number of patients for correct evaluation. The BIS is a proprietary index, and its algorithm is extremely complex; in addition, it is different with various versions of the monitor. All of this requires technical sophistication beyond the level of an individual anesthesiologist. Is the BIS an Index for Amnesia or Sedation? When the BIS was evaluated as a measure of sedation, loss of consciousness was usually included in the assessment. For example, with the observer’s assessment of the alertness/sedation scale (45), three of six scores represent unconsciousness (scores 2, 1, and 0). Therefore, with the BIS assessed as a monitor of sedation, it is important to know the authors’ definition of sedation: whether it also reflects deeper levels of CNS depression, including unconsciousness. When Kearse et al. (38) carefully analyzed the relationship between the BIS readings and conscious processing of information during propofol sedation and hypnosis, they could not find a gradual, continuous “descent from alertness to varying stages of vigilance, inattention, and unresponsiveness.” They found that volunteers simply did or did not respond to commands. Leslie et al. (46) reported that the BIS predicted propofol-induced suppression of learning during regional anesthesia. They used a “trivial pursuit” type of question task and obtained BIS of 91 for suppression of learning by 50%. When the relation between the BIS and presence or absence of recall was studied on a wider scale, it was found that the slopes of the isoflurane curve reflecting the relation were different from those of propofol or midazolam, and no logistic relation could be derived for alfentanil (19). Conclusion It is possible to conclude that the BIS is most promising as a monitor of unconsciousness. The BIS is an empirical index derived statistically from a database which included many, but not all, types of anesthetics and their combinations. Therefore, when the BIS is used with a new drug or new patient population that was not in the original database, it must be revalidated. This may lead to additional changes in the BIS algorithm. At present, there is not enough evidence to suggest that the BIS could provide a unifying clinical measure of anesthetic depth that reflects all components of anesthesia. The introduction of the BIS did not change the perception that the search for a reliable index of anesthetic depth should be transformed into a search for separate indices of different components of anesthesia.
Academia and Clinic18 August 2009Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA StatementFREEDavid Moher, PhD, Alessandro Liberati, MD, DrPH, Jennifer Tetzlaff, BSc, and Douglas G. Altman, DSc, the PRISMA Group*David Moher, PhDFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, Alessandro Liberati, MD, DrPHFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, Jennifer Tetzlaff, BScFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, and Douglas G. Altman, DScFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, the PRISMA Group*Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-151-4-200908180-00135 SectionsSupplemental MaterialAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail Editor's Note: In order to encourage dissemination of the PRISMA Statement, this article is freely accessible on the Annals of Internal Medicine Web site (www.annals.org) and will be also published in PLOS Medicine, BMJ, Journal of Clinical Epidemiology, and Open Medicine. The authors jointly hold the copyright of this article. For details on further use, see the PRISMA Web site (www.prisma-statement.org).Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field (1, 2), and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research (3), and some health care journals are moving in this direction (4). As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews.Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in four leading medical journals in 1985 and 1986 and found that none met all eight explicit scientific criteria, such as a quality assessment of included studies (5). In 1987, Sacks and colleagues (6) evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in six domains. Reporting was generally poor; between one and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement (7).In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized, controlled trials (8). In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1).Box 1. Conceptual Issues in the Evolution From QUOROM to PRISMA Download figure Download PowerPoint TerminologyThe terminology used to describe a systematic review and meta-analysis has evolved over time. One reason for changing the name from QUOROM to PRISMA was the desire to encompass both systematic reviews and meta-analyses. We have adopted the definitions used by the Cochrane Collaboration (9). A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyze and summarize the results of the included studies. Meta-analysis refers to the use of statistical techniques in a systematic review to integrate the results of included studies.Developing the PRISMA StatementA three-day meeting was held in Ottawa, Ontario, Canada, in June 2005 with 29 participants, including review authors, methodologists, clinicians, medical editors, and a consumer. The objective of the Ottawa meeting was to revise and expand the QUOROM checklist and flow diagram, as needed.The executive committee completed the following tasks, prior to the meeting: a systematic review of studies examining the quality of reporting of systematic reviews, and a comprehensive literature search to identify methodological and other articles that might inform the meeting, especially in relation to modifying checklist items. An international survey of review authors, consumers, and groups commissioning or using systematic reviews and meta-analyses was completed, including the International Network of Agencies for Health Technology Assessment (INAHTA) and the Guidelines International Network (GIN). The survey aimed to ascertain views of QUOROM, including the merits of the existing checklist items. The results of these activities were presented during the meeting and are summarized on the PRISMA Web site (www.prisma-statement.org).Only items deemed essential were retained or added to the checklist. Some additional items are nevertheless desirable, and review authors should include these, if relevant (10). For example, it is useful to indicate whether the systematic review is an update (11) of a previous review, and to describe any changes in procedures from those described in the original protocol.Shortly after the meeting a draft of the PRISMA checklist was circulated to the group, including those invited to the meeting but unable to attend. A disposition file was created containing comments and revisions from each respondent, and the checklist was subsequently revised 11 times. The group approved the checklist, flow diagram, and this summary paper.Although no direct evidence was found to support retaining or adding some items, evidence from other domains was believed to be relevant. For example, Item 5 asks authors to provide registration information about the systematic review, including a registration number, if available. Although systematic review registration is not yet widely available (12, 13), the participating journals of the International Committee of Medical Journal Editors (ICMJE) (14) now require all clinical trials to be registered in an effort to increase transparency and accountability (15). Those aspects are also likely to benefit systematic reviewers, possibly reducing the risk of an excessive number of reviews addressing the same question (16, 17) and providing greater transparency when updating systematic reviews.The PRISMA StatementThe PRISMA Statement consists of a 27-item checklist (Table 1; see also Table S1, for a downloadable Word template for researchers to re-use) and a four-phase flow diagram (Figure 1; see also Figure S1, for a downloadable Word template for researchers to re-use). The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses. We have focused on randomized trials, but PRISMA can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions. PRISMA may also be useful for critical appraisal of published systematic reviews. However, the PRISMA checklist is not a quality assessment instrument to gauge the quality of a systematic review.Table 1. Checklist of Items to Include When Reporting a Systematic Review or Meta-AnalysisFigure 1. Flow of information through the different phases of a systematic review. Download figure Download PowerPoint From QUOROM to PRISMAThe new PRISMA checklist differs in several respects from the QUOROM checklist, and the substantive specific changes are highlighted in Table 2. Generally, the PRISMA checklist “decouples” several items present in the QUOROM checklist and, where applicable, several checklist items are linked to improve consistency across the systematic review report.Table 2. Substantive Specific Changes Between the QUOROM Checklist and the PRISMA ChecklistThe flow diagram has also been modified. Before including studies and providing reasons for excluding others, the review team must first search the literature. This search results in records. Once these records have been screened and eligibility criteria applied, a smaller number of articles will remain. The number of included articles might be smaller (or larger) than the number of studies, because articles may report on multiple studies and results from a particular study may be published in several articles. To capture this information, the PRISMA flow diagram now requests information on these phases of the review process.EndorsementThe PRISMA Statement should replace the QUOROM Statement for those journals that have endorsed QUOROM. We hope that other journals will support PRISMA; they can do so by registering on the PRISMA Web site. To underscore to authors, and others, the importance of transparent reporting of systematic reviews, we encourage supporting journals to reference the PRISMA Statement and include the PRISMA Web address in their instructions to authors. We also invite editorial organizations to consider endorsing PRISMA and encourage authors to adhere to its principles.The PRISMA Explanation and Elaboration PaperIn addition to the PRISMA Statement, a supporting Explanation and Elaboration document has been produced (18) following the style used for other reporting guidelines (19–21). The process of completing this document included developing a large database of exemplars to highlight how best to report each checklist item, and identifying a comprehensive evidence base to support the inclusion of each checklist item. The Explanation and Elaboration document was completed after several face-to-face meetings and numerous iterations among several meeting participants, after which it was shared with the whole group for additional revisions and final approval. Finally, the group formed a dissemination subcommittee to help disseminate and implement PRISMA.DiscussionThe quality of reporting of systematic reviews is still not optimal (22–27). In a recent review of 300 systematic reviews, few authors reported assessing possible publication bias (22), even though there is overwhelming evidence both for its existence (28) and its impact on the results of systematic reviews (29). Even when the possibility of publication bias is assessed, there is no guarantee that systematic reviewers have assessed or interpreted it appropriately (30). Although the absence of reporting such an assessment does not necessarily indicate that it was not done, reporting an assessment of possible publication bias is likely to be a marker of the thoroughness of the conduct of the systematic review.Several approaches have been developed to conduct systematic reviews on a broader array of questions. For example, systematic reviews are now conducted to investigate cost-effectiveness (31), diagnostic (32) or prognostic questions (33), genetic associations (34), and policy making (35). The general concepts and topics covered by PRISMA are all relevant to any systematic review, not just those whose objective is to summarize the benefits and harms of a health care intervention. However, some modifications of the checklist items or flow diagram will be necessary in particular circumstances. For example, assessing the risk of bias is a key concept, but the items used to assess this in a diagnostic review are likely to focus on issues such as the spectrum of patients and the verification of disease status, which differ from reviews of interventions. The flow diagram will also need adjustments when reporting individual patient data meta-analysis (36).We have developed an explanatory document (18) to increase the usefulness of PRISMA. For each checklist item, this document contains an example of good reporting, a rationale for its inclusion, and supporting evidence, including references, whenever possible. We believe this document will also serve as a useful resource for those teaching systematic review methodology. We encourage journals to include reference to the explanatory document in their Instructions to Authors.Like any evidence-based endeavor, PRISMA is a living document. 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[PMID: CrossrefMedlineGoogle In to A Article, and Disclosure From Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United The following to the PRISMA Altman, DSc, Centre for Statistics in Medicine United PhD, University Hospital MD, Health Research & Health PLoS Medicine United PhD, Hospital of Ontario, A. & Research and PhD, PLoS Medicine the of United PhD, Cochrane Centre United and of and MD, of Medicine, Clinical Epidemiology and University Ontario, PhD, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario J. PhD, University of United MD, PhD, of Medicine, Clinical Epidemiology and University Ontario, PhD, of Health MD, of and Medicine, University of MD, PhD, Medical United MD, The Cochrane Centre PhD, Ottawa Hospital Research Institute Ontario, MD, of Medicine, Clinical Epidemiology and University Ontario, PhD, United MD, University of MD, PhD, Systematic Reviews United and for Health and University of the and Alessandro Liberati, MD, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario MD, Centre for the of the of Health PhD, The United MD, Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Moher, PhD, Ottawa Methods Centre, Ottawa Hospital Research Institute Ontario, MD, Annals of Internal Medicine for Medical MD, Health Research Centre Health and Technology Assessment Ontario, Canada; at the of the first meeting of the group, Ontario, MD, University of Hospital of Ontario, PhD, Health International G. MD, PhD, Evidence-Based Jennifer Tetzlaff, BSc, Ottawa Methods Centre, Ottawa Hospital Research Institute Ontario, The Cochrane Cochrane Collaboration United at the of the first meeting of the group, United and MD, Institute of University of Ottawa Ontario, PRISMA was by the Canadian Institutes of Health Università di Modena e Reggio Emilia, Italy; Research Clinical Evidence The Cochrane Collaboration; and Liberati is in through of the of University and Altman is by Research Moher is by a University of Ottawa Research of the any in the or of the PRISMA no a role in the Moher, PhD, Ottawa Methods Centre, Ottawa Hospital Research Institute, The Ottawa Ottawa, Canada; Moher and Ottawa Methods Centre, Ottawa Hospital Research Institute, The Ottawa Ottawa, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Centre for Statistics in Medicine, University of Oxford, United of the PRISMA is in the PRISMA Statement for Reporting Systematic Reviews and of Studies Health Explanation and Elaboration Alessandro Liberati Douglas G. Altman Jennifer
Open appendectomy is commonly performed under either general or spinal anesthesia. Postoperative quality of recovery, a multidimensional patient-centered measure of outcomes after surgery, is affected by the choice of anesthesia technique. The objective of our study was to compare the effects of general and spinal anesthesia on the immediate postoperative quality of recovery in adults undergoing open appendectomy. In this prospective cohort study, 74 patients were assigned to either the general (n=37) or the spinal anesthesia (n=37) groups. The primary outcome was the total Quality of Recovery-15 score measured 24 hours postoperatively. Secondary outcomes included postoperative pain scores, analgesic consumption, incidence of postoperative nausea and vomiting, time to first oral intake, time to first ambulation, and length of hospital stay. Intergroup comparisons were performed using the chi-square test, Fisher exact test, independent t test, or Mann-Whitney U test, as appropriate. Patients in the spinal anesthesia group had significantly higher Quality of Recovery-15 scores than those in the general anesthesia group (P=.001). They also exhibited lower pain scores at 1, 2, 6, and 12 hours postoperatively (P<.001), reduced consumption of diclofenac and tramadol, and a decreased incidence of postoperative nausea and vomiting (P<.001). The time to first mobilization, time to first oral intake, and length of hospital stay were also significantly lower in the spinal anesthesia group (P<.001). Spinal anesthesia is the preferred anesthesia technique for patients undergoing open appendectomy. It may provide improved postoperative recovery, with lower pain scores and improved analgesia. It may also reduce the need for additional analgesics, decrease the incidence of nausea and vomiting, and improve intrahospital patient recovery trajectories.
Among patients who underwent general anesthesia (GA) multiple times with different methods, we aimed to compare the incidence and severity of postoperative nausea and vomiting (PONV) when the GA method was changed. Subjects were healthy intellectually disabled patients who underwent multiple dental procedures under GA. Methods of general anesthesia were classified as (1) nitrous oxide-sevoflurane (NOS), (2) sevoflurane-remifentanil (SRF), and (3) propofol-remifentanil (PRF). Patients who experienced PONV had an alternative method of GA utilized for subsequent cases. PONV incident rates and severity scores overall and between groups were calculated and compared statistically for analysis. PONV occurred in 186 (6.5%) of the 2872 cases and in 85 (28.8%) of the 295 patients included in this study. Statistical paired comparisons of the mean incidence of PONV demonstrated a decrease of 25.2% when the GA method was changed from NOS to SRF, 40.4% when changed from NOS to PRF, and 36.4% when changed from SRF to PRF (P < .05). Statistical paired comparisons of the mean 5-point PONV severity score similarly demonstrated a decrease of 0.53 when the GA method was changed from NOS to SRF, 0.92 when changed from NOS to PRF, and 0.62 when changed from SRF to PRF (P < .05). The highest PONV incidence rates and severity were noted with NOS, whereas PONV decreased significantly with SRF and PRF use. The absence of nitrous oxide and use of propofol were suggested as ways to alter the method of general anesthesia to reduce the incidence and improve the severity of PONV.
ObjectiveHip and femur fractures in older adults are linked to high morbidity, mortality, and socioeconomic costs. This meta-analysis compares regional anesthesia and general anesthesia for these surgeries, focusing on perioperative safety and outcomes.MethodsFifteen studies (6829 participants) from 2009 to 2024 were analyzed. Primary outcomes included 30-day mortality, postoperative delirium, and cardiovascular events; secondary outcomes covered intraoperative blood loss, hospital stay, and pain. Pooled effect sizes were calculated using random-effects models with odds ratios and 95% confidence intervals. Heterogeneity was assessed using the I2 statistic. Risk of bias was evaluated with Risk of Bias 2.0 (randomized controlled trials) and Risk Of Bias In Nonrandomized Studies of Interventions (observational studies). Certainty of evidence was rated using the Grading of Recommendations Assessment, Development and Evaluation approach.ResultsPooled analysis showed no significant difference in 30-day mortality between regional anesthesia and general anesthesia (odds ratio = 0.89 (0.72-1.10), p = 0.28, I2 = 34%). Regional anesthesia was associated with significantly lower hypotension rates (odds ratio = 0.28 (0.18-0.43), p < 0.001, I2 = 52%). There was a nonsignificant trend toward lower postoperative delirium with regional anesthesia (odds ratio = 0.78 (0.60-1.01), p = 0.06, I2 = 46%). Pain management favored general anesthesia in one large trial (severe pain: 28.8% vs. 42.3%, p < 0.01), but other studies showed no difference. No significant differences were found in long-term mortality or functional recovery (p > 0.05 for all). Substantial heterogeneity (I2 > 50%) was noted for some outcomes because of variations in age, fracture type, and study design.ConclusionRegional anesthesia may offer perioperative benefits, including reduced hypotension and a possible (but not statistically confirmed) reduction in postoperative delirium. General anesthesia provides better early pain control in some patients and remains suitable for complex cases. Individualized anesthesia plans are recommended. Future research should prioritize standardized outcomes and larger trials.
Background and Objectives: The SARS-CoV-2 pandemic disrupted oral and maxillofacial surgery (OMS) services worldwide because of the high aerosol-generating nature of head-and-neck procedures, restricted access to elective dental care, and systemic reallocation of hospital resources. Continuous longitudinal multi-year data covering both the pandemic and the post-pandemic phases from regional Romanian (and more broadly central and southeastern European) emergency centers remain scarce. We aimed to quantify the impact of the pandemic on OMS activity in a large Romanian regional referral center and to evaluate post-pandemic resilience. Materials and Methods: We conducted a retrospective single-center study of all inpatient admissions to the OMS Clinic of a tertiary emergency hospital in western Romania between 1 January 2018 and 31 December 2024. Three periods were pre-specified: pre-pandemic (2018-2019), pandemic (2020-2022) and post-pandemic (2023-2024). A Newey-West segmented interrupted-time-series (ITS) regression and a negative-binomial monthly count model with Fourier seasonality were fitted; length of hospital stay was further analyzed with a multivariable gamma-log generalized linear model adjusted for age, sex, county, primary ICD-10 chapter and total ICD-10 codes. Variables analyzed included case volume, demographics, primary and secondary ICD-10 diagnoses, length of hospital stay (LOS), case complexity (total ICD-10 codes per admission) and in-hospital mortality. Results: A total of 11,628 inpatient admissions corresponding to 8084 unique patients (56.5% male; mean age 52.2 ± 19.2 years) were analyzed. Compared with the pre-pandemic baseline (mean 2037 admissions/year), annual volume dropped by 45.1% in 2020, 44.0% in 2021 and 32.3% in 2022, with a nadir of -76% during the first state of emergency (April 2020; n = 34 admissions). Recovery was rapid; 2024 exceeded the pre-pandemic baseline by +10.1% on raw counts and by +16.2% on admissions per 100,000 catchment population using year-specific INS denominators. The segmented ITS regression confirmed an immediate level drop of -114.2 admissions/month in March 2020 (95% CI -133.1 to -95.3; p < 0.001) and a positive post-intervention slope of +2.06 admissions/month (95% CI 1.23-2.88; p < 0.001), with observed monthly volume returning to the counterfactual projection by October 2023. The case mix shifted significantly (χ2 = 406.9, p < 0.0001); elective benign neoplasm admissions were reduced from 7.2% to 2.0%, while neoplasms of uncertain behavior nearly doubled from 15.7% to 27.5%. Case complexity increased during the pandemic (mean ICD codes 4.08 ± 2.42 vs. 3.44 ± 2.30; p < 0.001); after exclusion of administrative codes (whole Z chapter and U07.x), the difference attenuated to 3.34 vs. 3.17 codes (still p < 0.001 by Kruskal-Wallis), indicating that the largest portion of the unadjusted increase was driven by the new mandatory pre-admission SARS-CoV-2 screening code Z11.5 rather than true clinical complexity. Notably, the clinically interpretable proxy R63.3 (feeding difficulty) independently rose from 41.5% to 53.1%. The crude median LOS did not differ between the pre-pandemic and pandemic periods (3.07 vs. 3.06 d; p = 0.19) and dropped significantly post-pandemic (2.22 d; p < 0.001); however, after multivariable adjustment for case mix, age, sex, county and code count, the LOS was 15.7% shorter during the pandemic (adjusted ratio 0.84, 95% CI 0.82-0.87; p < 0.001) and 22.8% shorter post-pandemic (adjusted ratio 0.77, 95% CI 0.75-0.80; p < 0.001) relative to baseline. Conclusions: The pandemic caused a severe but transient contraction of OMS activity accompanied by increased case complexity and a marked shift away from elective surgery. Inpatient volume returned to and exceeded the pre-pandemic baseline by 2024. These results support the value of standing pandemic-preparedness protocols, sustained access to preventive dental care, and integrated tele-triage pathways for future public-health crises.
Although large language models (LLMs) show potential for patient education, their accuracy, usability, and comprehensibility lack validation in high-risk pediatric anesthesia. Rigorous evaluation is therefore essential prior to widespread clinical use in perioperative parental anesthesia education. This study aims to evaluate the accuracy, reliability, and readability of responses generated by 5 LLMs to parental inquiries regarding pediatric anesthesia, and to assess their suitability for clinical use in perioperative caregiver education. Two expert anesthesiologists identified 33 parental questions on pediatric anesthesia by screening authoritative resources and Google Trends. On December 14, 2025, these questions were submitted to 5 LLMs (DeepSeek-V3.2, ChatGPT-5, Gemini 2.5 Flash, Copilot, and Perplexity) via official web interfaces with default settings and zero-shot prompting, with each query in a separate conversation. Responses were standardized for blinded assessment. Two pediatric anesthesiologists with ≥10 years of clinical experience independently evaluated accuracy and reliability using the 4-point Likert accuracy scale, DISCERN, Ensuring Quality Information for Patients (EQIP), Journal of the American Medical Association (JAMA) benchmark, and Global Quality Score (GQS). After text preprocessing, readability was evaluated using 6 algorithms (Automated Readability Index [ARI], Flesch Reading Ease Score [FRES], Gunning Fog Index [GFI], Flesch-Kincaid Grade Level [FKGL], Coleman-Liau Index [CL], and the Simple Measure of Gobbledygook [SMOG]) via an online calculator. Interrater reliability was analyzed using the intraclass correlation coefficient (ICC); differences across models were assessed with the Kruskal-Wallis H test; and deviations from the sixth-grade benchmark were evaluated using 1-sample Wilcoxon signed-rank tests (P<.05 considered significant). All 5 LLMs demonstrated high clinical accuracy (>90%; P=.12), with Gemini reaching 100%. Nevertheless, safety risks and content hallucinations were still observed. Excluding Gemini and Copilot, the remaining 3 models (ChatGPT, DeepSeek, and Perplexity) each produced unsafe content in 3.03% (n=1) of the 33 queries. Hallucinations were detected in all models except Gemini, with DeepSeek and Perplexity showing the highest hallucination rate (3/33, 9.09%). Furthermore, Perplexity showed superior reliability on DISCERN (median 41; P<.05), yet no model achieved a "good" rating. Gemini achieved the highest EQIP (median 66.67%; P<.05) despite lower GQS (median 3). Transparency was universally poor (JAMA median ≤1), with DeepSeek and ChatGPT showing a "floor effect." ChatGPT had superior readability, but all models exceeded the recommended 6-grade complexity level. In this study, 5 LLMs generally provided clinically accurate information when responding to parental questions about pediatric anesthesia. However, limitations were also identified, including hallucinated content, safety-related deficiencies, limited source transparency, and readability levels exceeding recommended standards. Therefore, LLM-generated information should be interpreted with caution and should not replace clinician guidance.
General anesthesia (GA) is the predominant choice for open inguinal hernia repair but may be associated with a higher risk of postoperative complications, particularly in patients with multiple comorbidities. Spinal anesthesia (SA) is therefore considered as an alternative for high-risk patients. However, its potential benefits in reducing postoperative complications remain unclear. This study aimed to compare 30-day outcomes between SA and GA in high-risk patients undergoing initial open inguinal hernia repair. Patients who underwent initial open inguinal hernia repair were identified in the ACS-NSQIP database from 2005 to 2024. High-risk status was defined as a Modified Frailty Index (mFI) ≥3 and American Society of Anesthesiology (ASA) score ≥3. Exclusion criteria included emergency surgery, ventilator dependency, procedures not performed by general surgeons, cases with concomitant bowel resection, and cases where the primary anesthesia type was neither SA nor GA. A 1:1 propensity-score matching was performed to balance demographics and comorbidities between patients who received SA versus GA, and thirty-day outcomes were then compared. Additionally, a multivariable logistic regression analysis that included all high-risk patients was conducted to evaluate thirty-day outcomes while adjusting for all preoperative variables. A total of 118 high-risk patients underwent open inguinal hernia repair under SA, of whom 106 were successfully propensity-score matched to 106 of the 1,365 patients who received GA. After matching, 30-day mortality rates were comparable between SA and GA (0.94% vs. 0%, p = 1.00), as were rates of organ system complications, including cardiac (0.94% vs. 1.89%, p = 1.00), pulmonary (2.83% vs. 0.94%, p = 0.62), and renal complications (1.89% vs. 0%, p = 0.50). Operative time (63.44 ± 30.61 vs. 65.05 ± 30.74 min, p = 0.70), as well as length of stay for outpatient cases (0.28 ± 0.63 vs. 0.32 ± 0.95 days, p = 0.79) were comparable between SA and GA. All other 30-day outcomes were likewise comparable. Multivariable analysis confirmed that the 30-day outcomes of SA and GA were comparable for all high-risk patients. In high-risk patients undergoing open inguinal hernia repair, this study showed no evidence of a difference in 30-day outcomes between SA and GA; however, given the limited statistical power, these findings should not be interpreted as evidence of equivalence. The choice between SA and GA should therefore be guided by patient-specific factors, surgical complexity, and surgeon and center expertise. Further prospective studies are needed to validate these findings.
We replaced the traditional double-lumen endotracheal intubation anesthesia strategy with an electroacupuncture-assisted tubeless anesthesia strategy to investigate its impact on the quality of postoperative recovery. In this retrospective study, 215 patients undergoing video-assisted thoracoscopic surgery were allocated to a tubeless group (Group T, n = 56), receiving electroacupuncture (at Hegu [LI4], Lieque [LU7], Neiguan [PC6], and Chize [LU5]) combined with regional blocks, or a control group (Group C, n = 159), receiving standard intubation. The primary outcome was the Quality of Recovery-15 (QoR-15) score at 24 hours postoperatively. The secondary outcomes were QoR-15 scores at 48 and 72 hours postoperatively, total intraoperative opioid consumption, postanesthesia care unit stay duration, blood gas analysis results, number of patient-controlled analgesia pump presses, time to first oral intake, time to first ambulation, length of hospital stay, hospitalization costs, and incidence rates of postoperative nausea and vomiting, postoperative sore throat, and postoperative pulmonary complications. The QoR-15 scores at 24 and 48 hours postoperatively were significantly higher in Group T than in Group C (P < .001; P < .001, respectively). Despite higher perioperative PaCO2, the tubeless group demonstrated a significantly shorter postanesthesia care unit stay, reduced opioid use, fewer complications, and faster overall recovery. The electroacupuncture-assisted tubeless anesthesia strategy offers significantly improved quality of postoperative recovery, faster patient rehabilitation, shorter overall hospital stay, and lower hospital costs.
To compare the incidence of intraoperative hypotension between oral 5-aminolevulinic acid (5-ALA)-guided photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) and white light transurethral resection of bladder tumor (WL-TURBT) performed under spinal anesthesia, and to identify risk factors for hypotension with a focus on spinal sensory block level. We retrospectively reviewed 279 consecutive patients who underwent transurethral resection of bladder tumor (TURBT) under spinal anesthesia between June 2018 and March 2023 (PDD-TURBT, n = 162; WL-TURBT, n = 117). Hyperbaric bupivacaine was used without sedation. Intraoperative hypotension was defined as mean arterial pressure < 60 mmHg and/or vasopressor use. Propensity score matching was performed, and logistic regression analyses were conducted to identify independent predictors. After matching, 103 patients remained in each group. Intraoperative hypotension occurred more frequently in the PDD-TURBT group than in the WL-TURBT group (60.2% vs. 27.2%, p < 0.001), and vasopressor use was also higher (49.5% vs. 23.3%, p < 0.001). Perioperative mean arterial pressure was significantly lower in the PDD-TURBT group from anesthesia induction through postoperative day 1. In multivariable analysis of the overall cohort, oral 5-ALA use (odds ratio 3.30) and a maximum intraoperative sensory block level of T6 or higher (odds ratio 2.72) were independent predictors of hypotension. In the PDD-TURBT subgroup, a maximum intraoperative sensory block level of T6 or higher remained an independent risk factor (odds ratio 3.33). Under spinal anesthesia, oral 5-ALA-guided PDD-TURBT carries a higher risk of intraoperative hypotension than WL-TURBT. Excessive cephalad spread of spinal block (levels of T6 or higher) independently increases this risk, highlighting the need for careful block level management.
Frozen shoulder is a common disorder causing pain, stiffness, disability, and sleep disturbance. While often linked to psychological comorbidities, the impact of preoperative mental health and insomnia on recovery outcomes remains unclear. The purpose of this study was to investigate the effects of preoperative anxiety, depression, and insomnia on postoperative recovery in patients undergoing manipulation under anesthesia (MUA) for frozen shoulder. This study was a secondary analysis of a prospective observational cohort study. A total of 197 patients with primary frozen shoulder were enrolled and treated with MUA. Preoperatively, the Insomnia Severity Index (ISI) and Hospital Anxiety and Depression Scale (HADS) classified patients: 33 with clinical insomnia (ISI ≥ 15) and 45 with psychological distress (PD, including anxiety or depression, HADS anxiety ≥ 8 and depression ≥ 8). Shoulder passive range of motion (ROM), pain (visual analog scale, VAS), and functional scores (Constant-Murley Score [CMS], Oxford Shoulder Score [OSS]) were assessed at 3 and 6 months postoperatively. Outcomes were compared between patients with/without insomnia or PD. To control for multiple comparisons, all p-values were adjusted using the False Discovery Rate (FDR) method. In the insomnia analysis, the insomnia group had a significantly lower proportion of male patients (12.1% vs. 28.7%, p = 0.048) and a lower mean BMI (22.0 ± 2.4 vs. 23.0 ± 2.7, p = 0.033) compared to the group without insomnia. Furthermore, baseline abduction was significantly more restricted in the insomnia group (67.2° ± 21.9 vs. 81.8° ± 24.8, p = 0.001) and OSS was significantly worse (38.5 ± 8.1 vs. 32.6 ± 5.5, p < 0.001). Preoperative PD was more common in right-side cases (60.0% vs. 42.8%, p = 0.042) and was associated with worse baseline external rotation. Following MUA, all patient groups achieved substantial clinical improvement. At 3 and 6 months postoperatively, after FDR adjustment, there were no statistically significant or clinically meaningful differences in ROM, VAS, CMS, or OSS between patients with and without insomnia, nor between patients with and without PD. All observed mean differences between groups were small and fell well below established minimal clinically important difference (MCID) thresholds (e.g., at 6 months, CMS mean difference between PD and no PD was 1.84 [95% CI -0.92 to 4.60]; adjusted p = 0.796). Although preoperative clinical insomnia and PD are associated with worse baseline pain and functional presentation, they were not associated with poorer postoperative recovery following MUA in this cohort. At the 3 and 6 months postoperative follow-ups, there were no statistical differences in pain or ROM between patients with and without these preoperative conditions.
Intrathecal adjuvants are frequently used in spinal anaesthesia for lower-limb surgery to enhance block quality and prolong postoperative analgesia. However, evidence remains fragmented across individual agents. This systematic review with frequentist network meta-analysis aimed to compare the efficacy and safety of intrathecal adjuvants in patients undergoing lower limb orthopaedic surgery to evaluate the effectiveness and safety of intrathecal adjuvants combined with long-acting local anaesthetics for lower limb orthopaedic surgery. A systematic search of PubMed, CENTRAL, and Embase was conducted to retrieve English-language RCTs involving adult patients undergoing lower limb orthopaedic surgery under single-shot spinal anaesthesia. We included trials evaluating any intrathecal drug or placebo added to a long-acting local anaesthetic. Our primary outcome was the duration of effective analgesia, defined as the time to the first analgesic requirement, in hours. We selected randomised controlled trials (RCTs) reported in English. We included 183 RCTs, for a total of 14,431 patients and 27 interventions. Morphine combined with ketorolac, morphine alone followed by diamorphine, clonidine combined with morphine and ketamine combined with midazolam provided the greatest prolongation of effective analgesia. Morphine also significantly reduced pain at 12 h and postoperative opioid consumption with no impact on motor block duration. Dexmedetomidine reduced pain intensity at 12 h but substantially prolonged motor block duration and increased the incidence of bradycardia. Morphine and neostigmine showed an increased risk of postoperative nausea and vomiting, while several interventions increased the risk of pruritus. The certainty of evidence ranged from low to very low due to within-study bias, reporting bias, high heterogeneity, imprecision and incoherence. Considering the body of evidence in an NMA framework, intrathecal morphine appears to offer a potentially favourable efficacy-safety balance. Dexmedetomidine may prolong motor block and increase the risk of bradycardia. The certainty of the evidence was low to very low and needs caution interpretation. PROSPERO CRD42024557751.
Spinal cord injury is a critical issue in neurosurgery, lacking established clinical methods for functional restoration. This study reports the effects of a fusogen sealant, composed of polyethylene glycol and chitosan, in an experimental model of complete spinal cord transection in pigs. To evaluate the functional and morphological recovery of the spinal cord in an animal model of complete transection following treatment with a polyethylene glycol-chitosan conjugate. Hungarian Mangalica pigs (m = 20.0 ± 2.0 kg, N = 5) underwent complete transection of the thoracic spinal cord, followed by an extended laminectomy and transpedicular fixation. In the experimental group (N = 3), a synthesized gel based on a polyethylene glycol-chitosan conjugate was applied to the spinal gap; the other group (N = 2) served as a control. The postoperative period lasted 60 days and included multi-component rehabilitation. Clinical-functional status was assessed using established neurological scales. In vivo retrograde tracing of the spinal cord was performed using hydroxystilbamidine (FluoroGold). Following the experiment, immunofluorescent histology was conducted using primary antibodies to neurofilament (NF-200), a fluorochrome-conjugated secondary antibody, and the nuclear dye 4',6-diamidino-2-phenylindole (DAPI). The resulting morphology was examined via fluorescence and light microscopy. Control animals maintained lower paraplegia, anesthesia, and pelvic dysfunction throughout the experiment. In contrast, the experimental group showed positive changes, including the return of sensation from day two. By the end of the study, all animals in this group could assume an upright posture and ambulate on all limbs. These outcomes were statistically significant. Microscopy revealed axons traversing the injury site in the experimental group, whereas control samples showed degenerative post-traumatic changes. This study demonstrates that a fusogen sealant based on a polyethylene glycol-chitosan conjugate promotes significant morpho-functional recovery after complete spinal cord transection, supporting its therapeutic potential.
The swift progress of digital and sensor technologies is hastening the incorporation of remote monitoring into anesthesiology. While several reviews have explored telemedicine and artificial intelligence in anesthesia, most existing summaries either focus on conceptual outlook or lack systematic comparison of technical platforms and original clinical validation data. The present review provides a comprehensive, clinically oriented synthesis of remote monitoring in anesthesia, with clear focuses on technical principles, perioperative applications, platform comparisons, and evidence-based clinical outcomes. We critically assess clinical advantages and implementation hurdles, covering the full perioperative pathway - preoperative evaluation, intraoperative observation, and postoperative recovery. A head-to-head comparison of fifth generation of cellular network technology (5G), the Internet of Things (IoT), and cloud computing platforms is presented to clarify their infrastructure demands and suitability for real-world clinical scenarios. Notably, this review summarizes available clinical evidence, including evidence from the Trial of Remote Continuous versus Intermittent National Early Warning Score Monitoring after major surgery (TRaCINg) - a feasibility randomized controlled trial whose exploratory findings suggest that continuous remote monitoring may reduce unplanned intensive care unit admissions, shorten hospital stays, and facilitate earlier detection of postoperative complications. We further propose innovative solutions including multimodal data fusion and federated learning-driven predictive analytics to overcome current limitations in data interoperability, security, and clinical effectiveness. Accordingly, this paper synthesizes the latest advances in remote monitoring technology in anesthesia, clarifies its unique value relative to existing reviews, and provides practical guidance for clinical translation and future research.
Monitored anesthesia care (MAC) is increasingly used for various procedures, but sedation-related upper airway obstruction may lead to hypoxemia or conversion to general anesthesia. This study evaluated whether preoperative tongue base thickness (TT), measured using ultrasonography, can predict upper airway obstruction during MAC. In this single-center prospective observational study, adult patients undergoing transcatheter aortic valve implantation or endovascular aortic repair under MAC were enrolled. TT was measured preoperatively using submental ultrasonography. Upper airway obstruction was defined as disappearance of the capnogram that reappeared after jaw elevation. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal TT cutoff and diagnostic performance. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios were calculated. The STOP-BANG score and composite criteria combining TT and STOP-BANG were also evaluated. Data from 42 patients were analyzed, and upper airway obstruction occurred in 21 (50.0%). The median TT was 59.8 mm in the non-obstruction group and 61.0 mm in the obstruction group (p = 0.466). The ROC analysis identified a TT cut-off value of 58 mm (area under the curve = 0.566). For TT ≥ 58 mm, sensitivity, specificity, PPV, and NPV were 76.2%, 42.9%, 57.1%, and 64.3%, respectively (LR + 1.33, LR - 0.56). Combining TT with the STOP-BANG score did not improve predictive performance. Preoperative TT measurement showed limited diagnostic performance for predicting airway obstruction during MAC, and its combination with the STOP-BANG score did not significantly improve predictive performance.
Congenital bleeding disorders stem from genetic defects affecting procoagulant proteins (such as von Willebrand Factor, factor VIII, or factor IX) or platelet proteins (such as integrin αIIbβ3 or glycoprotein Ibα). Despite advances in our knowledge of the hemostatic system, there are still gaps in our understanding of the interplay between the various hemostatic actors, limiting the development of efficient therapeutic agents for each of these disorders. Mouse models have a proven record in their use as preclinical tools for the development and testing of therapeutics for bleeding disorders, with several bleeding models being available. However, a lack of standardization for most of these models complicates inter-laboratory comparisons. It is recommended, therefore, that experimental variables are standardized as much as possible to ensure reproducible results, including parameters like temperature and anesthesia. Also, the balance between the use of male and female mice should be considered. Murine hemostasis is relatively similar to human hemostasis, representing a clear strength in translation to the clinic. Among available bleeding models, the tail clip assay is popular for its simplicity, although its standardization might be improved. Other techniques, such as the saphenous vein and laser-induced bleeding models, offer high reproducibility and real-time visualization but require advanced surgical or technological skills. A primary weakness is that most knockout mice do not exhibit the spontaneous hemorrhagic events or joint damage characteristic of human patients. Additionally, species-specific differences can occasionally hamper the testing of therapeutic candidates.