With the proliferation of and even preceding many of the early 1980s perfusion studies employing gaseous microemboli (GME) detectors (1,2), Dr. Bruce D. Butler was compelled to write about the principles of gaseous emboli in blood and flowing systems. Prior to penning the editorial, Dr. Butler hailed from the Department of Anesthesiology at the University of Texas Medical School and had published on the topic of underwater air embolism and the removal of GME by the lungs (3). Dr. Butler’s article is more of a review article and less of an opinion piece especially with 40 references and his skill at distilling the current research in 1983 into five sources of GME in perfusion circuits. He listed five sources: 1) suction of blood and air, 2) cavitation, 3) mechanical blows to the circuit, 4) release of GME with warming blood, and 5) injection or entrainment of GME into the bypass circuit. There has not been any other source of GME identified since one may classify siphon and vacuum venous drainage as “suction of air” into the bypass circuit (4). Of course, there are many sources of systemic GME from non-bypass circuit sources such as insertion of the aortic cannula and removing the aortic cross clamp to just name two (5). Dr. Butler’s treatment of the five sources of GME includes theory and mathematics making his article an excellent source of information on GME and mandatory reading for students of perfusion. This JECT classic had high impact at the time and has been referenced in many articles since its 1983 publication—both signs of an excellent article. Dr. Butler’s recommendations in this classic editorial have been born out in the bubble detection literature following 1983. He calls for quantification of GME using Doppler-type measurement systems and goes on to warn the reader of the lack of consistency in the devices and the need to validate GME measurement devices—problems that continue to plague us today. As an industry, clinicians and manufacturers have worked to reduce the gaseous microemboli load that a patient receives during cardiac surgical procedures. We have devices that are clinically available to monitor and measure micro (less than 300 micron diameter) gaseous emboli in the circuit and in the patient’s arterial system. Perhaps the greatest lesson we may learn from this issue’s JECT classic is to invest our time and energy to validate the GME measurement systems that are available for use during the surgery. Clinicians must continue to describe the patient dose-response to embolic load in regard to neurologic dysfunction but more importantly, we need to strive to identify the problem areas in devices and to eliminate systemic GME during cardiac surgery (6). The technology to quantitate and monitor microemboli is available. Our challenge is to apply the technology to build more effective circuit components as prime volume and surface area decrease (7), and to use the GME measurement technology to improve cardiac surgical and per-fusion techniques, which will ultimately improve outcome for the patient.
During cardiopulmonary bypass (CPB), anticoagulation of the blood is the paramount responsibility of a perfusionist. The perfusionist should ensure the termination of cardiotomy suction at the onset of protamine sulfate (protamine) administration to prevent compromising the integrity of the extracorporeal circuit (AmSect. Standards and Guidelines for Perfusion Practice. 2023. https://www.amsect.org/Policy-Practice/AmSECTs-Standards-and-Guidelines). Although coagulopathy causes the largest mortality risk in adult CPB cases, standardization is not seen universally, and practice often varies between institutions (Stammers et al. Perfusion. 2001;16(3):189-198. https://doi.org/10.1177/026765910101600304; Jansa et al. Ann Thorac Surg. 2022;113(2):506-510. https://doi.org/10.1016/j.athoracsur.2021.04.059). Activated clotting times (ACTs) were measured in five swine subjects that were heparinized and placed on CPB for a total of approximately 6 h each. Samples of blood were drawn from the CPB circuit; ACTs were measured before the administration of protamine, after a protamine test dose (PTD), and after 1/3 of the full protamine dose had been introduced to each sample. Protamine dosing was determined by a 1:100 ratio of protamine to heparin. 60 blood samples were included in the final analysis. The mean ACT after the PTD was 290.4 s (seconds), and 147.5 s after 1/3 of the full protamine dose. ACTs after the PTD decreased significantly by an average of 38.2% (p < 0.0001), and by 50.8% (p < 0.0001) after 1/3 of the full protamine dose was given. This investigation demonstrated an analysis of heparin reversal via protamine administration. The findings revealed that in the majority of samples, the PTD was sufficient to decrease the ACT below 480 s, the determined benchmark upon which CPB can be safely conducted. After 1/3 of the full protamine dose was given, nearly every sample's ACT reached a value considered unsafe for bypass. The interpretation of the data suggests that there are significant grounds for advocating for a more disciplined approach to cardiotomy suction termination to preserve the integrity of the CPB circuit and to safely conduct CPB.
Although the use of the heart-lung machine (HLM) is routine in cardiac operating theaters, there is still a lack of evidence-based guidelines concerning the optimal speed to reach full flow during initiation to reduce critical episodes of cerebral ischemia. Therefore, we have designed a study to compare two distinct initiation times for the commencement of cardiopulmonary bypass (CPB). We conducted a randomized, monocentric, double-blind, prospective study to assess the impact of two different CPB initiation speeds - rapid initiation at 30 s and slow initiation at 180 s - on cerebral tissue oxygenation (TOI via NIRS), arterial oxygen pressure, hematocrit (HCT) variation, and the incidence of postoperative delirium. The target flow rate was set at 2.4 L/min/m2, with adjustments made according to the patient's body surface area. The absolute values of the tissue oxygenation index (TOI) and HCT showed no differences between the study during the first 180 s following commencement of CPB. Patients in the fast group exhibited significantly lower arterial oxygen pressure at the initiation of the (P < 0.05). Additionally, patients in the fast group experienced a higher incidence of delirium in the second and third days following surgery. While clinically relevant, the elevated incidence of delirium fell short of being statistically significant, with post-operative days 2 and 3 having P-values of 0.06 and 0.08, respectively. The results of this study indicate that, despite the absence of a significant difference in TOI between the study groups, patients in the slow group exhibited a not statistically significant trend for a lower incidence of delirium, as defined by CAMICU-7, in comparison to those in the fast group.
Minimizing Gaseous microemboli (GME) introduced into the CPB circuit can help alleviate neurologic injury. This study focuses on understanding how suction flow rate and the reservoir level can influence the introduction of GME past the venous reservoir during CPB. An in vitro mock CPB loop filled with bovine blood was used to simulate adult CPB. A Gampt BCC-300 bubble detector measured bubble size, volume, and count at three locations: post-reservoir (venous), post-oxygenator/arterial filter (arterial), and the venous inlet to the reservoir (recirculation). Room air was added into the suction line at 200 mL/min and mixed with blood to simulate aerated suction return. Bubble transmission was measured for three minutes at three reservoir levels, 200 mL, 500 mL, and 1000 mL, and at four pump sucker flow rates: 25 RPM (0.32 L/min), 50 RPM (0.65 L/min), 75 RPM (0.99 L/min), and 100 RPM (1.32 L/min). GME count data were pooled from three commonly used, coated, disposable reservoirs/oxygenator combinations: Medtronic Affinity Fusion, Terumo CAPIOX FX25, and Sorin Inspire 8F. A total of 284 measurements were conducted, and the data from all reservoir manufacturers were analyzed and averaged. A statistically significant interaction was noticed between roller pump suction rate and reservoir level (p-value < 0.0001) at the venous sensor. As the suction flow rate increased, the reservoir level decreased, or a combination of the two occurred, a significant increase in GME count was observed at the post-reservoir sensor. Analysis of the GME count from the post-oxygenator/filter sensor revealed a significant increase as the suction flow rate increased from 25 RPM to 100 RPM. A minimum effective suction flow rate and maximum practical reservoir level are recommended to prevent the transmission of GME through the cardiopulmonary bypass circuit and potentially to the patient. Care should be taken to continuously monitor these variables throughout the case and adjust them accordingly.
End-organ hypoperfusion from cardiopulmonary shock may require mechanical circulatory support (MCS). However, patients receiving MCS risk the development of hemorrhagic complications, including gastrointestinal bleeding (GI). Examining potential risk factors for these complications improves clinical understanding. The purpose of this investigation was to study the risk for GI bleeding in MCS patients. Following IRB approval, patient characteristics, previously reported comorbidities, and the incidence of GI bleeding were reviewed from January 2017 to October 2023. Clinical variables underwent machine learning with autovalidation. Support vector machine modeling provided the best performance among the ensemble models tested. In this study of 156 patients who underwent 284 MCS procedures, the incidence of GI bleeding was 6.0% CI 3.3-10.4%. Following machine learning, patients with insulin-dependent diabetes were associated with GI bleeding. The Receiver Operating Characteristic (ROC) curve demonstrated an area under the curve (AUC) of 0.85 with a misclassification rate of 7.5%. The relative risk of the need for major transfusion (>2 packed red blood cell units/episode) was 1.7 CI 1.1-2.5. The majority (87%), but not all, of these patients received unfractionated heparin therapy. Finally, hospital length of stay was increased in patients with GI bleeding. Insulin-dependent diabetes was associated with increased risk for GI bleeding during MCS, and these patients more often required major transfusions. Further evaluation of continuous anticoagulation therapy is warranted. Knowledge derived from this analytical study may guide the development of institutional protocols to improve care in this patient population.
Providing sufficient organ perfusion during cardiopulmonary bypass (CPB) is a common research topic among extracorporeal technology researchers. The application of an elevated cardiac index (CI) to enhance CPB flow, coupled with the adoption of pulsatile flow, constitutes a novel approach designed to improve organ perfusion and oxygen delivery (DO2). this study aims to assess the effects of increased CI and pulsatile flow on organ perfusion during CPB. In this pilot study, thirty patients scheduled for on-pump coronary artery bypass graft (CABG) surgery with an estimated prolonged CPB time were enrolled. Patients were randomly divided into two study groups. Patients in the control group were managed with a CI of 2.4 L/min/m2, while patients in the study group received a CI equal to 2.6 to 3 L/min/m2 with pulsatile flow (PF) throughout the bypass run. Lactate fluctuations, creatinine variation, inotrope needs, blood transfusion requirements, ICU and hospital length of stay were assessed and noted. Participants in the study group exhibited lower creatinine levels throughout the assessment period; however, this difference did not reach statistical significance (P > 0.05). Participants in the study group consistently exhibited significantly lower lactate concentrations over the course of the investigation (P < 0.05). Patients in the study groups experienced a reduced duration of both ICU and hospital lengths of stay; however, this difference did not reach statistical significance (P > 0.05). This prospective study concludes that an increased CI in conjunction with PF during CPB can markedly enhance organ perfusion, as evidenced by a statistically significant reduction in lactate production observed throughout the duration of the bypass.
A 17-year-old male patient diagnosed with a single ventricle, in a failed Fontan stage, was evaluated prior to heart transplantation. The patient had a panel-reactive antibody (PRA) for human leucocyte antigen (HLA) I of 18% and for HLA II of 37%, so the decision was made to administer three doses of immunoglobulin while waiting for a donor heart. Once extracorporeal circulation was initiated, the apheresis machine extracted blood from the patient's venous drainage and returned it to the oxygenator reservoir. A total of 8278 mL of blood was processed, and 4224 mL of plasma was extracted. For replacement, 1341 mL of fresh frozen plasma and 2700 mL of 5% albumin were used. 75 mL of citrate-dextrose acid (CDA) was used as an anticoagulant. The procedure lasted 135 min. On the tenth postoperative day, the PRA for HLA I and II was 0%. On the thirtieth postoperative day, a catheterization with endomyocardial biopsy showed no evidence of immunological rejection. An echocardiogram showed good function of the heart graft. One year later, a catheterization with endomyocardial biopsy showed no signs of humoral rejection. The patient is currently in the third-year post-transplant and continues to show no signs of rejection in their progression. Plasmapheresis during cardiopulmonary bypass is a reproducible, safe, and effective technique. It may be indicated for sensitized patients on the heart transplant waiting list.
The accuracy and precision of continuous in-line blood gas monitoring (CILBGM) are crucial for optimal blood gas management during cardiopulmonary bypass (CPB) and improved patient outcomes. CILBGM devices, such as the CDI 500/550 system, measure PaO2 and PaCO2, and B-Capta measures PaO2 through direct contact with arterial blood. However, the Quantum perfusion system with Quantum Ventilation2 (Quantum System) does not measure but calculates PaO2 and PaCO2 using several non-invasive sensors and proprietary formulas. We have observed that the calculated in-line PaO2 and PaCO2 values from Quantum System are frequently significantly higher than those obtained from iSTAT, a point-of-care blood analyzer, exceeding acceptable targets. We conducted a retrospective study involving 81 patients who underwent cardiac surgery using the Quantum System with its own CILBGM and the FX05 oxygenator. The aim was to identify the degree, timing, and possible patterns of error of the calculated in-line PaO2 and PaCO2. Our study showed that the errors of calculated in-line PaO2 exceed the acceptable target at the 1st blood gas series and during the rewarming and rewarmed periods, correlating with patient weight. The calculated in-line PaCO2 exhibited an upward drift during the rewarming period, correlating with the temperature gradient rather than patient weight. Based on several correlations identified, we derived a formula to predict FiO2 based on patient weight, which would achieve the target PaO2 at the 1st blood gas series when using the FX05 oxygenator. We identified when and how the errors in calculating in-line PaO2 and PaCO2 occurred and developed several recommendations to minimize significant deviations from actual PaO2 and PaCO2 during CPB. Our results suggest that achieving acceptable PaO2 and PaCO2 calculations throughout CPB using a single universal formula for each, embedded in the Quantum System, is challenging due to the variety of oxygenators available, different patient sizes, and changing conditions during CPB.
A critical aspect of cardiopulmonary bypass (CPB) is achieving full anticoagulation to prevent thrombosis and consumptive coagulation (CCA). Systemic anticoagulation with heparin during CPB should be completely neutralized by administering protamine to restore normal hemostasis. Activated clotting time (ACT) is a major marker of anticoagulation management during CPB. However, studies have shown that ACT measurements can vary predictably with different point-of-care testing ACT devices, suggesting the importance of considering the ACT device when determining the target ACT. Otherwise, the amount of heparin used and circulating during CPB can be unnecessarily high. Calculating an optimal protamine dose (PD) is challenging. Yet, newer strategies and heparin concentration-based dosing indicate that average doses of 60-90 mg/m2 are generally sufficient. This equates to a protamine-to-heparin ratio of approximately 0.5-0.8:1 of the first heparin bolus to establish the target ACT before going on CPB or a 0.3-0.5:1 of the total heparin dose during CPB. PD exceeding 90 mg/m2 may result in residual free protamine. Excessive use of heparin and protamine has been associated with increased post-operative bleeding. This review discusses several considerations in planning an anticoagulation strategy during CPB, focusing on the predictable differences of ACT devices and strategies to determine the optimal PD. The aim is to administer a safe and minimal amount of heparin to protect the CPB circuit and patient from thrombosis and CCA, and to administer the optimal amount of protamine to completely neutralize the circulating heparin without leaving residual free protamine.
The demand for allied healthcare professionals has surged, raising concerns about the rising costs of education. Tuition for post-baccalaureate and master's programs in perfusion technology ranges from $18,000 to $106,500 annually, often surpassing $100,000 in total expenses. This financial burden presents significant challenges for prospective students, restricting their entry into the field. High costs could lead to a reduction in the number of qualified perfusionists, negatively impacting patient care. To address these challenges, partnerships between academic institutions and healthcare organizations could facilitate the development of scholarships or sponsored work studies. Additionally, policymakers should advocate for increased funding and other initiatives to help alleviate the financial strain allied health professionals face. Creating innovative solutions to these financial challenges may lead to a more diverse group of professionals in the field, enriching perspectives and approaches to patient care. Investing in accessible education will strengthen the healthcare system, benefiting providers and patients.
Patients receiving mechanical circulatory support (MCS) risk the development of sepsis. Examining risk factors for the development of sepsis and their relationships to MCS may allow for an improved understanding of these complications. Following IRB approval, patient characteristics, previously reported comorbidities, and the incidence of sepsis were studied in 199 patients who received 244 MCS therapies from January 2017 to October 2023. The clinical variables underwent ensemble machine learning modeling. Significant comorbidities predicting sepsis from the ensemble machine modeling underwent decision-tree analysis. In this study, the incidence of sepsis was 20% (95% CI: 16-26%). Following machine learning modeling, patients with a history of congestive heart failure or a history of previous cardiac surgery were associated with an increased risk for developing sepsis. The c-index statistic for this model was 0.76, with a misclassification rate of 19%. Decision-tree analysis observed that patients without chronic cardiovascular disease but with a history of prior cardiac surgery have a 60.3% (95% CI: 60.1-65.2%) incidence of sepsis during MCS therapy. Patients with a history of chronic cardiovascular disease and with a history of congestive heart failure have an 18.1% (95% CI: 17.2-18.7%) incidence of developing sepsis. The incidence of sepsis is high in this patient population. The novel associations of patients who have histories of congestive heart failure or previous cardiac surgery requiring MCS suggest an increased systemic inflammatory state exists that escalates the risk for developing sepsis. Further investigation into these background inflammatory conditions in patients requiring MCS is warranted.
Adult venoarterial extracorporeal membrane oxygenation (VA ECMO) is a costly life support therapy, where patient selection remains a significant hinge-point in determining patient outcomes. Despite this, few sites have formalized patient selection criteria, and even fewer have a robust multidisciplinary ECMO team to determine patient candidacy. Analyzing current literature revealed weaknesses in existing research on VA ECMO patient selection criteria. Significant issues include the use of small sample sizes, lack of randomized controlled trials, lack of personalization of ECMO initiation decisions, study heterogeneity, and inclusion of patients who received ECMO without including patients who were considered for but not given ECMO. Among the available studies, the Survival After Venoarterial ECMO (SAVE) score has shown the greatest promise in selecting VA ECMO patients, excluding those undergoing extracorporeal cardiopulmonary resuscitation (ECPR) and postcardiotomy (PC) ECMO. The SAVE score has demonstrated good discrimination in non-ECPR and non-PC ECMO groups. Further research is needed on the predictive value of SAVE score risk classes and the discrimination of the SAVE score excluding PC ECMO and ECPR groups. The modified SAVE score, which also includes lactate assessment, has shown the greatest promise for selecting ECPR and PC ECMO patients for VA ECMO. The modified SAVE score requires more external validation. Site-level research indicates that consultation with a multidisciplinary ECMO team, which collectively makes decisions about ECMO candidacy, has resulted in significantly improved patient survival outcomes compared with a one- or two-physician decision-making mechanism for VA ECMO initiation. The ECMO team approach is a rich area for future research, and sites should publish their patient outcomes before and after implementation.
Fluid and electrolyte balance is closely managed in extracorporeal membrane oxygenation (ECMO) patients. Neglecting oxygenator-related insensible fluid losses can distort fluid balance and electrolyte levels. While ECMO oxygenator insensible losses are reported, they remain undefined for the Medtronic Nautilus oxygenator. Through in vitro analysis of the Nautilus, we quantified insensible water losses while concurrently observing sodium behavior. Insensible water losses were determined using a closed circuit. A 12-hour pilot run was conducted to saturate the oxygenator and determine probable water loss rates and sodium accumulation behaviors. Fluid loss and sodium measurements were made at 0, 6, and 12 h. Immediately following the pilot run, three randomly assigned sweep gas rates, 0.5, 1.0, and 1.5 L/min, were evaluated over a 24 h period and replicated in triplicate. The circuit parameters were consistent and controlled for each trial. Data were collected at 0, 12, and 24 h for visualized water loss in the reservoir. After each trial, sterile water was introduced into the circuit via syringe and recorded as replacement volume. Sodium measurements were made for three trials (0.5, 1.0, and 1.5) and collected at 0 and 24 h. Using linear regression analysis, the following insensible water loss equations were produced. Visualized volume: 2.74 mL/h per 1 L/min sweep gas rate or 65.66 mL/day per 1 L/min of sweep gas rate (p < 0.001). Replacement volume: 3.02 mL/h per 1 L/min of sweep gas rate or 72.5 mL/day per 1 L/min of sweep rate (p < 0.001). Sodium accumulation was observed, but not statistically significant due to the small sample size. Insensible water loss in the Nautilus ECMO oxygenator increases linearly with sweep gas rate (p < 0.001), leading to sodium accumulation through evaporation. These losses and the associated risk for hypernatremia should be considered when managing a patient's fluid and electrolyte balance on ECMO.
As demand for perfusionists grows due to increased cardiac procedures and retirements, improving first-time pass rates is essential to addressing workforce shortages. This quantitative study analyzed academic, demographic, and clinical variables as predictors of success on the American Board of Cardiovascular Perfusion (ABCP) exam. Data were collected from 103 students enrolled in the master's-level Carlow University-University of Pittsburgh Medical Center (UPMC) Cardiovascular Perfusion program between 2017 and 2022 (IRB #02232024-1). Student-level variables included undergraduate GPA, grades in prerequisite courses, clinical experience hours, and admission status (graduate vs. undergraduate). Associations between these variables and first-time ABCP exam success were examined. Logistic regression analysis revealed that higher performance in Introduction to Cardiac Perfusion (B = 1.002, p = .008) and Hematology (B = .636, p = .028) significantly predicted first-time success on the ABCP exam. Admission as an undergraduate student was also a significant predictor (p = .004). However, neither the number of clinical experience hours nor the student's cohort year showed statistical significance (p > .05). Academic performance in key foundational courses and student background (such as admission status) were significantly associated with first-time ABCP exam success. In contrast, the amount of clinical experience did not demonstrate a meaningful impact on pass rates. Further research should utilize a richer dataset that captures a more comprehensive view of perfusion program curricula, including detailed clinical training components. This would help clarify how specific educational experiences contribute to ABCP exam success and overall program outcomes.
Although unfractionated heparin (UFH) has traditionally been used for anticoagulation during extracorporeal membrane oxygenation (ECMO), bivalirudin may be preferred due to fewer complications. A prior medication use evaluation of ECMO patients who received bivalirudin resulted in dosing updates for our pharmacist-directed bivalirudin protocol. This study intended to evaluate the efficacy and safety of bivalirudin for anticoagulation during ECMO support post-protocol initiation. This was a retrospective, single-center, pre-post study. Adult patients requiring ECMO support for at least 24 h and who received bivalirudin between January 1, 2015 to July 31, 2018 (pre-group) and May 1, 2019 to June 30, 2021 (post-group) were included. There were 38 patients in the pre- and 35 patients in the post-group. The primary outcome, median time to two consecutive activated partial thromboplastin times (aPTTs) within therapeutic range for the initial goal range, was 8.9 h in the pre- and 14.2 h in the post-group (p = 0.517). In a subgroup analysis of the post-group, the primary outcome was higher in patients with COVID-19 (26.5 vs. 8.6 h, p = 0.018). The median number of dose adjustments to achieve goal aPTT was higher in COVID-19 patients (4 vs. 2, p = 0.017). These results suggest that a standardized pharmacist-directed protocol for bivalirudin in ECMO achieves timely therapeutic anticoagulation levels. Patients with COVID-19 trended toward longer times to two consecutive therapeutic aPTTs. Further studies are needed to evaluate dosing strategies in patients with and without COVID-19.
Cardioplegia is essential for myocardial protection during cardiac surgery. The COVID-19 pandemic disrupted supply chains, affecting the availability of commercial cardioplegia solutions in Thailand and prompting institutions to modify their strategies. This study evaluates the distribution, selection, and adaptation of cardioplegia practices among Thai cardiac surgical centers during the pandemic. A nationwide survey was conducted in cardiac surgical centers performing ≥100 cases per year. Data on cardioplegia availability, usage, and preferences across different surgeries were collected via direct or telephone interviews with surgeons or perfusionists. Descriptive statistical analyses were applied. St. Thomas-based cardioplegia remained the most widely used (95%), with 77.1% of institutions preparing custom formulations due to supply shortages. Histidine-tryptophan-ketoglutarate (HTK) was the second most used (76%), particularly in aortic and complex congenital surgeries, followed by del Nido cardioplegia (27%), often in modified formulations. Most centers (74%) used two to three cardioplegia solutions. Blood cardioplegia was preferred for coronary artery bypass grafting (89.2%) and valve procedures (78.4%), whereas HTK dominated in aortic (54.1%) and complex congenital surgeries (71.4%). Despite the pandemic, St. Thomas-based cardioplegia remained dominant in Thailand, with increasing reliance on HTK and modified del Nido cardioplegia. The widespread use of custom-made cardioplegia highlights the impact of supply chain disruptions. Post-pandemic studies are essential to evaluate long-term adaptations and refine myocardial protection strategies.
This study aimed to assess whether continuous furosemide administration during cardiopulmonary bypass (CPB) in minimally invasive cardiac surgery (MICS) reduces the incidence of cardiac surgery-associated acute kidney injury (AKI). A total of 100 patients undergoing MICS with CPB were randomly assigned to receive either continuous furosemide infusion or no continuous furosemide during CPB. The primary endpoint was the incidence of AKI. Secondary endpoints included the cardiac surgery-associated neutrophil gelatinase-associated lipocalin (CSA-NGAL) score, urine output within 12 h postoperatively, postoperative furosemide dose requirements, red blood cell transfusion volume, PaO2/FiO2 ratio, duration of mechanical ventilation, length of stay in the intensive care unit (ICU) and hospital, and in-hospital mortality. AKI occurred in 8 patients (16%) in the continuous furosemide group and in 6 patients (12%) in the non-continuous group (relative risk, 0.72; 95% CI, 0.23-2.23). Among the secondary endpoints, urine output within the first 3 h postoperatively and the PaO2/FiO2 ratio were significantly higher in the continuous furosemide group. However, subgroup analyses revealed no significant differences between the two groups. Continuous furosemide administration during CPB did not effectively reduce the incidence of AKI. However, it was associated with a significant increase in postoperative urine output and an improvement in the PaO2/FiO2 ratio.
Extracorporeal membrane oxygenation (ECMO) has a history that is a testament to the pioneering spirit of medical innovators. It is intricately linked with the development of cardiopulmonary bypass (CPB) technology. The journey of ECMO can be traced back to the mid-20th century when experiments with CPB began to support patients undergoing cardiac surgery. However, it was not until the 1970s that ECMO emerged as a standalone therapy. Throughout the following decades, ECMO technology advanced rapidly, with improvements in circuit design, oxygenators, and pump technology enhancing its safety and efficacy. ECMO's versatility soon became apparent as it was employed in various clinical scenarios, including acute respiratory distress syndrome (ARDS), cardiac failure, and even as a bridge to lung or heart transplantation. In recent years, efforts have focused on miniaturisation, cost reduction, and the development of portable systems, enabling their use outside traditional intensive care settings. Today, ECMO remains not just a tool but a lifeline in the management of life-threatening cardiorespiratory failure. It offers hope and a second chance to patients when conventional therapies fall short, underscoring its critical importance in critical care medicine, cardiology, transplant and cardiothoracic surgery. This article provides a concise yet comprehensive overview of the history and recent advancements in ECMO.
Rapid growth of our mechanical cardiac support program, coupled with limited experience among bedside nursing staff in the care of patients supported with the Berlin Heart (BH VAD), created the need for a targeted educational intervention. We designed an educational module combining didactic sessions with high-fidelity simulation of a patient supported with a BH VAD. A novel, high-fidelity BH VAD simulator was designed and tested by our team. Members of the cardiothoracic intensive care unit (CICU) staff participated in didactic sessions and high-fidelity simulations. Pre- and post-experience surveys were administered to gauge staff confidence and basic knowledge regarding caring for a patient supported with a BH VAD. Follow-up surveys were administered 6-8 weeks after the educational module was completed. 82 total staff members participated in the simulation. There were significant improvements in feelings of being prepared to care for a patient supported with a BH VAD [pre-participation median response 3 (range 2-4), post-participation median 4 (range 3-4), p < 0.001]. There were also significant improvements in knowledge assessment before and after the educational module [median number of questions answered pre-participation correctly: 2 (range 0-3); median answered post-participation correctly: 3 (range 2-3); p < 0.001]. These gains were maintained at a 6-8-week follow-up. High-fidelity simulation with a novel BH VAD simulator, coupled with focused didactics, led to significant improvements in staff confidence and knowledge. This combination of training methods resulted in sustained improvements at 6-8-week follow-up. This approach to staff training can build and solidify knowledge of mechanically supported patients for the nursing staff in a CICU.
Hemodilution during cardiopulmonary bypass (CPB) is a standard perfusion strategy used to reduce blood viscosity and enhance microcirculatory flow. The hemodilution rate, expressed as hemoglobin (Hb) concentration, is a key control index in CPB and is currently estimated from total blood volume (TBV). The objective of this study was to propose a novel formula to accurately predict Hb concentration at the initiation of CPB (HbCPB) by incorporating circulating blood volume, laboratory data, physical measurements, and patient history. We retrospectively analyzed 577 adult patients who underwent elective CPB at Fujita Health University Hospital from January 2016 to December 2020. Thirty-six preoperative variables - including demographics, laboratory data, circuit parameters, and indices such as TBV and ideal weight - were standardized. Categorical variables underwent one-hot encoding. We compared generalized linear models (GLM), support vector regression (SVR), and multilayer perceptron (MLP). Model performance was evaluated using the coefficient of determination (R2), mean squared error (MSE), and Bland-Altman analysis (bias and 95% limits of agreement [LoA]). Predictions from two conventional TBV-based formulas were used as benchmarks. Of 993 screened cases, 577 met inclusion criteria (447 males, mean age 66.8 ± 11.7 years; 130 females, 69.5 ± 10.6 years). SVR on standardized predictors achieved the highest accuracy (R2 = 0.498, MSE = 0.517), outperforming GLM (R2 = 0.429, MSE = 0.797) and MLP (R2 = 0.332, MSE = 0.669). Conventional formulas showed lower performance (R2 = 0.325, MSE ≥ 1.48). Bland-Altman analysis for SVR demonstrated minimal bias (-0.0028 g/dL) and narrower LoA (-1.42 to 1.41 g/dL) than conventional methods (bias -1.33 g/dL; LoA -3.49 to 0.83 g/dL). These findings suggest that an SVR-based model improves prediction of HbCPB over conventional approaches, supporting optimized transfusion management and reduced hemodilution-related risks.