2019 EACTS/EACTA/EBCP guidelines on cardiopulmonary bypass in adult cardiac surgery

2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery

Clinical practice guidelines consolidate and evaluate all pertinent evidence on a specific topic available at the time of their formulation. The goal is to assist physicians in determining the most effective management strategies for patients with a particular condition. These guidelines assess the impact on patient outcomes and weigh the risk-benefit ratio of various diagnostic or therapeutic approaches. While not a replacement for textbooks, they provide supplementary information on topics relevant to current clinical practice and become an essential tool to support the decisions made by specialists in daily practice. Nonetheless, it is crucial to understand that these recommendations are intended to guide, not dictate, clinical practice, and should be adapted to each patient's unique needs. Clinical situations vary, presenting a diverse array of variables and circumstances. Thus, the guidelines are meant to inform, not replace, the clinical judgement of healthcare professionals, grounded in their professional knowledge, experience and comprehension of each patient's specific context. Moreover, these guidelines are not considered legally binding; the legal duties of healthcare professionals are defined by prevailing laws and regulations, and adherence to these guidelines does not modify such responsibilities. The European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Cardiothoracic Anaesthesiology and Intensive Care (EACTAIC) and the European Board of Cardiovascular Perfusion (EBCP) constituted a task force of professionals specializing in cardiopulmonary bypass (CPB) management. To ensure transparency and integrity, all task force members involved in the development and review of these guidelines submitted conflict of interest declarations, which were compiled into a single document available on the EACTS website (https://www.eacts.org/resources/clinical-guidelines). Any alterations to these declarations during the development process were promptly reported to the EACTS, EACTAIC and EBCP. Funding for this task force was provided exclusively by the EACTS, EACTAIC and EBCP, without involvement from the healthcare industry or other entities. Following this collaborative endeavour, the governing bodies of EACTS, EACTAIC and EBCP oversaw the formulation, refinement, and endorsement of these extensively revised guidelines. An external panel of experts thoroughly reviewed the initial draft, and their input guided subsequent amendments. After this detailed revision process, the final document was ratified by all task force experts and the leadership of the EACTS, EACTAIC and EBCP, enabling its publication in the European Journal of Cardio-Thoracic Surgery, the British Journal of Anaesthesia and Interdisciplinary CardioVascular and Thoracic Surgery. Endorsed by the EACTS, EACTAIC and EBCP, these guidelines represent the official standpoint on this subject. They demonstrate a dedication to continual enhancement, with routine updates planned to ensure that the guidelines remain current and valuable in the ever-progressing arena of clinical practice.

Perfusion education and training in Europe anno 2023

Background: In the absence of uniform European regulations, there have been many differences in the training of perfusionists across Europe. Furthermore, there has been no uniform or single European accreditation of the profession. One of the objectives of The European Board of Cardiovascular Perfusion (EBCP) is to standardise and monitor training of perfusionists across Europe whilst offering support in accordance with national regulations. This goal is particularly imminent as there have been numerous newly founded National perfusion societies, particularly from Eastern European countries, which are now established members of EBCP.Purpose: In this article, we provide an updated overview or 'snapshot' of current European perfusion training programs that were accessible in 2022. Nationally acquired data refers to 2022 unless stated otherwise. The last overview of Perfusion education in Europe was reported over 15 years ago including 20 countries.Research Design: For this report thirty-two national EBCP delegates plus representatives from Austria were contacted at the beginning of 2023 to complete a pro forma questionnaire about their national perfusion training programmes. The data has been summarized in this article and five additional derived parameters were calculated.Results: We received responses from 31 countries, providing specific national training characteristics which are summarized, listed and benchmarked by country in this article.Conclusion: There have been several national and supranational initiatives towards the recognition of perfusion as a profession in Europe, however so far without success for the majority of countries. For this reason, it remains essential for EBCP, as the only European professional perfusionist body, to define education standards and competencies for perfusionists and to monitor training by accreditation of dedicated perfusion schools across Europe.

Intraoperative high and low blood pressures are not associated with delirium after cardiac surgery: A retrospective cohort study

STUDY OBJECTIVE

To evaluate the associations between high and low intraoperative time-weighted average mean arterial pressures before, during and after cardiopulmonary bypass on postoperative delirium.

DESIGN

Single center retrospective cohort study.

SETTING

Operating rooms and postoperative care units.

PATIENTS

11,382 patients, 18 years of age or older who had cardiac surgery requiring cardiopulmonary bypass between January 2017 and December 2020 at the Cleveland Clinic Main Campus.

INTERVENTIONS

All cardiac surgery requiring bypass except procedures requiring deep hypothermic circulatory arrest.

MEASUREMENTS

Post operative delirium was assessed from 12 to 96 h postoperatively, using the Confusion Assessment Method and brief Confusion Assessment Methods. Hypotension and hypertension were defined as time-weighted average mean arterial pressure < 60 and > 80 mmHg.

MAIN RESULTS

Postoperative delirium occurred in 678 (6.0 %) of 11,382 patients. Confounder-adjusted associations, using multivariable logistic regression models, between hypotension (time-weighted average mean arterial pressure < 60 mmHg) and hypertension (time-weighted average mean arterial pressure > 80 mmHg) and postoperative delirium were not statistically significant or clinically meaningful before, during, or after the cardiopulmonary bypass.

CONCLUSIONS

This large single-center cohort analysis found no evidence that exposure to high or low blood pressures during various intraoperative phases of cardiac surgery are associated with postoperative delirium.

Andexanet Alfa-Associated Heparin Resistance in Cardiac Surgery: Mechanism and In Vitro Perspectives

BACKGROUND

Andexanet alfa (andexanet) is the only Food and Drug Administration-approved antidote for direct FXa (factor Xa) inhibitors but has been reported to cause resistance to unfractionated heparin (UFH). This has delayed anticoagulation for procedures requiring cardiopulmonary bypass. The mechanism, andexanet and UFH dose dependence, and thrombotic risk of andexanet-associated heparin resistance are unknown.

METHODS

The effect of andexanet in vitro was determined using activated clotting times and thromboelastography. Ex vivo cardiopulmonary bypass circuits were used to determine whether andexanet impaired anticoagulation for extracorporeal circulation. Kinetics of AT (antithrombin) inhibition of FXa and thrombin were measured in the presence of andexanet. Equilibrium modeling and thrombin generation assay validation were used to predict the role of andexanet, AT, and UFH concentrations in andexanet-associated heparin resistance.

RESULTS

Andexanet prevented UFH-mediated prolongation of activated clotting times and thromboelastography times. At lower concentrations of andexanet, heparin resistance could be overcome with suprapharmacologic doses of UFH, but not at higher andexanet concentrations. Andexanet rendered standard doses of UFH inadequate to prevent circuit thrombosis, and suprapharmacologic UFH doses were only partially able to overcome this. Scanning electron microscopy demonstrated coagulation activation in circuits. Andexanet prevented UFH enhancement of AT-mediated inhibition of FXa and thrombin. Equilibrium modeling and thrombin generation assay validation demonstrated that andexanet creates a triphasic equilibrium with UFH and AT: initial UFH unresponsiveness, normal UFH responsiveness when andexanet is depleted, and finally AT depletion. Sufficient cardiopulmonary bypass heparinization can only occur at low therapeutic andexanet doses and normal AT levels. Higher andexanet doses or AT deficiency may require high UFH doses and potentially AT supplementation.

CONCLUSIONS

Andexanet causes heparin resistance due to redistribution of UFH-bound AT. If andexanet cannot be avoided before heparinization and direct thrombin inhibitors are undesirable, our in vitro study suggests excess UFH should be considered as a potential strategy before AT supplementation.

Handheld Point-of-Care Devices for Snakebite Coagulopathy: A Scoping Review

Venom-induced consumption coagulopathy (VICC) is a common complication of snakebite that is associated with hypofibrinogenemia, bleeding, disability, and death. In remote tropical settings, where most snakebites occur, the 20-minute whole blood clotting test is used to diagnose VICC. Point-of-care (POC) coagulation devices could provide an accessible means of detecting VICC that is better standardized, quantifiable, and more accurate. In this scoping review, the mechanistic reasons that previously studied POC devices have failed in VICC are considered, and evidence-based recommendations are made to prioritize certain devices for clinical validation studies. Four small studies have evaluated a POC international normalized ratio (INR) device in patients with Australian Elapid, Daboia russelii, and Echis carinatus envenoming. The devices assessed in these studies either relied on a thrombin substrate endpoint, which is known to underestimate INR in patients with hypofibrinogenemia, have been recalled due to poor accuracy, or have since been discontinued. Sixteen commercially available POC devices for measuring INR, activated clotting time, activated partial thromboplastin time, fibrinogen, D-dimer, and fibrin(ogen) degradation products have been reviewed. POC INR devices that detect fibrin clot formation, as well as a novel POC device that quantifies fibrinogen were identified, which show promise for use in patients with VICC. These devices could support more accurate allocation of antivenom, reduce the time to antivenom administration, and provide improved clinical trial outcome measurement instruments. There is an urgent need for these promising POC coagulation devices to be validated in prospective clinical snakebite studies.

Heparin consumption and inflammatory response according to the coating of cardiopulmonary bypass circuits in cardiac surgery: A retrospective analysis

INTRODUCTION

There are several types of surface treatments (coatings) aimed at improving the biocompatibility of cardiopulmonary bypass (CPB) circuit. Some coatings appear to require higher doses of heparin to maintain anticoagulation goals, and some of them might induce postoperative coagulopathy. In this study, we compared the amount of heparin required, postoperative bleeding, and inflammatory response according to three types of coatings.

METHOD

We retrospectively included 300 consecutive adult patients who underwent cardiac surgery with CPB and received one of three coatings (Phisio®, Trillium®, and Xcoating™). Our primary objective was to compare, according to coating, the amount of heparin required to maintain an ACT > 400s during CPB. Our secondary objectives were to compare postoperative bleeding for 48 h and CRP rate.

RESULTS

Baseline characteristics were comparable between groups except for age and preoperative CRP. We did not find a significant difference between the 3 coatings regarding the amount of heparin reinjected. However, we found less postoperative bleeding with the Xcoating™ circuit compared to the Phisio® circuit (-149 mL [-289; -26.5]; p = 0.02) and a lower elevation of CRP with the Phisio® circuit (2.8 times higher than preoperative CRP) compared to Trillium® (4.9 times higher) and Xcoating™ (6.4 times higher); p < 10-3.

CONCLUSION

The choice of coating did not influence the amount of heparin required during CPB; however, the post-CPB inflammatory syndrome may be impacted by this choice.

Documentation of the current state of cardiopulmonary bypass management in Türkiye

Since the first successful use of cardiopulmonary bypass (CPB), much has changed in its technology, area of use, and management. Despite suggestions in guidelines, the institutional behavior may change based on institutional experience and established habits. This so-called "deviation" may alter management strategies in favorable or unfavorable ways. As the official Cardiopulmonary Bypass Study Group of the Association of Perfusionists in Türkiye, we aimed to document the current state of CPB management in Türkiye and make suggestions based on current guidelines. A 20-item questionnaire e-mailed to 682 perfusionists in 110 centers in Türkiye, and 177 (25.95%) responses were recorded from 97 centers. The questionnaire included main parameters regarding the management of CPB. We believe that by documenting the current state of CPB management strategies in Türkiye, suboptimal management strategies can be improved and suggestions for more favorable outcomes can be made.

The evolving role of the modern perfusionist: Insights from processed electro-encephalography

Introduction: Since its origin in the 1920s, electroencephalography (EEG) has become a viable option for anesthesia and perfusion teams to monitor anesthetic delivery, optimizing drug dosage and enhancing patient safety. Patients undergoing cardiopulmonary bypass (CPB) are at particular high risk for excessive or inadequate anesthetic doses. During CPB, traditional physiological indicators such as heart rate and blood pressure can be significantly altered. These abnormalities are compounded by rapid changes in anesthetic concentration from hemodilution, circuit absorption, and altered pharmacokinetics. Method: This narrative highlights the use of processed EEG with spectral analysis for anesthetic management during CPB. Conclusion: We emphasize that neuromonitoring using processed EEG during CPB can assess adequacy of anesthesia delivery and monitor for pathologic conditions that can compromise brain function such as inadequate cerebral blood flow, emboli, and seizures. This information is highly valuable for the clinical team including the perfusionist, who regularly diagnose and manage these pathological conditions.

Andexanet alfa-associated heparin resistance in cardiac surgery: mechanism and in vitro perspectives

Background

Andexanet alfa (andexanet) is the only FDA-approved antidote for direct factor Xa (FXa) inhibitors but has been reported to cause resistance to unfractionated heparin (UFH). This has delayed anticoagulation for procedures requiring cardiopulmonary bypass (CPB). The mechanism, andexanet and UFH dose dependence, and thrombotic risk of andexanet-associated heparin resistance are unknown.

Methods

The effect of andexanet in vitro was determined using activated clotting times (ACT) and thromboelastography (TEG). Ex vivo CPB circuits were used to determine whether andexanet impaired anticoagulation for extracorporeal circulation. Kinetics of antithrombin (AT) inhibition of FXa and thrombin were measured in the presence of andexanet. Equilibrium modeling and thrombin generation assay (TGA) validation were used to predict the role of andexanet, AT, and UFH concentrations in andexanet-associated heparin resistance.

Results

Andexanet prevented UFH-mediated prolongation of ACT and TEG times. At lower concentrations of andexanet, heparin resistance could be overcome with suprapharmacologic doses of UFH, but not at higher andexanet concentrations. Andexanet rendered standard doses of UFH inadequate to prevent circuit thrombosis, and suprapharmacologic UFH doses were only partially able to overcome this. Scanning electron microscopy demonstrated coagulation activation in circuits. Andexanet prevented UFH enhancement of AT-mediated inhibition of FXa and thrombin. Equilibrium modeling and TGA validation demonstrated that andexanet creates a triphasic equilibrium with UFH and AT: initial UFH unresponsiveness, normal UFH responsiveness when andexanet is depleted, and finally AT depletion. Sufficient CPB heparinization can only occur at low therapeutic andexanet doses and normal AT levels. Higher andexanet doses or AT deficiency may require both AT supplementation and very high UFH doses.

Conclusions

Andexanet causes heparin resistance due to redistribution of UFH-bound AT. If andexanet cannot be avoided prior to heparinization and direct thrombin inhibitors are undesirable, our in vitro study suggests excess UFH should be considered as a potential strategy prior to AT supplementation.

Highlights

Andexanet alfa causes heparin resistance not by depleting antithrombin, but rather by sequestering heparin-bound antithrombin such that it cannot act as an anticoagulant.Heparin responsiveness in the presence of Andexanet alfa is triphasic such that the effect of a dose of heparin can now be predicted in vitro based on the relative concentrations of andexanet, heparin, and antithrombin.The in vitro insights provided by this work provide a rational starting point for further clinical elucidation of the problem and management of andexanet-associated heparin resistance.

Heparin resistance management during cardiac surgery: a literature review and future directions

INTRODUCTION

Heparin, a commonly used anticoagulant in cardiac surgery, binds to antithrombin III (ATIII) to prevent clot formation. However, heparin resistance (HR) can complicate surgical procedures, leading to increased thromboembolic risks and bleeding complications. Proper diagnosis and management of HR are essential for optimizing surgical outcomes.

METHODOLOGY

Diagnosis of HR involves assessing activated clotting time (ACT) and HR assays. Management strategies were identified through a comprehensive review of the literature, including studies exploring heparin dosage adjustments, antithrombin supplementation, and alternative anticoagulants in cardiac surgery patients with HR. A thorough search of relevant studies on HR was conducted using multiple scholarly databases and relevant keywords, resulting in 59 studies that met the inclusion criteria.

DISCUSSION

HR occurs when patients do not respond adequately to heparin therapy, requiring higher doses or alternative anticoagulants. Mechanisms of HR include AT III deficiency, PF4 interference, and accelerated heparin clearance. Diagnosis involves assessing ACT and HR assays. HR in cardiac surgery can lead to thromboembolic events, increased bleeding, prolonged hospital stays, and elevated healthcare costs. Management strategies include adjusting heparin dosage, supplementing antithrombin levels, and considering alternative anticoagulants. Multidisciplinary management of HR involves collaboration among various specialities. Strategies include additional heparin doses, fresh frozen plasma (FFP) administration, and antithrombin concentrate supplementation. Emerging alternatives to heparin, such as direct thrombin inhibitors and nafamostat mesilate, are also being explored.

CONCLUSION

Optimizing the management of HR is crucial for improving surgical outcomes and reducing complications in cardiac surgery patients. Multidisciplinary approaches and emerging anticoagulation strategies hold promise for addressing this challenge effectively.

Ultrafiltration in cardiac surgery: Results of a systematic review and meta-analysis

Background: Ultrafiltration is used with cardiopulmonary bypass to reduce the effects of hemodilution and restore electrolyte balance. We performed a systematic review and meta-analysis to analyze the effect of conventional and modified ultrafiltration on intraoperative blood transfusion.Methods: Utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement, we systematically searched MEDLINE, EMBASE, Web of Science, and Cochrane Library to perform a meta-analysis of studies of randomized controlled trials (RCTs) and observational studies evaluating conventional ultrafiltration (CUF) and modified ultrafiltration (MUF) on the primary outcome of intraoperative red cell transfusions.Results: A total of 7 RCTs (n = 928) were included, comparing modified ultrafiltration (n = 473 patients) to controls (n = 455 patients) and 2 observational studies (n = 47,007), comparing conventional ultrafiltration (n = 21,748) to controls (n = 25,427). Overall, MUF was associated with transfusion of fewer intraoperative red cell units per patient (n = 7); MD -0.73 units; 95% CI -1.12 to -0.35 p = 0.04; p for heterogeneity = 0.0001, I2 = 55%) compared to controls. CUF was no difference in intraoperative red cell transfusions compared to controls (n = 2); OR 3.09; 95% CI 0.26-36.59; p = 0.37; p for heterogeneity = 0.94, I2 = 0%. Review of the included observational studies revealed an association between larger volumes (>2.2 L in a 70 kg patient) of CUF and risk of acute kidney injury (AKI).Conclusion: The results of this systematic review and meta-analysis suggest that MUF is associated with fewer intraoperative red cell transfusions. Based on limited studies, CUF does not appear to be associated with a difference in intraoperative red cell transfusion.

Mean Arterial Pressure (MAP) Trial: study protocol for a multicentre, randomized, controlled trial to compare three different strategies of mean arterial pressure management during cardiopulmonary bypass

BACKGROUND

One of the main goals of cardiopulmonary bypass (CPB) is targeting an adequate mean arterial pressure (MAP) during heart surgery, in order to maintain appropriate perfusion pressures in all end-organs. As inheritance of early studies, a value of 50-60 mmHg has been historically accepted as the "gold standard" MAP. However, in the last decades, the CPB management has remarkably changed, thanks to the evolution of technology and the availability of new biomaterials. Therefore, as highlighted by the latest European Guidelines, the current management of CPB can no longer refer to those pioneering studies. To date, only few single-centre studies have compared different strategies of MAP management during CPB, but with contradictory findings and without achieving a real consensus. Therefore, what should be the ideal strategy of MAP management during CPB is still on debate. This trial is the first multicentre, randomized, controlled study which compares three different strategies of MAP management during the CPB.

METHODS

We described herein the methodology of a multicentre, randomized, controlled trial comparing three different approaches to MAP management during CPB in patients undergoing elective cardiac surgery: the historically accepted "standard MAP" (50-60 mmHg), the "high MAP" (70-80 mmHg) and the "patient-tailored MAP" (comparable to the patient's preoperative MAP). It is the aim of the study to find the most suitable management in order to obtain the most adequate perfusion of end-organs during cardiac surgery. For this purpose, the primary endpoint will be the peak of serum lactate (Lmax) released during CPB, as index of tissue hypoxia. The secondary outcomes will include all the intraoperative parameters of tissue oxygenation and major postoperative complications related to organ malperfusion.

DISCUSSION

This trial will assess the best strategy to target the MAP during CPB, thus further improving the outcomes of cardiac surgery.

TRIAL REGISTRATION

NCT05740397 (retrospectively registered; 22/02/2023).

Protamine dosing and its impact in cardiac surgery transfusion practice-A retrospective bi-institutional analysis

BACKGROUND

Bleeding after cardiac surgery is common and continues to require 10-20% of the national blood supply. Transfusion of allogeneic blood is associated with increased morbidity and mortality. Excessive protamine in the absence of circulating heparin after weaning off CPB can cause anticoagulation and precipitate bleeding. Hence, adequate dose calculation of protamine is crucial yet under evaluated.

STUDY DESIGN

Retrospective cohort study.

METHODS

We conducted a retrospective bi-institutional analysis of cardiac surgical patients who underwent cardiopulmonary bypass (CPB)-assisted cardiac surgery to assess the impact of protamine dosing in transfusion practice. Total 762 patients were identified from two institutions using electronic medical records and the Society of Thoracic Surgery (STS) database who underwent cardiac surgery using CPB. Patients were similar in demographics and other baseline characteristics. We divided patients into two groups based on mg of protamine administered to neutralize each 100 U of unfractionated heparin (UFH)-low-ratio group (Protamine: UFH ≤ 0.8) and high-ratio group (Protamine: UFH > 0.8).

RESULTS

We observed a higher rate of blood transfusion required in high-ratio group (ratio >0.8) compared with low-ratio group (ratio ≤0.8) (p < .001). The increased requirement was consistently demonstrated for intraoperative transfusions of red blood cells, plasma, platelets, and cryoprecipitate.

CONCLUSION

High protamine to heparin ratio may cause increased bleeding and transfusion in cardiac surgical patients. Protamine to heparin ratio of 0.8 or lower is sufficient to neutralize circulating heparin after weaning off cardiopulmonary bypass.

Perioperative hemostatic management of patients with type A aortic dissection

Coagulopathy is common in patients undergoing thoracic aortic repair for Stanford type A aortic dissection. Non-critical administration of blood products may adversely affect the outcome. It is therefore important to be familiar with the pathologic conditions that lead to coagulopathy in complex cardiac surgery. Adequate care of these patients includes the collection of the medical history regarding the use of antithrombotic and anticoagulant drugs, and a sophisticated diagnosis of the coagulopathy with viscoelastic testing and subsequently adapted coagulation therapy with labile and stable blood products. In addition to the above-mentioned measures, intraoperative blood conservation measures as well as good interdisciplinary coordination and communication contribute to a successful hemostatic management strategy.

Minimum protamine dose required to neutralize heparin in cardiac surgery: a single-centre, prospective, observational cohort study

PURPOSE

Excess protamine contributes to coagulopathy following cardiopulmonary bypass (CPB) and may increase blood loss and transfusion requirements. The primary aim of this study was to find the least amount of protamine necessary to neutralize residual heparin following CPB using the gold standard assays of anti-IIa and anti-Xa activity. Secondary objectives were to evaluate whether the post-CPB activated clotting time could be used as a surrogate marker for quantifying heparin neutralization.

METHODS

Twenty-eight consecutive patients undergoing elective cardiac surgery were enrolled. Protamine administration was standardized through an infusion pump at 25 mg·min-1. Blood samples were withdrawn prior to and following administration of 150, 200, 250, and 300 mg protamine and analyzed for activated clotting time and anti-IIa and -Xa activity.

RESULTS

Following a mean (standard deviation) cumulative heparin dose of 67,700 (19,400) units and a CPB duration of 113 (71) min, protamine requirements varied widely. Eight out of 25 (32%) patients showed complete neutralization of anti-IIa and -Xa activity at the first sampling point (150 mg protamine; protamine:heparin ratio, 0.3 [0.1]). A protamine:heparin ratio of 0.5 (0.2) was sufficient for heparin neutralization in > 90% of patients. After CPB, a low to mid-range activated clotting time correlated well with anti-IIa and -Xa activity.

CONCLUSIONS

The protamine:heparin ratio required to neutralize residual unfractionated heparin (UFH) following CPB is variable. A protamine:heparin ratio of 0.3 was sufficient to neutralize UFH in some patients, while a ratio of 0.5 is sufficient to neutralize both residual anti-IIa and -Xa activity in most patients. Larger studies are necessary to confirm these findings and evaluate their clinical implications.

STUDY REGISTRATION

ClinicalTrials.gov (NCT03787641); registered 26 December 2018.

The multivariable prognostic models for severe complications after heart valve surgery

Background

To provide multivariable prognostic models for severe complications prediction after heart valve surgery, including low cardiac output syndrome (LCOS), acute kidney injury requiring hemodialysis (AKI-rH) and multiple organ dysfunction syndrome (MODS).

Methods

We developed multivariate logistic regression models to predict severe complications after heart valve surgery using 930 patients collected retrospectively from the first affiliated hospital of Sun Yat-Sen University from January 2014 to December 2015. The validation was conducted using a retrospective dataset of 713 patients from the same hospital from January 2016 to March 2017. We considered two kinds of prognostic models: the PRF models which were built by using the preoperative risk factors only, and the PIRF models which were built by using both of the preoperative and intraoperative risk factors. The least absolute shrinkage selector operator was used for developing the models. We assessed and compared the discriminative abilities for both of the PRF and PIRF models via the receiver operating characteristic (ROC) curve.

Results

Compared with the PRF models, the PIRF modes selected additional intraoperative factors, such as auxiliary cardiopulmonary bypass time and combined tricuspid valve replacement. Area under the ROC curves (AUCs) of PRF models for predicting LCOS, AKI-rH and MODS are 0.565 (0.466, 0.664), 0.688 (0.62, 0.757) and 0.657 (0.563, 0.751), respectively. As a comparison, the AUCs of the PIRF models for predicting LOCS, AKI-rH and MODS are 0.821 (0.747, 0.896), 0.78 (0.717, 0.843) and 0.774 (0.7, 0.847), respectively.

Conclusions

Adding the intraoperative factors can increase the predictive power of the prognostic models for severe complications prediction after heart valve surgery.

Point-of-Care Measurement of Kaolin Activated Clotting Time during Cardiopulmonary Bypass: A Single Sample Comparison between ACT Plus and i-STAT

Heparin anticoagulation monitoring by point-of-care activated clotting time (ACT) is essential for cardiopulmonary bypass (CPB) initiation, maintenance, and anticoagulant reversal. Concerns exist regarding the comparability of kaolin activated ACT devices. The current study, therefore, evaluated the agreement of ACT assays using parallel measurements performed on two commonly used devices. Measurements were conducted in a split-sample fashion on both the ACT Plus (Medtronic, Minneapolis, MN) and i-STAT (Abbott Point of Care, Princeton, NJ) analyzers. Blood samples from 100 adult patients undergoing elective cardiac surgery with CPB were assayed at specified time points: before heparinization, following systemic heparinization, after CPB initiation, every 30 minutes during CPB, and following protamine administration. A cutoff value of 400 seconds (s) was used as part of the local protocol. Measurements were compared using t tests or Wilcoxon signed-rank tests, linear regression, and Bland-Altman analyses. Parallel ACT measurements demonstrated a good linear correlation (r = .831, p < .001). The overall median difference between both measurements was significantly different from zero, amounting to 87 (14-189) (p < .001), with limits of agreement of -124 and 333s. The i-STAT-derived ACT values were systematically lower than the ACT Plus values, which was more pronounced during CPB. Fourteen patients received additional heparin during CPB at a median ACT Plus value of 414s, with a concomitant median i-STAT value of 316s. Assuming 308s as the theoretical i-STAT cutoff value based on the linear regression equation and an ACT Plus threshold of 400s, 29 patients would have received additional heparin. Based on these results, kaolin point-of-care ACT devices cannot be used interchangeably. Device-specific predefined target values are warranted to avert heparin overdosing during CPB.

Hematic Antegrade Repriming: A Reproducible Method to Decrease the Cardiopulmonary Bypass Insult

The current practice of cardiopulmonary bypass (CPB) requires a preoperative priming of the circuit that is frequently performed with crystalloid solutions. Crystalloid priming avoids massive embolism but is unable to eliminate all microbubbles contained in the circuit. In addition, it causes a sudden hemodilution which is correlated with transfusion requirements and an increased risk of cognitive impairment. Several repriming techniques using autologous blood, collectively termed retrograde autologous priming (RAP), have been demonstrated to reduce the hemodilutional impact of CPB. However, the current heterogeneity in the practice of RAP limits its evidence and benefits. Here, we describe hematic antegrade repriming as an easy and reliable method that could be applied with any circuit in the market to decrease transfusion requirements, emboli, and inflammatory responses, reducing costs and the impact of CPB on postoperative recovery.

Blood management in a patient with anti-Oka antibody who underwent cardiac surgery using cardiopulmonary bypass: a case report

Background

Cardiac surgery under cardiopulmonary bypass (CPB) is often associated with massive bleeding and blood transfusion. For patients requiring specific blood products, meticulous blood management is critical to reduce blood loss, as well as the need for transfusion. Here, we have described the intraoperative blood management in a patient with anti-Ok^a antibody, who underwent cardiac surgery with CPB.

Case presentation

A 79-year-old woman was scheduled for open aortic valve replacement and tricuspid valve annuloplasty under hypothermic CPB. Her blood type was A RhD(+) Ok(a−), and anti-Ok^a, an extremely rare antibody against erythrocyte antigen, was detected. Eight units of Ok(a−) frozen thawed red cells (FTRCs), and six units of red blood cells donated by three Ok(a−) individuals were collected just prior to surgery. Although she was anemic, acute normovolemic hemodilution was conducted after anesthesia induction to preserve the autologous whole blood. Four units of FTRCs were loaded in the CPB priming solution, and modified ultrafiltration was adopted during CPB to prevent further hemodilution. After CPB termination, two units of FTRCs, four units of fresh frozen plasma, and ten units of platelet concentrate were intensively transfused, facilitating surgical hemostasis and stable hemodynamics. The autologous whole blood was returned to the patient in the intensive care unit. Since the hemoglobin and hematocrit levels were maintained postoperatively, no additional transfusion was required throughout her hospital stay.

Conclusions

Multidisciplinary intraoperative blood management in a patient with anti-Ok^a antibody facilitated successful cardiac surgery using CPB, along with effective use of limited blood products.

Incident Reporting in Perfusion: Current Perceptions on PIRS-2

The Australia and New Zealand College of Perfusionists' (ANZCP) Perfusion Incident Reporting System was established in 1998 and has evolved to an open access on-line incident perfusion reporting system (PIRS-2). Changes were made to PIRS-2 to promote learning from what went well in unexpected situations. A 9-question survey was e-mailed to the PIRS-2 contact group to elicit feedback on attitudes to voluntarily reporting perfusion-related incidents and near-miss events to PIRS-2. In August 2019, a 9-question survey using SurveyMonkey^® (San Mateo Ca) was e-mailed to 198 perfusionists currently on the ANZCP PIRS-2 e-mail contacts group. Responses for all responding practicing perfusionists were totaled and expressed as a percentage of the total number of respondents. The respondents were then grouped by region and responses were expressed as a percentage of respondents from each region as well as for grouped responses from Australia/New Zealand (ANZ) and non-ANZ respondents. The response rate was 49.5% with 95 practicing perfusionists completing the survey. In the 12 months before the survey, 22% of respondents had submitted reports to PIRS-2, whereas 79% had read e-mailed reports. Unit culture was the most frequently cited barrier to reporting from all respondents (19%; 0% to 40% by region). Twenty-five percentage of Australian respondents cited unit culture as a barrier to reporting vs. 0% of New Zealand respondents. A combination of concern of discovery and identification of region ranked second as a barrier for 17% of all respondents. The open access ANZCP PIRS-2 voluntary incident reporting in perfusion was widely viewed as relevant and beneficial to both individual practice and to team performance. A high likelihood to considering reporting incidents is tempered by the well-established barriers of ease of the reporting system, the fix and forget phenomenon, concerns of discovery, and a defensive unit culture.

Associations between oxygen delivery and cardiac index with hyperlactatemia during cardiopulmonary bypass

Objective

Metabolism management plays an essential role during cardiopulmonary bypass (CPB). There are different metabolic management devices integrated to heart-lung machines; the most commonly used and accepted metabolic target is indexed oxygen delivery (DO_2i) (280 mL/min/m²) and cardiac index (CI) (2.4 L/min/m²), which can be managed independently or according to other metabolic parameters. Our objective was to compare lactate production during CPB procedures using different metabolic management: DO_2i in relation to indexed oxygen extraction ratio (O₂ER_i) and CI in relation to mixed venous oxygen saturation (SvO₂).

Methods

Data on 500 CPB procedures were retrospectively collected in a specialized regional tertiary cardiac surgery center in Italy between September and 2012 and November 2019. In group A, the DO_2i with 280 mL/min/m² target in relation to O₂ER_i 25% was used; in group B, CI with 2.4 L/min/m² target in relation to SvO₂ 75% was used. During CPB, serial arterial blood gas analyses with blood lactate and glucose determinations were obtained. Hyperlactatemia (HL) was defined as a peak arterial blood lactate concentration >3 mmol/L. The postoperative outcome of patients with or without HL was compared.

Results

Eight pre- and intraoperative factors were found to be significantly associated with peak blood lactate level during CPB at univariate analysis. HL (>3 mmol/L) was detected in 15 (6%) patients of group A and in 42 (16.8%) patients of group B (P = .022); hyperglycemia (>160 mg/dL) was found in 23 (9.2%) patients of group A and in 53 (21.2%) patients of group B (P = .038). Patients with HL during CPB had a significant increase in serum creatinine value, higher rate of prolonged mechanical ventilation time and intensive care unit stay. A cutoff of DO_2i <270 mL/min/m² in relation to O₂ER_i >35% in group A and a cutoff of CI <2.4 L/min/m² in relation to SvO₂ <65% in group B were found to have a positive predictive value of 80% and 75% for HL, respectively. A cutoff of DO_2i >290 mL/min/m² in relation to O₂ER_i 24% in group A and a cutoff of CI >2.4 L/min/m² in relation to SvO₂ >75% in group B were found to have a negative predictive value of 78% and 62% for HL, respectively.

Conclusions

This retrospective observational analysis showed that management of DO_2i in relation to O₂ER_i was 16% more specific in terms of negative predictive value for HL during CPB compared with the use of CI in relation to SvO₂. Group A reported a significant reduction in the incidence of intraoperative lactate peak, correlated with postoperative reduction of serum creatinine value, mechanical ventilation time, and intensive care unit stay, compared with group B.