Lack of efficacy of aprotinin over tranexamic acid in type A aortic dissection repair.

BACKGROUND: The role of aprotinin in modern cardiac surgery is not well defined. While licensed for use in isolated coronary artery bypass grafting it is more commonly used for cases deemed to be at an increased risk of bleeding. The relative efficacy, and safety profile, of aprotinin as compared to other antifibrinolytics in these high-risk cases is uncertain. STUDY DESIGN AND METHODS: A retrospective observational study with propensity matching to determine whether aprotinin versus tranexamic acid reduced bleeding or transfusion requirements in patients presenting for surgical repair of type A aortic dissection (TAD). RESULTS: Between 2016 and 2022, 250 patients presented for repair of TAD. A total of 231 patients were included in the final analysis. Bleeding and transfusion were similar between both groups in both propensity matched and unmatched cohorts. Compared to tranexamic acid, aprotinin use did not reduce transfusion requirements for any product. Rates of bleeding in the first 12 h, return to theater and return to intensive care unit with an open packed chest were similar between groups. There was no difference in rates of renal failure, stroke, or death. CONCLUSION: Aprotinin did not reduce the risk of bleeding or transfusion requirements in patients undergoing repair of type A aortic dissections. Efficacy of aprotinin may vary depending on the type of surgery performed and the underlying pathology.

Assessing the impact of different heparin dosing regimens for cardiopulmonary bypass on anticoagulation: the HepDOSE pilot study.

PURPOSE: It has been suggested that a larger heparin dose during cardiopulmonary bypass (CPB) is associated with reduced perioperative coagulopathy and thromboembolic complications. We investigated the effect of different heparin doses during routine elective cardiac surgery. Our primary outcomes include blood loss and transfusion and secondary outcomes investigate the effects on coagulation biomarkers. METHODS: In this prospective pilot trial, we allocated 60 patients undergoing cardiac surgery on CPB in a single tertiary cardiac centre into three groups to receive an initial dose of 300, 400, or 500 units (U) per kilogram of intravenous heparin prior to the commencement of CPB. Blood was sampled after induction of anesthesia, at 30 and 60 min of CPB, and three minutes after heparin reversal with protamine. Samples were analyzed for fibrinopeptide A (FPA), fibrinopeptide B (FPB), D-dimer, and thrombin-antithrombin (TAT) complexes. Postoperative blood loss and transfusion was measured for the first 24-hr period after surgery. RESULTS: The total mean (95% CI) administered heparin dose in the 300 U·kg-1, 400 U·kg-1, and 500 U·kg-1 groups were 39,975 (36,528 to 43,421) U, 43,195 (36,940 to 49,449) U and 47,900 (44,807 to 50,992) U, respectively. There were no statistically significant differences in FPA, FPB or D-dimer levels at the measured time intervals. There was a trend towards lower TAT levels while on CPB with greater heparin dosing, which was statistically significant after the administration of protamine. The clinical significance appears to be negligible, as there is no difference in overall blood loss and amount of packed red blood cell transfusion or other blood product transfusion. CONCLUSION: This pilot study indicates that, while larger heparin dosing for routine cardiac surgery results in subtle biochemical changes in coagulation, there is no demonstrable benefit in postoperative blood loss or transfusion requirements.

RéSUMé: OBJECTIF: Il a été suggéré qu'une dose plus élevée d'héparine pendant la circulation extracorporelle (CEC) serait associée à une réduction de la coagulopathie périopératoire et des complications thromboemboliques. Nous avons étudié l'effet de différentes doses d'héparine au cours d'une chirurgie cardiaque non urgente de routine. Nos critères d'évaluation principaux comprenaient la perte de sang et la transfusion, et les critères d'évaluation secondaires exploraient les effets sur les biomarqueurs de la coagulation. MéTHODE: Dans cette étude pilote prospective, nous avons réparti 60 patient·es bénéficiant d'une chirurgie cardiaque sous CEC dans un seul centre cardiaque tertiaire en trois groupes à recevoir une dose initiale de 300, 400 ou 500 unités (U) par kilogramme d'héparine intraveineuse avant le début de la CEC. Le sang a été prélevé après l'induction de l'anesthésie, à 30 et 60 minutes de CEC, et trois minutes après la neutralisation de l'héparine avec la protamine. Les échantillons ont été analysés pour les complexes fibrinopeptide A (FPA), fibrinopeptide B (FPB), D-dimère et thrombine-antithrombine (TAT). La perte de sang postopératoire et la transfusion ont été mesurées pendant la première période de 24 heures après la chirurgie. RéSULTATS: La dose moyenne totale (IC 95 %) d'héparine administrée dans les 300 U·kg−1, 400 U·kg−1, et 500 U·kg−1 était de 39 975 (36 528 à 43 421) U, 43 195 (36 940 à 49 449) U et 47 900 (44 807 à 50 992) U, respectivement. Il n'y avait aucune différence statistiquement significative dans les taux de FPA, FPB ou D-dimères aux intervalles de temps mesurés. Une tendance à des niveaux de TAT plus bas pendant la CEC a été observée avec une dose d'héparine plus élevée, ce qui était statistiquement significatif après l'administration de protamine. La signification clinique semble négligeable, car il n'y a pas de différence dans la perte de sang globale et la quantité de transfusion de concentrés globulaires ou d'autres produits sanguins. CONCLUSION: Cette étude pilote indique que, bien qu'une dose plus importante d'héparine pour la chirurgie cardiaque de routine entraîne des changements biochimiques subtils dans la coagulation, il n'y a aucun avantage démontrable en matière de saignement postopératoire ou de besoins transfusionnels.

Anaesthesia for Minimally Invasive Cardiac Surgery.

Minimally invasive cardiac surgery (MICS) has been used since the 1990s and encompasses a wide range of techniques that lack full sternotomy, including valve and coronary artery graft surgery as well as transcatheter procedures. Due to the potential benefits offered to patients by MICS, these procedures are becoming more common. Unique anaesthetic knowledge and skills are required to overcome the specific challenges presented by MICS, including mastery of transoesophageal echocardiography (TOE) and the provision of thoracic regional analgesia. This review evaluates the relevance of MICS to the anaesthetist and discusses pre-operative assessment, the relevant adjustments to intra-operative conduct that are necessary for these techniques, as well as post-operative care and what is known about outcomes.

Comparison of Blood and Blood Product Transfusion in COVID-19 and Non-COVID-19 Patients Requiring Extracorporeal Membrane Oxygenation for Severe Respiratory Failure.

COVID-19 has resulted in an exponential increase in patients with severe respiratory failure requiring extracorporeal membrane oxygenation (ECMO). Patients on ECMO regularly require high volumes of blood and blood products but, so far, there has been no comparison of transfusion requirements between COVID-19 and non-COVID-19. Using electronic patient records at two major UK ECMO centres, Royal Papworth Hospital and University Hospital South Manchester, we reviewed the transfusion requirements of patients requiring ECMO between January 2019 to December 2021. A total of 271 patients, including 168 COVID-19 patients were available for analysis. Since COVID-19 patients spent almost twice as long on ECMO (27.1 vs. 14.16 days, p ≤ 0.0001) we indexed transfusion in both groups to days on ECMO to allow comparison. COVID-19 patients required less red blood cells (RBC) per day (0.408 vs. 0.996, p = 0.0005) but more cryoprecipitate transfusions (0.117 vs. 0.106, p = 0.022) compared to non-COVID-19 patients. COVID-19 patients had more than double the mortality of non-COVID-19 patients (47% vs. 20.4%, p = 0.0001) and those who died during the study period had higher platelet transfusion requirements (p = 0.007) than their non-COVID-19 counterparts. Transfusion requirements and coagulopathy differ between COVID-19 and non-COVID-19 patients. The distinctly different transfusion patterns between the two groups remain difficult to interpret, but further investigations may help explain the haematological aspects of severe COVID-19 infection.

Whole-blood Point-of-Care Activated Partial Thromboplastin Time Ratio (APR) is not Accurate Enough to Monitor Heparin Therapy in Patients with Severe Respiratory Failure Secondary to SARS-Cov-2 Infection Supported with Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO).

Support with VV-ECMO requires anticoagulation with unfractionated heparin to prevent thrombotic complications. This must be monitored due to bleeding risk. A point-of-care (POC) method of testing aPTT and APR was evaluated for agreement with laboratory methods. In a prospective observational study, patients supported on VV-ECMO as a result of severe respiratory failure secondary to Covid-19 infection were given heparin as part of standard therapy. The aPTT was measured (i) at the bedside using the Hemochron Signature Elite device and (ii) at the hospital laboratory. Duplicate results were compared. Agreement between the POC and laboratory tests was poor, as assessed using the Bland-Altman method. The maximum difference between POC and laboratory methods was 133% and the minimum was 0%. Overall bias was 7.3% and limits of agreement were between -43.8% and 58.5%. Correlation increased when results were normalised to platelet count and creatinine. This POC test is insufficiently accurate for use as the primary method of heparin monitoring in patients requiring VV-ECMO for Covid-19. Platelets and renal function may influence the result of this whole blood POC test.

Pulsatile Perfusion during Cardiopulmonary Bypass: A Literature Review.

The use of cardiopulmonary bypass (CPB) in cardiac surgery has often been associated with postoperative organ dysfunction. Roller and centrifugal pumps produce non-pulsatile flow (NPF) by default, and this still is the most widely used mode of perfusion. The development of pulsatile pumps has allowed comparisons to be made with NPF. Pulsatile flow (PF) mimics the arterial pulse generated by the heart and is thought to be more physiological by some. This review aims to examine the proposed mechanisms behind the potential physiological benefits of PF during CPB and to summarize the current clinical evidence. MEDLINE and EMBASE were used to identify articles published over a 25 year period from 1995 to 2020. A literature review was conducted to determine the effects of PF on organ functions. A total of 44 articles were considered. Most of the articles published on PF were randomized controlled trials (RCTs). However, there was a wide variation in study methodology, method of pulse generation and how pulsatility was measured. Most of the evidence in favor of PF showed a marginal improvement on renal and pulmonary outcomes. In these studies, pulsatility was generated by an intra-aortic balloon pump. In conclusion, there is a lack of good quality RCTs that can inform on the short- and long-term clinical outcomes of PF. Further research is required in order to draw a conclusion with regards to the benefits of PF on organ function.

Lactate during ex-situ heart perfusion does not predict the requirement for mechanical circulatory support following donation after circulatory death (DCD) heart transplants.

BACKGROUND: Ex-situ heart perfusion (ESHP) is commonly used for the reanimation and preservation of hearts following donation after circulatory determined death (DCD). The only commercially available existing ESHP device promotes perfusate lactate levels for assessment of heart viability. The reliability of this marker is yet to be confirmed for DCD heart transplantation. METHODS: This is a single center, retrospective study examining DCD heart transplants from March 1, 2015 to June 30, 2020. Recipients were divided into 2 groups dependent upon their requirement for or absence of mechanical circulatory support post-transplant. Lactate profiles obtained during ESHP were analyzed. Hearts were procured using the direct procurement and perfusion (DPP) method. RESULTS: Fifty-one DCD heart transplant recipients were studied, of which 20 (39%) were dependent on mechanical circulatory support (MCS) following transplantation, (2% Ventricular Assist Device (VAD), 16% Extra Corporeal Membrane Oxygenation (ECMO) and 21% Intra-aortic balloon pumps (IABP). There was no difference in arterial lactate profiles on ESHP at any time point for those dependent upon MCS support (MCS) and those that were not (no MCS) post-transplant. After 3 hours of ESHP, the arterial lactate was >5mmol/L in 80% upon MCS vs 62% no MCS, p = .30. There was also no difference in ESHP rising arterial lactate concentrations, (15% MCS vs 13% non MCS, p = 1.00). CONCLUSION: For DCD hearts transplants retrieved using the DPP technique, lactate profiles do not seem to be a reliable predictor of mechanical circulatory support requirement post-transplant.

Cardiac Transplantation following Cobalt Cardiomyopathy from Bilateral Metal-on-Metal Hip Replacements.

A fifty-two-year-old man underwent heart transplantation at our centre after four years of developing progressive heart failure symptoms due to cobalt toxicity-related cardiomyopathy. Between the ages of forty and forty-two, he underwent bilateral metal-on-metal hip arthroplasties for early onset osteoarthritis. Six years later, he developed increasing fatigue and pericardial effusions. Following a prolonged period of deterioration without a clear cause, the diagnosis of cobalt toxicity-related cardiomyopathy due to cobalt-chromium alloy hip prostheses was eventually made. He underwent bilateral revision hip arthroplasties and was listed for heart transplantation. Metal-on-metal joint replacement is a rare cause of iatrogenic cobalt toxicity. Anaesthetists may encounter patients with unexplained symptoms of heart failure, having a high index of suspicion presenting an opportunity for early diagnosis and intervention before end-stage disease develops.

Association of Passive Lung Insufflation Oxygen Fraction in Adult Patients on Cardiopulmonary Bypass with Postoperative Pulmonary Outcomes: A Retrospective Cohort Study.

OBJECTIVES: To determine whether FIO2 of passive lung insufflation during cardiopulmonary bypass correlates with postoperative pulmonary function. DESIGN: A retrospective, observational study SETTING: A single-center, university-affiliated, specialist cardiothoracic center in the United Kingdom. PARTICIPANTS: Adult patients presenting for nonemergency, nontransplant cardiac surgery requiring cardiopulmonary bypass without the need for deep hypothermic circulatory arrest between January 1, 2018, and December 31, 2018. INTERVENTIONS: Passive insufflation of the lungs during cardiopulmonary bypass with fresh gas flow of varying FIO2. Patients were sorted retrospectively into low FIO2 (0.21-0.44), intermediate FIO2 (0.45-0.69), and high FIO2 (0.7-1.0) groups. The primary outcome was the difference between the PaO2:FIO2 on the first postinduction blood gas and on the first blood gas recorded postoperatively in the intensive care unit (ICU) (delta PaO2:FIO2). Secondary outcomes were ICU and hospital lengths of stay, requirement for respiratory support, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS: Nine hundred patients were included in the authors' analysis (low FIO2 n = 307, intermediate FIO2 n = 459, high FIO2 n = 134). There was no significant difference in delta PaO2:FIO2 among the groups (low FIO2 = 52.5 [-38.8 to 152.4], intermediate FIO2 = 71.8 [-39.4 to 165.1], high FIO2 = 60.2 [-19.2 to 184.0], p = 0.25). There were no significant differences among groups for any secondary outcomes. CONCLUSION: Fresh gas flow with a low FIO2 delivered to the lungs without positive airway pressure during cardiopulmonary bypass was not associated with improved postoperative pulmonary function when compared to higher FIO2 levels.

Optimal protamine dosing after cardiopulmonary bypass: The PRODOSE adaptive randomised controlled trial.

BACKGROUND: The dose of protamine required following cardiopulmonary bypass (CPB) is often determined by the dose of heparin required pre-CPB, expressed as a fixed ratio. Dosing based on mathematical models of heparin clearance is postulated to improve protamine dosing precision and coagulation. We hypothesised that protamine dosing based on a 2-compartment model would improve thromboelastography (TEG) parameters and reduce the dose of protamine administered, relative to a fixed ratio. METHODS AND FINDINGS: We undertook a 2-stage, adaptive randomised controlled trial, allocating 228 participants to receive protamine dosed according to a mathematical model of heparin clearance or a fixed ratio of 1 mg of protamine for every 100 IU of heparin required to establish anticoagulation pre-CPB. A planned, blinded interim analysis was undertaken after the recruitment of 50% of the study cohort. Following this, the randomisation ratio was adapted from 1:1 to 1:1.33 to increase recruitment to the superior arm while maintaining study power. At the conclusion of trial recruitment, we had randomised 121 patients to the intervention arm and 107 patients to the control arm. The primary endpoint was kaolin TEG r-time measured 3 minutes after protamine administration at the end of CPB. Secondary endpoints included ratio of kaolin TEG r-time pre-CPB to the same metric following protamine administration, requirement for allogeneic red cell transfusion, intercostal catheter drainage at 4 hours postoperatively, and the requirement for reoperation due to bleeding. The trial was listed on a clinical trial registry (ClinicalTrials.gov Identifier: NCT03532594). Participants were recruited between April 2018 and August 2019. Those in the intervention/model group had a shorter mean kaolin r-time (6.58 [SD 2.50] vs. 8.08 [SD 3.98] minutes; p = 0.0016) post-CPB. The post-protamine thromboelastogram of the model group was closer to pre-CPB parameters (median pre-CPB to post-protamine kaolin r-time ratio 0.96 [IQR 0.78-1.14] vs. 0.75 [IQR 0.57-0.99]; p < 0.001). We found no evidence of a difference in median mediastinal/pleural drainage at 4 hours postoperatively (140 [IQR 75-245] vs. 135 [IQR 94-222] mL; p = 0.85) or requirement (as a binary outcome) for packed red blood cell transfusion at 24 hours postoperatively (19 [15.8%] vs. 14 [13.1%] p = 0.69). Those in the model group had a lower median protamine dose (180 [IQR 160-210] vs. 280 [IQR 250-300] mg; p < 0.001). Important limitations of this study include an unblinded design and lack of generalisability to certain populations deliberately excluded from the study (specifically children, patients with a total body weight >120 kg, and patients requiring therapeutic hypothermia to <28°C). CONCLUSIONS: Using a mathematical model to guide protamine dosing in patients following CPB improved TEG r-time and reduced the dose administered relative to a fixed ratio. No differences were detected in postoperative mediastinal/pleural drainage or red blood cell transfusion requirement in our cohort of low-risk patients. TRIAL REGISTRATION: ClinicalTrials.gov Unique identifier NCT03532594.

Anesthesia for minimally invasive cardiac surgery.

Due to its potential benefits and increased patient satisfaction minimal invasive cardiac surgery (MICS) is rapidly gaining in popularity. These procedures are not without challenges and require careful planning, pre-operative patient assessment and excellent intraoperative communication. Assessment of patient suitability for MICS by a multi-disciplinary team during pre-operative workup is desirable. MICS requires additional skills that many might not consider to be part of the standard cardiac anesthetic toolkit. Anesthetists involved in MICS need not only be highly skilled in performing transesophageal echocardiography (TEE) but need to be proficient in multimodal analgesia, including locoregional or neuroaxial techniques. MICS procedures tend to cause more postoperative pain than standard median sternotomies do, and patients need analgesic management more in keeping with thoracic operations. Ultrasound guided peripheral regional anesthesia techniques like serratus anterior block can offer an advantage over neuroaxial techniques in patients on anti-platelet therapy or anticoagulation with low molecular weight or unfractionated heparin The article reviews the salient points pertaining to pre-operative assessment and suitability, intraoperative process and postoperative management of minimally invasive cardiac procedures in the operating theatre as well as the catheterization lab. Special emphasis is given to anesthetic management and analgesia techniques.

Thrombotic risk in central venoarterial extracorporeal membrane oxygenation post cardiac surgery.

INTRODUCTION: Post-cardiotomy cardiogenic shock is an accepted indication for venoarterial extracorporeal membrane oxygenation. The true incidence and risk factors for the development of thrombosis in this setting remain unclear. METHODS: Patients supported with central venoarterial extracorporeal membrane oxygenation due to ventricular dysfunction precluding weaning from cardiopulmonary bypass were retrospectively identified. Electronic records from a single institution spanning a 4-year period from January 2015 to December 2018 were interrogated to assess the incidence of thrombosis. The relationship to exposures including intracardiac stasis and procoagulant usage was explored. RESULTS: Twenty-four patients met the inclusion criteria and six suffered major intracardiac thrombosis. All cases of thrombosis occurred early, and none survived to hospital discharge. The lack of left ventricular ejection conferred a 46% risk of developing thrombosis compared to 0% if ejection was maintained (p = 0.0093). Aprotinin use was also associated with thrombus formation (p = 0.035). There were no significant differences between numbers of patients receiving other procoagulants when grouped by thrombosis versus no thrombosis. CONCLUSION: Stasis is the predominant risk factor for intracardiac thrombosis. This occurs rapidly and the outcome is poor. As a result, we suggest early left ventricular decompression. Conventional management of post-bypass coagulopathy seems safe if the aortic valve is opening.

Monitoring indirect impact of COVID-19 pandemic on services for cardiovascular diseases in the UK.

OBJECTIVE: To monitor hospital activity for presentation, diagnosis and treatment of cardiovascular diseases during the COVID-19) pandemic to inform on indirect effects. METHODS: Retrospective serial cross-sectional study in nine UK hospitals using hospital activity data from 28 October 2019 (pre-COVID-19) to 10 May 2020 (pre-easing of lockdown) and for the same weeks during 2018-2019. We analysed aggregate data for selected cardiovascular diseases before and during the epidemic. We produced an online visualisation tool to enable near real-time monitoring of trends. RESULTS: Across nine hospitals, total admissions and emergency department (ED) attendances decreased after lockdown (23 March 2020) by 57.9% (57.1%-58.6%) and 52.9% (52.2%-53.5%), respectively, compared with the previous year. Activity for cardiac, cerebrovascular and other vascular conditions started to decline 1-2 weeks before lockdown and fell by 31%-88% after lockdown, with the greatest reductions observed for coronary artery bypass grafts, carotid endarterectomy, aortic aneurysm repair and peripheral arterial disease procedures. Compared with before the first UK COVID-19 (31 January 2020), activity declined across diseases and specialties between the first case and lockdown (total ED attendances relative reduction (RR) 0.94, 0.93-0.95; total hospital admissions RR 0.96, 0.95-0.97) and after lockdown (attendances RR 0.63, 0.62-0.64; admissions RR 0.59, 0.57-0.60). There was limited recovery towards usual levels of some activities from mid-April 2020. CONCLUSIONS: Substantial reductions in total and cardiovascular activities are likely to contribute to a major burden of indirect effects of the pandemic, suggesting they should be monitored and mitigated urgently.

Evaluation of Point-of-Care ACT Coagulometers and Anti-Xa Activity During Cardiopulmonary Bypass.

OBJECTIVE: The activated clotting time (ACT) is used worldwide to confirm safe heparin anticoagulation for cardiopulmonary bypass. For the present study, the performances of 2 commonly used ACT devices were compared with each other and with anti-Xa levels throughout the surgical procedure in order to understand whether they can be used interchangeably. DESIGN: Prospective study. SETTING: Tertiary care center. PARTICIPANTS: The study comprised 33 elective adult cardiac surgical patients. INTERVENTIONS: Blood samples were taken at standard times throughout the surgery (after induction, after heparin bolus, 4 samples at 30-minute intervals during cardiopulmonary bypass, after protamine), and ACTs and anti-Xa levels were analyzed. Data were compared using receiver operating characteristics and LOESS regression. MEASUREMENTS AND MAIN RESULTS: The correlation between anti-Xa levels and the Hemochron ACT (Instrumentation Laboratory, Bedford, MA) was acceptable (r = 0.82, 95% confidence interval [CI] 0.757-0.868; p < 0.0001), as was the correlation between anti-Xa levels and the i-STAT (Abbott Point of Care, Abbott Park, IL) (r = 0.81, 95% CI 0.738-0.858; p < 0.0001). The correlation between the 2 ACT methods was poorer (r = 0.77, 95% CI 0.707-0.828; p < 0.0001) than their correlation to anti-Xa levels. When compared with anti-Xa levels, the sensitivity and specificity were mediocre for both devices, although the i-STAT performed better than the Hemochron ACT. The Hemochron ACT read higher values than the i-STAT ACT throughout the course of the surgery. CONCLUSION: The correlation between the Hemochron ACT and i-STAT ACT is moderate, and they have different sensitivity and specificity when compared with anti-Xa levels. This suggests that ACT devices should not be used interchangeably, but cut-off values for safe anticoagulation during cardiopulmonary bypass should be determined for each type of device, particularly when switching supplier.

Pulsatile Versus Nonpulsatile Flow During Cardiopulmonary Bypass: Extent of Hemolysis and Clinical Significance.

Pulsatile flow has been used during cardiopulmonary bypass (CPB) for decades and its use is increasing with advancing extracorporeal technology. Pulsatile flow generates higher circuit pressures and shear forces than nonpulsatile flow at comparable pump flow and patient mean arterial pressure. Very little is known about the effect this has on erythrocytes. We included 62 adult patients (32 in the pulsatile group and 30 in the nonpulsatile group) undergoing elective coronary artery bypass grafting in this prospective observational study. Blood samples were collected at routine sampling times throughout surgery and were analyzed for the presence of free heme and globin using mass spectroscopy. Patient characteristics, CPB, and aortic cross-clamp times, pump flow as well as patient mean arterial pressure were similar in both groups. Maximum circuit pressure in the pulsatile flow group was statistically significantly higher than that in the nonpulsatile flow group (257.12 vs. 190.64 mmHg, p < 0.0001). Both heme and globin levels were higher in the pulsatile flow group. This reached statistical significance with globin at 30 minutes of CPB and with heme after aortic unclamping. We conclude that pulsatile CPB using roller pumps results in a greater extent of hemolysis. The clinical significance, however, is not yet known.

Are We Able to Dose Protamine Accurately Yet? A Review of the Protamine Conundrum.

Without anticoagulation, cardiopulmonary bypass would not have developed over the last nearly 60 years into one of the most influential innovations in medicine; without the ability to reverse anticoagulation, cardiac surgery might not have become the common intervention, which is now practiced globally. Despite the recent breathtaking developments in extracorporeal technology, heparin and protamine remain the pillars of anticoagulation and its reversal until this day. However, there is still much controversy in particular about protamine dosing regimens. A number of recent publications investigating various approaches to dosing protamine have rekindled this debate. This review is seeking to capture the current thinking about protamine dosing after cessation of cardiopulmonary bypass.