Objective To evaluate whether transfusion of cell saver salvaged, stored at the bedside for up to 24 hours, would decrease the number of post-operative allogeneic RBC transfusions and donor exposures, and possibly improve clinical outcomes. Design Prospective, randomized, controlled, clinical trial. Setting Pediatric cardiac intensive care unit. Patients Infants <20kg (n = 106) presenting for cardiac surgery with cardiopulmonary bypass. Interventions Subjects were randomized to a cell saver transfusion group where cell saver blood was available for transfusion up to 24 hours post-collection, or to a control group. Cell saver subjects received cell saver blood for volume replacement and/or RBC transfusions. Control subjects received crystalloid or albumin for volume replacement and RBCs for anemia. Blood product transfusions, donor exposures, and clinical outcomes were compared between groups. Measurements and Main Results Children randomized to the cell saver group had significantly fewer RBC transfusions (cell saver: 0.19 ± 0.44 v. control: 0.75 ± 1.2; p = 0.003) and coagulant product transfusions in the first 48 hours post-op (cell saver: 0.09 ± 0.45 v. control: 0.62 ± 1.4; p = 0.013), and significantly fewer donor exposures (cell saver: 0.60 ± 1.4 v. control: 2.3 ± 4.8; p =0.019). This difference persisted over the first week post-op, but did not reach statistical significance (cell saver: 0.64 ± 1.24 v. control: 1.1 ± 1.4; p =0.07). There were no significant clinical outcome differences. Conclusion Cell saver blood can be safely stored at the bedside for immediate transfusion for 24 hours post-collection. Administration of cell saver blood significantly reduces the number of RBC and coagulant product transfusions and donor exposures in the immediate post-operative period. Reduction of blood product transfusions has the potential to reduce transfusion-associated complications and decrease post-operative morbidity. Larger studies are needed to determine whether this transfusion strategy will improve clinical outcomes.

This Boot Camp session introduced residents early in their training to aortic cannulation, principles and management of cardiopulmonary bypass, and crisis management. Based on a modular approach, technical skills and knowledge of cardiopulmonary bypass can be acquired and assessed by using simulations, but further work with more comprehensive educational modules and practice will accelerate the path to mastery of these critical skills.

BACKGROUND: Currently no ideal alternative exists for heparin for cardiopulmonary bypass (CPB). Dabigatran is a direct thrombin inhibitor for which a reversal agent exists. The primary end point of the study was to explore whether Dabigatran was an effective anticoagulant for 120 minutes of simulated CPB. METHODS: The study was designed in 2 sequential steps. Throughout, human blood from healthy donors was used for each experimental step. Initially, increasing concentrations of Dabigatran were added to aliquots of fresh whole blood, and the anticoagulant effect measured using kaolin/tissue factor–activated thromboelastography (rapidTEG). The dynamics of all thromboelastography (TEG) measurements were studied with repeated measures analysis of variance (ANOVA). Based on these data, aliquots of blood were treated with high-concentration Dabigatran and placed in a Chandler loop as a simple ex vivo bypass model to assess whether Dabigatran had sufficient anticoagulant effects to maintain blood fluidity for 2 hours of continuous contact with the artificial surface of the PVC tubing. Idarucizumab, humanized monoclonal antibody fragment, was used to verify the reversibility of Dabigatran effects. Finally, 3 doses of Dabigatran were tested in a simulated CPB setup using a heart–lung machine and a commercially available bypass circuit with an arteriovenous (A-V) loop. The primary outcome was the successful completion of 120 minutes of simulated CPB with dabigatran anticoagulation, defined as lack of visible thrombus. Thromboelastographic reaction (R) time was measured repeatedly in each bypass simulation, and the circuits were continuously observed for clot. Scanning Electron Microscopy (SEM) was used to visualize fibrin formation in the filters meshes during CPB. RESULTS: In in vitro blood samples, Dabigatran prolonged R time and reduced the dynamics of clot propagation (as measured by speed of clot formation [Angle], maximum rate of thrombus generation [MRTG], and time to maximum rate of thrombus generation [TMRTG]) in a dose-dependent manner. In the Chandler Loop, high doses of Dabigatran prevented clot formation for 120 minutes, but only at doses higher than expected. Idarucizumab decreased R time and reversed anticoagulation in both in vitro and Chandler Loops settings. In the A-V loop bypass simulation, Dabigatran prevented gross thrombus generation for 120 minutes of simulated CPB. CONCLUSIONS: Using sequential experimental approaches, we showed that direct thrombin inhibitor Dabigatran in high doses maintained anticoagulation of blood for simulated CPB. Idarucizumab reduced time for clot formation reversing the anticoagulation action of Dabigatran.

Background Antifibrinolytic medications such as epsilon-aminocaproic acid (EACA) are used in pediatric heart surgery to decrease surgical bleeding and transfusion. Dosing schemes for neonates are often based on adult regimens, or are simply empiric, in part due to the lack of neonatal pharmacokinetic information. We sought to determine the pharmacokinetics of EACA in neonates undergoing cardiac surgery and to devise a dosing regimen for this population. Methods Ten neonates undergoing cardiac surgery with cardiopulmonary bypass were given EACA according to standard practice, and blood was drawn at 10 time points to determine drug concentrations. Time-concentration profiles were analyzed using nonlinear mixed effects models. Parameter estimates (standardized to a 70 kg person) were used to develop a dosing regimen intended to maintain a target concentration shown to inhibit fibrinolysis in neonatal plasma (50 mg/L). Results Pharmacokinetics were described using a two compartment model plus an additional compartment for the cardiopulmonary bypass pump. First order elimination was described with a clearance of 5.07 L/h*(WT/70) 0.75. Simulation showed a dosing regimen with a loading dose of 40 mg/kg, and an infusion of 30 mg/kg/h, with a pump prime concentration of 100 mg/L maintained plasma concentrations above 50 mg/L in 90% of neonates during cardiopulmonary bypass surgery. Conclusions EACA clearance, expressed using allometry, is reduced in neonates compared to older children and adults. Loading dose and infusion dose are approximately half those required in children and adults.

BACKGROUND: Heparin is the standard anticoagulant for cardiopulmonary bypass (CPB); however, there are problems with its use that make the development of suitable alternatives desirable. Currently, no ideal alternative exists. We have previously reported that the direct thrombin inhibitor dabigatran can prevent coagulation in simulated CPB at high concentrations. These high concentrations may cause difficulties in achieving the reversal of dabigatran with idarucizumab, given the markedly different pharmacokinetics of the 2 drugs. Herein, we test the hypothesis that the addition of the anti-Xa drug rivaroxaban would provide suitable anticoagulation at a lower concentration of dabigatran given likely synergy between the 2 classes of drugs. The primary goal of the study was to investigate whether the addition of rivaroxaban reduces the concentration of dabigatran necessary to allow 2 hours of simulated CPB. METHODS:The study was performed in sequential steps. Blood collected from consenting healthy donors was used throughout. First, we added graded concentrations of dabigatran and rivaroxaban alone and in combination and assessed inhibition of anticoagulation using thromboelastometry. Using results from this step, combinations of dabigatran and rivaroxaban were tested in both Chandler loop and simulated CPB circuits. Dabigatran and rivaroxaban were added before recalcification, and the circuits were run for 120 minutes. In both models of CPB, 120 minutes of circulation without visible thrombus was considered successful. In the Chandler loop system, idarucizumab was added to reverse anticoagulant effects. In the CPB circuits, the arterial line filters were examined using scanning electron microscope (SEM) to qualitatively assess for fibrin deposition. RESULTS: In vitro analysis of blood samples treated with dabigatran and rivaroxaban showed that dabigatran and rivaroxaban individually prolonged clotting time (CT) in a dose-dependent manner. However, when combined, the drugs behaved synergistically. In the Chandler loop system, dabigatran 2400 and 4800 ng/mL plus rivaroxaban (150 ng/mL) effectively prevented clot formation and reduced the dynamics of clot propagation for 120 minutes. Idarucizumab (250-1000 µg/mL) effectively reversed anticoagulation. In the CPB circuits, dabigatran (2500 ng/mL) and rivaroxaban (200 ng/mL) were successful in allowing 120 minutes of simulated CPB and prevented fibrin deposition. Biomarkers of coagulation activation did not increase during simulated CPB. Heparin controls performed similarly to dabigatran and rivaroxaban. CONCLUSIONS: The dual administration of oral anticoagulant drugs (dabigatran and Rivaroxaban) with different pharmacologic mechanisms of action produced synergistic inhibition of coagulation in vitro and successfully prevented clotting during simulated CPB. (Anesth Analg 2022;135:52-9) KEY POINTS• Question: Do lower concentrations of dabigatran administered with rivaroxaban prevent clotting during simulated cardiopulmonary bypass (CPB)? • Findings: Dabigatran and rivarox...

The development of standards and guidelines by professional societies offers clinicians guidance toward providing evidence-based care. The ultimate goals of standards and guidelines are to standardize care and improve patient safety and outcomes while also minimizing risk. The American Society of ExtraCorporeal Technology (AmSECT) currently offers perfusionists several clinical resources, primarily the Standards and Guidelines for Perfusion Practice; however, no document exists specific to pediatric perfusion. Historically, the development of a pediatric-specific document has been limited by available scientific evidence due to smaller patient populations, sample sizes, and variable techniques among congenital perfusionists. In the current setting of evolving clinical practices and increasingly complex cardiac operations, a subcommittee of pediatric perfusionists developed the Standards and Guidelines for Pediatric and Congenital Perfusion Practice. The development process included a comprehensive literature review for supporting evidence to justify new recommendations or updates to the existing AmSECT Adult Standards and Guidelines document. Multiple revisions incorporating feedback from the community led to a finalized document accepted by the AmSECT membership and made available electronically in May 2019. The Standards and Guidelines for Pediatric and Congenital Perfusion Practice is an essential tool for pediatric perfusionists and serves as the backbone for institutionally based protocols, promotes improved decision-making, and identifies opportunities for future research and collaboration with other disciplines. The purpose of this manuscript is to summarize the process of development, the content, and recommended utilization of AmSECT’s Standards and Guidelines for Pediatric and Congenital Perfusion Practice.

Background– Heparin anticoagulation has been used successfully for cardiopulmonary bypass (CPB). However, an alternative anticoagulant approach is desirable due to the cases of heparin-induce thrombocytopenia. Dabigatran provides anticoagulation for an in-vitro model of simulated CPB. The current analysis tests the hypothesis that dabigatran provides sufficient anticoagulation for CPB in intact rabbits. Methods – Nonlinear mixed effects models were used to estimate dabigatran parameters for a 2-compartment pharmacokinetic model in 10 New Zealand White rabbits. A dabigatran infusion designed to maintain a plasma concentration of 90 µg/mL was run throughout CPB based on the pharmacokinetics. Animals were subjected to sternotomy, and anticoagulated with intravenous dabigatran (6 animals) or heparin (4 animals). Rabbits were cannulated centrally using the right atrium and ascending aorta and CPB was maintained for 120 minutes. Measurement of activated clotting time, thromboelastometric reaction time (R), and blood gases were performed during CPB. Then, the animals were sacrificed and the brain and one kidney were removed for histology. Sections of the arterial filters were inspected using electron microscopy. Results – The observed dabigatran concentrations during CPB were above the target concentration, ranging from 137 ± 40 μg/mL at 5 min of CPB to 428 ± 150 μg/mL at 60 min, and 295 ± 35 μg/mL at 120 min. All rabbits completed 2 hours of CPB without visible thrombosis. In the two groups reaction time (R) values were elevated, reaching 10262 ± 4198 sec (dabigatran group) and 354 ± 141 sec (heparin group) at 120 min of CPB. Brains and kidneys showed no evidence of thrombosis or ultrastructural damage. Sections of the arterial line filter showed minimal or no fibrin. There was no significant difference in outcomes between dabigatran and heparin treated animals. Conclusions – In this first-use, proof of concept study, we have shown that dabigatran provides acceptable anticoagulation similar to heparin to prevent thrombosis using a rabbit CPB model.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse reaction to heparin. Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are routinely anticoagulated with heparin before the initiation of bypass. Heparin is contraindicated, however, in patients with acute HIT, and alternatives to routine practice are often used. While guidelines have recently been published addressing this topic 10, there remains variance between institutions in how these cases are treated. Our goal was to better delineate practice trends in the diagnosis and management of HIT patients requiring CPB. METHODS: We surveyed members of the Society of Cardiovascular Anesthesiologists (SCA) and the American Society for Extracorporeal Technology (AmSECT) using an online survey tool. RESULTS: We received 304 completed surveys (5.8% response rate), 75% completed by an anesthesiologist, and 24% by a perfusionist. The majority of respondents used clinical history and/or antibody testing (71% and 63%, respectively) to diagnose HIT. Seventy-five percent of respondents reported using an institutional protocol for HIT-CPB cases. Most respondents (89%) reported having at least 1 case in the last 3 years, with a total case experience of at least 785 cases (785 = the minimum number of cases in each case volume category × the number of respondents choosing that category). The strategy recommended in published guidelines, bivalirudin, was the most commonly reported alternative anticoagulation strategy (75%) used by respondents in HIT cases, with most (83%) using the activated clotting time (ACT) to monitor anticoagulation. CONCLUSIONS: Most responding SCA and AmSECT members reported that their institution used a protocol or guideline for HIT/CPB cases, and most guidelines directed the use of bivalirudin as an alternative anticoagulant. Various other methods such as plasmapheresis are also being used with success in this patient population. Further research, including comparison studies of alternative anticoagulant strategies, is required to elucidate the best approach to these difficult cases.