Coagulation Profile of Neonates Undergoing Arterial Switch Surgery With Crystalloid Priming of the Cardiopulmonary Bypass Circuit.

OBJECTIVES: The aim was to evaluate changes in the coagulation profile of cyanotic neonates, to analyze the effects of cardiopulmonary bypass (CPB) with crystalloid priming on their coagulation status, and to determine factors predicting a requirement for hemostasis-derived transfusion. DESIGN: Retrospective cohort. SETTING: Single-center, tertiary academic hospital. PARTICIPANTS: In total, 100 consecutive neonates who underwent arterial switch surgery between December 2014 and June 2020. INTERVENTIONS: Rotational thromboelastometry (ROTEM) and coagulation parameters before surgery and before termination of CPB were evaluated. Transfusion of platelets, fresh frozen plasma, and fibrinogen, defined as hemostasis-derived transfusion (HD transfusion), were determined. Patients with and without HD transfusion were compared to identify predictors. MEASUREMENTS AND MAIN RESULTS: After CPB, fibrinogen was reduced by 24.5% (interquartile range [IQR] 8.9-32.1) to 201 mg/dL (IQR 172-249), resulting in a reduction of FIBTEM A10 by 20% (1.8-33.3) to 8 mm (6-11). The platelet count decreased by a median of 47.2% (25.6-61.3) to 162 × 103/µL (119-215). However, the median fibrinogen concentration and platelet count remained within normal range. Neonates with abnormal ROTEM results were more likely to receive HD transfusions. The HD transfusions were more likely with lower preoperative FIBTEM maximum clot firmness values (p = 0.031), lower hemoglobin concentrations at termination of CPB (p = 0.02), and longer CPB duration (p = 0.017). Perioperative hemostasis without any HD transfusion was achieved in 64 neonates. CONCLUSIONS: Guidance from ROTEM analyses facilitates hemostasis management after neonatal CPB. Circuit miniaturization with transfusion-free CPB is associated with acceptable changes in ROTEM in most patients, and allows sufficient hemostasis without any HD transfusions in most patients.

Acute Kidney Injury After Neonatal Aortic Arch Surgery: Deep Hypothermic Circulatory Arrest Versus Moderate Hypothermia With Distal Aortic Perfusion.

BACKGROUND: Acute kidney injury (AKI) is a common complication observed after neonatal aortic arch repair. We studied its incidence after procedures carried out using deep hypothermic circulatory arrest (DHCA) versus moderate hypothermia with distal aortic perfusion (MHDP), usually through the common femoral artery. In both groups, continuous regional cerebral perfusion (RCP) was used during the time required for aortic arch repair. METHODS: A total of 125 neonates underwent aortic arch repair. Between 2007 and 2012, DHCA with RCP was used in 51 neonates. From 2013 to 2019, MHDP with RCP was performed on 74 newborns. Operative complexity was similar in both periods. Acute kidney injury was defined as a significant elevation of serum creatinine and was classified according to the neonatal modified n-KDIGO (neonatal Kidney Disease: Improving Global Outcomes) stages 1 to 3 (Kidney Disease Improving: Global Outcomes). RESULTS: Acute kidney injury was observed in a total of 68 patients (68/125: 54.4%). In the majority (44/68: 64.7%), n-KDIGO stage 1 occurred. Stage 2 (n = 14) and stage 3 (n = 10) were observed more frequently after DHCA versus MHDP: 29.4% (15/51) versus 12.2% (9/74), P = .02. At cardiopulmonary bypass end, lactate levels were significantly higher (P = .001) after DHCA: 3.4 (2.9-4.3) mmol/L compared to 2.7 (2.3-3.7) mmol/L after MHDP. Early mortality was 12% (15/125) in the entire cohort. It was 17.6% (9/51) after DHCA versus 8.1% (6/74) after MHDP, however not statistically significant (P = .16). CONCLUSION: Mild (stage 1) AKI occurred frequently after neonatal aortic arch repair. The use of MHDP was associated with a significantly lower incidence of moderate (stage 2) and severe (stage 3) AKI forms.

Cardiopulmonary Bypass Strategy to Facilitate Transfusion-Free Congenital Heart Surgery in Neonates and Infants.

Priming the cardiopulmonary bypass (CPB) circuit without the addition of homologous blood constitutes the basis of blood-saving strategies in open-heart surgery. For low-weight patients, in particular neonates and infants, this implies avoidance of excessive hemodilution during extracorporeal circulation. The circuit has to be miniaturized and tubing must be cut as short as possible to reduce the priming volume to prevent unacceptable hemodilution with initiating CPB. During perfusion, measures should be taken to prevent blood loss from the primary circuit to avoid replacement by additional volume. Favorable factors such as mild hypothermia/normothermia and high heparin concentrations during extracorporeal circulation promote earlier hemostasis after coming off bypass.Lower mortality score, first chest entry, higher hemoglobin concentration before going on bypass, and shorter CPB duration support transfusion-free CPB procedure. Reduced postoperative morbidity and mortality were observed when CPB was performed without blood transfusion. In our experience, this can be achieved in at least 70% of CPBs, even in low-weight patients.Bloodless CPB circuit priming should become a widespread reality, even in neonates and young infants, in any open-heart procedure.

Asanguineous priming of miniaturized paediatric cardiopulmonary bypass circuits for congenital heart surgery: independent predictors associated with transfusion requirements and effects on postoperative morbidity.

OBJECTIVES: In paediatric cardiac surgery, body weight-adjusted miniaturized cardiopulmonary bypass (CPB) circuits within a comprehensive blood-sparing approach can reduce transfusion requirements. Haemodilution resulting from mixing the patient's blood with a CPB crystalloid solution may be reduced to the extent that asanguineous priming becomes possible. Therefore, we adopted asanguineous priming in our clinical routine. Our goal was to report the effects of asanguineous priming on transfusion requirements, clinical features associated with transfusion and effects on in-hospital morbidity. METHODS: Data of all paediatric patients with body weights up to 15 kg treated within a 2-year period between May 2013 and May 2015 were retrospectively analysed. The incidence of transfusions was analysed and periprocedural haemoglobin concentrations were evaluated. Predictors associated with transfusion requirements, duration of ventilation or length of stay in the intensive care unit were evaluated by multivariable analyses. RESULTS: Data from 579 patients with body weights up to 15 kg were analysed. The ability to avoid transfusion depended on body weight: in patients <3 kg, the rate (95% confidence interval) of transfusion during CPB was 0.53 (0.37-0.69), and in patients >8 kg, the rate was 0.14 (0.10-0.19). The respective rates of transfusions throughout the hospital stay were 1.00 (0.90-1.00) and 0.67 (0.60-0.73). Body weight, preoperative haemoglobin concentration, duration of CPB and palliative surgery were independently associated with transfusion during CPB. Transfusion, particularly transfusion during CPB, was independently associated with longer mechanical ventilation time (hazard ratio 3.52, confidence interval 2.66-4.65) and length of stay in the intensive care unit (hazard ratio 2.52, confidence interval 1.91-3.32). CONCLUSIONS: Asanguineous priming is feasible using miniaturized CPB circuits. It may help to avoid blood transfusions in patients on CPB and reduce transfusion requirements and transfusion-related morbidity.

Additional veno-venous gas exchange as a problem-solving strategy for an oxygenator not transferring oxygen in paediatric cardiopulmonary bypass.

OBJECTIVES: Oxygenator failure during cardiopulmonary bypass constitutes a life-threatening event, especially when perfusion is conducted under normothermia. An alternative solution to emergency oxygenator changeover is described. METHODS: A supplementary oxygenator is added in the venous line without interrupting perfusion. De-airing is achieved through the cardiotomy reservoir. Oxygen supply is adapted to ensure physiologic partial oxygen pressure. RESULTS: On 5 occasions in the past 4 years, Capiox Baby FX 05 oxygenator (n = 4) and Capiox FX15 (n = 1) failed to exchange blood gases after bypass run ranging from 290 min to 563 min. Hypoxia ensued with partial oxygen pressure values of 49-79 mmHg with a fraction of inspired oxygen of 1. An additional veno-venous Terumo Capiox FX 05 oxygenator immediately improved oxygenation with resulting partial oxygen pressure increasing to at least 291 mmHg. CONCLUSIONS: An additional veno-venous oxygenator effectively corrects failing oxygenator during cardiopulmonary bypass. The method does not require circulation arrest. It does not carry the risk of air embolism. It can be carried out without any help from a second perfusionist or member of operation team.

Complex Cardiac Surgery on Patients with a Body Weight of Less Than 5 kg without Donor Blood Transfusion.

Performing safe cardiac surgery in neonates or infants whose parents are Jehovah's Witnesses is only possible in a coordinated team approach. An unconditional prerequisite is a cardiopulmonary bypass (CPB) circuit with a very low priming volume to minimize hemodilution. In the past decade, we have developed a functional blood-sparing approach at our institution. The extracorporeal circuit was miniaturized. This had to be recently adapted, faced with a challenge associated with the switch to high-volume crystalloid cardioplegia. A filtration circuit was added. Here, we report an open heart surgery on three consecutive children of Jehovah's Witness parents with a body weight of 2.7, 4.5, and 4.8 kg, respectively. Procedures consisted of one arterial switch operation and two repairs of complete atrioventricular septal defects. Our static priming volume of less than 90 mL resulted in a nadir hematocrit during CPB of 27.7% (Hb 8.9 g/dL) in a patient which happened to have the lowest body weight of 2.7 kg. The two other patients had their lowest hematocrit at 31.4% (Hb 10.2 g/dL). The three children could be treated without any kind of transfusion of blood which had left the circulation or its extensions, in accordance with the parents' wishes, and enjoy favorable outcomes without transfusion of blood products during their entire hospital stay.

Accuracy of predicted haemoglobin concentration on cardiopulmonary bypass in paediatric cardiac surgery: effect of different formulae for estimating patient blood volume.

INTRODUCTION: When applying a blood-conserving approach in paediatric cardiac surgery with the aim of reducing the transfusion of homologous blood products, the decision to use blood or blood-free priming of the cardiopulmonary bypass (CPB) circuit is often based on the predicted haemoglobin concentration (Hb) as derived from the pre-CPB Hb, the prime volume and the estimated blood volume. We assessed the accuracy of this approach and whether it may be improved by using more sophisticated methods of estimating the blood volume. PATIENTS AND METHODS: Data from 522 paediatric cardiac surgery patients treated with CPB with blood-free priming in a 2-year period from May 2013 to May 2015 were collected. Inclusion criteria were body weight <15 kg and available Hb data immediately prior to and after the onset of CPB. The Hb on CPB was predicted according to Fick's principle from the pre-CPB Hb, the prime volume and the patient blood volume. Linear regression analyses and Bland-Altman plots were used to assess the accuracy of the Hb prediction. Different methods to estimate the blood volume were assessed and compared. RESULTS: The initial Hb on CPB correlated well with the predicted Hb (R2=0.87, p<0.001). A Bland-Altman plot revealed little bias at 0.07 g/dL and an area of agreement from -1.35 to 1.48 g/dL. More sophisticated methods of estimating blood volume from lean body mass did not improve the Hb prediction, but rather increased bias. CONCLUSION: Hb prediction is reasonably accurate, with the best result obtained with the simplest method of estimating the blood volume at 80 mL/kg body weight. When deciding for or against blood-free priming, caution is necessary when the predicted Hb lies in a range of ± 2 g/dL around the transfusion trigger.

Routine Application of Bloodless Priming in Neonatal Cardiopulmonary Bypass: A 3-Year Experience.

A restrictive transfusion strategy led us to routinely try to conduct donor-blood free open-heart surgery even in neonates. The cardio-pulmonary bypass (CPB) circuit was minimized by priming volumina at 73 ml for the smallest patients with body weight up to 2.5 kg and 85-95 ml for those with body weight of more than 2.5 kg, and by positioning the console as close as possible to operation table. Measures were applied to save blood during the procedure. Transfusion threshold of 8 g/dl hemoglobin was retained. Effort was made to avoid transfusion while on CPB or to postpone transfusion towards CPB end. From 2013 to 2015, 149 consecutive neonates underwent 150 open-heart procedures without blood in priming volume. Weight was lower than 2.5 kg in five instances. The most frequent operations were arterial switch operation (n = 54) and Norwood procedure (n = 17). Transfusion-free operation was achieved in 44 procedures. The great majority (42/44 = 95%) involved biventricular repair and included 50% (27/54) of arterial switch operations. 106 patients were transfused: 63 mostly towards CPB end, and 43 after coming off bypass. Transfusion-free procedures were associated with postoperative lower lactate concentration (p = 0.0013) and shorter duration of mechanical ventilation (p = 0.0009). Seven patients were discharged from hospital without getting any transfusion of blood or blood products. In conclusion, routine application of bloodless priming in neonatal cardiopulmonary bypass is safe and beneficial. It results into a good number (29%= 44/150) of transfusion-free operations. Postponing transfusion towards CPB end favors an overall restrictive transfusion strategy for all patients.

Effect of modified ultrafiltration on bivalirudin elimination and postoperative blood loss after on-pump coronary artery bypass grafting: assessment of different filtration strategies.

OBJECTIVE: Bivalirudin has a short elimination half-life of approximately 25 to 30 minutes, but no antidote is available. We assessed the effect of four different strategies of modified ultrafiltration after cardiopulmonary bypass on the bivalirudin elimination and postoperative blood loss. METHODS: Five groups of seven patients undergoing elective "on-pump" coronary artery bypass grafting were enrolled in this controlled randomized investigation. The filtration strategies varied with regard to the filtration flow, the filtrate volume, the addition of vacuum suction to the filter system, and the performance of hemodiafiltration. Filtration was started after weaning from cardiopulmonary bypass (CPB). The cumulative postoperative blood drainage at 12 hours was recorded. RESULTS: Bivalirudin half-life in the control group was 0.6 +/- 0.11 hours, and the blood loss was 958 +/- 472 mL. Hemofiltration with a constant flow of 300 mL/m(2) body surface area/min and a filtrate volume of 3000 mL reduced the elimination half-life significantly to 0.47 +/- 0.11 hours. Adding the process of dialysis to hemofiltration resulted in a half-life of 0.52 +/- 0.04 hours and reduced the 12-hour postoperative blood loss significantly, compared to the control group, to 444 +/- 220 mL. The other strategies failed to augment the bivalirudin elimination and postoperative drainage effectively. CONCLUSION: Zero-balanced modified hemodiafiltration without addition of vacuum suction is effective in improving the elimination of bivalirudin after CPB and reducing the postoperative blood loss. Zero-balanced hemodiafiltration should be considered for the augmented elimination of bivalirudin in complex surgical procedures with a high risk of bleeding complications. However, larger investigations are warranted to confirm these results.