Impact of On-Bypass Red Blood Cell Transfusion on Severe Postoperative Morbidity or Mortality in Children

Coagulation after paediatric miniaturised versus conventional cardiopulmonary bypass: Retrospective cohort study

BACKGROUND

Cardiopulmonary bypass (CPB) causes coagulation disorders after surgery. This study aimed to compare the coagulation parameters after congenital cardiac surgery with miniaturised CPB (MCPB) versus conventional CPB (CCPB).

METHODS

We gathered information about children who underwent cardiac surgery between 1/1/2016 and 12/31/2019. Using propensity score-matched data, we compared the coagulation parameters and postoperative outcomes of the MCPB and CCPB groups.

RESULTS

A total of 496 patients (327 with MCPB, 169 withCCPB) underwent congenital cardiac surgery, and 160 matched pairs in each group were enrolled in the analysis. Compared with CCPB children, MCPB children had a lowermean prothrombin time (14.9 ± 2.0 vs 16.4 ± 4.1; p < 0.001)and international normalised ratio (1.3 ± 0.2 vs. 1.4 ± 0.3; p < 0.001), but higher thrombin time (23.4 ± 20.4 vs 18.2 ± 4.4; p = 0.002). The CCPB group had greaterperioperative changes inprothrombin time, international normalised ratio, fibrinogen, and antithrombin III activity (all p < 0.01) but lower perioperative changesin thrombin time (p = 0.001) thanthe MCPB group. Ultra-fasttrack extubation and blood transfusionrates, postoperative blood loss, and intensive care unitlength of stay were considerably decreased in the MCPB group. There were no considerable intergroup differences in the activated partial thromboplastin time or platelet count.

CONCLUSIONS

Compared with CCPB, MCPB was associated with lower coagulation changes and better early outcomes, including shorter intensive care unit stay and less postoperative blood loss.

Recent advancements in pediatric cardiopulmonary bypass technology for better outcomes of pediatric cardiac surgery

Background

Pediatric cardiac surgery is in itself very enigmatic and individualized. Presently, there has been a slew of new developments aimed primarily toward pediatric cardiopulmonary bypass for safer, patient-centered pediatric cardiac surgery. Still, lot of technological challenges need to be resolved, and their safer application in pediatric and neonate patients requires further refinement.

Main body of the abstract

Considering various significant yet unresolved issues of pediatric cardiac bypass, an exhaustive literature search was done on various internet databases with standard keywords. There are various new recent improvements; as the first oxygenator explicitly designed for neonatal patients; pediatric oxygenators with low prime volumes and surface areas that allow flows up to 2 L/min; pediatric oxygenators with integrated arterial filters; and miniature ultrafiltration devices that allow for high rates of ultrafiltrate removal. These advancements can significantly reduce cardiopulmonary bypass circuit surface areas and prime volumes. These advancements could reduce or eliminate the requirement for homologous red blood cells during or after surgery with reduction or eliminate bypass-related hemodilution, and inflammation. Because of the immaturity of the neonatal hemostatic system, conventional coagulation tests alone are insufficient to guide neonatal hemostatic therapy. Myocardial preservation techniques, safe temperature with duration are still debatable and yet to be fully explored.

Short conclusion

This review is based on Standards for Quality Improvement Reporting Excellence guidelines to provide a framework for reporting new knowledge to find better management strategy for pediatric cardiac cases.

Efficacy and safety of aprotinin in paediatric cardiac surgery: A systematic review and meta-analysis

BACKGROUND

The relicensing of aprotinin in Europe and Canada has stimulated discussions on its usefulness in paediatric cardiac surgery.

OBJECTIVE

To systematically evaluate the available evidence on the efficacy and safety of aprotinin in paediatric cardiac surgery.

DESIGN

Systematic review of all randomised and observational studies comparing aprotinin with tranexamic acid, epsilon aminocaproic acid, placebo or no drug in paediatric cardiac surgery. Meta-analyses were performed on efficacy and safety outcomes.

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science and Embase were searched from January 2000 to March 2021.

ELIGIBILITY CRITERIA

Studies that enrolled children under 18 years undergoing cardiac surgery with cardiopulmonary bypass.

RESULTS

Thirty-two studies enrolling a total of 63 894 paediatric cardiac procedures were included. Aprotinin significantly reduced total blood loss [mean difference -4.70 ml kg-1, 95% confidence interval (CI), -7.88 to -1.53; P = 0.004], postoperative transfusion requirements and the incidence of surgical re-exploration for bleeding [odds ratio (OR) 0.74, 95% CI, 0.56 to 0.97; P = 0.03]. Aprotinin had no effects on 30-day mortality (OR 1.02, 95% CI, 0.93 to 1.11; P = 0.73) and on other safety outcomes, except for the incidence of renal replacement therapy (RRT), which was significantly increased in patients given aprotinin (OR 1.29, 95% CI, 1.08 to 1.54; P = 0.006). Findings from observational and randomised controlled trials did not largely differ. A sub-group analysis in neonates showed that aprotinin significantly reduced packed red blood cell transfusions and the incidence of postoperative surgical re-exploration for bleeding and/or tamponade. When compared with lysine analogues, aprotinin was more effective at reducing bleeding and transfusion without increasing the risk of side effects.

CONCLUSION

This meta-analysis suggests that aprotinin is effective and well tolerated in paediatric cardiac surgery. Given the large heterogeneity of the results and the risk of selection bias in observational studies, large randomised controlled trials are warranted.

Effects of cardiopulmonary bypass with low-priming volume on clinical outcomes in children undergoing congenital heart disease surgery

Background

Cardiopulmonary bypass (CPB) with high-priming volume can significantly activate the inflammatory response and increse the usage of packed red blood cells (PRBCs). As risks and complications related to transfusions are increasing, many cardiac centers are focusing on reducing the priming volume of CPB. In our center, efforts have also been made to reduce the priming volume, and the effects of CPB with low-priming volume on clinical outcomes in children undergoing congenital heart disease (CHD) surgery were investigated in this study to provide referential experiences for pediatric CPB.

Methods

The clinical case data of 158 children undergoing CHD surgery with CPB were collected. The children were divided into the low-priming-volume group (group A, n = 79) and the traditional group (group B, n = 79) according to the priming volume. The amount of PRBCs transfused, the postoperative hematological test results and the clinical outcomes of the two groups were compared by the independent sample t-test or the chi-square test.

Results

The amount of PRBCs transfused during CPB and during the whole operation were significantly lower in group A than in group B (p < 0.01), but the hemoglobin (Hb) concentration was higher in group A on the first day after surgery (p < 0.01) and before hospital discharge. However, the latter showed no statistical significant difference. The lowest postoperative platelet count was higher in group A than in group B (p < 0.05). There was no statistical difference in the postoperative inflammatory markers and the main clinical outcomes between the two groups.

Conclusions

The usage of PRBCs in CPB with low-priming volume decreased significantly, but the postoperative Hb concentration and platelet count could still be maintained at a high level, improving the use efficiency of PRBCs. CPB with low-priming volume did not affect the postoperative recovery of patients, so it is worthy of continuous promotion and optimization.

Effect of retrograde autologous priming based on miniaturized cardiopulmonary bypass in children undergoing open heart surgery: A STROBE compliant retrospective observational study

To evaluate the effectiveness of retrograde autologous priming (RAP) based on miniaturized cardiopulmonary bypass (CPB) circuit in children undergoing open heart surgery.We performed a retrospective analysis of all patients (≤15 kg) who underwent open heart surgery with CPB in our center from January 1, 2017, to July 31, 2019. Propensity score matching was used to adjust for significant covariates, and multivariable stratified analysis was used to assess the association of the RAP technique with clinical outcomes.A total of 1111 patients were analyzed. There were 355 (32.0%) children who underwent RAP, and 756 (68.0%) were in the non-RAP group. After propensity score matching, there were a total of 638 patients, with 319 patients in each group. The bloodless priming rate was significantly higher (P = .013), and the ultrafiltration rate was significantly lower (P = .003) in the RAP group than in the non-RAP group. Compared with patients in the non-RAP group, patients in the RAP group had a shorter postoperative mechanical ventilation time (P < .001) and shorter lengths of stay in the intensive care unit (ICU) (P < .001) and the hospital (P < .001). No differences were noted in postoperative hematocrit (P = .920), postoperative 24-hour blood loss (P = .435), and hospital mortality (P = .563). In the stratified analysis, the difference remained statistically significant (P < .05) when the patient weight was >4 kg or the Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery (STAT) category was <3. However, when the patient weight was ≤4 kg or the STAT category was ≥3, there was no significant difference between the 2 groups in terms of bloodless priming, ultrafiltration, postoperative mechanical ventilation time, or length of stay in the ICU or the hospital (P > .05).The RAP technique based on miniaturized CPB system was safe and effective for children who underwent congenital heart surgery. The RAP technique can significantly reduce the priming volume, improve the rate of bloodless priming, and reduce blood product application. It was also associated with a shorter postoperative mechanical ventilation time and shorter lengths of stay in the ICU and the hospital.

Recent achievements and future developments in neonatal cardiopulmonary bypass

A primary goal of improving neonatal cardiopulmonary bypass has been making the circuit smaller and reduce the blood contacting surfaces. As bypass circuit size has decreased, bloodless surgery has become possible even in neonates. Since transfusion guidelines are difficult to construct based on existing literature, these technical advances should be taken advantage of in conjunction with an individualized transfusion scheme, based on monitoring of oxygen availability to the tissues. For the majority of neonatal heart operations, several centers have shifted toward normothermic bypass even for complex neonatal surgeries, in order to avoid the adverse effects of hypothermia. Deep hypothermic circulatory arrest is no longer a necessity but an option, and selective antegrade cerebral perfusion has become common practice; however, technical uncertainties with regard to this technique have to be addressed, based on reliable neurologic monitoring. Maintenance of patient-specific heparin concentrations during bypass is another key goal, since neonates have lower baseline antithrombin concentrations and, therefore, a higher risk for inadequate thrombin inhibition and postoperative bleeding. Due to the immaturity of their hemostatic system, the standard coagulation tests alone are inappropriate to guide hemostatic therapy in neonates. The use of indirect heparin concentration assays and global viscoelastic assays in the operating room is likely to represent the optimal strategy, and requires validation in neonates. Monitoring of global and regional indexes of oxygen availability and consumption on bypass have become possible; however, their use in neonates still has outstanding technical issues which should be addressed and hence needs further validation. Due to the immaturity of the neonatal myocardium, single-shot cold cardioplegia solutions are thought to confer the best myocardial protection; their superiority when compared to more conventional modalities, however, remains to be demonstrated.

Comparison of two cardiopulmonary bypass strategies with a miniaturized tubing system: a propensity score-based analysis

INTRODUCTION

The existing cardiopulmonary bypass tubing system has already been significantly improved in our hospital by reducing the priming volume; thus, we further employed a new cardiopulmonary bypass strategy in children based on a miniaturized cardiopulmonary bypass circuit. We aimed to compare the effectiveness of new and conventional strategies by analyzing the outcomes after congenital heart surgery.

METHODS

We performed a database analysis of all patients undergoing congenital heart surgery with cardiopulmonary bypass at Shenzhen Children's Hospital from 1 May 2015 to 30 June 2017. Propensity score matching was used to adjust for significant covariates, and multivariable regression models and stratified analysis were used to assess the association of cardiopulmonary bypass strategy with outcomes.

RESULTS

Of 925 total patients, 55.35% were in the conventional strategy group and 44.65% were in the new strategy group. After propensity score matching, there were 610 patients in total, with 305 patients in each group. In the multivariable regression models, the cardiopulmonary bypass strategy was not significantly associated with successful early extubation (p > 0.05), reintubation (p > 0.05), or nasal continuous positive airway pressure (p > 0.05) rates. The new strategy group had fewer hospital stays (p = 0.04) and intensive care unit stays (p < 0.05) compared with patients who underwent conventional strategy. The difference remained statistically significant (p < 0.05) when The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category was <3.

CONCLUSION

The implementation of a new cardiopulmonary bypass strategy, with selective ultrafiltration based on a miniaturized cardiopulmonary bypass circuit system, was safe and effective for children who underwent congenital heart surgery in a Chinese hospital. The new cardiopulmonary bypass strategy was associated with fewer hospital and intensive care unit stays.

Superior blood-saving effect and postoperative recovery of comprehensive blood-saving strategy in infants undergoing open heart surgery under cardiopulmonary bypass

BACKGROUND

Optimization of blood-saving strategies during open heart surgery in infants is still required. This study aimed to study a comprehensive blood-saving strategy during cardiopulmonary bypass (CPB) on postoperative recovery in low-weight infants undergoing open heart surgery.

METHODS

This was a prospective study of 86 consecutive infants (weighing <5 kg) with acyanotic congenital heart disease treated at the Tianjin Chest Hospital between March and December 2016, and randomized to the control (traditional routine CPB) and comprehensive blood-saving strategy groups. The primary endpoints were blood saving and clinical prognosis. The secondary endpoints were safety and laboratory indicators, prior to CPB (T1), after 30 minutes of CPB (T2), after modified ultrafiltration (T3), and postoperative 12 (T4), 24 (T5), 48 (T6), and 72 h (T7).

RESULTS

The total priming volume and banked red blood cells in the comprehensive strategy group were significantly lower than in the control group (P = .009 and P = .04, respectively). In the comprehensive strategy group, immediately after CPB, the amount of salvaged red blood cells exceeded the priming red blood cells by 40 ± 11 mL. Postoperatively, the comprehensive strategy group showed a significant decrease in the inotrope score (P = .03), ventilation time (P = .03), intensive care unit stay (P = .04), and hospital stay (P = .03) in comparison with the control group.

CONCLUSION

The comprehensive blood-saving strategies for CPB were associated with less blood use and favorable postoperative recovery in low-weight infants with congenital heart disease undergoing open heart surgery.

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.