Normothermic versus hypothermic cardiopulmonary bypass in low-risk paediatric heart surgery: a randomised controlled trial

Comparative outcomes of cardioplegic arrest versus beating heart in pediatric undergoing extracardiac total cavopulmonary connection

BACKGROUND

Total cavopulmonary connection (TCPC) is a definitive palliative procedure for functionally univentricular congenital heart disease. The study aims to compare the impact of on-pump cardioplegic arrest and on-pump beating heart cardiopulmonary bypass (CPB) on the prognosis of pediatric patients undergoing extracardiac TCPC.

METHODS

The medical data of patients (< 18 years) who underwent extracardiac TCPC with CPB between January 2008 and December 2020 in the cardiac surgery center were retrospectively analyzed. Depending on CPB strategies, the patients were assigned to the beating-heart (BH) and cardioplegic arrest (CA) groups. Data including baseline characteristics, intra/postoperative variables, and clinical outcomes were collected for analysis with 1:1 propensity score matching and multivariable stepwise logistic regressions.

RESULTS

Fifty-seven matched patient pairs were obtained. No significant difference existed between the two groups in the in-hospital mortality (3.5% vs. 1.8%, P = 1) and one-year survival rate (100% vs. 96.4%, P = 0.484). The BH group had significantly less intraoperative platelet transfusion (10 mL vs. 150 mL, P = 0.019) and blood loss (100 mL vs. 150 mL, P = 0.033) than the CA group. The CA group had significantly higher vasoactive-inotropic scores (P < 0.05) and longer postoperative ICU stays (2.0 d vs. 3.7 d, P = 0.017). No significant difference existed between the two groups in the incidence of postoperative adverse events.

CONCLUSION

Although both CPB strategies are safe and feasible for extracardiac TCPC, the BH technique would cause less intraoperative platelet transfusion and blood loss, and achieve faster early-term postoperative recovery.

Early outcomes of experience warm surgery in children undergoing complete repair of tetralogy of Fallot in developing countries

OBJECTIVES

While significant evidence supports the benefits of normothermic cardiopulmonary bypass (NCPB) over hypothermic techniques, many institutions in developing countries, including ours, continue to employ hypothermic methods. This study aimed to assess the early postoperative outcomes of normothermic cardiopulmonary bypass (NCPB) for complete surgical repair via the Tetralogy of Fallot (TOF) within our national context.

METHODS

We conducted this study in the Pediatric Cardiac Intensive Care Unit (PCICU) at the University Children's Hospital. One hundred patients who underwent complete TOF repair were enrolled and categorized into two groups: the normothermic group (n = 50, temperature 35-37 °C) and the moderate hypothermic group (n = 50, temperature 28-32 °C). We evaluated mortality, morbidity, and postoperative complications in the PCICU as outcome measures.

RESULTS

The demographic characteristics were similar between the two groups. However, the cardiopulmonary bypass (CPB) time and aortic cross-clamp (ACC) time were notably longer in the hypothermic group. The study recorded seven deaths, yielding an overall mortality rate of 7%. No significant differences were observed between the two groups concerning mortality, morbidity, or postoperative complications in the PCICU.

CONCLUSIONS

Our findings suggest that normothermic procedures, while not demonstrably effective, are safe for pediatric cardiac surgery. Further research is warranted to substantiate and endorse the adoption of this technique.

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Depth of anesthesia, temperature, and postoperative delirium in children and adolescents undergoing cardiac surgery

BACKGROUND

After pediatric cardiosurgical interventions, postoperative delirium can occur, which can be associated with undesirable consequences during and after the hospital stay. It is therefore important to avoid any factors causing delirium as far as possible. Electroencephalogram (EEG) monitoring can be used during anesthesia to individually adjust dosages of hypnotically acting drugs. It is necessary to gain knowledge about the relationship between intraoperative EEG and postoperative delirium in children.

METHODS

In a dataset comprising 89 children (53 male, 36 female; median age: 0.99 (interquartile range: 0.51, 4.89) years) undergoing cardiac surgery involving use of a heart-lung machine, relationships between depth of anesthesia as measured by EEG (EEG index: Narcotrend Index (NI)), sevoflurane dosage, and body temperature were analyzed. A Cornell Assessment of Pediatric Delirium (CAP-D) score ≥ 9 indicated delirium.

RESULTS

The EEG could be used in patients of all age groups for patient monitoring during anesthesia. In the context of induced hypothermia, EEG monitoring supported individually adjusted sevoflurane dosing. The NI was significantly correlated with the body temperature; decreasing temperature was accompanied by a decreasing NI. A CAP-D score ≥ 9 was documented in 61 patients (68.5%); 28 patients (31.5%) had a CAP-D < 9. Delirious patients with an intubation time ≤ 24 h showed a moderate negative correlation between minimum NI (NImin) and CAP-D (rho = -0.41, 95% CI: -0.70 - -0.01, p = 0.046), i.e., CAP-D decreased with increasing NImin. In the analysis of all patients' data, NImin and CAP-D showed a weak negative correlation (rho = -0.21, 95% CI: -0.40 - 0.01, p = 0.064). On average, the youngest patients had the highest CAP-D scores (p = 0.002). Patients with burst suppression / suppression EEG had a longer median intubation time in the intensive care unit than patients without such EEG (p = 0.023). There was no relationship between minimum temperature and CAP-D score.

CONCLUSIONS

The EEG can be used to individually adjust sevoflurane dosing during hypothermia. Of the patients extubated within 24 h and classified as delirious, patients with deeper levels of anesthesia had more severe delirium symptoms than patients with lighter levels of anesthesia.

Warm versus cold blood cardioplegia in paediatric congenital heart surgery: a randomized trial

OBJECTIVES

Intermittent cold blood cardioplegia is commonly used in children, whereas intermittent warm blood cardioplegia is widely used in adults. We aimed to compare clinical and biochemical outcomes with these 2 methods.

METHODS

A single-centre, randomized controlled trial was conducted to compare the effectiveness of warm (≥34°C) versus cold (4-6°C) antegrade cardioplegia in children. The primary outcome was cardiac troponin T over the 1st 48 postoperative hours. Intensive care teams were blinded to group allocation. Outcomes were compared by intention-to-treat using linear mixed-effects, logistic or Cox regression.

RESULTS

97 participants with median age of 1.2 years were randomized (49 to warm, 48 to cold cardioplegia); 59 participants (61%) had a risk-adjusted congenital heart surgery score of 3 or above. There were no deaths and 92 participants were followed to 3-months. Troponin release was similar in both groups [geometric mean ratio 1.07; 95% confidence interval (CI) 0.79-1.44; P = 0.66], as were other cardiac function measures (echocardiography, arterial and venous blood gases, vasoactive-inotrope score, arrhythmias). Intensive care stay was on average 14.6 h longer in the warm group (hazard ratio 0.52; 95% CI 0.34-0.79; P = 0.003), with a trend towards longer overall hospital stays (hazard ratio 0.66; 95% CI 0.43-1.02; P = 0.060) compared with the cold group. This could be related to more unplanned reoperations on bypass in the warm group compared to cold group (3 vs 1).

CONCLUSIONS

Warm blood cardioplegia is a safe and reproducible technique but does not provide superior myocardial protection in paediatric heart surgery.

Novel cfDNA Methylation Biomarkers Reveal Delayed Cardiac Cell Death after Open-heart Surgery

The use of cardiopulmonary bypass (CPB) is thought to cause delayed cardiac damage. DNA methylation-based liquid biopsies are novel biomarkers for monitoring acute cardiac cell death. We assessed cell-free DNA molecules as markers for cardiac damage after open-heart surgery. Novel cardiomyocyte-specific DNA methylation markers were applied to measure cardiac cfDNA in the plasma of 42 infants who underwent open-heart surgery. Cardiac cfDNA was elevated following surgery, reflecting direct surgery-related tissue damage, and declined thereafter in most patients. The concentration of cardiac cfDNA post-surgery correlated with the duration of CPB and aortic cross clamping. Strikingly, cardiac cfDNA at 6 h predicted duration of mechanical ventilation and maximal vasoactive-inotropic score better than did maximal troponin levels. Cardiac cfDNA reveals heart damage associated with CPB, and can be used to monitor cardiac cell death, to predict clinical outcome of surgery and to assess performance of cardioprotective interventions.

Challenges and solutions to recruitment of neonates and children having cardiac surgery into a study using a novel sampling device

OBJECTIVE

To narratively describe the challenges and solutions required in delivering a non-commercial study of children undergoing cardiac surgery using a novel subcutaneous hormone collection device.

RESULTS

The challenges faced by the research team are divided into those of conducting healthcare research in children and those specific to this study. Many of the issues of conducting healthcare research in children can and have been overcome by structural and institutional culture change-normalising and embedding research as part of good clinical care. The issues specific to insertion and maintenance of the novel collection device can be overcome by education and support of the clinical teams. The increased incentives and resources of commercial research may have overcome many of these.

The lower threshold of hypothermic oxygen delivery to prevent neonatal acute kidney injury

BACKGROUND

Oxygen delivery during cardiopulmonary bypass (CPB) is closely related to postoperative acute kidney injury (AKI). The value of critical indexed oxygen delivery (DO₂i) is a key indicator to reflect oxygen supply in cardiovascular surgery. However, the target DO₂i value for neonates undergoing hypothermic CPB remains unclear.

METHODS

One hundred and twenty-six consecutive newborns (≤28 days) undergoing arterial switch operations were retrospectively divided into two groups according to AKI occurrence. Baseline characteristics, intraoperative variables, and clinical outcomes were collected. Multivariate logistic regression analysis and receiver-operating characteristic curve were performed to investigate the association between DO₂i and AKI.

RESULTS

Neonates in the no-AKI group (n = 67) had significantly higher nadir bypass flow and DO₂i during the hypothermic phase compared with the AKI group (n = 59). AKI group had remarkably higher incidences of hepatic dysfunction and peritoneal dialysis requirement compared with newborns without AKI. Mixed venous oxygen saturation (SvO₂) was comparable between the two groups. Base excess (BE)(P = 0.011) value during the hypothermic phase of the AKI group was higher than the no-AKI group. Multivariate analysis showed that hypothermic DO₂i was negatively associated with AKI. The cut-off value of hypothermic DO₂i was 269 mL min^-1 m^-2.

CONCLUSIONS

The importance of hypothermic DO₂i should be highlighted, even when SvO₂ was satisfactory. A lower threshold of DO₂i > 269 mL min^-1 m^-2 may help protect neonates from the risk of postoperative AKI.

IMPACT

The key message of our article is that the lower threshold of DO₂i > 269 mL min^-1 m^-2 may help protect neonates from the risk of AKI after on-pump hypothermic cardiovascular surgery. The critical DO₂i value for neonates undergoing hypothermic CPB remains unclear, and our study may add new evidence for this matter based on the 6-year experience of our center. In this study, the lowest critical value of DO₂i in neonatal hypothermic CPB is determined for the first time, which provides a reference for intra-CPB management strategy to improve the postoperative outcomes of newborns.

Effectiveness of Mild to Moderate Hypothermic Cardiopulmonary Bypass on Early Clinical Outcomes

BACKGROUND

Intraoperative hypothermia is an integral part of cardiopulmonary bypass (CPB), and a precise degree of hypothermia may improve the early clinical outcomes of cardiac surgery. Presently, there is no agreement on an accurate, advantageous temperature range for routine use in CPB. To address this issue, we conducted a retrospective observational study to compare the effects of different hypothermic temperature ranges on primary (inotropic support, blood loss, and platelet count) and secondary (ventilation support and in-hospital stay) outcomes in patients undergoing elective cardiac surgery.

METHODS

Data were retrieved from the medical database of the Cardiovascular Surgery Department, King Edward Medical University, Lahore-Pakistan (a tertiary care hospital), dating from February 2015 to December 2017. Patients were divided into mild (34 °C to 36 °C), intermediate (31 °C to 33 °C), or moderate (28 °C to 30 °C) hypothermic groups.

RESULTS

Out of 275 patients, 245 (89.09%) fit the inclusion criteria. The cohort with mild hypothermic CPB temperatures presented better clinical outcomes in terms of requiring less inotropic support, less blood loss, fewer blood transfusions, improved platelet counts, shorter in-hospital stays, and required less ventilation support, when compared with other hypothermic groups.

CONCLUSIONS

Mild hypothermic CPB (34 °C to 36 °C) may produce better clinical outcomes for cardiac surgery and improve the quality of health of cardiac patients.

[Results of implementation of a perioperative Patient Blood Management program in cardiovascular surgery]

BACKGROUND AND OBJECTIVE

Cardiovascular surgery (CCV) patients have a high incidence of perioperative anemia and bleeding that determines a high rate of allogeneic blood transfusion (AST). This is associated with an increase in morbidity, mortality and prolongs length of stay in hospital. Unnecessary transfusion is one of the measures to avoid and Patient Blood Management (PBM) programs have proven their effectiveness. Our objective was to reduce the transfusion of patients in cardiac surgery, without inferior results in morbidity and mortality, length of stay in hospital and being cost-effective, through the implementation of a PBM program.

MATERIAL AND METHODS

A mixed cohort study of 226 patients divided into 2 groups: retrospective pre-PBM (GP), from 2016, and intervention group (IG), prospective from 2018, with the results of the implementation of the guide.

RESULTS

The clinical results obtained allowed reducing the TSA from 92.59% to 79.69% (P<.001), saving 2.59 units of CH and 2.5 of PFC per patient (P<.001). A decrease was found in patients with fever (12.35% vs 1.56% with P=.006) and the need to escalate antibiotics (64.8% vs 42.19%, P=.002). The rest of postoperative complications and mortality at 3months did not present statistically significant differences. The length of stay was reduced by an average 3.6days in the IG, (95%CI: -8.10 to 0.9, P=.18). The cost decreased by 163.29€ per patient, taking into account exclusively the saving of blood components.

CONCLUSION

The PBM program is effective in reducing TSA in cardiac surgery in a tertiary hospital with high complexity patients and high transfusion rate. There are signs suggestive of a decrease in infections and a tendency to decrease the length of stay and mortality. In the economic approximation carried out, the cost of the intervention was lower than the savings implied by the decrease in transfusion.

Effect of dexmedetomidine on perioperative hemodynamics and organ protection in children with congenital heart disease: A randomized controlled trial

BACKGROUND

This study aimed to investigate the effects of dexmedetomidine (Dex) on hemodynamics and organ protection in congenital heart disease (CHD) children who underwent open-heart surgery under cryogenic cardiopulmonary bypass.

METHODS

Ninety children were randomly allocated to group C (0.9% saline 0.2 μg/kg/hour), group D1 (Dex 0.2 μg/kg/hour), and group D2 (Dex 0.4 μg/kg/hour) (n = 30 per group). All participants received fentanyl, propofol and 1% sevoflurane for anesthesia induction. Hemodynamic data were measured from T0 (before the induction) to T7 (30 minutes after extubation). The difference of arterial internal jugular vein bulbar oxygen difference and cerebral oxygen extraction ratio were calculated according to Fick formula. Enzyme-linked immunosorbent assay was performed to detect the serum myocardial, brain and kidney injury markers. The incidence of acute kidney injury (AKI) was calculated by serum creatinine level. Tracheal extubation time, postoperative pain score and emergence agitation score were also recorded.

RESULTS

Compared with group C, group D1, and D2 exhibited reduction in hemodynamic parameters, myocardial and brain injury indicators, and tracheal extubation time. There were no significant differences in blood urea nitrogen and neutrophil gelatinase-associated lipocalin or incidence of AKI among the 3 groups. Besides, the incidence of tachycardia, nausea, vomiting and moderate agitation, and the FLACC scale in group D1 and D2 were lower than those in group C. Moreover, Dex 0.4 g/kg/hour could further reduce the dosage of fentanyl and dopamine compared with Dex 0.2 g/kg/hour.

CONCLUSIONS

Dex anesthesia can effectively maintain hemodynamic stability and diminish organ injuries in CHD children.

Safety of Normothermic Cardiopulmonary Bypass in Pediatric Cardiac Surgery: A System Review and Meta-Analysis

Objectives: Hypothermic cardiopulmonary bypass (HCPB) has been used successfully in cardiac surgery for more than half a century, although adverse effects have been reported with its use. Many studies on temperature management during CPB published to date have shown that normothermic CPB (NCPB) provides more benefits to children undergoing cardiac surgery. The present meta-analysis investigated the effect of NCPB on clinical outcomes based on results of randomized controlled trials and observational studies on pediatric cardiac surgery. Methods: Databases such as PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Clinical Trials.gov were searched from inception to May 2021 to identify relevant studies published in English. Results: The present meta-analysis included 13 studies characterizing a total of 837 pediatric patients. The random effects model exhibited that the NCPB group had reduced revision for postoperative bleeding [odds ratio (OR): 0.11; 95% confidence interval (CI): 0.01-0.89; I ² = 0%, P = 0.04], serum lactate 2-4 h after CPB (mean difference: -0.60; 95% CI: -1.09 to -0.11; I ² = 82%, P = 0.02), serum creatinemia 24 h after CPB (mean difference: -2.73; 95% CI: -5.06 to -0.39; I ² = 83%, P = 0.02), serum creatinemia 48 h after CPB (mean difference: -2.08; 95% CI: -2.78 to -1.39; I ² = 0%, P < 0.05), CPB time (mean difference: -19.10, 95% CI: -32.03 to -6.18; I ² = 96%, P = 0.04), and major adverse events (OR: 0.37; 95% CI: 0.15-0.93; Z = 2.12, P = 0.03) after simple congenital surgery compared with the HCPB group. Conclusion: NCPB is as safe as HCPB in pediatric congenital heart surgery. Moreover, NCPB provides more advantages than HCPB in simple congenital heart surgery.

Neurodevelopmental outcomes of children with congenital heart disease: A review

Congenital heart defects are the most common birth anomaly affecting approximately 1% of births. With improved survival in this population, there is enhanced ability to assess long-term morbidities including neurodevelopment. There is a wide range of congenital heart defects, from those with minimal physiologic consequence that do not require medical or surgical intervention, to complex structural anomalies requiring highly specialized medical management and intricate surgical repair or palliation. The impact of congenital heart disease on neurodevelopment is multifactorial. Susceptibility for adverse neurodevelopment increases with advancing severity of the defect with initial risk factors originating during gestation. Complex structural heart anomalies may pre-dispose the fetus to abnormal circulatory patterns in utero that ultimately impact delivery of oxygen rich blood to the fetal brain. Thus, the brain of a neonate born with complex congenital heart disease may be particularly vulnerable from the outset. That vulnerability is compounded during the newborn period and through childhood, as this population endures a myriad of medical and surgical interventions. For each individual patient, these factors are likely cumulative and synergistic with progression from fetal life through childhood. This review discusses the spectrum of risk factors that may impact neurodevelopment in children with congenital heart disease, describes current recommendations and practices for neurodevelopmental follow-up of children with congenital heart disease and reviews important neurodevelopmental trends in this high risk population.

Part II. Comparison of Neurodevelopmental Outcomes Between Normothermic and Hypothermic Pediatric Cardiopulmonary Bypass

Objectives: In the previous study we demonstrated that normothermic cardiopulmonary bypass (N-CPB, ≥35°C) provided better early clinical outcomes compared to mild/moderate hypothermic cardiopulmonary bypass (H-CPB, 28-34°C) for congenital heart surgery. In this follow-up study we compare early neurodevelopmental outcomes 2-3 years post-surgery. Methods: In this retrospective, non-randomized observational study, the medical notes of children from our previous cohort were reviewed after 2-3 years. Demographic and neurodevelopmental outcomes were tabulated to enable blinded statistical analysis comparing outcomes between N-CPB and H-CPB surgery for congenital heart defects. Multivariate logistic regression models were developed to identify any differences in outcomes after adjustment for confounders. Results: Ninety-five children who underwent H-CPB (n = 50) or N-CPB (n = 45) were included. The proportions of patients with one or more adverse neurodevelopmental outcomes 2-3 years later were 14/50 (28.0%) in the H-CPB group and 11/45 (24.4%) in N-CPB, which was not significantly different between groups (p = 0.47). The two CPB groups were balanced for demographic and surgical risk factors, with the exception of genetic conditions. A higher incidence of H-CPB patients acquired learning difficulties [23.1% compared to 2.56% for N-CPB (p = 0.014)] and neurological deficits [30.8% compared to 7.69% for N-CPB (p = 0.019)], but these differences were not robust to adjustment for genetic syndromes. Conclusions: Our study did not reveal any significant differences in early neurodevelopmental outcomes between H-CPB or N-CPB surgery for congenital heart defects. The most important factor in predicting outcomes was, as expected, the presence of a genetic syndrome. We found no evidence that CPB temperature affects early neurodevelopmental outcomes.