Efficacy and safety of milrinone in preventing low cardiac output syndrome in infants and children after corrective surgery for congenital heart disease

Effect of nitric oxide delivery via cardiopulmonary bypass circuit on postoperative oxygenation in adults undergoing cardiac surgery (NOCARD trial): a randomised controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass induces a significant systemic inflammatory response, contributing to various postoperative complications, including pulmonary dysfunction, myocardial and kidney injuries.

OBJECTIVE

To investigate the effect of Nitric Oxide delivery via the cardiopulmonary bypass circuit on various postoperative outcomes.

DESIGN

A prospective, single-centre, double-blinded, randomised controlled trial.

SETTING

Rabin Medical Centre, Beilinson Hospital, Israel.

PATIENTS

Adult patients scheduled for elective cardiac surgery were randomly allocated to one of the study groups.

INTERVENTIONS

For the treatment group, 40 ppm of nitric oxide was delivered via the cardiopulmonary bypass circuit. For the control group, nitric oxide was not delivered.

OUTCOME MEASURES

The primary outcome was the incidence of hypoxaemia, defined as a p a O2 /FiO 2 ratio less than 300 within 24 h postoperatively. The secondary outcomes were the incidences of low cardiac output syndrome and acute kidney injury within 72 h postoperatively.

RESULTS

Ninety-eight patients were included in the final analysis, with 47 patients allocated to the control group and 51 to the Nitric Oxide group. The Nitric Oxide group exhibited significantly lower hypoxaemia rates at admission to the cardiothoracic intensive care unit (47.1 vs. 68.1%), P  = 0.043. This effect, however, varied in patients with or without baseline hypoxaemia. Patients with baseline hypoxaemia who received nitric oxide exhibited significantly lower hypoxaemia rates (61.1 vs. 93.8%), P  = 0.042, and higher p a O2 /FiO 2 ratios at all time points, F (1,30) = 6.08, P  = 0.019. Conversely, this benefit was not observed in patients without baseline hypoxaemia. No significant differences were observed in the incidence of low cardiac output syndrome or acute kidney injury. No substantial safety concerns were noted, and toxic methaemoglobin levels were not observed.

CONCLUSIONS

Patients with baseline hypoxaemia undergoing cardiac surgery and receiving nitric oxide exhibited lower hypoxaemia rates and higher p a O2 /FiO 2 ratios. No significant differences were found regarding postoperative pulmonary complications and overall outcomes.

TRIAL REGISTRATION

NCT04807413.

Cerebral autoregulation monitoring using the cerebral oximetry index after neonatal cardiac surgery: A single-center retrospective cohort study

OBJECTIVE

To investigate whether cerebral autoregulation is impaired after neonatal cardiac surgery and whether changes in autoregulation metrics are associated with different congenital heart defects or the incidence of postoperative neurologic events.

METHODS

This is a retrospective observational study of neonates undergoing monitoring during the first 72 hours after cardiac surgery. Archived data were processed to calculate the cerebral oximetry index (COx) and derived metrics. Acute neurologic events were identified by an electronic medical record review. The Skillings-Mack test and the Wilcoxon signed-rank test were used to analyze the evolution of autoregulation metrics over time; the Mann-Whitney U test was used for comparison between groups.

RESULTS

We included 28 neonates, 7 (25%) with hypoplastic left heart syndrome and 21 (75%) with transposition of the great arteries. Overall, the median percentage of time spent with impaired autoregulation, defined as percentage of time with a COx >0.3, was 31.6% (interquartile range, 21.1%-38.3%). No differences in autoregulation metrics between different cardiac defects subgroups were observed. Seven patients (25%) experienced a postoperative acute neurologic event. Compared to the neonates without an acute neurologic event, those with an acute neurologic event had a higher COx (0.16 vs 0.07; P = .035), a higher percentage of time with a COx >0.3 (39.4% vs 29.2%; P = .017), and a higher percentage of time with a mean arterial pressure below the lower limit of autoregulation (13.3% vs 6.9%; P = .048).

CONCLUSIONS

COx monitoring after cardiac surgery allowed for the detection of impaired cerebral autoregulation, which was more frequent in neonates with postoperative acute neurologic events.

Impact of nitric oxide via cardiopulmonary bypass on pediatric heart surgery: a meta-analysis of randomized controlled trials

OBJECTIVE

The impact of nitric oxide (NO) administered via cardiopulmonary bypass (CPB) on pediatric heart surgery remains controversial. The objective of this study is to conduct a comprehensive systematic review and meta-analysis to examine the impact of NO administered via CPB on pediatric heart surgery.

METHODS

This study searched 7 electronic databases to identify Randomized Controlled Trials (RCTs) on the impact of NO administration during CPB on postoperative outcomes in pediatric heart surgery. The searched databases included Embase, Medline (though PubMed), Cochrane Library, Web of Science, Wan Fang database, China National Knowledge Infrastructure (CNKI), and ClinicalTrials.gov from their inception to November 2, 2022. The included RCTs compared NO administration during CPB with standard CPB procedures or placebo gas treatment in pediatric heart surgery. fixed-effects models and/or random-effects models were used to estimate the effect size with 95% confidence interval (CI). Heterogeneity among studies was indicated by p-values and I2. All analyses were performed using Review Manager software (version 5.4) in this study.

RESULTS

A total of 6 RCTs including 1,739 children were identified in this study. The primary outcome was duration of postoperative mechanical ventilation, with the length of hospital and intensive care unit (ICU) stay as the second outcomes. Through a pooled analysis, we found that exogenous NO administered via CPB for pediatric heart surgery could not shorten the duration of postoperative mechanical ventilation when compared with the control group (standardized mean difference (SMD) -0.07, CI [-0.16, 0.02], I2 = 45%, P = 0.15). Additionally, there were also no difference between the two groups in terms of length of hospital stay (mean difference (MD) -0.29, CI [-1.03, 0.46], I2 = 32%, P = 0.45) and length of ICU stay (MD -0.22, CI [-0.49 to 0.05], I2 = 72%, P = 0.10).

CONCLUSIONS

This meta-analysis showed that exogenous NO administration via CBP had no benefits on the duration of mechanical ventilation, the length of postoperative hospital, and ICU stay after pediatric heart surgery.

The Year in Review: Anesthesia for Congenital Heart Disease 2023

This review highlights published literature in 2023 that is related to the anesthetic management of patients with congenital heart disease (CHD). Though not inclusive of all topics, 31 articles are discussed and four primary themes emerged: transfusion and hemostasis, outcomes and risk assessment, monitoring, and pharmacology.

Monitoring of cerebral blood flow autoregulation: physiologic basis, measurement, and clinical implications

Cerebral blood flow (CBF) autoregulation is the physiologic process whereby blood supply to the brain is kept constant over a range of cerebral perfusion pressures ensuring a constant supply of metabolic substrate. Clinical methods for monitoring CBF autoregulation were first developed for neurocritically ill patients and have been extended to surgical patients. These methods are based on measuring the relationship between cerebral perfusion pressure and surrogates of CBF or cerebral blood volume (CBV) at low frequencies (<0.05 Hz) of autoregulation using time or frequency domain analyses. Initially intracranial pressure monitoring or transcranial Doppler assessment of CBF velocity was utilised relative to changes in cerebral perfusion pressure or mean arterial pressure. A more clinically practical approach utilising filtered signals from near infrared spectroscopy monitors as an estimate of CBF has been validated. In contrast to the traditional teaching that 50 mm Hg is the autoregulation threshold, these investigations have found wide interindividual variability of the lower limit of autoregulation ranging from 40 to 90 mm Hg in adults and 20-55 mm Hg in children. Observational data have linked impaired CBF autoregulation metrics to adverse outcomes in patients with traumatic brain injury, ischaemic stroke, subarachnoid haemorrhage, intracerebral haemorrhage, and in surgical patients. CBF autoregulation monitoring has been described in both cardiac and noncardiac surgery. Data from a single-centre randomised study in adults found that targeting arterial pressure during cardiopulmonary bypass to above the lower limit of autoregulation led to a reduction of postoperative delirium and improved memory 1 month after surgery compared with usual care. Together, the growing body of evidence suggests that monitoring CBF autoregulation provides prognostic information on eventual patient outcomes and offers potential for therapeutic intervention. For surgical patients, personalised blood pressure management based on CBF autoregulation data holds promise as a strategy to improve patient neurocognitive outcomes.

Comparison of Levosimendan Versus Milrinone After the Arterial Switch Operation for Infants ≤3 kg

Background: Various inotropes and inodilators have been utilized to treat low cardiac output syndrome after the arterial switch operation. The use of levosimendan, a calcium sensitizer has been limited in this setting. This study compares the effects of levosimendan with milrinone in managing low cardiac output after the arterial switch operation. Methods: A retrospective, comparative study was conducted in a tertiary care hospital on patients weighing up to 3 kg undergoing the arterial switch operation between January 2017 and January 2022. Patients received a loading dose followed by continuous infusion of either levosimendan or milrinone. Echocardiographic, hemodynamic and biochemical parameters were compared. Results: Forty-three patients received levosimendan and 42 patients received milrinone as the primary test drug. Cardiac index of less than 2.2 L/min/m2 on postoperative day 1 and 2 was found in 9.3% and 2.3% of patients receiving levosimendan versus 26.2% and 11.9% in those receiving milrinone, respectively (P = .04 and .08, respectively). Early lactate-clearance and better central venous oxygen saturations were noted in the levosimendan group. Prevalence of acute kidney injury was higher in the milrinone group (50% vs 28%; P = .03). Use of peritoneal dialysis in the milrinone group versus levosimendan was 31% and 16.3%, respectively (P = .11). There was no difference in hospital mortality between the groups (milrinone, 3; levosimendan, 2, P = .62). Conclusions: Levosimendan is safe and as effective as milrinone to treat low cardiac output syndrome occurring in neonates after the arterial switch operation. In addition we found that levosimendan was renal protective when compared with milrinone.

Milrinone in persistent pulmonary hypertension of newborn: a scoping review

Persistent pulmonary hypertension of the newborn (PPHN) is a common neonatal condition in newborns admitted to the neonatal intensive care units (NICUs). PPHN has still a high mortality and morbidity. Inhaled nitric oxide (iNO) is the first line vasodilator therapy for PPHN in high income countries. In low-to-middle income countries (LMICs), availability of iNO remains scarce and expensive. The purpose of this scoping review was to evaluate the current existing literature for milrinone therapy in PPHN and to identify the knowledge gaps in milrinone use in infants with PPHN. The available evidence for milrinone remains limited both as monotherapy and as an adjuvant to iNO. The studies were heterogeneous, conducted in different settings, with different populations and more importantly the endpoints of these trials were short-term outcomes such as changes in oxygenation and blood pressure. Large prospective studies investigating long-term outcomes, mortality, and the need for Extracorporeal membrane oxygenation (ECMO) are warranted. Randomized controlled trials with milrinone as monotherapy are needed in LMICs where iNO availability remains limited. IMPACT: Milrinone has a potential role in the management of PPHN both as an adjuvant to iNO as well as a monotherapy. This scoping review identified the problems existing in the published literature on milrinone and the barriers to generalization of these results. Multi-centre randomized controlled trials on milrinone, especially involving centers from low- and middle-income countries are needed, where it can be evaluated as first-line pulmonary vasodilator therapy.

Time-Varying Clearance in Milrinone Pharmacokinetics from Premature Neonates to Adolescents

BACKGROUND AND OBJECTIVES

Milrinone is an inotrope and vasodilator used for prophylaxis or treatment of low cardiac output syndrome after weaning from cardiopulmonary bypass (CPB). It is renally eliminated and has an acceptable therapeutic range of 100-300 μg/L, but weight-based dosing alone is associated with poor target attainment. We aimed to develop a population pharmacokinetic model for milrinone from premature neonates to adolescents, and to evaluate how age, renal function and recovery from CPB may impact dose selection.

METHODS

Fifty paediatric patients (aged 4 days to 16 years) were studied after undergoing cardiac surgery supported by CPB. Data from 29 premature neonates (23-28 weeks' postmenstrual age) treated for prophylaxis of low systemic blood flow were available for a pooled pharmacokinetic analysis. Population parameters were estimated using non-linear mixed effects modelling (NONMEM 7.5.1).

RESULTS

There were 369 milrinone measurements available for analysis. A one-compartment model with zero-order input and first-order elimination was used to describe milrinone disposition. Population parameters were clearance 17.8 L/70 kg [95% CI 15.8-19.9] and volume 20.4 L/h/70 kg [95% CI 17.8-22.1]. Covariates included size, postmenstrual age and renal function for clearance, and size and postnatal age for volume. Milrinone clearance is reduced by 39.5% [95% CI 24.0-53.7] immediately after bypass, and recovers to baseline clearance with a half-time of 12.0 h [95% CI 9.7-15.2]. Milrinone volume was 2.07 [95% CI 1.87-2.27] times greater at birth than the population standard and decreased over the first days of life with a half-time of 0.977 days [95% CI 0.833-1.12].

CONCLUSION

Milrinone is predominately renally eliminated and so renal function is an important covariate describing variability in clearance. Increasing clearance over time likely reflects increasing cardiac output and renal perfusion due to milrinone and return to baseline following CPB.

An Update on Pharmacologic Management of Neonatal Hypotension: When, Why, and Which Medication

Anti-hypotensive treatment, which includes dopamine, dobutamine, epinephrine, norepinephrine, milrinone, vasopressin, terlipressin, levosimendan, and glucocorticoids, is a long-established intervention in neonates with arterial hypotension (AH). However, there are still gaps in knowledge and issues that need clarification. The main questions and challenges that neonatologists face relate to the reference ranges of arterial blood pressure in presumably healthy neonates in relation to gestational and postnatal age; the arterial blood pressure level that potentially affects perfusion of critical organs; the incorporation of targeted echocardiography and near-infrared spectroscopy for assessing heart function and cerebral perfusion in clinical practice; the indication, timing, and choice of medication for each individual patient; the limited randomized clinical trials in neonates with sometimes conflicting results; and the sparse data regarding the potential effect of early hypotension or anti-hypotensive medications on long-term neurodevelopment. In this review, after a short review of AH definitions used in neonates and existing data on pathophysiology of AH, we discuss currently available data on pharmacokinetic and hemodynamic effects, as well as the effectiveness and safety of anti-hypotensive medications in neonates. In addition, data on the comparisons between anti-hypotensive medications and current suggestions for the main indications of each medication are discussed.

Congenital Diaphragmatic Hernia: Pulmonary Hypertension and Pulmonary Vascular Disease

This review provides a comprehensive summary of the current understanding of pulmonary hypertension (PH) in congenital diaphragmatic hernia, outlining the underlying pathophysiologic mechanisms, methods for assessing PH severity, optimal management strategies, and prognostic implications.

Clinical characteristics and outcomes of patients who underwent neonatal cardiac surgery: ten years of experience in a tertiary surgery center

OBJECTIVE

To evaluate the outcomes after neonatal cardiac surgery at our institute, and identify factors associated with operative mortality.

METHODS

We examined 224 neonates who underwent cardiac surgery at a single institution from 2013 to 2022. Relevant data, such as demographic information, operative details, and postoperative records, were gathered from medical and surgical records. Our primary focus was on the operative mortality.

RESULTS

Median age and weight at surgery were 12 (7-20) days and 3.4 (3.0-3.8) kg, respectively. Overall mortality was 14.3% (32/224). Mortality rates showed improvement over time (2013-2017 vs. 2018-2022), with rates decreasing from 21.9% to 10.6% (p = 0.023). ECMO use, extubation failure, lactate > 4.8 mmol/l and VIS > 15.5 on 24 h after operation were significantly associated with operative mortality, according to multivariate logistic regression analysis. Patients admitted to the cardiac intensive care unit (CICU) before surgery and those with prenatal diagnosis showed lower operative mortality. Median follow-up time of 192 hospital survivors was 28.0 (11.0-62.3) months. 10 patients experienced late deaths, and 7 patients required reinterventions after neonatal cardiac surgery. Risk factors for composite end-point of death and reintervention on multivariable analysis were: surgical period (HR = 0.230, 95% CI 0.081-0.654; p = 0.006), prolonged ventilation (HR = 4.792, 95% CI 1.296-16.177; p = 0.018) and STAT categories 3-5 (HR = 5.936, 95% CI 1.672-21.069; p = 0.006).

CONCLUSIONS

Our institution has observed improved surgical outcomes in neonatal cardiac surgery over the past five years with low mortality, but late death and reintervention remain necessary in some patients. The location and prenatal diagnosis prior to surgery may affect the outcomes of neonates undergoing congenital heart disease operations.

Reassessing the role of milrinone in the treatment of heart failure and pulmonary hypertension in neonates and children: a systematic review and meta-analysis

To evaluate milrinone's impact on pediatric cardiac function, focusing on its specific role as an inotrope and lusitrope, while considering its systemic and pulmonary vasodilatory effects. Search of PubMed, EMBASE, and the Cochrane Library up to August 2023. We included all studies that evaluated milrinone in children under 18 years old in neonatal, pediatric, or cardiac intensive care units. We excluded case reports, studies that did not provide tabular information on milrinone's outcomes, and studies focused on non-intensive care populations. We extracted data on the research design, objectives, study sample, and results of each study, including the impact of milrinone and any associated factors. We screened a total of 9423 abstracts and 41 studies were ultimately included. Milrinone significantly improved left ventricular ejection fraction (WMD 3.41 [95% CI 0.61 - 6.21]), left ventricle shortening fraction (WMD 4.25 [95% CI 3.43 - 5.08]), cardiac index (WMD 0.50 [95% CI 0.32 to 0.68]), left ventricle output (WMD 55.81 [95% CI 4.91 to 106.72]), serum lactate (WMD -0.59 [95% CI -1.15 to -0.02]), and stroke volume index (WMD 2.95 [95% CI 0.09 - 5.82]). However, milrinone was not associated with improvements in ventricular myocardial performance index (WMD -0.01 [95% CI -0.06 to 0.04]) and ventricular longitudinal strain (WMD -2.14 [95% CI -4.56 to 0.28]). Furthermore, milrinone was not associated with isovolumetric relaxation time reduction (WMD -8.87 [95% CI -21.40 to 3.66]).

CONCLUSION

Our meta-analysis suggests potential clinical benefits of milrinone by improving cardiac function, likely driven by its systemic vasodilatory effects. However, questions arise about its inotropic influence and the presence of a lusitropic effect. Moreover, milrinone's pulmonary vasodilatory effect appears relatively weaker compared to its systemic actions. Further research is needed to elucidate milrinone's precise mechanisms and refine its clinical applications in pediatric practice.

WHAT IS KNOWN

• Milrinone is a phosphodiesterase III inhibitor that has been used to treat a variety of pediatric and neonatal conditions. • Milrinone is believed to exert its therapeutic effects by enhancing cardiac contractility and promoting vascular relaxation.

WHAT IS NEW

• Milrinone may not have a significant inotropic effect. • Milrinone's pulmonary vasodilatory effect is less robust than its systemic vasodilatory effect.

Determining Optimal Mean Arterial Blood Pressure Based on Cerebral Autoregulation in Children after Cardiac Surgery

To evaluate the feasibility of continuous determination of the optimal mean arterial blood pressure (opt-MAP) according to cerebral autoregulation and to describe the opt-MAP, the autoregulation limits, and the time spent outside these limits in children within 48 h of cardiac surgery. Cerebral autoregulation was assessed using the correlation coefficient (COx) between cerebral oxygenation and MAP in children following cardiac surgery. Plots depicting the COx according to the MAP were used to determine the opt-MAP using weighted multiple time windows. For each patient, we estimated (1) the time spent with MAP outside the autoregulation limits and (2) the burden of deviation, defined as the area between the MAP curve and the autoregulation limits when the MAP was outside these limits. Fifty-one patients with a median age of 7.1 (IQR 0.7-52.0) months old were included. The opt-MAP was calculated for 94% (IQR 90-96) of the monitored time. The opt-MAP was significantly lower in neonates < 1 month old. The patients spent 24% (18-31) of the time outside of the autoregulation limits, with no significant differences between age groups. Continuous determination of the opt-MAP is feasible in children within the first 48 h following cardiac surgery.

Association between Serum Lactate and Morbidity and Mortality in Neonates: A Systematic Review and Meta-Analysis

OBJECTIVE

Lactate is a marker of hypoperfusion in critically ill patients. Whether lactate is useful for identifying and stratifying neonates with a higher risk of adverse outcomes remains unknown. This study aimed to investigate the association between lactate and morbidity and mortality in neonates.

METHODS

A meta-analysis was performed to determine the association between blood lactate levels and outcomes in neonates. Ovid MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched from inception to 1 May 2021. A total of 49 observational studies and 14 data accuracy test studies were included. The risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies and the QUADAS-2 tool for data accuracy test studies. The primary outcome was mortality, while the secondary outcomes included acute kidney injury, necessity for renal replacement therapy, neurological outcomes, respiratory morbidities, hemodynamic instability, and retinopathy of prematurity.

RESULTS

Of the 3184 articles screened, 63 studies fulfilled all eligibility criteria, comprising 46,069 neonates. Higher lactate levels are associated with mortality (standard mean difference, -1.09 [95% CI, -1.46 to -0.73]). Using the estimated sensitivity (0.769) and specificity (0.791) and assuming a prevalence of 15% for adverse outcomes (median of prevalence among studies) in a hypothetical cohort of 10,000 neonates, assessing the lactate level alone would miss 346 (3.46%) cases (false negative) and wrongly diagnose 1776 (17.76%) cases (false positive).

CONCLUSIONS

Higher lactate levels are associated with a greater risk of mortality and morbidities in neonates. However, our results do not support the use of lactate as a screening test to identify adverse outcomes in newborns. Research efforts should focus on analyzing serial lactate measurements, rather than a single measurement.

Evaluation of perfusion index and left ventricular output changes in low cardiac output syndrome after arterial switch operation

INTRODUCTION

Transposition of great arteries is one of newborns' most common cyanotic CHDs, and its treatment is arterial switch operation in the first days of life. Low cardiac output syndrome may develop in the early postoperative period. In this study, we evaluated perfusion index and left ventricular output blood flow changes in patients who underwent arterial switch operation and developed low cardiac output syndrome.

METHODS

This study was conducted prospectively in newborns with transposition of great arteries who underwent arterial switch operation between 1st August 2020 and 1st August 2022. Low cardiac output syndrome score and left ventricular output were investigated. Initially, 6th, 12th, 18th, and 24th hour perfusion index and left ventricular output values of patients with and without low cardiac output syndrome were recorded. The results were evaluated statistically.

RESULTS

A total of 60 patients were included in the study. Sex distribution was equal. The median age at the time of surgery was 5 days (interquartile range 3-7 days), and the median weight was 3.1 kg (interquartile range 2.9-3. 4). Low cardiac output syndrome was detected in 30% (n = 18) of cases. The median perfusion index of patients who developed low cardiac output syndrome was significantly lower at the 12th, 18th, and 24th hours (p < 0.05) (0.99 versus 1.25, 0.86 versus 1.21, and 0.96 versus 1.33, respectively). Similarly, the median left ventricular output of patients who developed low cardiac output syndrome was significantly lower at 12th, 18th, and 24th hours (p < 0.05) (95 versus 110 ml/kg/min, 89 versus 109 ml/kg/min, and 92 versus 112 ml/kg/min, respectively). There was a significant correlation between perfusion index values and left ventricular output at all measurements (r > 0.500, p < 0.05).

CONCLUSION

Perfusion index and left ventricular output measurements decreased in newborns who developed low cardiac output syndrome after arterial switch operation, especially at 12th and 18th hours. Serial perfusion index and left ventricular output measurements can be instructive in predicting low cardiac output syndrome development.

Factors associated with the need for inotropic support following pulmonary artery banding surgery for CHD

OBJECTIVE

We aimed to identify factors independently associated with the need for inotropic support for low cardiac output or haemodynamic instability after pulmonary artery banding surgery for CHD.

METHODS

We performed a retrospective chart review of all neonates and infants who underwent pulmonary banding between January 2016 and June 2019 at our institution. Bivariate and multivariable analyses were performed to identify factors independently associated with the use of post-operative inotropic support, defined as the initiation of inotropic infusion(s) for depressed myocardial function, hypotension, or compromised perfusion within 24 hours of pulmonary artery banding.

RESULTS

We reviewed 61 patients. Median age at surgery was 10 days (25%,75%:7,30). Cardiac anatomy was biventricular in 38 patients (62%), hypoplastic right ventricle in 14 patients (23%), and hypoplastic left ventricle in 9 patients (15%). Inotropic support was implemented in 30 patients (49%). Baseline characteristics of patients who received inotropic support, including ventricular anatomy and pre-operative ventricular function, were not statistically different from the rest of the cohort. Patients who received inotropic support, however, were exposed to larger cumulative doses of ketamine intraoperatively - median 4.0 mg/kg (25%,75%:2.8,5.9) versus 1.8 mg/kg (25%,75%:0.9,4.5), p < 0.001. In a multivariable model, cumulative ketamine dose greater than 2.5mg/kg was associated with post-operative inotropic support (odds ratio 5.5; 95% confidence interval: 1.7,17.8), independent of total surgery time.

CONCLUSIONS

Inotropic support was administered in approximately half of patients who underwent pulmonary artery banding and more commonly occurred in patients who received higher cumulative doses of ketamine intraoperatively, independent of the duration of surgery.

Administration of Milrinone Following Tetralogy of Fallot Repair Increases Postoperative Volume Administration Without Improving Cardiac Output

BACKGROUND

Phosphodiesterase inhibitors are known to relieve symptoms in the setting of heart failure, although their effects in restrictive ventricular physiology have been poorly characterized. We explored the association between the use of milrinone and volume administration during the first 72 hours following surgical repair of tetralogy of Fallot (TOF).

METHODS

We reviewed all cases of primary surgical repair of TOF with pulmonary stenosis or atresia at Boston Children's Hospital between 2011 and 2020. To adjust for baseline differences between patients who did and did not receive milrinone, we matched patients with similar propensity scores in a 1:1 ratio (use of milrinone versus not). We then compared the need for volume administration during the first 72 hours postoperatively, vital signs, and measures of cardiac output between the matched cohorts. Additionally, in the group of patients receiving milrinone, linear regression modeling was used to explore the relationship between total dose of milrinone and total volume administration.

RESULTS

Among 351 included patients, 134 received perioperative milrinone. A total of 212 patients (106 per group) were matched based on anatomic and surgical risks using a propensity score. After propensity matching, compared with nonmilrinone-treated patients, milrinone-treated patients were given postoperative volume more frequently (66% vs 52%; difference 14% [95% confidence interval, CI, 1%-27%]; P = .036). Milrinone-treated patients had a slower recovery of tachycardia during the first 12 hours (difference in slope 0.30 [95% CI, 0.14-0.47] beats per minute [BPM]/h; P < .001), and the intergroup difference peaked at 12 hours postoperatively (8 [95% CI, 5-12] BPM). Milrinone administration was not associated with improved cardiac output, including arteriovenous oxyhemoglobin saturation difference. In propensity-matched patients receiving milrinone, the total volume administered during the first 72 postoperative hours was significantly associated with the cumulative dose of postoperative milrinone ( r = 0.20; 95% CI, 0.01-0.38; P = .036). Based on the slope of the regression line, for every 1000 µg/kg of milrinone (equivalent to ~0.25 µg/kg/min for 72 hours) administered in the first 72 postoperative hours, an estimated 11.0 (95% CI, 0.6-21.4) mL/kg additional volume was administered.

CONCLUSIONS

The use of milrinone within the first 72 hours following TOF repair is associated with more frequent administration of volume, a positive association between a higher total dose of postoperative milrinone and the amount of postoperative volume administered, a higher heart rate, and a lower blood pressure, but is not associated with improved cardiac output.

The beneficial use of nitric oxide during cardiopulmonary bypass on postoperative outcomes in children and adult patients: a systematic review and meta-analysis of 2897 patients

PURPOSE

Investigate inhaled nitric oxide's influence on mortality rates, mechanical ventilation and cardiopulmonary bypass duration, and length of stay in the intensive care unit and hospital when administered during cardiopulmonary bypass.

METHODS

Following the PRISMA guidelines, we searched four electronic databases (PubMed, EMBASE, Cochrane Library, and Web of Science) up to 4th March 2023. The protocol was registered in the PROSPERO database with ID: CRD42023423007. Using Review Manager software, we reported outcomes as risk ratios (RRs) or mean difference (MD) and confidence intervals (CIs).

RESULTS

The meta-analysis included a total of 17 studies with 2897 patients. Overall, there were no significant differences in using nitric oxide over control concerning mortality (RR = 1.03, 95% CI 0.73 to 1.45; P = 0.88) or cardiopulmonary bypass duration (MD = -0.14, 95% CI - 0.96 to 0.69; P = 0.74). The intensive care unit days were significantly lower in the nitric oxide group than control (MD = -0.80, 95% CI - 1.31 to -0.29; P = 0.002). Difference results were obtained in terms of the length of stay in the hospital according to sensitivity analysis (without sensitivity [MD = -0.41, 95% CI - 0.79 to -0.02; P = 0.04] vs. with sensitivity [MD = -0.31, 95% CI - 0.69 to 0.07; P = 0.11]. Subgroup analysis shows that, in children, nitric oxide was favored over control in significantly reducing the duration of mechanical ventilation (MD = -4.58, 95% CI - 5.63 to -3.53; P < 0.001).

CONCLUSION

Using inhaled nitric oxide during cardiopulmonary bypass reduces the length of stay in the intensive care unit, and for children, it reduces the duration of mechanical ventilation.

Improving Outcomes for Infants After Cardiopulmonary Bypass Surgery for Congenital Heart Disease: A Commentary on Recent Randomized Controlled Trials

The recent NITRIC and STRESS trials demonstrate opportunities to perform pragmatic large randomized trials in congenital heart disease. We discuss lessons learnt from these trials which can inform future trial design and conduct in the field of pediatric heart surgery.

Evidence-Based Guidelines for Acute Stabilization and Management of Neonates with Persistent Pulmonary Hypertension of the Newborn

Persistent pulmonary hypertension of the newborn, or PPHN, represents a challenging condition associated with high morbidity and mortality. Management is complicated by complex pathophysiology and limited neonatal specific evidence-based literature, leading to a lack of universal contemporary clinical guidelines for the care of these patients. To address this need and to provide consistent high-quality clinical care for this challenging population in our neonatal intensive care unit, we sought to develop a comprehensive clinical guideline for the acute stabilization and management of neonates with PPHN. Utilizing cross-disciplinary expertise and incorporating an extensive literature search to guide best practice, we present an approachable, pragmatic, and clinically relevant guide for the bedside management of acute PPHN. KEY POINTS: · PPHN is associated with several unique diagnoses; the associated pathophysiology is different for each unique diagnosis.. · PPHN is a challenging, dynamic, and labile process for which optimal care requires frequent reassessment.. · Key management goals are adequate tissue oxygen delivery, avoiding harm..

Ventriculo-arterial coupling for predicting cardiac index increase in infants after heart surgery

OBJECTIVES

The aim of this study was to test the ability of ventriculo-arterial coupling (VAC) to predict cardiac index (CI) response after milrinone infusion.

METHODS

This was a retrospective, observational study. We measured arterial blood pressure and echocardiography-derived variables, including CI, systemic vascular resistance index, arterial elastance (Ea) and end-systolic ventricular elastance before and after 18-24 h of milrinone infusion. VAC was calculated as the ratio of Ea to end-systolic elastance. Infants with over 15% increase in the CI were defined as CI responders. Logistical regression was used to evaluate predictors of CI responders.

RESULTS

We enrolled 92 infants who underwent cardiac surgery and received milrinone infusion, of whom 45 infants were CI responders. High VAC (odds ratio = 5.534, 95% confidence interval 2.339-13.090) and high Ea (odds ratio = 3.035, 95% confidence interval 1.459-6.310) were independently associated with cardiac index responders. Pre-milrinone VAC predicted CI responsiveness with a cut-off value of 1.12 (area under the curve = 0.900, 95% confidence interval 0.819-0.953, P < 0.0001). Furthermore, we observed a decrease in the infant's VAC, Ea and systemic vascular resistance index after milrinone infusion.

CONCLUSIONS

In infants with congenital heart disease after surgery, a pre-milrinone VAC >1.12 can predict the increase in the CI following milrinone infusion.

Milrinone for treatment of elevated lactate in the pre-operative newborn with hypoplastic left heart syndrome

BACKGROUND

There is a paucity of information reported regarding the use of milrinone in patients with hypoplastic left heart syndrome prior to the Norwood procedure. At our institution, milrinone is initiated in the pre-operative setting when over-circulation and elevated serum lactate levels develop. We aimed to review the responses associated with the administration of milrinone in the pre-operative hypoplastic left heart syndrome patient. Second, we compared patients who received high- versus low-dose milrinone prior to Norwood procedure.

METHODS

Single-centre retrospective study of patients diagnosed with hypoplastic left heart syndrome between January 2000 and December 2019 who underwent Norwood procedure. Patient characteristics and outcomes were compared.

RESULTS

During the study period, 375 patients were identified; 79 (21%) received milrinone prior to the Norwood procedure with median lactate 2.55 mmol/l, and SpO2 93%. Patients who received milrinone were older at the time of Norwood procedure (6 vs. 5 days) and were more likely to be intubated and sedated. In a subset analysis stratifying patients to low- versus high-dose milrinone, median lactate decreased from time of initiation (2.39 vs 2.75 to 1.6 vs 1.8 mmol/l) at 12 hours post-initiation, respectively. Repeated measures analysis showed a significant decrease in lactate levels by 4 hours following initiation of milrinone, that persisted over time, with no significant difference in mean arterial pressure.

CONCLUSIONS

The use of milrinone in the pre-operative over-circulated hypoplastic left heart syndrome patient is well tolerated, is associated with decreased lactate levels, and was not associated with significant hypotension or worsening of excess pulmonary blood flow.

Delivery exogenous nitric oxide via cardiopulmonary bypass in pediatric cardiac surgery reduces the duration of postoperative mechanical ventilation-A meta-analysis of randomized controlled trials

Objectives

Cardiopulmonary bypass (CPB) is a major part of cardiac surgery that provokes systemic inflammatory reactions, myocardial ischemia, and ischemia and reperfusion damage. The aim of this study is to summarize the available evidence and evaluate whether exogenous nitric oxide administered via CPB circuits can improve recovery after cardiac surgery in children.

Method

A comprehensive search of the PubMed Medline, Ovid, Cochrane Library and Embase databases was conducted in September 2022. Only randomized controlled trials that compared nitro oxide with placebo or standard care were included.

Results

This pooled analysis included 5 RCTs containing 1642 patients. There were significant differences in the duration of postoperative mechanical ventilation between the nitric oxide group and the control group (mean difference -5.645 h; 95% CL = -9.978, -1.313; P = 0.01). Meta-analysis of the length of ICU stay and hospital stay showed no significant differences.

Conclusion

Delivering nitric oxide via CPB in pediatric cardiac surgery has an effect on reducing the duration of mechanical ventilation. Considering the small effect size, we should be cautious and think comprehensively in clinical practice.

A multi-site survey of providers on the management of heart failure with dilated cardiomyopathy in children

We conducted a scientific survey of paediatric practitioners who manage heart failure with dilated cardiomyopathy in children. The survey covered management from diagnosis to treatment to monitoring, totalling 63 questions. There were 54 respondents from 40 institutions and 3 countries. There were diverse selections of management options by the respondents in general, but also unanimity in some management options. Variation in practice is likely due to the relative paucity of scientific data in this field and lack of strong evidence-based recommendations from guidelines, which presents an opportunity for future research and quality improvement efforts as the evidence base continues to grow.

Prophylactic use of levosimendan in preoperative setting for surgical repair of congenital heart disease in children

Introduction

Low cardiac output syndrome (LCOS) is a significant cause of morbidity and the leading cause of mortality after pediatric cardiac surgery. Levosimendan has been shown safe and effective in pediatrics to treat LCOS. We aimed to review our local strategy with preoperative prophylactic Levosimendan infusion to minimize LCOS after heart surgery in identified high-risk patients.

Methods

Retrospective monocentric study. As there is no reliable cardiac output measurement in children, we recorded hemodynamic parameters as surrogates of cardiac output after extracorporeal circulation through an electronic patient survey system at different time points.

Results

Seventy-two children received Levosimendan before surgery between 2010 and 2019. As expected, most patients were newborns and infants with prolonged open-heart surgeries. Median cardiopulmonary bypass time was 182 [137-234] min, and aortic clamping time was 95 [64-126] min. The postoperative hemodynamic parameters, vasoactive-inotropic score, and urine output remained stable throughout the first 48 h. Only a tiny portion of the patients had combined surrogate markers of LCOS with a maximal median arterial lactate of 2.6 [1.9-3.5] mmol/L during the first six postoperative hours, which then progressively normalized. The median arterio-venous difference in oxygen saturation was 31 [23-38] % between 12 and 18 h post-surgery and gradually decreased. The median venous-to-arterial CO2 difference was the highest at 10 [7-12] mmHg between 12 and 18 h post-surgery. Nine patients (13%) required extracorporeal membrane oxygenation. No patient required dialysis or hemofiltration. Mortality was 0%.

Conclusion

Before congenital heart surgery, preoperative prophylactic administration of Levosimendan seems effective and safe for decreasing occurrence and duration of LCOS in high-risk children.

Management of tetralogy of Fallot in the pediatric intensive care unit

Tetralogy of Fallot (ToF) is one of the most common congenital cyanotic heart lesions and can present to a variety of health care professionals, including teams working in pediatric intensive care. Pediatric intensive care teams may care for a child with ToF pre-operatively, peri-operatively, and post-operatively. Each stage of management presents its own unique challenges. In this paper we discuss the role of pediatric intensive care in each stage of management.

Comparison of the efficacy of inhaled versus infused milrinone in the management of persistent pulmonary hypertension of the newborn in resource-limited settings: A randomized clinical trial

BACKGROUND

The standard treatment for persistent pulmonary hypertension of the newborn (PPHN) is inhaled nitric oxide (iNO), which is not available in Iran. Consequently, other drugs, such as milrinone, are prescribed. So far, no study has investigated the effectiveness of inhaled milrinone in the management of PPHN. The present study aimed to improve the management of PPHN in the absence of iNO.

METHODS

In this randomized clinical trial, neonates with PPHN, admitted to the neonatal intensive care unit of Hazrat Ali-Asghar and Akbar-Abadi hospitals, were treated with intravenous dopamine infusion and randomly divided into two groups, receiving milrinone through inhalation or infusion rout. The neonates were evaluated by Doppler echocardiography, clinical examinations, and oxygen demand test. The neonates were also evaluated for the clinical symptoms and mortality in the follow-up.

RESULTS

A total of 31 infants, with a median age of 2 days (interquartile range = 4), were included in this study. There was a significant decrease in the peak systolic and mean pulmonary arterial pressure in both inhalation and infusion groups following milrinone administration, with no significant difference between the groups (p = 0.584 and p = 0.147, respectively). There was no significant difference between the two groups regarding the mean systolic blood pressure before and after treatment. Additionally, diastolic blood pressure was significantly lower in the infusion group after treatment (p = 0.020); however, the amount of reduction was not significantly different between the groups (p = 0.928). Overall, 83.9% of the participants achieved full recovery, 75% of whom were in the infusion group and 93.3% in the inhalation group (p = 0.186).

CONCLUSION

Milrinone inhalation can have similar effects to milrinone infusion as an adjunct treatment in the management of PPHN. Also, infusion and inhalation of milrinone showed similar safety.

Diagnosis and Management of Pediatric Heart Failure

Heart failure is a highly morbid syndrome, recognized as a major cause of adult mortality. Heart failure in pediatric patients, whether in the setting of congenital or acquired heart disease, is similarly associated with high mortality and resource utilization. Understanding the clinical presentation, diagnosis, and initial stabilization of pediatric heart failure is paramount for any acute care clinician as it may mimic common childhood ailments like viral respiratory or gastrointestinal illnesses. Pediatric heart failure occurs in patients with palliated or unpalliated congenital heart disease, familial or acquired cardiomyopathy, acquired valve disease, and myocarditis. This review will focus on heart failure in pediatric patients with structurally normal hearts and will summarize what is known about patterns of presentation, etiologies, diagnostic evaluation, and the acute and chronic management of this highly morbid syndrome.

Heart Failure with Preserved Ejection Fraction in Children

Diastolic dysfunction (DD) refers to abnormalities in the mechanical function of the left ventricle (LV) during diastole. Severe LVDD can cause symptoms and the signs of heart failure (HF) in the setting of normal or near normal LV systolic function and is referred to as diastolic HF or HF with preserved ejection fraction (HFpEF). Pediatric cardiologists have long speculated HFpEF in children with congenital heart disease and cardiomyopathy. However, understanding the risk factors, clinical course, and validated biomarkers predictive of the outcome of HFpEF in children is challenging due to heterogeneous etiologies and overlapping pathophysiological mechanisms. The natural history of HFpEF varies depending upon the patient's age, sex, race, geographic location, nutritional status, biochemical risk factors, underlying heart disease, and genetic-environmental interaction, among other factors. Pediatric onset HFpEF is often not the same disease as in adults. Advances in the noninvasive evaluation of the LV diastolic function by strain, and strain rate analysis with speckle-tracking echocardiography, tissue Doppler imaging, and cardiac magnetic resonance imaging have increased our understanding of the HFpEF in children. This review addresses HFpEF in children and identifies knowledge gaps in the underlying etiologies, pathogenesis, diagnosis, and management, especially compared to adults with HFpEF.

Home Milrinone in Pediatric Hospice Care of Children with Heart Failure

CONTEXT

The symptom profile of children dying from cardiac disease, especially heart failure, differs from those with cancer and other non-cardiac conditions. Treatment with vasoactive infusions at home may be a superior therapy for symptom control for these patients, rather than traditional pain and anxiety management with morphine and benzodiazepines.

OBJECTIVES

We report our experience using outpatient milrinone in children receiving hospice care for end-stage heart failure.

METHODS

Retrospective review of a contemporary cohort of all patients at Lucile Packard Children's Hospital, Stanford who were discharged on intravenous milrinone and hospice care between 2008 and 2021. Clinical data, including cardiac diagnosis, milrinone dose and route of administration, total milrinone days, symptoms reported, rehospitalization rates, concurrent therapies and complications were analyzed.

RESULTS

Among 8 patients, median duration of home milrinone infusion was 191 (33, 572) days with the longest support duration 1,054 days. All (100%) patients were also receiving diuretics at the time of death. Five (63%) were receiving no other pain control medications until the active phase of dying. From milrinone initiation to last outpatient assessment, a reduction in the number of patients reporting respiratory discomfort, abdominal pain, weight loss/lack of appetite, and fatigue was observed. Six (75%) died at home.

CONCLUSION

We used milrinone with oral diuretics effectively for symptom control in children with heart failure on palliative care. Our experience was that this combination can be used safely in the outpatient setting for long-term use without the addition of opiates, benzodiazepines, or supplemental oxygen in most cases.

Early-Stage Vasoactive-Inotropic Score and Left Ventricular Ejection Fraction Following Cardiac Surgery: A Comparison of Two Non-invasive Heart Function Monitoring Technologies in the Prognosis of Infants

Objectives: This study aimed to compare the efficiencies of the vasoactive-inotropic score (VIS) and left ventricular ejection fraction (LVEF) in predicting the condition and prognosis of children with congenital heart disease (CHD). Methods: We retrospectively reviewed the medical charts of 104 infants aged < 1 year who underwent cardiac surgery with cardiopulmonary bypass. The maximum and mean postoperative VIS in the first and second 24 hours [VIS (24MAX), VIS (24MEA), VIS (48MAX), and VIS (48MEA)] were recorded. Similarly, LVEF within 24 hours following surgery was monitored. Receiver operator curve (ROC), regression analysis, chi-square test, and t-test were used to analyze both heart function monitoring technologies Results: Receiver operating characteristic analysis revealed that VIS was strongly associated with adverse events and death [area under ROC (AUROC) > 0.90, P = 0.00], with the two most representative scores being VIS (24MEA) and VIS (48MAX), with cut-off points of 19.42 (sensitivity = 100%; specificity = 93.90%) and 22 (sensitivity = 100%; specificity = 93.90%), respectively for death, and 18.02 (sensitivity = 91.70%; specificity = 89.10%) and 17.75 (sensitivity = 91.70%; specificity = 90.20%), respectively for adverse events. Infants with higher VIS had significantly higher mortality, higher incidence of clinical adverse events, higher lactic acid value, and longer mechanical ventilation and ICU stay (P < 0.05). However, LVEF within 24 hours following surgery was not associated with death (AUROC = 0.65, P = 0.33) or adverse events (AUROC = 0.53, P = 0.81). Moreover, there was no significant change in the length of ICU stay, duration of mechanical ventilation, and lactate value (P > 0.05). Conclusions: Vasoactive-inotropic score at an early stage following surgery was significantly associated with the condition and prognosis of infants with congenital heart disease; however, the predictive value of LVEF within 24 hours following surgery was lower.

The use of milrinone in neonates with persistent pulmonary hypertension of the newborn - a randomised controlled trial pilot study (MINT 1)

OBJECTIVE

To assess the impact of milrinone administration on time spent on nitric oxide (iNO) in infants with acute pulmonary hypertension (aPH). We hypothesized that intravenous milrinone used in conjunction with iNO would reduce the time on iNO therapy and the time spent on invasive ventilation in infants ≥34 weeks gestation with a diagnosis of aPH. We aimed to assess the practicality of instituting the protocol and contributing to a sample size calculation for a definitive multicentre study.

STUDY DESIGN

This was a multicentre, randomized, double-blind, two arm pilot study, with a balanced (1:1) allocation. Infants with a gestation ≥34 weeks and a birth weight ≥2000 grams aPH, an oxygenation index of ≥10, and commenced on iNO were eligible. Participants on iNO were assigned to either a milrinone infusion (intervention) or a normal saline infusion (placebo) for up to 35 h. The primary outcome was time on iNO and feasibility of conducting the protocol.

RESULTS

The trial was terminated early after 4 years of enrollment due to poor recruitment. Four infants were allocated to the intervention arm and 5 to the placebo arm. The groups were well matched for baseline variables. No differences were seen in any of the primary or secondary outcomes.

CONCLUSION

Conducting an interventional trial in the setting of acute pulmonary hypertension in infants is not feasible using our current approach. Future studies in this area require alternative trial design to improve recruitment as this topic remains understudied in the neonatal field.

TRIAL REGISTRATION

www.isrctn.com ; ISRCTN:12949496; EudraCT Number:2014-002988-16.

Hemodynamic assessment in children after cardiac surgery: A pilot study on the value of infrared thermography

Introduction

Low cardiac output syndrome in the postoperative period after cardiac surgery leads to an increase in tissue oxygen extraction, assessed by the oxygen extraction ratio. Measurement of the oxygen extraction ratio requires blood gases to be taken. However, the temperature of the skin and various parts of the body is a direct result of blood flow distribution and can be monitored using infrared thermography. Thus, we conducted a prospective clinical study to evaluate the correlation between the thermal gradient obtained by infrared thermography and the oxygen extraction ratio in children at risk for low cardiac output after cardiac surgery.

Methods

Children aged 0 to 18 years, having undergone cardiac surgery with cardio-pulmonary bypass in a pediatric intensive care unit were included in the study. One to 4 thermal photos were taken per patient using the FLIR One Pro thermal imaging camera. The thermal gradient between the central temperature of the inner canthus of the eye and the peripheral temperature was compared to the concomitant oxygen extraction ratio calculated from blood gases.

Results

41 patients were included with a median age of 6 months (IQR 3-48) with median Risk Adjustment for Congenital Heart Surgery-1 score was 2 (IQR 2-3). Eighty nine thermal photos were analyzed. The median thermal gradient was 2.5 °C (IQR 1,01-4.04). The median oxygen extraction ratio was 35% (IQR 26-42). Nine patients had an oxygen extraction ratio ≥ 50%. A significant but weak correlation was found between the thermal gradient and the oxygen extraction ratio (Spearman's test p = 0.25, p = 0.016). Thermal gradient was not correlated with any other clinical or biologic markers of low cardiac output. Only young age was an independent factor associated with an increase in the thermal gradient.

Conclusion

In this pilot study, which included mainly children without severe cardiac output decrease, a significant but weak correlation between thermal gradient by infrared thermography and oxygen extraction ratio after pediatric cardiac surgery was observed. Infrared thermography is a promising non-invasive technology that could be included in multimodal monitoring of postoperative cardiac surgery patients. However, a clinical trial including more severe children is needed.

3D morphable systems via deterministic microfolding for vibrational sensing, robotic implants, and reconfigurable telecommunication

DNA and proteins fold in three dimensions (3D) to enable functions that sustain life. Emulation of such folding schemes for functional materials can unleash enormous potential in advancing a wide range of technologies, especially in robotics, medicine, and telecommunication. Here, we report a microfolding strategy that enables formation of 3D morphable microelectronic systems integrated with various functional materials, including monocrystalline silicon, metallic nanomembranes, and polymers. By predesigning folding hosts and configuring folding pathways, 3D microelectronic systems in freestanding forms can transform across various complex configurations with modulated functionalities. Nearly all transitional states of 3D microelectronic systems achieved via the microfolding assembly can be easily accessed and modulated in situ, offering functional versatility and adaptability. Advanced morphable microelectronic systems including a reconfigurable microantenna for customizable telecommunication, a 3D vibration sensor for hand-tremor monitoring, and a bloomable robot for cardiac mapping demonstrate broad utility of these assembly schemes to realize advanced functionalities.

Methylprednisolone for Heart Surgery in Infants - A Randomized, Controlled Trial

BACKGROUND

Although perioperative prophylactic glucocorticoids have been used for decades, whether they improve outcomes in infants after heart surgery with cardiopulmonary bypass is unknown.

METHODS

We conducted a multicenter, prospective, randomized, placebo-controlled, registry-based trial involving infants (<1 year of age) undergoing heart surgery with cardiopulmonary bypass at 24 sites participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database. Registry data were used in the evaluation of outcomes. The infants were randomly assigned to receive prophylactic methylprednisolone (30 mg per kilogram of body weight) or placebo, which was administered into the cardiopulmonary-bypass pump-priming fluid. The primary end point was a ranked composite of death, heart transplantation, or any of 13 major complications. Patients without any of these events were assigned a ranked outcome based on postoperative length of stay. In the primary analysis, the ranked outcomes were compared between the trial groups with the use of odds ratios adjusted for prespecified risk factors. Secondary analyses included an unadjusted odds ratio, a win ratio, and safety outcomes.

RESULTS

A total of 1263 infants underwent randomization, of whom 1200 received either methylprednisolone (599 infants) or placebo (601 infants). The likelihood of a worse outcome did not differ significantly between the methylprednisolone group and the placebo group (adjusted odds ratio, 0.86; 95% confidence interval [CI], 0.71 to 1.05; P = 0.14). Secondary analyses (unadjusted for risk factors) showed an odds ratio for a worse outcome of 0.82 (95% CI, 0.67 to 1.00) and a win ratio of 1.15 (95% CI, 1.00 to 1.32) in the methylprednisolone group as compared with the placebo group, findings suggestive of a benefit with methylprednisolone; however, patients in the methylprednisolone group were more likely than those in the placebo group to receive postoperative insulin for hyperglycemia (19.0% vs. 6.7%, P<0.001).

CONCLUSIONS

Among infants undergoing surgery with cardiopulmonary bypass, prophylactic use of methylprednisolone did not significantly reduce the likelihood of a worse outcome in an adjusted analysis and was associated with postoperative development of hyperglycemia warranting insulin in a higher percentage of infants than placebo. (Funded by the National Center for Advancing Translational Sciences and others; STRESS ClinicalTrials.gov number, NCT03229538.).

Routine Perioperative Esmolol After Infant Tetralogy of Fallot Repair: Single-Center Retrospective Study of Hemodynamics

OBJECTIVES

Currently, surgical repair of tetralogy of Fallot (TOF) is associated with an 1.1% 30-day mortality rate. Those with junctional ectopic tachycardia (JET) and restrictive right ventricular physiology have poorer outcomes. Routine postoperative adrenergic or inodilator therapy has been reported, while beta-blockade following cardiopulmonary bypass has not. This study evaluated routine perioperative treatment with esmolol in infants undergoing TOF repair.

DESIGN

Retrospective chart review of the perioperative course following TOF repair.

SETTING

Single-center case series describing perioperative management of TOF in a cardiac ICU.

PATIENTS

This study reviewed all patients less than 18 months old who underwent TOF repair, excluding cases of TOF with absent pulmonary valve or atrioventricular septal defect, at our institution from June 2018 to April 2021.

INTERVENTIONS

This review investigates the hemodynamic effects of esmolol following cardiopulmonary bypass for TOF repair.

MEASUREMENTS AND MAIN RESULTS

Preoperative clinical characteristics and perioperative course were extracted from the medical record. Descriptive statistics were used. Twenty-six patients receiving perioperative esmolol after TOF repair were identified and included. Postoperative hemodynamic parameters were within a narrow range with minimal vasoactive support in most patients. Three of 26 patients experienced JET, and one of 26 of whom had a brief cardiac arrest. Median and interquartile range (IQR) for hospital and postoperative length of stay was 7 days (IQR, 6-9 d) and 6 days (IQR, 5-8 d), respectively. There were no 30-day or 1-year mortalities.

CONCLUSIONS

In this infant cohort, our experience is that the routine use of postoperative esmolol is associated with good cardiac output with minimal requirement for vasoactive support in most patients. We believe optimal postoperative management of infant TOF repair requires a meticulous multidisciplinary approach, which in our experience is enhanced with routine postoperative esmolol treatment.

Acute Cardiac Care for Neonatal Heart Disease

This manuscript is one component of a larger series of articles produced by the Neonatal Cardiac Care Collaborative that are published in this supplement of Pediatrics. In this review article, we summarize the contemporary physiologic principles, evaluation, and management of acute care issues for neonates with complex congenital heart disease. A multidisciplinary team of authors was created by the Collaborative's Executive Committee. The authors developed a detailed outline of the manuscript, and small teams of authors were assigned to draft specific sections. The authors reviewed the literature, with a focus on original manuscripts published in the last decade, and drafted preliminary content and recommendations. All authors subsequently reviewed and edited the entire manuscript until a consensus was achieved. Topics addressed include cardiopulmonary interactions, the pathophysiology of and strategies to minimize the development of ventilator-induced low cardiac output syndrome, common postoperative physiologies, perioperative bleeding and coagulation, and common postoperative complications.

Nuclear Cell-Free DNA Predicts Adverse Events After Pediatric Cardiothoracic Surgery

BACKGROUND

Preoperative risk stratification in cardiac surgery includes patient and procedure factors that are used in clinical decision-making. Despite these tools, unidentified factors contribute to variation in outcomes. Identification of latent physiologic risk factors may strengthen predictive models. Nuclear cell-free DNA (ncfDNA) increases with tissue injury and drops to baseline levels rapidly. The goal of this investigation is to measure and to observe ncfDNA kinetics in children undergoing heart operations with cardiopulmonary bypass (CPB), linking biomarkers, organ dysfunction, and outcomes.

METHODS

This is a prospective observational study of 116 children <18 years and >3 kg undergoing operations with CPB. Plasma ncfDNA samples were collected and processed in a stepwise manner at predefined perioperative time points. The primary outcome measure was occurrence of postoperative cardiac arrest or extracorporeal membrane oxygenation.

RESULTS

Data were available in 116 patients (median age, 0.9 years [range, 0-17.4 years]; median weight, 7.8 kg [range, 3.2-98 kg]). The primary outcome was met in 6 of 116 (5.2%). Risk of primary outcome was 2% with ncfDNA <20 ng/mL and 33% with ncfDNA >20 ng/mL (odds ratio, 25; CI, 3.96-158; P = .001). Elevated ncfDNA was associated with fewer hospital-free days (P < .01).

CONCLUSIONS

This study analyzes ncfDNA kinetics in children undergoing operations with CPB for congenital heart disease. Elevated preoperative ncfDNA is strongly associated with postoperative arrest and extracorporeal membrane oxygenation. Further studies are needed to validate this technology as a tool to predict morbidity in children after cardiac surgical procedures.

Vasoactive-inotropic score/inotropic score and short-term outcomes in pediatrics undergoing cardiac surgery: A retrospective analysis from single center

BACKGROUND AND AIM OF THE STUDY

This study aimed to investigate the association between vasoactive-inotropic score/inotropic score (VIS/IS) and short-term outcomes in pediatric patients after cardiac surgery at a tertiary care center in an unselected pediatric population in China.

METHODS

This study carried out retrospective observation of 401 patients between April and June 2021 at a tertiary care center. VIS and IS were assessed intraoperatively (VIS-op, IS-op) and 2 h (VIS2h, IS2h), 24 h (VIS24h, IS24h), and 48 h (VIS48h, IS48h) postoperatively. The primary outcome was prolonged mechanical ventilation (PMV). Secondary outcomes included poor prognosis and length of stay in the pediatric intensive care unit and hospital.

RESULTS

Mean age of the included pediatric patients was 26.5 months. Pediatric cardiac procedures were performed within an average operation duration of 167.6 ± 70.8 min. Overall, the PMV group (n = 93) experienced significantly longer ACC duration, cardiopulmonary bypass duration, operation duration, and a higher prevalence of fluid accumulation overload than the non-PMV group (n = 93). Multivariate logistic regression analysis revealed that longer operation duration (odds ratio [OR]: 1.015; 95% confidence interval [95% CI]: 1.003, 1.026; p = .012) and higher VIS48h (OR: 1.188; 95% CI: 1.077, 1.311; p = .001) were strongest predictors for PMV. VIS48h had better discrimination power for PMV than other time intervals, and the area under the curve was 0.780 (95% CI, 0.721, 0.839; p = .000).

CONCLUSIONS

VIS48h independently predicted short-term outcomes after cardiac surgery in an unselected pediatric population in China and showed better prediction accuracy and discrimination capability than other time intervals.

Elevated nuclear and mitochondrial cell-free deoxyribonucleic acid measurements are associated with death after infant cardiac surgery

OBJECTIVES

Mortality rates following pediatric cardiac surgery with cardiopulmonary bypass have declined over decades, but have plateaued in recent years. This is in part attributable to persistent issues with postoperative global inflammation and myocardial dysfunction, commonly manifested by systemic inflammatory response syndrome and low cardiac output syndrome, respectively. Quantified cell-free DNA (cfDNA), of nuclear or mitochondrial origin, has emerged as a biomarker for both inflammation and myocardial injury. Recent data suggest that nuclear cfDNA (ncfDNA) may quantify inflammation, whereas mitochondrial cfDNA (mcfDNA) may correlate with the degree of myocardial injury. We hypothesize that threshold levels of ncfDNA and mcfDNA can be established that are sensitive and specific for postoperative mortality mediated through independent pathways, and that association will be enhanced with combined analysis.

METHODS

Prospective observational study of infants younger than age 1 year undergoing planned surgery with cardiopulmonary bypass. The study received institutional review board approval. Samples were drawn before skin incision, immediately after completion of cardiopulmonary bypass, and subsequently at predetermined intervals postoperatively. Association of early postoperative ncfDNA and mcfDNA levels with mortality were assessed by logistic regression with cut-points chosen by receiving operating characteristic curve exploration.

RESULTS

Data were available in 59 patients. Median age and weight were 122 days (interquartile range, 63-154 days) and 4.9 kg (interquartile range, 3.9-6.2 kg). Median STAT category was 3 (interquartile range, 1-4). The primary outcome of death was met in 3 out of 59 (5%). Combined analysis of ncfDNA and mcfDNA levels at 12 hours after the initiation of cardiopulmonary bypass with death at a threshold of 50 ng/mL ncfDNA and 17 copies/μL mcfDNA yielded 100% sensitivity and negative predictive value. The specificity (91%) and positive predictive value (38%) increased through combined analysis compared with univariate analysis. Combined analysis exhibited high specificity (93%) and negative predictive value (78%) for prolonged (>30 postoperative days) hospitalization.

CONCLUSIONS

Combined analysis of early postoperative ncfDNA and mcfDNA can stratify risk of mortality and prolonged hospitalization following infant cardiac surgery. Evaluation of both ncfDNA and mcfDNA to identify states of generalized inflammation and myocardial injury may allow for targeted interventions and improved outcomes.

A systematic review of clinical study evidence for pulmonary vasodilator therapy following surgery with cardiopulmonary bypass in children with CHD

OBJECTIVES

Complications from pulmonary hypertension are one of the leading contributors to morbidity and mortality post-cardiopulmonary bypass surgery in children with CHD. Pulmonary vasodilator therapies are commonly used post-operatively, but the optimal target patient population, therapy choice, timing of therapy initiation, and duration of therapy are not well defined.

METHODS

We used PubMed and EMBASE to identify studies from 2000 to 2020 investigating the use of pulmonary vasodilator therapy post-cardiopulmonary bypass in children aged 0-18 years. To ensure eligibility criteria, studies were systematically reviewed by two independent reviewers.

RESULTS

We identified 26 studies of 42,971 children across four medication classes; 23 were single centre, 14 were prospective, and 11 involved randomisation (four of which employed a placebo-control arm). A disproportionate number of children were from a single retrospective study of 41,872 patients. Definitions varied, but change in pulmonary haemodynamics was the most common primary outcome, used in 14 studies. Six studies had clinical endpoints, with mortality the primary endpoint for two studies. Treatment with inhaled nitric oxide, iloprost, and sildenafil all resulted in improved haemodynamics in specific cohorts of children with post-operative pulmonary hypertension, although improved outcomes were not consistently demonstrated across all treated children. Iloprost may be a cheaper alternative to inhaled nitric oxide with similar haemodynamic response.

CONCLUSION

Studies were predominantly single-centre, a control arm was rarely used in randomised studies, and haemodynamic endpoints varied significantly. Further research is needed to reduce post-operative morbidity and mortality from pulmonary hypertension in children with CHD.

Effect of Nitric Oxide via Cardiopulmonary Bypass on Ventilator-Free Days in Young Children Undergoing Congenital Heart Disease Surgery: The NITRIC Randomized Clinical Trial

IMPORTANCE

In children undergoing heart surgery, nitric oxide administered into the gas flow of the cardiopulmonary bypass oxygenator may reduce postoperative low cardiac output syndrome, leading to improved recovery and shorter duration of respiratory support. It remains uncertain whether nitric oxide administered into the cardiopulmonary bypass oxygenator improves ventilator-free days (days alive and free from mechanical ventilation).

OBJECTIVE

To determine the effect of nitric oxide applied into the cardiopulmonary bypass oxygenator vs standard care on ventilator-free days in children undergoing surgery for congenital heart disease.

DESIGN, SETTING, AND PARTICIPANTS

Double-blind, multicenter, randomized clinical trial in 6 pediatric cardiac surgical centers in Australia, New Zealand, and the Netherlands. A total of 1371 children younger than 2 years undergoing congenital heart surgery were randomized between July 2017 and April 2021, with 28-day follow-up of the last participant completed on May 24, 2021.

INTERVENTIONS

Patients were assigned to receive nitric oxide at 20 ppm delivered into the cardiopulmonary bypass oxygenator (n = 679) or standard care cardiopulmonary bypass without nitric oxide (n = 685).

MAIN OUTCOMES AND MEASURES

The primary end point was the number of ventilator-free days from commencement of bypass until day 28. There were 4 secondary end points including a composite of low cardiac output syndrome, extracorporeal life support, or death; length of stay in the intensive care unit; length of stay in the hospital; and postoperative troponin levels.

RESULTS

Among 1371 patients who were randomized (mean [SD] age, 21.2 [23.5] weeks; 587 girls [42.8%]), 1364 (99.5%) completed the trial. The number of ventilator-free days did not differ significantly between the nitric oxide and standard care groups, with a median of 26.6 days (IQR, 24.4 to 27.4) vs 26.4 days (IQR, 24.0 to 27.2), respectively, for an absolute difference of -0.01 days (95% CI, -0.25 to 0.22; P = .92). A total of 22.5% of the nitric oxide group and 20.9% of the standard care group developed low cardiac output syndrome within 48 hours, needed extracorporeal support within 48 hours, or died by day 28, for an adjusted odds ratio of 1.12 (95% CI, 0.85 to 1.47). Other secondary outcomes were not significantly different between the groups.

CONCLUSIONS AND RELEVANCE

In children younger than 2 years undergoing cardiopulmonary bypass surgery for congenital heart disease, the use of nitric oxide via cardiopulmonary bypass did not significantly affect the number of ventilator-free days. These findings do not support the use of nitric oxide delivered into the cardiopulmonary bypass oxygenator during heart surgery.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12617000821392.

Assessment of the effect of two regimens of milrinone infusion in paediatric patients with pulmonary artery hypertension undergoing corrective cardiac procedure: A prospective observational study

Background

The aim of the study was to compare the effect of two different regimens of milrinone in pediatric patients with pulmonary artery hypertension (PAH) undergoing corrective procedure.

Materials and Methods

This randomized prospective study included 100 pediatric patients undergoing corrective cardiac surgeries. Group E: Milrinone was started as infusion 0.5 μg/kg/min without a loading dose after induction of anesthesia and continued as infusion 0.5-0.75 μg/kg/min in the pediatric cardiac surgical intensive care unit (PSICU). Group L: Milrinone was started as a loading dose 50 μg/kg over 10 min before weaning from cardiopulmonary bypass (CPB) followed by infusion 0.5-0.75 μg/kg/min in the PSICU. We compared heart rate, mean arterial blood pressure, central venous pressure, cardiac index (CI), mean pulmonary arterial pressure (MPAP), serum lactate level, urine output, vasoactive inotropic score, mechanical ventilation duration, and intensive care unit (ICU)- and hospital length of stay between the groups.

Results

There was an increase in mean arterial blood pressure, CI, and urine output in Group E compared to Group L (P < 0.05). MPAP, serum lactate level, and requirement of inotropes and vasopressors were lower in Group E compared to Group L (P < 0.05). Mechanical ventilation duration, ICU, and hospital length of stay were shorter in Group E than Group L (P < 0.05).

Conclusions

Early use of milrinone in patients with PAH undergoing corrective cardiac surgeries improved CI and mean arterial pressure, decreased MPAP, improved urine output, decreased serum lactate level, and decreased requirement of inotropes and vasopressors after weaning from CPB compared to the milrinone bolus group.

Study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial

Background: Peritoneal dialysis (PD) is a commonly used therapy after infant cardiac surgery. It is unclear whether early PD commenced soon after admission to an intensive care unit (ICU) after cardiac surgery results in better outcomes. Objective: To describe the study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial. Design, setting, participants and intervention: The EPICS trial is an open, randomised, two-group, single-centre clinical study of infants ≤ 180 days of age who had cardiac surgery (in Risk-Adjusted Classification for Congenital Heart Surgery version 1 categories 3-6) with cardiopulmonary bypass. Participants will be randomly assigned 1:1 to early PD (treatment group) or no early PD (control group). Those assigned to the treatment group will begin receiving PD soon after ICU admission and continue receiving it for 24 hours. Those in the control group will not receive PD during the first 24 hours. Main outcome measures: The primary outcome is a composite measure consisting of one or more of death, cardiac arrest, emergency chest reopening, and requirement for extracorporeal membrane oxygenation (ECMO) within 90 days. The main secondary outcomes are duration of mechanical ventilation, ICU length of stay, hospital length of stay, vasoactive-inotropic score at 24 hours, and cumulative per cent fluid balance by end of Day 2. At Day 90, events such as mortality, requirement for ECMO, cardiac arrest, chest reopening, volume of packed red blood cell transfusion, postoperative infection, readmission to ICU, renal injury and brain injury will be assessed. Conclusions: The EPICS trial aims to evaluate the role of early PD after infant cardiac surgery in lowering the rate of a composite major outcome. In addition, it will test the effect of early PD on duration of mechanical ventilation, and on ICU and hospital length of stay. Trial registration: ACTRN12617001614381.

PICU Pharmacology

The care of the critically-ill child often includes medications used to optimize organ function, treat infections, and provide comfort. Pediatric pharmacology has some key differences that should be leveraged for safe pharmacologic management.

Medical Therapies for Heart Failure in Hypoplastic Left Heart Syndrome

Significant surgical and medical advances over the past several decades have resulted in a growing number of infants and children surviving with hypoplastic left heart syndrome (HLHS) and other congenital heart defects associated with a single systemic right ventricle (RV). However, cardiac dysfunction and ultimately heart failure (HF) remain the most common cause of death and indication for transplantation in this population. Moreover, while early recognition and treatment of single ventricle-related complications are essential to improving outcomes, there are no proven therapeutic strategies for single systemic RV HF in the pediatric population. Importantly, prototypical adult HF therapies have been relatively ineffective in mitigating the need for cardiac transplantation in HLHS, likely due to several unique attributes of the failing HLHS myocardium. Here, we discuss the most commonly used medical therapies for the treatment of HF symptoms in HLHS and other single systemic RV patients. Additionally, we provide an overview of potential novel therapies for systemic ventricular failure in the HLHS and related populations based on fundamental science, pre-clinical, clinical, and observational studies in the current literature.