Persistent acute kidney injury and fluid accumulation with outcomes after the Norwood procedure: report from NEPHRON

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common, but its impact on clinical outcomes is variable. Parsing AKI into sub-phenotype(s) and integrating pathologic positive cumulative fluid balance (CFB) may better inform prognosis. We sought to determine whether durational sub-phenotyping of CS-AKI with CFB strengthens association with outcomes among neonates undergoing the Norwood procedure.

METHODS

Multicenter, retrospective cohort study from the Neonatal and Pediatric Heart and Renal Outcomes Network. Transient CS-AKI: present only on post-operative day (POD) 1 and/or 2; persistent CS-AKI: continued after POD 2. CFB was evaluated per day and peak CFB during the first 7 postoperative days. Primary and secondary outcomes were mortality, respiratory support-free and hospital-free days (at 28, 60 days, respectively). The primary predictor was persistent CS-AKI, defined by modified neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

CS-AKI occurred in 59% (205/347) neonates: 36.6% (127/347) transient and 22.5% (78/347) persistent; CFB > 10% occurred in 18.7% (65/347). Patients with either persistent CS-AKI or peak CFB > 10% had higher mortality. Combined persistent CS-AKI with peak CFB > 10% (n = 21) associated with increased mortality (aOR: 7.8, 95% CI: 1.4, 45.5; p = 0.02), decreased respiratory support-free (predicted mean 12 vs. 19; p < 0.001) and hospital-free days (17 vs. 29; p = 0.048) compared to those with neither.

CONCLUSIONS

The combination of persistent CS-AKI and peak CFB > 10% after the Norwood procedure is associated with mortality and hospital resource utilization. Prospective studies targeting intra- and postoperative CS-AKI risk factors and reducing CFB have the potential to improve outcomes.

Pharmacokinetic Modeling Using Real-World Data to Optimize Unfractionated Heparin Dosing in Pediatric Patients on Extracorporeal Membrane Oxygenation and Evaluate Target Achievement-Clinical Outcomes Relationship

Unfractionated heparin (UFH) is a commonly used anticoagulant for pediatric patients undergoing extracorporeal membrane oxygenation (ECMO), but evidence is lacking on the ideal dosing. We aimed to (1) develop a population pharmacokinetic (PK) model for UFH, measured through anti-factor Xa assay; (2) optimize UFH starting infusions and dose titrations through simulations; and (3) explore UFH exposure-clinical outcomes relationship. Data from 218 patients admitted to Utah's Primary Children's Hospital were retrospectively collected. A 1-compartment PK model with time-varying clearance (CL) adequately described UFH PK. Weight on CL and volume of distribution and ECMO circuit change on CL were significant covariates. The typical estimates for initial CL and first-order rate constant to reach steady-state CL were 0.57 L/(h·10 kg) and 0.02/h. Comparable to non-ECMO patients, the typical steady-state CL was 0.81 L/(h·10 kg). Simulations showed that a 75 IU/kg UFH bolus dose followed by starting infusions of 25 and 20 IU/h/kg for patients aged younger than 6 years and 6 years or older, respectively, achieved the therapeutic target in 56.6% of all patients, whereas only 3.1% exceeded the target. The proposed UFH titration schemes achieved the target in more than 90% of patients while less than 0.63% were above the target after 24 and 48 hours of treatment. The median intensive care unit survival time in patients within and below the target at 24 hours was 136 and 66 hours, respectively. In conclusion, PK model of UFH was developed for pediatric patients on ECMO. The proposed UFH dosing scheme attained the anti-factor Xa target rapidly and safely.

The final hospital need in children discharged from a cardiology acute care unit: a single-centre survey study

OBJECTIVE

Children with heart disease may require inpatient care for many reasons, but ultimately have a final reason for hospitalisation prior to discharge. Factors influencing length of stay in paediatric cardiac acute care units have been described but the last reason for hospitalisation has not been studied. Our aim was to describe Final Hospital Need as a novel measure, determine Final Hospital Need in our patients, and describe factors associated with this Need.

METHODS

Single-centre survey design. Discharging providers selected a Final Hospital Need from the following categories: cardiovascular, respiratory, feeding/fluid, haematology/ID, pain/sedation, systems issues, and other/wound issues. Univariable and multivariable analyses were performed separately for outcomes "cardiovascular" and "feeding/fluid."

MEASUREMENTS AND RESULTS

Survey response rate was 99% (624 encounters). The most frequent Final Hospital Needs were cardiovascular (36%), feeding/fluid (24%) and systems issues (13%). Probability of Final Hospital Need "cardiovascular" decreased as length of stay increased. Multivariate analysis showed Final Hospital Need "cardiovascular" was negatively associated with aortic arch repair, Norwood procedure, and Final ICU Need "respiratory" and "other." Final Hospital Need "feeding/fluid" was negatively associated with left-sided valve procedure, but positively associated with final ICU need "respiratory," and tube feeding at discharge.

CONCLUSIONS

Final Hospital Need is a novel measure that can be predicted by clinical factors including age, Final ICU Need, and type of surgery. Final Hospital Need may be utilised to track changes in clinical care over time and as a target for improvement work.

Nutritional management of postoperative chylothorax in children with CHD

INTRODUCTION

Chylothorax after congenital cardiac surgery is associated with increased risk of malnutrition. Nutritional management following chylothorax diagnosis varies across sites and patient populations, and a standardised approach has not been disseminated. The aim of this review article is to provide contemporary recommendations related to nutritional management of chylothorax to minimise risk of malnutrition.

METHODS

The management guidelines were developed by consensus across four dietitians, one nurse practitioner, and two physicians with a cumulative 52 years of experience caring for children with CHD. A PubMed database search for relevant literature included the terms chylothorax, paediatric, postoperative, CHD, chylothorax management, growth failure, and malnutrition.

RESULTS

Fat-modified diets and nil per os therapies for all paediatric patients (<18 years of age) following cardiac surgery are highlighted in this review. Specific emphasis on strategies for treatment, duration of therapies, optimisation of nutrition including nutrition-focused lab monitoring, and supplementation strategies are provided.

CONCLUSIONS

Our deliverable is a clinically useful guide for the nutritional management of chylothorax following paediatric cardiac surgery.

Early postoperative weight-based fluid overload is associated with worse outcomes after neonatal cardiac surgery

OBJECTIVES

Evaluate the association of postoperative day (POD) 2 weight-based fluid balance (FB-W) > 10% with outcomes after neonatal cardiac surgery.

METHODS

Retrospective cohort study of 22 hospitals in the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) registry from September 2015 to January 2018. Of 2240 eligible patients, 997 neonates (cardiopulmonary bypass (CPB) n = 658, non-CPB n = 339) were weighed on POD2 and included.

RESULTS

Forty-five percent (n = 444) of patients had FB-W > 10%. Patients with POD2 FB-W > 10% had higher acuity of illness and worse outcomes. Hospital mortality was 2.8% (n = 28) and not independently associated with POD2 FB-W > 10% (OR 1.04; 95% CI 0.29-3.68). POD2 FB-W > 10% was associated with all utilization outcomes, including duration of mechanical ventilation (multiplicative rate of 1.19; 95% CI 1.04-1.36), respiratory support (1.28; 95% CI 1.07-1.54), inotropic support (1.38; 95% CI 1.10-1.73), and postoperative hospital length of stay (LOS 1.15; 95% CI 1.03-1.27). In secondary analyses, POD2 FB-W as a continuous variable demonstrated association with prolonged durations of mechanical ventilation (OR 1.04; 95% CI 1.02-1.06], respiratory support (1.03; 95% CI 1.01-1.05), inotropic support (1.03; 95% CI 1.00-1.05), and postoperative hospital LOS (1.02; 95% CI 1.00-1.04). POD2 intake-output based fluid balance (FB-IO) was not associated with any outcome.

CONCLUSIONS

POD2 weight-based fluid balance > 10% occurs frequently after neonatal cardiac surgery and is associated with longer cardiorespiratory support and postoperative hospital LOS. However, POD2 FB-IO was not associated with clinical outcomes. Mitigating early postoperative fluid accumulation may improve outcomes but requires safely weighing neonates in the early postoperative period. A higher resolution version of the Graphical abstract is available as Supplementary information.

Optimal Fat-modified Diet Duration for the Treatment of Postoperative Chylothorax in Children

BACKGROUND

Dietary modification is the mainstay of treatment for postoperative chylothorax in children. However, optimal fat-modified diet (FMD) duration to prevent recurrence is unknown. Our aim was to determine the association between FMD duration and chylothorax recurrence.

METHODS

Retrospective cohort study conducted across six pediatric cardiac intensive care units within the United States. Patients <18 years who developed chylothorax within 30 days following cardiac surgery between January 2020 and April 2022 were included. Patients with a Fontan palliation or who died or were lost to follow-up or within 30 days of resuming a regular diet were excluded. FMD duration was defined as the first day of a FMD when chest tube output was <10 mL/kg/day without increasing until the resumption of a regular diet. Patients were classified into three groups (< 3 weeks, 3-5 weeks, >5 weeks) based on FMD duration.

RESULTS

105 patients were included; <3 weeks (n=61) 3-5 weeks (n=18), and >5 weeks (n=26). Demographic, surgical, and hospitalization characteristics were not different across groups. In the >5 weeks group, chest tube duration was longer compared to the <3 weeks and 3-5 weeks groups (median: 17.5 days (IQR: 9, 31) vs 10 and 10.5 days; p=0.04). There was no recurrence of chylothorax within 30 days once chylothorax was resolving regardless of FMD duration.

CONCLUSIONS

FMD duration was not associated with recurrence of chylothorax, suggesting FMD duration can safely be shortened to at least < 3 weeks from time of resolving chylothorax.

Association Between Mortality and Ventilator Parameters in Children With Respiratory Failure on ECMO

BACKGROUND

In refractory respiratory failure, extracorporeal membrane oxygenation (ECMO) is a rescue therapy to prevent ventilator-induced lung injury. Optimal ventilator parameters during ECMO remain unknown. Our objective was to describe the association between mortality and ventilator parameters during ECMO for neonatal and pediatric respiratory failure.

METHODS

We performed a secondary analysis of the Bleeding and Thrombosis on ECMO dataset. Ventilator parameters included breathing frequency, tidal volume, peak inspiratory pressure, PEEP, dynamic driving pressure, pressure support, mean airway pressure, and FIO2 . Parameters were evaluated before cannulation, on the calendar day of ECMO initiation (ECMO day 1), and the day before ECMO separation.

RESULTS

Of 237 included subjects analyzed, 64% were neonates, of whom 36% had a congenital diaphragmatic hernia. Of all the subjects, 67% were supported on venoarterial ECMO. Overall in-hospital mortality was 35% (n = 83). The median (interquartile range) PEEP on ECMO day 1 was 8 (5.0-10.0) cm H2O for neonates and 10 (8.0-10.0) cm H2O for pediatric subjects. By multivariable analysis, higher PEEP on ECMO day 1 in neonates was associated with lower odds of in-hospital mortality (odds ratio 0.77, 95% CI 0.62-0.92; P = .01), with a further amplified effect in neonates with congenital diaphragmatic hernia (odds ratio 0.59, 95% CI 0.41-0.86; P = .005). No ventilator type or parameter was associated with mortality in pediatric subjects.

CONCLUSIONS

Avoiding low PEEP on ECMO day 1 for neonates on ECMO may be beneficial, particularly those with a congenital diaphragmatic hernia. No additional ventilator parameters were associated with mortality in either neonatal or pediatric subjects. PEEP is a modifiable parameter that may improve neonatal survival during ECMO and requires further investigation.

Assessment of fluid balance after neonatal cardiac surgery: a description of intake/output vs. weight-based methods

BACKGROUND

Fluid overload associates with poor outcomes after neonatal cardiac surgery, but consensus does not exist for the most clinically relevant method of measuring fluid balance (FB). While weight change-based FB (FB-W) is standard in neonatal intensive care units, weighing infants after cardiac surgery may be challenging. We aimed to identify characteristics associated with obtaining weights and to understand how intake/output-based FB (FB-IO) and FB-W compare in the early postoperative period in this population.

METHODS

Observational retrospective study of 2235 neonates undergoing cardiac surgery from 22 hospitals comprising the NEonatal and Pediatric Heart and Renal Outcomes Network (NEPHRON) database.

RESULTS

Forty-five percent (n = 998) of patients were weighed on postoperative day (POD) 2, varying from 2 to 98% among centers. Odds of being weighed were lower for STAT categories 4 and 5 (OR 0.72; 95% CI 0.53-0.98), cardiopulmonary bypass (0.59; 0.42-0.83), delayed sternal closure (0.27; 0.19-0.38), prophylactic peritoneal dialysis use (0.58; 0.34-0.99), and mechanical ventilation on POD 2 (0.23; 0.16-0.33). Correlation between FB-IO and FB-W was weak for every POD 1-6 and within the entire cohort (correlation coefficient 0.15; 95% CI 0.12-0.17). FB-W measured higher than paired FB-IO (mean bias 12.5%; 95% CI 11.6-13.4%) with wide 95% limits of agreement (- 15.4-40.4%).

CONCLUSIONS

Weighing neonates early after cardiac surgery is uncommon, with significant practice variation among centers. Patients with increased severity of illness are less likely to be weighed. FB-W and FB-IO have weak correlation, and further study is needed to determine which cumulative FB metric most associates with adverse outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Anticoagulation practices associated with bleeding and thrombosis in pediatric extracorporeal membrane oxygenation; a multi-center secondary analysis

To determine associations between anticoagulation practices and bleeding and thrombosis during pediatric extracorporeal membrane oxygenation (ECMO), we performed a secondary analysis of prospectively collected data which included 481 children (<19 years), between January 2012 and September 2014. The primary outcome was bleeding or thrombotic events. Bleeding events included a blood product transfusion >80 ml/kg on any day, pulmonary hemorrhage, or intracranial bleeding, Thrombotic events included pulmonary emboli, intracranial clot, limb ischemia, cardiac clot, and arterial cannula or entire circuit change. Bleeding occurred in 42% of patients. Five percent of subjects thrombosed, of which 89% also bled. Daily bleeding odds were independently associated with day prior activated clotting time (ACT) (OR 1.03, 95% CI= 1.00, 1.05, p=0.047) and fibrinogen levels (OR 0.90, 95% CI 0.84, 0.96, p <0.001). Thrombosis odds decreased with increased day prior heparin dose (OR 0.88, 95% CI 0.81, 0.97, p=0.006). Lower ACT values and increased fibrinogen levels may be considered to decrease the odds of bleeding. Use of this single measure, however, may not be sufficient alone to guide optimal anticoagulation practice during ECMO.

Prediction Model with External Validation for Early Detection of Postoperative Pediatric Chylothorax

Earlier diagnosis of chylothorax following pediatric cardiac surgery is associated with decreased duration of chylothorax. Pleural fluid testing is used to diagnosis chylothorax which may delay detection in patients who are not enterally fed at time of chylothorax onset. Our aim was to develop and externally validate a prediction model to detect chylothorax earlier than pleural fluid testing in pediatric patients following cardiac surgery. A multivariable logistic regression model was developed to detect chylothorax using a stepwise approach. The model was developed using data from patients < 18 years following cardiac surgery from Primary Children's Hospital, a tertiary-care academic center, between 2017 and 2020. External validation used a contemporary cohort (n = 171) from Lucille Packard Children's Hospital. A total of 763 encounters (735 patients) were analyzed, of which 72 had chylothorax. The final variables selected were chest tube output (CTO) the day after sternal closure (dichotomized at 15.6 mL/kg/day, and as a continuous variable) and delayed sternal closure. The highest odds of chylothorax were associated with CTO on post-sternal closure day 1 > 15.6 mL/kg/day (odds ratio 11.3, 95% CI 6,3, 21.3). The c-statistic for the internal and external validation datasets using the dichotomized CTO variable were 0.78 (95% CI 0.73, 0.82) and 0.84 (95% CI, 0.78, 0.9) and performance improved when using CTO as a continuous variable (OR 0.84, CI: 95% CI 0.80, 0.87). Using the models described, chylothorax after pediatric cardiac surgery may be detected earlier and without reliance on enteral feeds.

Impact of a Surgical Wound Infection Prevention Bundle in Pediatric Cardiothoracic Surgery

BACKGROUND

The aim of this project was to decrease the incidence of surgical wound infection (SWI) to <1.5% in our pediatric cardiothoracic surgery patients using a prevention bundle and quality improvement process.

METHODS

An SWI prevention bundle addressing preoperative, intraoperative, and postoperative risks was implemented. The primary outcome was SWI based on Society of Thoracic Surgeons criteria (superficial, deep, or mediastinitis). Novel aspects of the bundle included standardization of surgical closure and wound coverage for 14 days with a negative pressure dressing or a silicone dressing. Data were collected from January 2017 to November 2021; bundle intervention began in December 2019. SWIs were tracked using a g-chart. Preintervention and postintervention cohorts were compared by standard descriptive statistics. There were no changes in SWI tracking methods during the study.

RESULTS

During the study, 1159 individuals underwent 1768 surgical interventions. Preintervention (n = 931) and postintervention (n = 837) groups were clinically similar, with fewer neonatal surgeries in the postintervention group. SWI decreased in all patients (preintervention period: 1 SWI per 22 surgeries; postintervention period: 1 SWI per 62.6 surgeries) and in neonates (preintervention period: 1 SWI per 12 surgeries; postintervention period: 1 SWI per 26.7 surgeries). Special cause variation was achieved in the entire cohort by March 2021 and in neonates by April 2021. Decreases in SWI occurred in superficial and deep wounds but not in mediastinitis. Annual rate of total SWIs decreased from 2.83% in 2019 to 1.15% in 2021. Intensive care unit and hospital length of stay did not change.

CONCLUSIONS

We demonstrated a reduction in SWI rates after implementing an SWI prevention bundle including standardized surgical closure and prolonged wound protection.

Fluid Accumulation After Neonatal Congenital Cardiac Operation: Clinical Implications and Outcomes

BACKGROUND

This study was conducted to determine the association between fluid balance metrics and mortality and other postoperative outcomes after neonatal cardiac operation in a contemporary multicenter cohort.

METHODS

This was an observational cohort study across 22 hospitals in neonates (≤30 days) undergoing cardiac operation. We explored overall percentage fluid overload, postoperative day 1 percentage fluid overload, peak percentage fluid overload, and time to first negative daily fluid balance. The primary outcome was in-hospital mortality. Secondary outcomes included postoperative duration of mechanical ventilation and intensive care unit (ICU) and hospital length of stay. Multivariable logistic or negative binomial regression was used to determine independent associations between fluid overload variables and each outcome.

RESULTS

The cohort included 2223 patients. In-hospital mortality was 3.9% (n = 87). Overall median peak percentage fluid overload was 4.9% (interquartile range, 0.4%-10.5%). Peak percentage fluid overload and postoperative day 1 percentage fluid overload were not associated with primary or secondary outcomes. Hospital resource utilization increased on each successive day of not achieving a first negative daily fluid balance and was characterized by longer duration of mechanical ventilation (incidence rate ratio, 1.11; 95% CI, 1.08-1.14), ICU length of stay (incidence rate ratio, 1.08; 95% CI, 1.03-1.12), and hospital length of stay (incidence rate ratio, 1.09; 95% CI, 1.05-1.13).

CONCLUSIONS

Time to first negative daily fluid balance, but not percentage fluid overload, is associated with improved postoperative outcomes in neonates after cardiac operation. Specific treatments to achieve an early negative fluid balance may decrease postoperative care durations.

Team Communication and Expectations Following Pediatric Cardiac Surgery: A Multi-Disciplinary Survey

Patients and families desire an accurate understanding of the expected recovery following congenital cardiac surgery. Variation in knowledge and expectations within the care team may be under-recognized and impact communication and care delivery. Our objective was to assess knowledge of common postoperative milestones and perceived efficacy of communication with patients and families and within the care team. An 18-question survey measuring knowledge of expected milestones for recovery after four index operations and team communication in the postoperative period was distributed electronically to multidisciplinary care team members at 16 academic pediatric heart centers. Answers were compared to local median data for each respondent's heart center to assess accuracy and stratified by heart center role and years of experience. We obtained 874 responses with broad representation of disciplines. More than half of all respondent predictions (55.3%) did not match their local median data. Percent matching did not vary by care team role but improved with increasing experience (35.8% < 2 years vs. 46.4% > 10 years, p = 0.2133). Of all respondents, 62.7% expressed confidence discussing the anticipated postoperative course, 78.6% denoted confidence discussing postoperative complications, and 55.3% conveyed that not all members of their care team share a common expectation for typical postoperative recovery. Most respondents (94.6%) stated that increased knowledge of local data would positively impact communication. Confidence in communication exceeded accuracy in predicting the timing of postoperative milestones. Important variation in knowledge and expectations for postoperative recovery in pediatric cardiac surgery exists and may impact communication and clinical effectiveness.

Preventing Cardiac Arrest in the Pediatric Cardiac Intensive Care Unit Through Multicenter Collaboration

Importance

Preventing in-hospital cardiac arrest (IHCA) likely represents an effective strategy to improve outcomes for critically ill patients, but feasibility of IHCA prevention remains unclear.

Objective

To determine whether a low-technology cardiac arrest prevention (CAP) practice bundle decreases IHCA rate.

Design, Setting, and Participants

Pediatric cardiac intensive care unit (CICU) teams from the Pediatric Cardiac Critical Care Consortium (PC4) formed a collaborative learning network to implement the CAP bundle consistent with the Institute for Healthcare Improvement framework; 15 hospitals implemented the bundle voluntarily. Risk-adjusted IHCA incidence rates were analyzed across 2 time periods, 12 months (baseline) and 18 months after CAP implementation (intervention) using difference-in-differences (DID) regression to compare 15 CAP and 16 control PC4 hospitals that chose not to participate in CAP but had IHCA rates tracked in the PC4 registry. Patients deemed at high risk for IHCA, based on a priori evidence-based criteria and empirical hospital-specific criteria, were selected to receive the CAP bundle. Data were collected from July 2018 to December 2019, and data were analyzed from March to August 2020.

Interventions

CAP bundle included 5 elements developed to promote increased situational awareness and communication among bedside clinicians to recognize and mitigate deterioration in high-risk patients.

Main Outcomes and Measures

Risk-adjusted IHCA incidence rate across all CICU admissions (IHCA events divided by all admissions).

Results

The bundle was activated in 2664 of 10 510 CAP hospital admissions (25.3%); admission characteristics were similar across study periods. There was a 30% relative reduction in risk-adjusted IHCA incidence rate at CAP hospitals (intervention period: 2.6%; 95% CI, 2.2-2.9; baseline: 3.7%; 95% CI, 3.1-4.0), but no change at control hospitals (intervention period: 2.7%; 95% CI, 2.3-2.9; baseline: 2.7%; 95% CI, 2.2-3.0). DID analysis confirmed significantly reduced odds of IHCA among all admissions at CAP hospitals compared with control hospitals during the intervention period vs baseline (odds ratio, 0.72; 95% CI, 0.56-0.91; P = .01). DID odds ratios were 0.72 (95% CI, 0.53-0.98) for the surgical subgroup, 0.74 (95% CI, 0.48-1.14) for the medical subgroup, and 0.72 (95% CI, 0.50-1.03) for the high-risk admission subgroup at CAP hospitals after intervention. All-cause risk-adjusted mortality rate did not change after intervention.

Conclusions and Relevance

Implementation of this CAP bundle led to significant IHCA reduction across multiple pediatric CICUs. Future studies may determine if this bundle can be effective in other critically ill populations.

Critical Care Unit Organizational and Personnel Factors Impact Cardiac Arrest Prevention and Rescue in the Pediatric Cardiac Population

OBJECTIVES

Patient-level factors related to cardiac arrest in the pediatric cardiac population are well understood but may be unmodifiable. The impact of cardiac ICU organizational and personnel factors on cardiac arrest rates and outcomes remains unknown. We sought to better understand the association between these potentially modifiable organizational and personnel factors on cardiac arrest prevention and rescue.

DESIGN

Retrospective analysis of the Pediatric Cardiac Critical Care Consortium registry.

SETTING

Pediatric cardiac ICUs.

PATIENTS

All cardiac ICU admissions were evaluated for cardiac arrest and survival outcomes.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Successful prevention was defined as the proportion of admissions with no cardiac arrest (inverse of cardiac arrest incidence). Rescue was the proportion of patients surviving to cardiac ICU discharge after cardiac arrest. Cardiac ICU organizational and personnel factors were captured via site questionnaires. The associations between organizational and personnel factors and prevention/rescue were analyzed using Fine-Gray and multinomial regression, respectively, accounting for clustering within hospitals. We analyzed 54,521 cardiac ICU admissions (29 hospitals) with 1,398 cardiac arrest events (2.5%) between August 1, 2014, and March 5, 2019. For both surgical and medical admissions, lower average daily cardiac ICU occupancy was associated with better cardiac arrest prevention. Better rescue for medical admissions was observed for higher registered nursing hours per patient day and lower proportions of "part time" cardiac ICU physician staff (< 6 service weeks/yr). Increased registered nurse experience was associated with better rescue for surgical admissions. Increased proportion of critical care certified nurses, full-time intensivists with critical care fellowship training, dedicated respiratory therapists, quality/safety resources, and annual cardiac ICU admission volume were not associated with improved prevention or rescue.

CONCLUSIONS

Our multi-institutional analysis identified cardiac ICU bed occupancy, registered nurse experience, and physician staffing as potentially important factors associated with cardiac arrest prevention and rescue. Recognizing the limitations of measuring these variables cross-sectionally, additional studies are needed to further investigate these organizational and personnel factors, their interrelationships, and how hospitals can modify structure to improve cardiac arrest outcomes.

Risk Factors Associated With Bleeding in Children With Cardiac Disease Receiving Extracorporeal Membrane Oxygenation: A Multi-Center Data Linkage Analysis

Background: Bleeding is a common complication of extracorporeal membrane oxygenation (ECMO) for pediatric cardiac patients. We aimed to identify anticoagulation practices, cardiac diagnoses, and surgical variables associated with bleeding during pediatric cardiac ECMO by combining two established databases, the Collaborative Pediatric Critical Care Research Network (CPCCRN) Bleeding and Thrombosis in ECMO (BATE) and the Extracorporeal Life Support Organization (ELSO) Registry.

Methods: All children (<19 years) with a primary cardiac diagnosis managed on ECMO included in BATE from six centers were analyzed. ELSO Registry criteria for bleeding events included pulmonary or intracranial bleeding, or red blood cell transfusion >80 ml/kg on any ECMO day. Bleeding odds were assessed on ECMO Day 1 and from ECMO Day 2 onwards with multivariable logistic regression.

Results: There were 187 children with 114 (61%) bleeding events in the study cohort. Biventricular congenital heart disease (94/187, 50%) and cardiac medical diagnoses (75/187, 40%) were most common, and 48 (26%) patients were cannulated directly from cardiopulmonary bypass (CPB). Bleeding events were not associated with achieving pre-specified therapeutic ranges of activated clotting time (ACT) or platelet levels. In multivariable analysis, elevated INR and fibrinogen were associated with bleeding events (OR 1.1, CI 1.0–1.3, p = 0.02; OR 0.77, CI 0.6–0.9, p = 0.004). Bleeding events were also associated with clinical site (OR 4.8, CI 2.0–11.1, p < 0.001) and central cannulation (OR 1.75, CI 1.0–3.1, p = 0.05) but not with cardiac diagnosis, surgical complexity, or cannulation from CPB. Bleeding odds on ECMO day 1 were increased in patients with central cannulation (OR 2.82, 95% CI 1.15–7.08, p = 0.023) and those cannulated directly from CPB (OR 3.32, 95% CI 1.02–11.61, p = 0.047).

Conclusions: Bleeding events in children with cardiac diagnoses supported on ECMO were associated with central cannulation strategy and coagulopathy, but were not modulated by achieving pre-specified therapeutic ranges of monitoring assays.

Successfully Reducing Fat-modified Diet Duration for Treating Postoperative Chylothorax in Children

BACKGROUND

Medical management, primarily a fat-modified diet (FMD), is the mainstay of treatment for the majority of patients with chylothorax. Duration of FMD is traditionally reported as 6 weeks, but no studies demonstrate the shortest effective duration that prevents recurrence of chylothorax. Our aim was to decrease FMD duration to 2 weeks in children with postoperative chylothorax without a significant increase in recurrence.

METHODS

Our single-center study included pediatric (<18 years of age) patients that developed chylothorax within 30 days of cardiac surgery. Patients with cavopulmonary anastomoses were excluded. The pre-intervention cohort was 19 patients diagnosed between 2/2014-6/2015, and the post-intervention cohort was 98 patients from 7/2015-12/2019. FMD duration was decreased from 6 weeks to 4 weeks in May 2016, and to 2 weeks in June 2018. Recurrence was defined as a return of a chylous effusion requiring chest tube placement or hospital readmission within 30 days of resuming a regular diet.

RESULTS

The median duration of FMD decreased from 42 days (interquartile range: 30,43) in the pre-intervention cohort to 26 days (interquartile range: 14,29) post-intervention, with no recurrence of chylothorax in any group. Compliance to the FMD duration instruction in the 6-week, 4-week, and 2-week groups was 100%, 84% and 67% respectively. Compared to the first 6 months, compliance to the 2-week FMD instruction during the final 12 months increased from 40% (6/15) to 79% (26/33).

CONCLUSIONS

At our center, FMD duration decreased from 6 weeks to 2 weeks without any recurrence of chylothorax.

Risk Factors for Mortality in Refractory Pediatric Septic Shock Supported with Extracorporeal Life Support

Risk factors for mortality in children with refractory pediatric septic shock who are supported with extracorporeal life support (ECLS) are largely unknown. Therefore, we performed univariable and multivariable analyses to determine risk factors for mortality among children (<19 years) who underwent an ECLS run between January 2012 and September 2014 at eight tertiary pediatric hospitals, and who had septic shock based on 2005 International Consensus Criteria. Of the 514 children treated with ECLS during the study period, 70 were identified with septic shock. The mortality rate was similar between those with (54.3%) and without septic shock (43.7%). Among those with septic shock, significant risk factors for mortality included cardiac failure or extracorporeal cardiopulmonary resuscitation (ECPR) as indication for ECLS cannulation compared with respiratory failure (P = 0.003), having a new neurologic event following cannulation (P = 0.032), acquiring a new infection following cannulation (P = 0.005), inability to normalize pH in the 48 hours following ECLS cannulation (P = 0.010), and requiring higher daily volume of platelet transfusions (P = 0.005). These findings can be used to help guide clinical decision making for children with septic shock that is refractory to medical management.

External validation of the Pediatric Extracorporeal Membrane Oxygenation Prediction model for risk adjusting mortality

INTRODUCTION

The Pediatric Extracorporeal Membrane Oxygenation Prediction (PEP) model was created to provide risk stratification for all pediatric patients requiring extracorporeal life support (ECLS). Our purpose was to externally validate the model using contemporaneous cases submitted to the Extracorporeal Life Support Organization (ELSO) registry.

METHODS

This multicenter, retrospective analysis included pediatric patients (<19 years) during their initial ECLS run for all indications between January 2012 and September 2014. Median values from the BATE dataset for activated partial thromboplastin time and internationalized normalized ratio were used as surrogates as these were missing in the ELSO group. Model discrimination was evaluated using area under the receiver operating characteristic curve (AUC), and goodness-of-fit was evaluated using the Hosmer-Lemeshow test.

RESULTS

A total of 4,342 patients in the ELSO registry were compared to 514 subjects from the bleeding and thrombosis on extracorporeal membrane oxygenation (BATE) dataset used to develop the PEP model. Overall mortality was similar (42% ELSO vs. 45% BATE). The c-statistic after external validation decreased from 0.75 to 0.64 and model calibration decreases most in the highest risk deciles.

CONCLUSION

Discrimination of the PEP model remains modest after external validation using the largest pediatric ECLS cohort. While the model overestimates mortality for the highest risk patients, it remains the only prediction model applicable to both neonates and pediatric patients who require ECLS for any indication and thus maintains potential for application in research and quality benchmarking.

Development of the Pediatric Extracorporeal Membrane Oxygenation Prediction Model for Risk-Adjusting Mortality

OBJECTIVES

To develop a prognostic model for predicting mortality at time of extracorporeal membrane oxygenation initiation for children which is important for determining center-specific risk-adjusted outcomes.

DESIGN

Multivariable logistic regression using a large national cohort of pediatric extracorporeal membrane oxygenation patients.

SETTING

The ICUs of the eight tertiary care children's hospitals of the Collaborative Pediatric Critical Care Research Network.

PATIENTS

Five-hundred fourteen children (< 19 yr old), enrolled with an initial extracorporeal membrane oxygenation run for any indication between January 2012 and September 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 514 first extracorporeal membrane oxygenation runs were analyzed with an overall mortality of 45% (n = 232). Weighted logistic regression was used for model selection and internal validation was performed using cross validation. The variables included in the Pediatric Extracorporeal Membrane Oxygenation Prediction model were age (pre-term neonate, full-term neonate, infant, child, and adolescent), indication for extracorporeal membrane oxygenation (extracorporeal cardiopulmonary resuscitation, cardiac, or respiratory), meconium aspiration, congenital diaphragmatic hernia, documented blood stream infection, arterial blood pH, partial thromboplastin time, and international normalized ratio. The highest risk of mortality was associated with the presence of a documented blood stream infection (odds ratio, 5.26; CI, 1.90-14.57) followed by extracorporeal cardiopulmonary resuscitation (odds ratio, 4.36; CI, 2.23-8.51). The C-statistic was 0.75 (95% CI, 0.70-0.80).

CONCLUSIONS

The Pediatric Extracorporeal Membrane Oxygenation Prediction model represents a model for predicting in-hospital mortality among children receiving extracorporeal membrane oxygenation support for any indication. Consequently, it holds promise as the first comprehensive pediatric extracorporeal membrane oxygenation risk stratification model which is important for benchmarking extracorporeal membrane oxygenation outcomes across many centers.

Development and Validation of a Score to Predict Mortality in Children Undergoing Extracorporeal Membrane Oxygenation for Respiratory Failure: Pediatric Pulmonary Rescue With Extracorporeal Membrane Oxygenation Prediction Score

OBJECTIVE

Our objective was to develop and validate a prognostic score for predicting mortality at the time of extracorporeal membrane oxygenation initiation for children with respiratory failure. Preextracorporeal membrane oxygenation mortality prediction is important for determining center-specific risk-adjusted outcomes and counseling families.

DESIGN

Multivariable logistic regression of a large international cohort of pediatric extracorporeal membrane oxygenation patients.

SETTING

Multi-institutional data.

PATIENTS

Prognostic score development: A total of 4,352 children more than 7 days to less than 18 years old, with an initial extracorporeal membrane oxygenation run for respiratory failure reported to the Extracorporeal Life Support Organization's data registry during 2001-2013 were used for derivation (70%) and validation (30%). Bidirectional stepwise logistic regression was used to identify factors associated with mortality. Retained variables were assigned a score based on the odds of mortality with higher scores indicating greater mortality. External validation was accomplished using 2,007 patients from the Pediatric Health Information System dataset.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The Pediatric Pulmonary Rescue with Extracorporeal Membrane Oxygenation Prediction score included mode of extracorporeal membrane oxygenation; preextracorporeal membrane oxygenation mechanical ventilation more than 14 days; preextracorporeal membrane oxygenation severity of hypoxia; primary pulmonary diagnostic categories including, asthma, aspiration, respiratory syncytial virus, sepsis-induced respiratory failure, pertussis, and "other"; and preextracorporeal membrane oxygenation comorbid conditions of cardiac arrest, cancer, renal and liver dysfunction. The area under the receiver operating characteristic curve for internal and external validation datasets were 0.69 (95% CI, 0.67-0.71) and 0.66 (95% CI, 0.63-0.69).

CONCLUSIONS

Pediatric Pulmonary Rescue with Extracorporeal Membrane Oxygenation Prediction is a validated tool for predicting in-hospital mortality among children with respiratory failure receiving extracorporeal membrane oxygenation support.

Platelet Inhibition in Shunted Infants on Aspirin at Short and Midterm Follow-Up

There are few data to guide aspirin therapy to prevent shunt thrombosis in infants. We aimed to determine if aspirin administered at conventional dosing in shunted infants resulted in ≥50% arachidonic acid (AA) inhibition in short and midterm follow-up using thromboelastography with platelet mapping (TEG-PM) and to describe bleeding and thrombotic events during follow-up. We performed a prospective observational study of infants on aspirin following Norwood procedure, aortopulmonary shunt alone, or cavopulmonary shunt surgery. We obtained TEG-PM preoperatively, after the third dose of aspirin, at the first postoperative clinic visit, and 2-8 months after surgery. The primary outcome was the proportion of subjects with ≥50% AA inhibition on aspirin. All bleeding and thrombotic events were collected. Of 24 infants analyzed, 13% had ≥50% AA inhibition at all designated time points after aspirin initiation; 38% had ≥50% AA inhibition after the third aspirin dose of aspirin, 60% at the first postoperative clinic visit, and 26% 2-8 months after surgery. Bleeding events occurred in eight subjects, and two had a thrombotic event. Bleeding events were associated with greater AA inhibition just prior to starting aspirin (p = 0.02) and after the third dose of aspirin (p = 0.04), and greater ADP inhibition before surgery (p = 0.03). The majority of infants failed to consistently have ≥50% AA inhibition when checked longitudinally postoperatively. Preoperative TEG-PM may be useful in identifying infants at higher risk of bleeding events on aspirin in the early postoperative period. Further research is needed to guide antiplatelet therapy in this population.

Preoperative platelet dysfunction predicts blood product transfusion in children undergoing cardiac surgery

OBJECTIVES

Excessive bleeding can be a problem during or after cardiac surgery. While cardiopulmonary bypass-associated platelet dysfunction is an important inducer of coagulopathy, preoperative platelet dysfunction can also contribute to this bleeding. We investigated the relationship between preoperative platelet dysfunction and transfusion of blood products given to children undergoing cardiac surgery.

METHODS

The platelet function analyser test measures platelet function in vitro by aspirating blood through a small standard hole (creating high shear) in a collagen membrane infused with a platelet agonist. The time taken to form a platelet plug is known as closure time and prolonged closure time (CT) indicates platelet dysfunction. Three hundred and thirty-eight children who had undergone surgery with cardiopulmonary bypass between 2008 and 2012 were included. The volume of red blood cells and fresh-frozen plasma transfused was recorded. The relationship between closure time and transfusion requirements was analysed using linear and logistic regression.

RESULTS

Patients with prolonged closure time had greater odds of getting red blood cells and fresh-frozen plasma transfusions compared with patients with normal closure time (P <0.01). On univariate analysis, age, weight, haematocrit, cardiopulmonary bypass time, Risk Adjustment for Congenital Heart Surgery score and closure time were associated with increased odds of red blood cells and fresh-frozen plasma transfusion in the operation theatre (P <0.05). However, when logistic multivariable regression analysis was applied, only age, cardiopulmonary bypass time and closure time remained as significant predictive factors for transfusion.

CONCLUSIONS

In children who have undergone cardiac surgery, when age and cardiopulmonary bypass time are accounted for, a prolonged preoperative closure time is significantly associated with increased odds of red blood cells and fresh-frozen plasma transfusion in the operation theatre. This may have implications for planning and utilization of blood products.

Congenital cardiac lesions involving systolic flow abnormalities are associated with platelet dysfunction in children

BACKGROUND

Shear stress-induced platelet dysfunction (PD) is prevalent among adults with aortic stenosis. Our aim was to determine whether abnormal platelet function was associated with specific congenital cardiac lesions in children.

METHODS

The charts of 407 children who had undergone cardiopulmonary bypass and had preoperative platelet function analysis were evaluated. Patients were assigned to 1 of 11 different lesion categories. Platelet dysfunction (PD) was defined as prolonged closure time (CT) as measured with a platelet function analyzer. Odds ratio (OR) estimates for prolonged CT were calculated for each lesion category. Mean CTs were compared with Tukey-Kramer separated means testing. Analysis of variance modeling was used to determine association between hematocrit value and CT.

RESULTS

CT in patients with ventricular septal defects (VSD) and right ventricular outflow tract obstruction (RVOTO) lesions was prolonged. OR analysis found that patients with VSDs (OR, 2.46) or RVOTO (OR, 2.88) had at least a 95% probability of an abnormal CT. In contrast, patients with atrial septal defect (ASD), bidirectional Glenn procedure (BDG), and pulmonary insufficiency (PI) had a reduced probability of a prolonged CT (p < 0.05). A similar pattern was seen in parametric analysis comparing mean CTs across lesion categories. A lower preoperative hematocrit value was associated with prolonged CTs across all lesion types (p < 0.05).

CONCLUSIONS

PD was common in children with congenital cardiac lesions involving systolic flow abnormalities and was uncommon among children with lesions having diastolic abnormalities. Lower preoperative hematocrit values were associated with prolonged CTs, suggesting subclinical bleeding secondary to excessive platelet shearing.