Formal Ethics Consultation in Extracorporeal Membrane Oxygenation Patients: A Single-Center Retrospective Cohort of a Quaternary Pediatric Hospital

OBJECTIVE

To examine characteristics associated with formal ethics consultation (EC) referral in pediatric extracorporeal membrane oxygenation (ECMO) cases, and document ethical issues presented.

DESIGN

Retrospective cohort study using mixed methods.

SETTING

Single-center quaternary pediatric hospital.

PATIENTS

Patients supported on ECMO (January 2012 to December 2021).

INTERVENTIONS

We compared clinical variables among ECMO patients according to the presence of EC. We defined optimal cutoffs for EC based on run duration, ICU length of stay (LOS), and sum of procedures or complications. To identify independent explanatory variables for EC, we used a forward stepwise selection multivariable logistic regression model. EC records were thematically characterized into ethical issues.

MEASUREMENTS AND MAIN RESULTS

Of 601 ECMO patients and 225 patients with EC in 10 years, 27 ECMO patients received EC (4.5% of ECMO patients, 12% of all ECs). On univariate analysis, use of EC vs. not was associated with multiple ECMO runs, more complications/procedures, longer ICU LOS and ECMO duration, cardiac admissions, decannulation outcome, and higher mortality. Cutoffs for EC were ICU LOS >52 days, run duration >160 hours, and >6 complications/procedures. Independent associations with EC included these three cutoffs and older age. The model showed good discrimination (area under the curve 0.88 [0.83, 0.93]) and fit. The most common primary ethical issues were related to end-of-life, ECMO discontinuation, and treatment decision-making. Moral distress was cited in 22 of 27 cases (82%).

CONCLUSION

EC was used in 4.5% of our pediatric ECMO cases, with most ethical issues related to end-of-life care or ECMO discontinuation. Older age, longer ICU LOS, prolonged runs, and multiple procedures/complications were associated with greater odds for EC requests. These data highlight our single-center experience of ECMO-associated ethical dilemmas. Historical referral patterns may guide a supported decision-making framework. Future work will need to include quality improvement projects for timely EC, with evaluation of impacts on relevant endpoints.

Risk Factors for Adverse Outcomes in Term Infants with CHD and Definitive Necrotising Enterocolitis

OBJECTIVES

To define the incidence of definitive necrotising enterocolitis in term infants with CHD and identify risk factors for morbidity/mortality.

METHODS

We performed a 20-year (2000-2020) single-institution retrospective cohort study of term infants with CHD admitted to the Boston Children's Hospital cardiac ICU with necrotising enterocolitis (Bell's stage ≥ II). The primary outcome was a composite of in-hospital mortality and post-necrotising enterocolitis morbidity (need for extracorporeal membrane oxygenation, multisystem organ failure based on the paediatric sequential organ failure assessment score, and/or need for acute gastrointestinal intervention). Predictors included patient characteristics, cardiac diagnosis/interventions, feeding regimen, and severity measures.

RESULTS

Of 3933 term infants with CHD, 2.1% (n = 82) developed necrotising enterocolitis, with 67% diagnosed post-cardiac intervention. Thirty (37%) met criteria for the primary outcome. In-hospital mortality occurred in 14 infants (17%), of which nine (11%) deaths were attributable to necrotising enterocolitis. Independent predictors of the primary outcome included moderate to severe systolic ventricular dysfunction (odds ratio 13.4,confidence intervals 1.13-159) and central line infections pre-necrotising enterocolitis diagnosis (odds ratio 17.7, confidence intervals 3.21-97.0) and mechanical ventilation post-necrotising enterocolitis diagnosis (odds ratio 13.5, confidence intervals 3.34-54.4). Single ventricle, ductal dependency, and feeding related factors were not independently associated with the primary outcome.

CONCLUSIONS

The incidence of necrotising enterocolitis was 2.1% in term infants with CHD. Adverse outcomes occurred in greater than 30% of patients. Presence of systolic dysfunction and central line infections prior to diagnosis and need for mechanical ventilation after diagnosis of necrotising enterocolitis can inform risk triage and prognostic counseling for families.

Social Drivers of Health and Pediatric Extracorporeal Membrane Oxygenation Outcomes

BACKGROUND

Relationships between social drivers of health (SDoH) and pediatric health outcomes are highly complex with substantial inconsistencies in studies examining SDoH and extracorporeal membrane oxygenation (ECMO) outcomes. To add to this literature with emerging novel SDoH measures, and to address calls for institutional accountability, we examined associations between SDoH and pediatric ECMO outcomes.

METHODS

This single-center retrospective cohort study included children (<18 years) supported on ECMO (2012-2021). SDoH included Child Opportunity Index (COI), race, ethnicity, payer, interpreter requirement, urbanicity, and travel-time to hospital. COI is a multidimensional estimation of SDoH incorporating traditional (eg, income) and novel (eg, healthy food access) neighborhood attributes ([range 0-100] higher indicates healthier child development). Outcomes included in-hospital mortality, ECMO run duration, and length of stay (LOS).

RESULTS

540 children on ECMO (96%) had a calculable COI. In-hospital mortality was 44% with median run duration of 125 hours and ICU LOS 29 days. Overall, 334 (62%) had cardiac disease, 92 (17%) neonatal respiratory failure, 93 (17%) pediatric respiratory failure, and 21 (4%) sepsis. Median COI was 64 (interquartile range 32-81), 323 (60%) had public insurance, 174 (34%) were from underrepresented racial groups, 57 (11%) required interpreters, 270 (54%) had urban residence, and median travel-time was 89 minutes. SDoH including COI were not statistically associated with outcomes in univariate or multivariate analysis.

CONCLUSIONS

We observed no significant difference in pediatric ECMO outcomes according to SDoH. Further research is warranted to better understand drivers of inequitable health outcomes in children, and potential protective mechanisms.

Hospital Access Patterns of Children With Technology Dependence

OBJECTIVES

We studied hospital utilization patterns among children with technology dependence (CTD). We hypothesized that increasing pediatric healthcare concentration requires those caring for CTD to selectively navigate healthcare systems and travel greater distances for care.

METHODS

Using 2017 all-encounter datasets from 6 US states, we identified CTD visits defined by presence of a tracheostomy, gastrostomy, or intraventricular shunt. We calculated pediatric Hospital Capability Indices for hospitals and mapped distances between patient residence, nearest hospital, and encounter facility.

RESULTS

Thirty-five percent of hospitals never saw CTD. Of 37 108 CTD encounters within the remaining 543 hospitals, most emergency visits (70.0%) and inpatient admissions (85.3%) occurred within 34 (6.3%) high capability centers. Only 11.7% of visits were to the closest facility, as CTD traveled almost 4 times further to receive care. When CTD bypassed nearer facilities, they were 10 times more likely to travel to high-capability centers (95% confidence interval: 9.43-10.8), but even those accessing low-capability facilities bypassed less capable, geographically closer hospitals. Transfer was more likely in nearest and low-capability facility encounters. CTD with Medicaid insurance, Black race, or from lower socioeconomic communities had lower odds of encounters at high-capability centers and of bypassing a closer institution than those with white race, private insurance, or from advantaged communities.

CONCLUSIONS

Children with technology dependence routinely bypass closer hospitals to access care in facilities with higher pediatric capability. This access behavior leaves many hospitals unfamiliar with CTD, which results in greater travel but less transfers and may be influenced by sociodemographic factors.

The Surprise Question as a Trigger for Primary Palliative Care Interventions for Children with Advanced Heart Disease

There is significant uncertainty in describing prognosis and a lack of reliable entry criteria for palliative care studies in children with advanced heart disease (AHD). This study evaluates the utility of the surprise question-"Would you be surprised if this child died within the next year?"-to predict one-year mortality in children with AHD and assess its utility as entry criteria for future trials. This is a prospective cohort study of physicians and nurses caring for children (1 month-19 years) with AHD hospitalized ≥ 7 days. AHD was defined as single ventricle physiology, pulmonary vein stenosis or pulmonary hypertension, or any cardiac diagnosis with signs of advanced disease. Primary physicians were asked the surprise question and medical record review was performed. Forty-nine physicians responded to the surprise question for 152 patients. Physicians responded "No, I would not be surprised if this patient died" for 54 (36%) patients, 20 (37%) of whom died within 1 year, predicting one-year mortality with 77% sensitivity, 73% specificity, 37% positive predictive value, and 94% negative predictive value. Patients who received a "No" response had an increased 1-year risk of death (hazard ratio 7.25, p < 0.001). Physician years of experience, subspecialty, and self-rated competency were not associated with the accuracy of the surprise question. The surprise question offers promise as a bedside screening tool to identify children with AHD at high risk for mortality and help physicians identify patients who may benefit from palliative care and advance care planning discussions.

Neonatal cardiac surgery in low resource settings: implications of birth weight

OBJECTIVE

We sought to evaluate the association between low birth weight (LBW) and outcomes following neonatal cardiac surgery in a low-income and middle-income country setting where LBW prevalence is high and its impact on surgical outcomes is undefined.

DESIGN

Single-centre retrospective cohort study.

SETTING

Referral paediatric hospital in Southern India PATIENTS: All neonatal cardiac surgical cases between January 2011 and December 2018. LBW was defined as <2.5 kg.

MAIN OUTCOME MEASURES

Patient demographics, corrective versus palliative surgery and postoperative outcomes were collected from the institutional database which undergoes regular audit as part of International Quality Improvement Collaborative for Congenital Heart Disease. In-hospital mortality was the primary outcome measure.

RESULTS

Of 569 neonatal cardiac operations, 123 (21.6%) had LBW (mean: 2.2±0.3 kg); 18.7% <2 kg and 21.1% were preterm (<37 weeks). Surgery type (corrective vs palliative) or non-cardiac anomalies were not associated with birth weight. Birth weight did not correlate with ICU length of stay (LOS) and mechanical ventilation but was lower in those with postoperative sepsis. Overall in-hospital mortality was 7.0%; LBW neonates had higher mortality (OR 2.16, 95% CI 1.09 to 4.29, p=0.025). Multivariable analyses revealed birth weight (OR per 100 g decrease in weight: 1.12; 95% CI 1.03 to 1.22), age at surgery (OR per day increase in age of 0.93; 95% CI 0.87 to 0.99) and palliative intervention (OR 4.46 (95% CI 1.91 to 10.44) as independent predictors of in-hospital mortality.

CONCLUSION

LBW adversely impacts in-hospital mortality outcomes following neonatal cardiac surgery in a resource-limited setting without increase in ICU or hospital LOS.

The Influence of Haemostatic System Maturation on the Dose-Response Relationship of Unfractionated Heparin

BACKGROUND

Unfractionated heparin (UFH) dosing and monitoring guidelines for children are often extrapolated from adult data. This practice is suboptimal given the inherent differences in haemostatic maturation and drug handling in children compared with adults.

OBJECTIVE

The aim of this work was to investigate the impact of haemostatic system maturation on the dose-response relationship of UFH in children.

METHODS

A quantitative model for haemostasis in adults was adapted to account for maturation in UFH pharmacokinetic (PK) parameters with and without age-related changes in coagulation factor concentrations. The adult and adapted models were used to predict the time courses of anti-factor Xa activity (aXa) and activated partial thromboplastin time (aPTT) in patients receiving UFH infusion. Predictions from both models were compared with observed aXa and aPTT measurements from 31 paediatric patients receiving UFH during extracorporeal membrane oxygenation (ECMO).

RESULTS

The model with maturation for both UFH PK and the haemostatic system had an improved aXa and aPTT predictive performance compared with maturation in UFH PK only and the original adult model. Despite the minor effect of haemostatic system maturation on baseline aPTT, it led to substantial changes in the time course of aPTT sensitivity to UFH. This finding suggests that between-subject variability in clotting factors concentrations is potentially a major contributor to the overall variability of aPTT response to UFH. In addition, time-varying clotting factors concentrations may explain within-subject changes in aPTT sensitivity to UFH.

CONCLUSION

We developed the first quantitative systems pharmacology (QSP) model that provides a mechanistic and quantitative basis for linking physiological and pharmacological maturation to UFH effect and response biomarkers. After appropriate clinical validation, the model could be useful for the development of paediatric-specific individualised UFH dosing recommendations.

Revisiting the Pharmacology of Unfractionated Heparin

Unfractionated heparin (UFH) is a commonly used anticoagulant therapy for the acute treatment and prevention of thrombosis. Its short duration of action, reversibility of effect by protamine sulfate, and extensive clinical experience are some of the advantages that support its use. However, the choice of dose and dosing regimen of UFH remains challenging for several reasons. First, UFH has a narrow therapeutic window and wide variability in the dose-response relationship. Second, its pharmacodynamic (PD) properties are difficult to characterise owing to the complex multidimensional mechanisms of interaction with the haemostatic system. Third, the complex heterogeneous chemical composition of UFH precludes precise characterisation of its pharmacokinetic (PK) properties. This review provides a comprehensive mechanistic approach to the interaction of UFH with the haemostatic system. The effect of chemical structure on its PK and PD properties is quantitatively described, and a framework for characterisation of the dose-response relationship of UFH for the purpose of dose optimisation is proposed.

Palliative care and paediatric cardiology: current evidence and future directions

Although outcomes for children with heart disease have improved substantially over the past several decades, heart disease remains one of the leading causes of paediatric mortality. For children who progress to advanced heart disease, disease morbidity is high, with many children requiring multiple surgical interventions and long-term intensive care hospitalisations. Care for children with advanced heart disease requires a multidisciplinary approach, and opportunities for earlier integration of palliative care are being explored. This Viewpoint summarises the relevant literature over the past decade. We also identify gaps in parent and provider understanding of prognosis and communication, propose indications for palliative care consultation in paediatric advanced heart disease, and summarise attitudes and perceived barriers to palliative care consultation. Areas for additional research that we identify include paediatric cardiologist education, parental distress, socioeconomic disparities, and patient-reported outcomes. Interdisciplinary clinical and research efforts are required to further advance the field and improve integration of palliative care in the care of children with heart disease.

Coagulation monitoring correlation with heparin dose in pediatric extracorporeal life support

Objectives:

Extracorporeal Life Support (ECLS) risks thrombotic and hemorrhagic complications. Optimal anti-coagulation monitoring is controversial. We compared coagulation tests evaluating the heparin effect in pediatric ECLS.

Methods:

A retrospective study of children (<18yrs) undergoing ECLS over 12 months in a tertiary pediatric intensive care unit (PICU). Variables included anti-Factor Xa activity (anti-Xa), activated partial thromboplastin time (aPTT), activated clotting time (ACT) and thromboelastogram (TEG®6s) parameters: ratio and delta reaction (R) times (the ratio and difference, respectively, between R times in kaolin assays with and without heparinase). Test results were correlated with unfractionated heparin infusion rate (IU/kg/hr) at the time of sampling. Mean test results of each ECLS run were evaluated according to the presence/absence of complications.

Results:

Thirty-two ECLS runs (31 patients) generated 695 data-points for correlation. PICU mortality was 22% and the thrombotic complication rate was 66%. The proportion of variation in coagulation test results explained by heparin dose was 13.3% for anti-Xa, 11.9% for ratio R time, and 9.9% for delta R time, compared with <1% for ACT and aPTT. Incorporating individual variation, age and antithrombin activity in a model with heparin dose explained less than 50% of the variation in test results. Correlation varied according to age, day of ECLS run and between individuals, with parallel dose-response lines noted between patients. Significantly lower mean anti-Xa was observed in PICU non-survivors and runs with thrombosis.

Conclusion:

Lower anti-Xa was observed in ECLS runs with complications. Although absolute results from anti-Xa and TEG6®s showed the best correlation with heparin dose, a large proportion of variation in results was unexplained by heparin, while dose response was similar between individuals. Population pharmacokinetic/pharmacodynamic modelling is required, as well as prospective trials to delineate the superior means of adjusting heparin therapy to prevent adverse clinical outcomes.

High-throughput SNP genotyping with the Masscode system

QIAGEN Genomics, Inc, has developed the Masscode tagging system for DNA labeling and detection. In this application, the Masscode system is described as applied to high-throughput single-nucleotide polymorphism (SNP) genotyping. The labeling system is based on a small-molecular-weight tag that is covalently attached through a photocleavable linker to a DNA oligonucleotide. The tagged oligonucleotide is used as a primer in an allele-specific PCR SNP discrimination assay. The allele-specific amplicons are differentiated through their Masscode tag assignments. After a photolysis step to cleave the tags from the amplicon, the samples are introduced into a single quadrupole mass spectrometry detection system for analysis. Genotyping determinations are based on the relative proportions of the paired allele tags. The system has a lower limit of detection in the femtomolar range (10(-15) M). At present, 30 different Masscode tags may be used simultaneously in a multiplex fashion to routinely provide more than 40,000 SNP genotyping measurements daily. Further developments will allow for the simultaneous detection of several hundred tags.

Antitumor efficacy, pharmacokinetics, and biodistribution of NX 211: a low-clearance liposomal formulation of lurtotecan

Lurtotecan is a clinically active water-soluble camptothecin analogue that has been formulated into a low-clearance unilamellar liposome, NX 211. Comparative studies between free drug and NX 211 have been performed assessing pharmacokinetics in nude mice, tissue distribution in tumor-bearing mice, and antitumor efficacy in xenografts. Compared with lurtotecan, NX 211 demonstrated a significant increase in plasma residence time and a subsequent 1500-fold increase in the plasma area under the drug concentration curve. The volume of distribution was also greatly restricted, suggesting altered tissue distribution. Evaluation of tissues 24 h after administration of either [14C]NX 211 or [14C]lurtotecan to ES-2 tumor-bearing mice demonstrated a 40-fold increase in radiolabeled compound in the tumors of NX 211-treated mice compared with mice treated with lurtotecan. In single-dose efficacy studies, NX 211 produced a consistent 3-fold or greater increase in therapeutic index compared with lurtotecan in both the KB and ES-2 xenograft models. When compared at equitoxic levels in repeat-dose efficacy studies, NX 211 generated durable cures lasting >60 days and a 2-8-fold increase in log10 cell kill, compared with lurtotecan and topotecan, respectively. Together, these data demonstrate that NX 211 has significant therapeutic advantage over lurtotecan and that the improved antitumor activity is consistent with increased exposure and enhanced drug delivery to tumor sites.

L-amino acid oxidase (LOX) modulation of melphalan activity against intracranial glioma

These studies evaluated the efficacy of sequential pretreatment with L-amino acid oxidase (LOX) and LOX antiserum in the modulation of melphalan activity against intracranial glioma in athymic nude mice. LOX produced statistically significant (P < 0.01) depletion of the large neutral amino acids isoleucine, leucine, methionine, phenylalanine, tyrosine, and valine in murine plasma at doses of 100 and 200 micrograms administered intravenously. Polyclonal anti-LOX antibody was successfully produced in mice, rabbits, and goats subsequent to immunization with LOX. Staphylococcal protein A-purified rabbit anti-LOX serum inhibited approximately 50% of LOX activity in vitro relative to control samples. This antiserum was used in vivo to inactivate LOX after it had depleted the large neutral amino acids, thereby preventing LOX-mediated catabolism of melphalan. Inoculation of three mice with rabbit anti-LOX serum after the treatment with LOX (100 micrograms) reduced LOX activity by 100%, 89%, and 100% at 6 h compared with reductions of 80%, 59%, and 52% over the same period in animals receiving LOX alone. In three separate studies using groups of eight to ten mice bearing intracranial human glioma xenografts, pretreatment with LOX followed by anti-LOX serum increased the antitumor activity of melphalan as compared with treatments with melphalan plus LOX, melphalan plus anti-LOX serum, or melphalan alone.

Enhancement of melphalan activity by inhibition of DNA polymerase-alpha and DNA polymerase-beta

Our previous studies exploring melphalan resistance in the human rhabdomyosarcoma xenograft TE-671 MR revealed elevation of DNA polymerase-alpha and DNA polymerase-beta. The present study evaluated the alteration of melphalan activity in TE-671 (melphalan-sensitive) and TE-671 MR (melphalan-resistant) subcutaneous xenografts in nude mice after DNA polymerase-alpha was inhibited using aphidicolin glycinate (AG) and DNA polymerase-beta was inhibited using dideoxycytidine (DDC). Administration of AG or DDC did not produce toxicity or demonstrate antineoplastic activity when given alone. AG (90 mg/m2) enhanced the activity of melphalan against TE-671, with growth delays increasing by 8.4, 15.8, and 21.2 days over the regimen with melphalan only. AG (180 mg/m2) only modestly increased melphalan activity against TE-671 MR, with the growth delays increasing from 9.6 and 12.1 days using melphalan alone to 12.1 and 14.5 days using melphalan plus AG. AG (180 mg/m2) plus melphalan (the dose lethal to 10% of animals) produced greater weight loss compared with melphalan alone, whereas DDC plus melphalan produced no additional toxicity. DDC modestly enhanced the activity of melphalan plus AG against TE-671 MR. AG plus O6-benzylguanine did not increase the activity of 1,3-bis(2-chloroethyl)-1-nitrosourea against TE-671 or TE-671 MR. AG (90 mg/m2 and 180 mg/m2) inhibited DNA polymerase-alpha to 80% and 72% of control in TE-671 and 64% and 37% in TE-671 MR, and DDC inhibited DNA polymerase-beta to 59% in TE-671 and 48% in TE-671 MR. These results suggest a role for AG-mediated enhancement of melphalan activity, particularly in the treatment of newly diagnosed, melphalan-sensitive tumors.

Adult lifetime prevalence of firesetting behaviors in a state hospital population

Hospital records of all patients under age 65 years old on the census of Worcester State Hospital (WSH) on October 25, 1988 (n = 279) were reviewed for indications of firesetting behaviors during the individuals' adult lifetime. The prevalence of firesetting behaviors was found to be 27.2%. The prevalence of firesetting episodes, a subset of firesetting behaviors, was found to be 17.6%. A stepwise discriminant function analysis was used to determine whether any factors significantly differentiated the members of the firesetting behavior group from the remainder of the population. This analysis revealed that the number of WSH admissions, the number of admissions to other inpatient facilities, and a history of injurious behavior to self are significant positive predictors of membership in the firesetting behaviors group. The results of the WSH analysis are very similar to those found at Northampton State Hospital in 1983. These high prevalence rates have implication for treatment, education, record keeping, and liability.