Bronchopulmonary dysplasia and diuretic use in an outpatient setting.

INTRODUCTION: During Neonatal Intensive Care Unit hospitalization, children born preterm with bronchopulmonary dysplasia (BPD) are frequently prescribed diuretics for chronic respiratory symptoms. However, less is known about diuretic use and weaning in an outpatient setting. The study sought to characterize clinical features associated with outpatient diuretic use and timing of diuretic weaning in children with BPD. METHODS: Data was obtained by chart review from 1224 registry participants born <32 weeks gestation, discharged between 2008 and 2023 and recruited from outpatient BPD clinics at Johns Hopkins Children's Center and the Children's Hospital of Philadelphia (97.4% diagnosed with BPD). Data was analyzed using Chi-square tests, t-tests, and ANOVA tests. RESULTS: Children on diuretics at their first pulmonary visit (n = 737) were more likely to have lower birth weights, earlier gestational age, and severe BPD compared to those not on diuretics (n = 487). Of those prescribed diuretics, most children were on a thiazide alone (46.4%) or a thiazide and a potassium sparing agent (44.8%) with a minority prescribed loop diuretics alone (3.3%) or loop diuretic combinations (4.7%). Most children weaned off diuretics by 2 years of age. Public insurance, early gestational age, technology dependence, home supplemental oxygen use and loop diuretics were associated with slower diuretic weaning. CONCLUSION: Outpatient diuretic use is common in children with BPD, however variations in diuretic use and diuretic combinations exist across centers. Time to wean off home supplemental oxygen is similar between children on one diuretic compared to none. Timing of outpatient diuretic weaning is influenced by diuretic class, respiratory support, and co-morbidities.

Surfactant treatment at birth in a contemporary cohort of preterm infants with bronchopulmonary dysplasia.

OBJECTIVE: Initial surfactant studies demonstrated improvements in survival and need for respiratory support. However, as the use of non-invasive respiratory support has increased the use of surfactant has decreased. We examined in a contemporary cohort of BPD patients if surfactant use was associated with BPD severity. STUDY DESIGN: An observational study using data from the BPD Collaborative Registry. RESULTS: 971 infants with BPD met entry criteria, 864 (89%) had received surfactant in the first 72 h of life (SURF) and the remainder had not (no surfactant). There was an association between SURF and BPD grade, with a greater likelihood of grade 3 BPD in infants who received surfactant in the DR or who had 2 or more doses. CONCLUSIONS: We speculate that the use of surfactant in the DR and use of multiple doses reflect the impact of perinatal factors beyond immaturity alone that increase the risk for grade 3 BPD.

Associations of PM2.5 exposure with emergency department visits and readmissions among preterm infants with bronchopulmonary dysplasia.

OBJECTIVES: To quantify the association of ambient air pollution (particulate matter, PM2.5) exposure with medically attended acute respiratory illness among infants with bronchopulmonary dysplasia (BPD). STUDY DESIGN: Single center, retrospective cohort study of preterm infants with BPD in Metropolitan Philadelphia. Multivariable logistic regression quantified associations of annual mean PM2.5 exposure (per µg/m3) at the census block group level with medically attended acute respiratory illness, defined as emergency department (ED) visits or hospital readmissions within a year after first hospital discharge adjusting for age at neonatal intensive care unit (NICU) discharge, year, sex, race, insurance, BPD severity, and census tract deprivation. As a secondary analysis, we examined whether BPD severity modified the associations. RESULTS: Of the 378 infants included in the analysis, 189 were non-Hispanic Black and 235 were publicly insured. Census block PM2.5 level was not significantly associated with medically attended acute respiratory illnesses, ED visits, or hospital readmissions in the full study cohort. We observed significant effect modification by BPD grade; each 1 µg/m3 higher annual PM2.5 exposure was medically attended acute respiratory illness (adjusted odds ratio [aOR] 1.65, 95% CI: 1.06-2.63) among infants with Grade 1 BPD but not among infants with grade 3 BPD (aOR 0.83, 95% CI: 0.47-1.48) (interaction p = .024). CONCLUSIONS: Cumulative PM2.5 exposure in the year after NICU discharge was not significantly associated with medically attended acute respiratory illness among infants with BPD. However, infants with Grade 1 BPD had significantly higher odds with higher exposures. If replicated, these findings could inform anticipatory guidance for families of these infants to avoid outdoor activities during high pollution days after NICU discharge.

Diuretic Tolerance to Repeated-Dose Furosemide in Infants Born Very Preterm with Bronchopulmonary Dysplasia.

OBJECTIVES: To assess the presence and timing of furosemide diuretic tolerance in infants with bronchopulmonary dysplasia (BPD), and to determine if tolerance is modified by thiazide co-administration. STUDY DESIGN: We performed a retrospective cohort study among infants born very preterm with BPD exposed to repeated-dose furosemide for 72 hours, measuring net fluid balance (total intake minus total output) as a surrogate of diuresis in the 3 days before and after exposure. The primary comparison was the difference in fluid balance between the first and third 24 hours of furosemide exposure. We fit a general linear model for within-subject repeated measures of fluid balance over time, with thiazide co-administration as an interaction variable. Secondary analyses included an evaluation of weight trajectories over time. RESULTS: In 83 infants, median fluid balance ranged between + 43.6 and + 52.7 ml/kg/d in the 3 days prior to furosemide exposure. Fluid balance decreased to a median of + 29.1 ml/kg/d in the first 24 hours after furosemide, but then increased to +47.5 ml/kg/d by the third 24-hour interval, consistent with tolerance (P < .001). Thiazides did not modify the change in fluid balance during furosemide exposure for any time-period. Weight decreased significantly in the first 24 hours after furosemide and increased thereafter (P < .001). CONCLUSIONS: The net fluid balance response to furosemide decreases rapidly during repeated-dose exposures in infants with BPD, consistent with diuretic tolerance. Clinicians should consider this finding in the context of an infant's therapeutic goals. Further research efforts to identify safe and effective furosemide dosage strategies are needed.

Associations of neighborhood social vulnerability with emergency department visits and readmissions among infants with bronchopulmonary dysplasia.

OBJECTIVES: To characterize associations of the CDC Social Vulnerability Index (SVI) with medically attended acute respiratory illness among infants with bronchopulmonary dysplasia (BPD). STUDY DESIGN: Retrospective cohort of 378 preterm infants with BPD from a single center. Multivariable logistic regression quantified associations of SVI with medically attended acute respiratory illness, defined as emergency department (ED) visits or hospital readmissions within a year after first hospital discharge. Mediation analysis quantified the extent to which differences in SVI may explain known Black-White disparities in medically attended acute respiratory illness. RESULTS: SVI was associated with medically attended respiratory illness (per SVI standard deviation increment, aOR 1.44, 95% CI: 1.17-1.78). Adjustment for race and ethnicity attenuated the association (aOR 1.27, 95% CI: 0.97-1.64). SVI significantly mediated 31% of the Black-White disparity in ED visits (p = 0.04). CONCLUSIONS: SVI was associated with, and may partially explain racial disparities in, medically attended acute respiratory illness among infants with BPD.

Can we balance early exogenous surfactant therapy and non-invasive respiratory support to optimise outcomes in extremely preterm infants? A nuanced review of the current literature.

Therapeutic advances have significantly improved the survival of premature infants. However, a high burden of bronchopulmonary dysplasia (BPD) persists. Aiming at prevention of neonatal lung injury, continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV) strategies have replaced mechanical ventilation for early respiratory support and treatment of respiratory distress syndrome. Multiple randomised controlled trials have demonstrated that broad application of CPAP/NIV decreases exposure to mechanical ventilation and reduces rates of BPD. Here, we explore why this treatment effect is not larger. We discuss that today's neonatal intensive care unit population evolving from the premature to the extremely premature infant demands better targeted therapy, and indicate how early and accurate identification of preterm infants likely to fail CPAP/NIV could increase the treatment effect and minimise the potential harm of delaying exogenous surfactant therapy in these infants. Finally, we argue that less invasive modes of surfactant administration may represent both a pragmatic and beneficial approach in combining CPAP/NIV and early surfactant. Beneficial treatment effects might be higher than reported in the literature when targeting this approach to preterm infants suffering from respiratory failure primarily due to surfactant deficiency. Considering ongoing limitations of current approaches and focusing both on prospects and potential harm of modified strategies, this commentary ultimately addresses the need and the challenge to prove that pushing early CPAP/NIV and strategies of early and less invasive surfactant application prevents lung injury in the long term.

Use of ventilation/perfusion mismatch to guide individualised CPAP level selection in preterm infants: a feasibility trial.

OBJECTIVE: To measure within-subject changes in ventilation/perfusion (V'/Q') mismatch in response to a protocol of individualised nasal continuous positive airway pressure (CPAP) level selection. DESIGN: Single-arm, non-randomised, feasibility trial. SETTING: Three centres in the Children's Hospital of Philadelphia neonatal care network. PATIENTS: Twelve preterm infants of postmenstrual age 27-35 weeks, postnatal age >24 hours, and receiving a fraction of inspired oxygen (FiO2) >0.25 on CPAP of 4-7 cm H2O. INTERVENTIONS: We applied a protocol of stepwise CPAP level changes, with the overall direction and magnitude guided by individual responses in V'/Q' mismatch, as determined by the degree of right shift (kilopascals, kPa) in a non-invasive gas exchange model. Best CPAP level was defined as the final pressure level at which V'/Q' improved by more than 5%. MAIN OUTCOME MEASURES: Within-subject change in V'/Q' mismatch between baseline and best CPAP levels. RESULTS: There was a median (IQR) within-subject reduction in V'/Q' mismatch of 1.2 (0-3.2) kPa between baseline and best CPAP levels, p=0.02. Best CPAP was observed at a median (range) absolute level of 7 (5-8) cm H2O. CONCLUSIONS: Non-invasive measures of V'/Q' mismatch may be a useful approach for identifying individualised CPAP levels in preterm infants. The results of our feasibility study should be interpreted cautiously and replication in larger studies evaluating the impact of this approach on clinical outcomes is needed. TRIAL REGISTRATION NUMBER: NCT02983825.

Pulmonary Hypertension in Preterm Infants Treated With Laser vs Anti-Vascular Endothelial Growth Factor Therapy for Retinopathy of Prematurity.

Importance: Anti-vascular endothelial growth factor (VEGF) therapy for retinopathy of prematurity (ROP) has potential ocular and systemic advantages compared with laser, but we believe the systemic risks of anti-VEGF therapy in preterm infants are poorly quantified. Objective: To determine whether there was an association with increased risk of pulmonary hypertension (PH) in preterm infants with ROP following treatment with anti-VEGF therapy as compared with laser treatment. Design, Setting, and Participants: This multicenter retrospective cohort study took place at neonatal intensive care units of 48 children's hospitals in the US in the Pediatric Health Information System database from 2010 to 2020. Participants included preterm infants with gestational age at birth 22 0/7 to 31 6/7 weeks who had ROP treated with anti-VEGF therapy or laser photocoagulation. Exposures: Anti-VEGF therapy vs laser photocoagulation. Main Outcomes and Measures: New receipt of pulmonary vasodilators at least 7 days after ROP therapy was compared between exposure groups, matched using propensity scores generated from preexposure variables, and adjusted for birth year and hospital. The odds of receiving an echocardiogram after 30 days of age was also included to adjust for secular trends and interhospital variation in PH screening. Results: Among 1577 patients (55.9% male) meeting inclusion criteria, 689 received laser photocoagulation and 888 received anti-VEGF treatment (95% bevacizumab, 5% ranibizumab). Patients were first treated for ROP at median 36.4 weeks' postmenstrual age (IQR, 34.6-38.7). A total of 982 patients (491 in each group) were propensity score matched. Good covariate balance was achieved, as indicated by a model variance ratio of 1.15. More infants who received anti-VEGF therapy were treated for PH, but when adjusted for hospital and year, this was no longer statistically significant (6.7%; 95% CI, 2.6-6.9 vs 4.3% 95% CI, 4.4-10.2; adjusted odds ratio, 1.62; 95% CI, 0.90-2.89; P = .10). Conclusions and Relevance: Anti-VEGF therapy was not associated with greater use of pulmonary vasodilators after adjustment for hospital and year. Our findings suggest exposure to anti-VEGF may be associated with PH, although we cannot exclude the possibility of residual confounding based on systemic comorbidities or hospital variation in practice. Future studies investigating this possible adverse effect seem warranted.

A whole blood microsampling furosemide assay: development, validation and use in a pediatric pharmacokinetic study.

Background: Furosemide is a commonly used diuretic for the treatment of edema. The pharmacokinetics of furosemide in neonates as they mature remains poorly understood. Microsampling assays facilitate research in pediatric populations. Results: We developed and validated a liquid chromatography-tandem mass spectrometry method for the quantitation of furosemide in human whole blood with volumetric absorptive microsampling (VAMS) devices (10 µl). Furosemide was stable in human whole blood VAMS under the study's assay conditions. This work established stability for furosemide for 161 days when stored as dried microsamples at -78°C. Conclusion: This method is being applied for the quantitation of furosemide in whole blood VAMS in an ongoing prospective pediatric clinical study. Representative clinical data are reported.

Association between postmenstrual age and furosemide dosing practices in very preterm infants.

OBJECTIVE: Furosemide renal clearance is slow after very preterm (VP) birth and increases with postnatal maturation. We compared furosemide dose frequency and total daily dose between postmenstrual age (PMA) groups in VP infants. STUDY DESIGN: Observational cohort study of VP infants exposed to a repeated-dose course of furosemide in Pediatrix neonatal intensive care units (NICU) from 1997 to 2016. RESULTS: We identified 6565 furosemide courses among 4638 infants. There were no statistically significant differences between PMA groups on the odds of receiving more frequent furosemide dosing. Furosemide courses initiated at <28 weeks PMA were associated with a higher total daily dose than those initiated at a later PMA. CONCLUSIONS: Furosemide dosing practices in the NICU are similar across PMA groups, despite maturational changes in drug disposition. Research is needed to identify and test rational dosing strategies across the PMA spectrum for this commonly used but unproven pharmacotherapy.

Development, validation, and implementation of an UHPLC-MS/MS method for the quantitation of furosemide in infant urine samples.

Furosemide is a diuretic drug used to increase urine flow in order to reduce the amount of salt and water in the body. It is commonly utilized to treat preterm infants with chronic lung disease of prematurity. There is a need for a simple and reliable quantitation of furosemide in human urine. We have developed and validated an ultra-high performance liquid chromatography-tandem mass spectrometry method for furosemide quantitation in human urine with an assay range of 0.100-50.0 µg/ml. Sample preparation involved solid-phase extraction with 10 µl of urine. Intra-day accuracies and precisions for the quality control samples were 94.5-106 and 1.86-10.2%, respectively, while inter-day accuracies and precision were 99.2-102 and 3.38-7.41%, respectively. Recovery for furosemide had an average of 23.8%, with an average matrix effect of 101%. Furosemide was stable in human urine under the assay conditions. Stability for furosemide was shown at 1 week (room temperature, 4, -20 and -78°C), 6 months (-78°C), and through three freeze-thaw cycles. This robust assay demonstrates accurate and precise quantitation of furosemide in a small volume (10 µl) of human urine. It is currently being implemented in an ongoing pediatric clinical study.

Prioritization framework for improving the value of care for very low birth weight and very preterm infants.

OBJECTIVE: Create a prioritization framework for value-based improvement in neonatal care. STUDY DESIGN: A retrospective cohort study of very low birth weight (<1500 g) and/or very preterm (<32 weeks) infants discharged between 2012 and 2019 using the Pediatric Health Information System Database. Resource use was compared across hospitals and adjusted for patient-level differences. A prioritization score was created combining cost, patient exposure, and inter-hospital variability to rank resource categories. RESULTS: Resource categories with the greatest cost, patient exposure, and inter-hospital variability were parenteral nutrition, hematology (lab testing), and anticoagulation (for central venous access and therapy), respectively. Based on our prioritization score, parenteral nutrition was identified as the highest priority overall. CONCLUSIONS: We report the development of a prioritization score for potential value-based improvement in neonatal care. Our findings suggest that parenteral nutrition, central venous access, and high-volume laboratory and imaging modalities should be priorities for future comparative effectiveness and quality improvement efforts.