237 - Inhaled Nitric Oxide (iNO) Use in Infants with Severe Bronchopulmonary Dysplasia (sBPD)

Poster Number: 237
Publication Number: 237.222

Caroline E. Minnick, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston-Salem, NC, United States; Laura C. Downey, Atrium Health Wake Forest Baptist, Winston Salem, NC, United States; Jeffrey S. Shenberger, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston-Salem, NC, United States

Background: iNO is FDA approved to treat term and near-term neonates with hypoxemic respiratory failure accompanied by clinical or echocardiographic evidence of pulmonary hypertension (PH). While there is strong evidence of clinical efficacy of iNO to manage acute persistent PH in newborns, outcomes following iNO treatment for PH crises in former premature infants with sBPD remains largely unreported.

Objective: To define the clinical characteristics and outcomes of infants with sBPD treated with iNO for PH crises at a level IV NICU.

Design/Methods: The cohort consisted of preterm infants admitted to Atrium Health Wake Forest Brenner Children's Hospital's NICU between 2015 and 2020. Using a hospital-wide iNO database, we identified a group of preterm infants treated with iNO after 28 days of life. We defined sBPD as requiring at least 30% O2 at 36 weeks and infants requiring at least 30% O2 at > 28 days of life who died prior to 36 weeks of age. All clinical data was obtained from the electronic medical record. Analysis was performed using parametric and non-parametric comparisons and correlation testing when appropriate.

Results: During the 6-year epoch, 125 NICU infants received iNO (4/100 admits) with a mean duration of use of 155±167 hrs. As shown in Table 1, of those receiving iNO, 25 were preterm infants with sBPD, four of whom were treated at least twice (35 total iNO treatments). Mean age of treatment was 138±71 days with median duration of use of 111 hrs (Q1: 61, Q3: 306). Pre-iNO FiO2 and O2 saturation index (OSI) were 90±15% and 20.1±7.5, respectively. The most common indications for iNO use were clinical deterioration consistent with PH (68%) and PH associated with pneumonia/sepsis (17%). Pre-iNO echocardiograms were performed in 22 of the 35 treatments with 82% of the studies showing evidence of PH by septal flattening, estimated right ventricular pressure, or both. iNO use was associated with reductions in both FiO2 and OSI (p < 0.05). Overall, 16 sBPD infants survived until discharge (64%). Of the survivors, 10 required tracheostomy, 56% were discharged on sildenafil and 75% on home O2. Surviving infants had lower initial OSI and greater reductions in FiO2 and OSI at first treatment (FiO2: 34% vs. 0%; OSI: 42% vs. -7%, p < 0.01). Survival also correlated with a > 25% reduction in both FiO2 and OSI (p < 0.01) after first iNO treatment [Table 2].Conclusion(s): In this single center study, iNO for acute PH deteriorations in sBPD accounted for 20% of all NICU iNO usage. Importantly, greater reductions in both FiO2 and OSI after iNO treatment was associated with survival. Nonetheless, most survivors required advanced respiratory care at the time of discharge.
Table 1. Characteristics of infants with Severe BPD treated with iNOOSI = oxygen saturation index; (mean airway pressure x FiO2) x 100/O2 saturation
"n": gestational age, birth weight, length of stay refers to number of patients; all other parameters are per iNO treatment