(669) Use of Inhaled Epoprostenol in Children With Pediatric Acute Respiratory Distress Syndrome

Introduction: Inhaled epoprostenol (iEpo) is a pulmonary vasodilator that improves oxygenation in adults with acute respiratory distress syndrome (ARDS). We hypothesized that iEpo would improve oxygenation in children with pARDS, especially those with pulmonary hypertension (pHTN).

Methods: Retrospective data were obtained from the electronic medical record for children < 18 years old who received mechanical ventilation and iEpo in a tertiary PICU from 2017-2022, and met Pediatric Acute Lung Injury Consensus Conference (PALICC) diagnostic criteria for pARDS. Patients who were post-operative from congenital heart surgery, died within 12 hours of iEpo initiation, or had iEpo initiated prior to PICU admission were excluded.

Results: A total of 18 patients were included, with a median age of 2.9 years (IQR 1.4-7.9). pARDS was classified as severe in 14 (78%) and underlying cause was respiratory in 10 (56%). Echocardiogram prior to iEpo showed pHTN in 8 (44%), no evidence of pHTN in 3 (17%), and was not performed in 7 (39%). Median OSI at the time of initiation was 22.9 (IQR 13.7-24.1), which was similar to the OSI at 6 hours (17.1, IQR 12.9-27.5) (p=0.44 by Wilcoxon signed-rank test of difference) and 12 hours after initiation (12.8, IQR 10.3-25.9, p=0.09). The majority of patients (12/18, 67%) had some decrease in OSI at 6 hours after iEpo initiation, and 5/18 (28%) were “responders” with a decrease in OSI of 20% or more. Responders did not differ by presence of pHTN (with pHTN 3/8 38% responders, without pHTN 1/3 33%, unknown 1/7 14%, p=0.8), underlying cause of pARDS (respiratory 2/10 20%, systemic 3/8 38%, p=0.6), severity of pARDS (mild/moderate 1/4 25% responders, severe 4/14 29% responders, p=1.0), or median age (responders 4.4 years, IQR 3.4-7.9; non-responders 1.7 years, IQR 1.3-7.3, p=0.35). The majority of responders (4/5, 80%) had some improvement in OSI by 1 hour after initiation, and all (5/5, 100%) had improvement by 3 hours after initiation of iEpo.

Conclusions: There was no statistically significant change in OSI at 6 or 12 hours after iEpo initiation in children with pARDS. Among the minority of children who responded with a substantial decrease in OSI, no clinical feature evaluated (including known pHTN) was predictive. However, improvement in OSI was seen within 3 hours in all responders.