598: SINGLE-INSTITUTION EXPERIENCE WITH APRV

Abstract

Introduction: High mean airway pressure (MAP) ventilation is used in pediatric ARDS to increase oxygenation. Nonconventional approaches include high-frequency oscillatory ventilation (HFOV) and airway pressure release ventilation (APRV). Pediatric HFOV has been relatively well described in literature; APRV has been only sporadically reported in the pediatric population. Our center has moved to APRV use before considering HFOV despite a paucity of data. The consequences of this shift are not well understood. This study describes our single-center experience with APRV and compare outcomes to published data. Methods: This is an early interim analysis of a convenience sample of 22 patients from a retrospective cohort study of 197 patients for whom APRV was used between January 2013 and December 2021. Demographics, pre-hospitalization characteristics, and admission variables were collected. We examined ventilator settings, blood gases, oxygenation index, P/F ratios before transition from conventional ventilation and in 12-hour time intervals after transition to APRV. Primary outcomes were mortality and 28-d ventilator free days (VFD). Results: Of the 22 patients, the mean age was 8.4 months and 54% were male. The most common comorbidity was congenital heart disease (40.9%) followed by chronic lung disease (13.6%). Eight-six percent of the patients were diagnosed with ARDS and 57.9% had bacterial pneumonia as the etiology of ARDS. Prior to switching to APRV, 64% of the patients were in pressure control mode of ventilation on a mean FiO2 of 74%. Half of the patients had neuromuscular blockade and 53% received nitric oxide prior to switch to APRV. The average mean airway pressure was 18 cm H2O in conventional ventilation and increased to 23 cm H2O with APRV. Median pHigh (IQR) was 28 (25-32) and median tHigh of 1.65 (1.5-2.7). There was an increase in recorded oxygen saturation (86% to 90%) at 4 hours. Only 32% of patients remained on APRV at 24 hours. Survival to discharge in this cohort was 36.4%. The 28-d VFD was 3.9, driven largely by high mortality. Conclusions: In patients receiving APRV, there was an increase in MAP and improvement in SaO2 after switching to APRV. There was a very high mortality rate in this small subset which requires further investigation.