631 - High frequency jet versus oscillator as initial ventilatory mode for congenital diaphragmatic hernia: a randomized clinical trial

Publication Number: 2616.631

Michelle J. Yang, University of Utah School of Medicine, Salt Lake City, UT, United States; Christian C. Yost, University of Utah School of Medicine, Salt Lake City, UT, United States; Bradley A.. Yoder, University of Utah, Salt Lake City, UT, United States

Background: Congenital diaphragmatic hernia (CDH) carries high mortality and morbidity, including chronic lung disease. Lung protective ventilator strategies, particularly high frequency ventilation, may minimize volutrauma and oxygen toxicity by optimizing lung inflation while avoiding excess tidal volumes. No randomized trials, including neonatal CDH, have compared high frequency oscillatory (HFO) to high frequency jet ventilation (JET).

Objective: To compare the effects on oxygenation and ventilation of HFO to JET as the initial mode of mechanical ventilation for CDH neonates.

Design/Methods: We conducted a prospective randomized trial of HFO vs JET as initial ventilator mode for neonatal CDH. We excluded infants with concurrent severe anomalies or syndromes and stratified by intrathoracic liver. The primary outcome was change in oxygenation index (OI) at 24 hours.

Results: From 2021 to 2025, we screened 74 infants and enrolled 40, 20 HFO and 20 JET. Demographic features were similar between groups (Table 1). There was no significant change in OI after 24 hours or at time of repair (Table 2). There were no differences in best values of oxygenation or ventilation within the first 24 hours of life. Though initial pCO2 was higher in the HFJV group (79 ± 28 vs 60 ± 23, P=0.003), all subsequent pCO2 comparisons were similar between groups and within normal range. Preoperative iNO (JET 25% v HFO 20%) and inotrope use (JET 35% v HFO 35%) use were similar between groups. More infants in the JET arm remained on study ventilator at 24 hours (95% v 68%) and at time of repair (60% v 30%); with any thoracic liver this difference was significant at time of repair (100% v 33%, P=0.005; Table 2). Six HFO but no JET switched HF modes. Among survivors there were no differences in ventilator days [JET 15.9 (12.5-33.4) v HFO 14.5 (5.7-23.2)] or discharge age [JET 81 (53-102) v HFO 77 (77-148)].

Conclusion(s): In this first ever randomized high frequency trial, measures of oxygenation and ventilation were similar with JET compared to HFO as initial ventilator mode for neonatal CDH. By time of operative repair, JET was preferred to HFO for CDH support in presence of any thoracic liver.

Table 1. Demographics comparing the two study cohorts
*JET: high frequency jet ventilator; HFO: high frequency oscillatory ventilator; o/e TFLV: observed to expected total fetal lung volume; defect size C/D by Congenital Diaphragmatic Hernia Study Group Grading System.

Table 2. Change in ventilator support and oxygenation index (OI) by initial ventilator mode.
Data as median (IQR) or n (%). HFO (high frequency oscillator); JET (high frequency jet ventilator); , delta/change from initial to 24 hours. * P < 0.05.