Positive End-Expiratory Pressure during Partial Liquid Ventilation: Impact on Lung Volume Recruitment and Gas Exchange

Abstract 1832 Poster Session I, Saturday, 5/1 (poster 48)

The application of positive end-expiratory pressure (PEEP) is used in certain types of respiratory failure to recruit lung volume, improve ventilation/perfusion matching, and improve gas exchange. Partial liquid ventilation (PLV^SM) using FRC amounts of perfluorocarbon recruits lung volume mechanically, and may alter the subsequent effects of applied PEEP. In 9 newborn piglets (1130 ± 22 gms) with saline lavage-induced lung injury (PaO2 < 100 torr at FiO2 1.0), we tested the hypothesis that PEEP applied during PLV would not affect gas exchange, compliance, end-expiratory lung volume (ΔEELV) or hemodynamics. PLV animals received intratracheal perflubron (LiquiVent®; 30.1 ±4.6 mL/kg); after 1 hour stabilization, PEEP was increased, then decreased at constant tidal volume in a stepwise fashion from 4 cm H₂O-8-12-8-4. After 30 minutes at each PEEP level, blood gases, blood pressures, heart rates, lung mechanics (VenTrack) and ΔEELV (mL/kg; respiratory inductive plethysmography) were measured. Data analysis used paired t-tests with Bonferroni correction. Mean ± SD are shown. (Table)

Table 1 No caption available

Conclusions: In an animal model of respiratory distress, the application of PEEP during PLV (over the range studied) resulted in changes in gas exchange and in EELV, in a similar fashion to PEEP applied during conventional ventilation. As PEEP was reduced, dynamic compliance increased while a/A fell, possibly due to both a redistribution of perflubron and evaporative losses. These data suggest that application of PEEP to the partially liquid-filled lung continues to recruit lung volume, likely by moving liquid out of airways towards the periphery.

Perflubron provided by/ equity in Alliance Pharmaceutical Corp (MCM, PM)