The effect of high frequency oscillatory ventilation combined with tracheal gas insufflation on extravascular lung water in patients with acute respiratory distress syndrome: a randomized, crossover, physiological study.

Abstract

Purpose: High frequency oscillation combined with tracheal gas insufflation (HFO-TGI) improves oxygenation in patients with Acute Respiratory Distress Syndrome (ARDS). There is limited physiologic data regarding the effects of HFO-TGI on hemodynamics and pulmonary edema during ARDS. The aim of this study was to investigate the effect of HFO-TGI on extravascular lung water (EVLW). Materials and Methods: We conducted a prospective, randomized, crossover study. Consecutive eligible patients with ARDS received sessions of conventional mechanical ventilation (CMV) with recruitment maneuvers (RMs), followed by HFO-TGI with RMs, or vice versa. Each ventilatory technique was administered for 8 hours. The order of administration was randomly assigned. Arterial/central venous blood gas analysis and measurement of hemodynamic parameters and EVLW were performed at baseline and after each 8-hour period using the single-indicator thermodilution technique. Results: Twelve patients received 32 sessions. PaO2/FiO2 and respiratory system compliance were higher (p<0.001 for both), while EVLW indexed to predicted body weight (EVLWI) and oxygenation index were lower (p=0.021 and 0.029, respectively) in HFO-TGI compared with CMV. There was a significant correlation between PaO2/FiO2 improvement and EVLWI drop during HFO-TGI (Rs=-0.452, p= 0.009). Conclusions: HFO-TGI improves gas exchange and lung mechanics in ARDS, and potentially attenuates EVLW accumulation.