Acute Hemodynamic Changes of Pressure-controlled Inverse Ratio Ventilation in the Adult Respiratory Distress Syndrome: A Transesophageal Echocardiographic and Doppler Study

Abstract

Twelve patients with the adult respiratory distress syndrome were included in this study and evaluated by transesophageal echocardiography and Doppler, assessing right and left ventricular intracardiac blood flow alterations with progressive increase of inspiration-to-expiration (I-E) ratios. Whereas midpulmonary artery flow parameters did not show any change, early left ventricular filling demonstrated a significant increase after switching the ventilatory mode from volume to pressure-controlled ventilation with 2:1 I-E ratio (end-inspiration: 39 +/- 26 cm with positive end-expiratory pressure [PEEP]-ventilation to 68 +/- 56 cm with pressure-controlled inverse-ratio ventilation, 2:1; p < 0.01; at end-expiration, from 67 +/- 21 cm with PEEP-ventilation to 83 +/- 36 cm with pressure-controlled ventilation 1:1; p < or = 0.05), resulting probably from different ventilatory flow and pressure curves. In the meanwhile, cardiac index demonstrated a significant augmentation (from 4.73 +/- 1.71 L/min.m2 to 5.56 +/- 1.66 L/min.m2; p < 0.05). Pressure-controlled inverse ratio ventilation results in both respiratory and hemodynamic advantages as is demonstrated by this study.