[Effects of the positive end-expiratory pressure increase on sublingual microcirculation in patients with acute respiratory distress syndrome]

Abstract

Objective: The aim of this study was to evaluate the impact of increased positive end-expiratory pressure on the sublingual microcirculation.

Methods: Adult patients who were sedated, under mechanical ventilation, and had a diagnosis of circulatory shock and acute respiratory distress syndrome were included. The positive end-expiratory pressure level was settled to obtain a plateau pressure of 30cmH₂O and then maintained at this level for 20minutes. Microcirculatory (obtained by videomicroscopy) and hemodynamic variables were collected at baseline and compared with those at the end of 20min.

Results: Twelve patients were enrolled. Overall, the microcirculation parameters did not significantly change after increasing the positive end-expiratory pressure. However, there was considerable interindividual variability. There was a negative, moderate correlation between the changes in the De Backer score (r=-0.58, p=0.048), total vessel density (r=-0.60, p=0.039) and baseline values. The changes in total vessel density (r=0.54, p=0.07) and perfused vessel density (r=0.52, p=0.08) trended toward correlating with the changes in the mean arterial pressure.

Conclusion: Overall, the microcirculation parameters did not significantly change after increasing the positive end-expiratory pressure. However, at individual level, such response was heterogeneous. The changes in the microcirculation parameters could be correlated with the baseline values and changes in the mean arterial pressure.

Keywords: Adult respiratory distress syndrome; Choque; Hemodinâmica; Hemodynamics; Mechanical ventilators; Microcirculation; Microcirculação; Positive end‐expiratory pressure; Pressão positiva expiratória final; Shock; Síndrome do desconforto respiratório do adulto; Ventiladores mecânicos.