Diagnostic value of increase in central venous pressure during SBT for prediction of weaning failure in mechanically ventilated patients

Abstract

Weaning from mechanical ventilation is a key element in the care of critically ill patients, and Spontaneous Breathing Trial (SBT) is a crucial step in this procedure. This cross-sectional study aimed to evaluate central venous pressure (CVP) values and their changes could independently predict the SBT outcome among mechanically ventilated patients. We hypothesized that an early rise on CVP could signal a cardiac failure when handling a massive increase on venous return following a discontinuation of positive pressure ventilation. This CVP rise could identify a subset of patients at high risk for extubation failure.

Methods: One hundred and fifty-nine mechanically ventilated patients who were candidates for SBT underwent a monitoring protocol that included a blind CVP assessment at the beginning, first 3 minutes, and end of SBT. Weaning failure was defined as re-intubation within 48 hours after extubation. Parametric and non-parametric variables were compared with T test and Mann-Whitney U test. Multivariate logistic regression test was performed to determine the predictive value of extubation failure of normal clinical variables and CVP at 3 minutes after the onset of SBT.

Results: Weaning failure was observed in nineteen patients. Increasing CVP values during SBT independently predicted extubation failure, and patients with lower Hemoglobin concentration, lower arterial oxygen saturation (SpO2), and longer MV duration had higher rates of re-intubation.