Central Venous Oxygen Saturation as a Predictor of the Outcome of Weaning From Mechanical Ventilation

Abstract

Weaning from mechanical ventilation represents a corner stone of management of critically ill patients. Successful weaning represents a great achievement in patient's critical course in the ICU. This makes the process of weaning one of the most difficult steps in ICU care, for those reason, such a study was done to create a new thinking about the predictors that facilitate patient weaning from mechanical ventilator. The aim of this study is to evaluate the central venous saturation as a predictor of the outcome of weaning from mechanical ventilation. Cohort, unicentric, clinical study research design was utilized in the current study. Sample consists of one hundred and twenty patients over a one year period, all patients passed the first SBT (spontaneous breathing trial) and weaned successfully from mechanical ventilation were extubated after undergoing a two-step weaning protocol (measurements of predictors followed by a T-tube trial). Extubation failure was defined as the need of re-intubation within 48 hrs. The weaning protocol evaluated hemodynamic, ventilation parameters, arterial and venous gases during mechanical ventilation (Immediately before T-tube trial), and at the 30^th min of spontaneous breathing trial. Findings of this study show that re-intubation rate was 30%. Analysis by logistic regression revealed that central venous saturation was the only variable able to discriminate outcome of extubation. Reduction of central venous saturation by >5% was an independent predictor of re-intubation, with odds ratio of 52.6 (95% confidence interval =16.34–169.42), a sensitivity of 87%, and a specificity of 90%. Reduction of central venous saturation during spontaneous breathing trial was associated with extubation failure and could reflect the increase of respiratory muscles oxygen consumption. Results of the present study indicated that central venous saturation was an early and independent predictor of extubation failure and may be a valuable accurate parameter to be included in weaning protocols.

Keywords: Central Venous Saturation - Mechanical Ventilation - Extubation.