Central venous oxygen saturation as a predictor of failure of weaning from mechanical ventilation

Abstract

Background In the process of weaning from mechanical ventilation, tolerance to the pre-extubation attempts of spontaneous breathing does not completely ensure a favorable outcome. In such conditions, it was possible to predict the result of extubation by the drop of central venous oxygen saturation (ScvO2) readings. Therefore, the evaluation of ScvO2 during spontaneous breathing trials may be considered as a novel predictor for weaning success.Patients and methods This was a prospective cohort clinical research that involved 50 patients admitted to the respiratory ICU of Abbassia Chest Hospital. Those patients were subjected to intubation and mechanical ventilation for the period of 2 successive days or more and followed up for signs of postextubation respiratory failure for 48 h. All patients were evaluated daily for fulfilling of the weaning criteria and were weaned in a two-step protocol: a spontaneous breathing trial for 30 min followed by extubation. Central blood gasses were evaluated in the beginning (first min) and at the end (30th min) of the trial. Hemodynamic and ventilatory parameters were also assessed.Results Thirty-nine (78%) patients had a successful extubation, while 11 (22%) patients failed the extubation process. Logistic regression analysis identified the change in ScvO2 as the only parameter with the ability to distinguish between both probable results of extubation. A reduction of more than 3.8% from the baseline value of ScvO2 was able to independently predict extubation failure with a sensitivity of 89.74%, a specificity of 90.91, and an odds ratio of 1.48 (95% confidence interval: 1.06–2.07).Conclusion ScvO2 is able to successfully and independently predict extubation failure (EF). Adding to that, being a rapid and accurate method with high sensitivity and specificity, it will help in early diagnosing of the extubation failure cases and their proper management.