The role of continuous positive airway pressure during weaning from mechanical ventilation in cardiac surgical patients

Abstract

We investigated the effects of providing patients with continuous positive airway pressure during a short weaning period from mechanical ventilation to extubation. Following elective primary aortocoronary bypass surgery employing cardiopulmonary bypass, 80 patients received intermittent positive pressure ventilation for 5 h. At the end of this time patients were randomly allocated to one of the following three groups for a 2 h period of spontaneous respiration prior to extubation: group CPAP0 = T‐piece circuit (n = 27); group CPAP5 = 5cmH2O of continuous positive airway pressure (n = 27); group CPAP10 = 10cmH2O of continuous positive airway pressure (n = 26). Following extubation, pulmonary gas exchange was assessed after 1,2,4, and 24 h. All patients had good pre‐operative lung function. There was a significant increase in the median alveolar‐arterial oxygen partial pressure difference and a decrease in the oxygenation index in all three groups during the period of added inspired oxygen which persisted until 24 h post‐extubation, but there were no differences between the groups. In patients with good pre‐operative lung function requiring primary aortocoronary bypass surgery, the use of continuous positive airway pressure confers no advantage over a simple T‐piece attachment during the short period of weaning from mechanical ventilation to extubation. Copyright © 1995, Wiley Blackwell. All rights reserved