A randomized clinical trial of continuous aspiration of subglottic secretions in cardiac surgery patients

Study objectives: To determine whether the application of continuous aspira tion of subglottic secretions (CASS) is associated with a decreased inciden ce of ventilator-associated pneumonia (VAP), Design: Prospective clinical trial. Setting: Cardiothoracic ICU (CTICU) of Barnes-Jewish Hospital, St. Louis, a university-affiliated teaching hospital. Patients: Three hundred forty-three patients undergoing cardiac surgery and requiring mechanical ventilation in the CTICU. Interventions: Patients were assigned to receive either CASS, using a speci ally designed endotracheal tube (Hi-Lo Evac; Mallinckrodt Inc; Athlone, Ire land), or routine postoperative medical care without CASS, Results: One hundred sixty patients were assigned to receive CASS, and 183 were assigned to receive routine postoperative medical care without CASS, T he two groups were similar at the time of randomization with regard to demo graphic characteristics, surgical procedures performed, and severity of ill ness. Risk factors for the development of VAP were also similar during the study period for both treatment groups. VAP was seen in 8 patients (5.0%) r eceiving CASS and in 15 patients (8.2%) receiving routine postoperative med ical care without CASS (relative risk, 0.61%; 95% confidence interval, 0.27 to 1.40; p = 0.238), Episodes of VAP occurred statistically later among pa tients receiving CASS ([mean +/- SD] 5.6 +/- 2.3 days) than among patients who did not receive CASS (2.9 +/- 1.2 days); (p = 0.006). No statistically significant differences for hospital mortality overall duration of mechanic al ventilation, lengths of stay in the hospital or CTICU, or acquired organ system derangements were found between the two treatment groups. No compli cations related to CASS were observed in the intervention group. Conclusions: Our findings suggest that CASS can be safely administered to p atients undergoing cardiac surgery. The occurrence of VAP can be significan tly delayed among patients undergoing cardiac surgery using this simple-to- apply technique.