CONTINUOUS ASPIRATION OF SUBGLOTTIC SECRETIONS IN PREVENTING VENTILATOR-ASSOCIATED PNEUMONIA

Objective: To determine whether continuous subglottic aspiration preve nts nosocomial pneumonia in mechanically ventilated patients. Design: A randomized, controlled, blinded study. Setting: Medical-surgical int ensive care unit. Patients: 190 patients who were admitted to the inte nsive care unit during a 33-month period and whose condition suggested the need for prolonged intubation (>3 days). Intervention: 76 patient s were randomly allocated to receive continuous aspiration of subglott ic secretions, and 77 control patients were allocated to receive usual care. Measurements: The numbers of cases of ventilator-associated pne umonia, ventilated days, days in intensive care unit, and deaths were recorded. The amount of subglottic secretions aspirated daily and surv eillance cultures in the subglottic secretions were also obtained peri odically. Etiologic diagnosis was based on the quantitative culture of secretions obtained by protected specimen brush or bronchoalveolar la vage. Results: The incidence rate of ventilator-associated pneumonia w as 19.9 episodes/1000 ventilator days in the patients receiving contin uous aspiration of subglottic secretions and 39.6 episodes/1000 ventil ator days in the control patients (relative risk, 1.98; 95% CI, 1.03 t o 3.82). This difference was due to a significant (P < 0.03) reduction in the number of gram-positive cocci and Haemophilus influenzae organ isms in the patients receiving continuous aspiration. However, no diff erences were observed in the number of Pseudomonas aeruginosa or Enter obacteriaceae organisms. Episodes of ventilator-associated pneumonia o ccurred later in patients receiving continuous aspiration (12.0 +/- 7. 1 days) than in the control patients (5.9 +/- 2.1 days) (P = 0.003). T he same microorganisms isolated from protected specimen brush or bronc hoalveolar lavage cultures in patients with ventilator-associated pneu monia were previously isolated from cultures of subglottic secretions in 85% of cases. No significant differences in outcome were found. Con clusions: The incidence of nosocomial pneumonia in mechanically ventil ated patients can be significantly reduced by using a simple method th at decreases the chronic microaspirations through the cuff of endotrac heal tubes.