PROSPECTIVE, RANDOMIZED STUDY OF VENTILATOR-ASSOCIATED PNEUMONIA IN PATIENTS WITH ONE VERSUS 3 VENTILATOR CIRCUIT CHANGES PER WEEK

OBJECTIVE: To assess the effect on the rate of ventilator-associated p neumonia (VAP) of decreasing the frequency of ventilator circuit chang es from three times to once per week. DESIGN: Prospective, randomized trial. SETTING: Medical intensive care unit (MICU), a 12-bed, critical -care internal medicine unit, and neurosciences intensive care unit (N ICU), a 21-bed, predominantly adult neurosurgical unit, of an urban un iversity hospital. PATIENTS: All 447 patients requiring mechanical ven tilation during October 1992 through June 1993. INTERVENTION: Patients were allocated randomly on the basis of permanent medical record numb ers: those with odd numbers had circuits changed three times per week, those with even numbers once per week. Intensive-care-unit surveillan ce was conducted in accordance with definitions and methods of the Nat ional Nosocomial Infections Surveillance System. RESULTS: In the MICU, the one-change-per-week group had a VAP rate of 7.3 per 1,000 ventila tor days, versus 5.9 for the three-per-week group (P=.6). In the NICU, the one-change-per-week group had a rate of 12.2 per 1,000 ventilator days, versus 12.6 for the three-per week group (P=.9). Considering pa tients in both units ventilated for no more than 7 days, the one-chang e-per-week group had a VAP rate of 5.9 per 1,000 ventilator days, vers us 9.0 per 1,000 for the three-changes-per-week soup (odds ratio [OR], 0.65; 95% confidence interval [CI95], 0.25 to 1.69). Including patien ts in the two units maintained on mechanical ventilation for more than 7 days, the one-change-per-week group had a VAP rate of 13.2 per 1,00 0 ventilator days, versus 9.6 per 1,000 for the three-changes-per-week group (OR 1.37; CI95, 0.71 to 2.65). CONCLUSIONS: Decreasing the freq uency of ventilator circuit changes from three times to once per week had no adverse effect on the overall rate of VAP. Less frequent ventil ator circuit changes may decrease the incidence of VAP among patients ventilated for no more than 1 week. However, the incidence of VAP may be higher among patients with once weekly circuit changes ventilated f or more than 1 week.