BACKGROUND: Aspiration of colonized oropharyngeal secretions is a major factor in the pathogenesis of ventilator-associated pneumonia (VAP). A tapered-cuff endotracheal tube (ETT) has been demonstrated to reduce aspiration around the cuff. Whether these properties are efficacious in reducing VAP is not known. METHODS: This 2-period, investigator-initiated observational study was designed to assess the efficacy of a tapered-cuff ETT to reduce the VAP rate. All intubated, mechanically ventilated patients over the age of 18 were included. During the baseline period a standard, barrel-shaped-cuff ETT (Mallinckrodt Hi-Lo) was used. All ETTs throughout the hospital were then replaced with a tapered-cuff ETT (TaperGuard). The primary outcome variable was the incidence of VAP per 1,000 ventilator days. RESULTS: We included 2,849 subjects, encompassing 15,250 ventilator days. The mean SD monthly VAP rate was 3.29 1.79/1,000 ventilator days in the standard-cuff group and 2.77 2.00/1,000 ventilator days in the tapered-cuff group (P .65). While adherence to the VAP prevention bundle was high throughout the study, bundle adherence was significantly higher during the standard-cuff period (96.5 2.7%) than in the tapered-cuff period (90.3 3.5%, P .01). CONCLUSIONS: In the setting of a VAP rate very near the average of ICUs in the United States, and where there was high adherence to a VAP prevention bundle, the use of a tapered-cuff ETT was not associated with a reduction in the VAP rate.