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Abstract

Introduction: Endotracheal tube (ETT) cuff pressure must be kept less than 30 cm H2O to prevent tracheal wall pressure necrosis, but must maintain an adequate seal for ventilation. Manometry and a minimal leak test (MLT) are both well-described methods for measuring cuff pressure. Methods: During a 2 month period, we used a manometer to obtain initial ETT cuff pressure measurements on all mechanically ventilated patients in a surgery ICU. Two different physicians then separately performed a MLT for each patient and measured the corresponding cuff pressure; these were compared between the two physicians. The VAP rate per ventilator days were calculated for the two months during the study period and compared to the two months immediately prior to the study. Results: Twenty-eight patients were included for a total of 50 events. The post-MLT measured cuff pressures by the two physicians were highly consistent, with an intraclass correlation coefficient of 0.872 (95% CI). The post-MLT measured cuff pressures were greater than 30 cm H2O in only 2 cases (4%; avg 32 cm H2O). During the first half of the study, the incidence of starting cuff pressures elevated above 30 cm H2O was not significantly different than the second month (19% vs 31%, p = 0.38); however, of the patients with elevated cuff pressures, the mean and elevation above the norm were both higher (47.5 ± 7.724 vs 38.89 ± 5.302 cm H20 and 17.5 ± 7.724 vs 8.89 ± 5.302 cm H20, p = 0.037). There was no difference in VAP rate during the study compared to historical controls (2.79 vs 2.99 VAPs per 1000 ventilator days, p = 0.961). Conclusions: The incidence of ventilator-associated pneumonia is not significantly increased due to the performance of a daily MLT. The MLT is a reliable indicator of endotracheal cuff pressure, does not undergo significant inter-observer subjective variation, and produces cuff pressures consistently within the acceptable range of less than 30 cm H2O. Additionally, we suspect that by emphasizing safe cuff pressures and daily cuff measurements during the course of our study we were able to decrease unacceptably high starting endotracheal cuff pressures.