A comparative audit of endotracheal tube cuff pressures across three intensive care units at a tertiary South African academic hospital

Abstract

Background. In many intensive care units (ICUs), endotracheal intubation with cuffed endotracheal tubes (ETTs) is a regular intervention in critically ill patients. Prolonged periods of intubation are common in this cohort of patients, so regular monitoring of the ETT cuff pressures is particularly important. Significant morbidity and mortality can be observed with under- and overinflation of the ETT cuff. Best practice guidelines suggest a safe ETT cuff pressure of 20 - 30 cm H2O, as measured by an aneroid manometer.

Objectives. To measure and compare ETT cuff pressures in adult intubated patients across three ICUs: trauma, neurosurgical, and multidisciplinary (a multidisciplinary ICU is overseen by the same intensivist; however, it has two separate nursing staff contingents in adjacent wards, so data from this ICU were recorded as ‘multidisciplinary team 1 (MDT 1) and multidisciplinary team 2 (MDT 2)’) at a tertiary academic hospital, and compare the frequency at which ETT cuff pressures appeared outside the recommended range. The secondary objective was to assess the degree of under- or overinflation and determine whether ETT cuff pressures varied significantly based on the time of day the measurements were taken (morning, afternoon and evening).

Methods. This prospective observational study was conducted at a tertiary Johannesburg academic hospital in Gauteng Province, South Africa. Altogether, 300 ETT cuff pressure measurements were collected from 137 patients across the three ICUs. These measurements were done at three different times during the day, mornings, afternoons and evenings, using a standardised manometer.

Results. Over 90% of the recorded ETT cuff pressures measured across the three ICUs were above the suggested optimal range of 20 - 30 cm H2O. The trauma ICU had the most overinflated ETT cuff pressures, with most pressures recorded to be >75 cm H2O. Slightly lower, but still overinflated, ETT cuff pressures were observed in the neurosurgical and multidisciplinary ICUs. Repeated measurements showed consistently elevated pressures, which suggests inadequate monitoring practices.

Conclusion. This study demonstrated a consistent trend of ETT cuff overinflation across all three ICUs, with almost all measurements significantly exceeding the recommended optimal range. No statistically significant differences in cuff pressures were observed based on the time of day the measurements were taken.