Endotracheal tube cuff pressures in adult patients undergoing general anaes- thesia in two Johannesburg academic hospitals

Abstract

Background: Endotracheal tube (ETT) cuff pressure commonly exceeds the recommended range of 20–30 cm H₂O during anaesthesia. A set volume of air will not deliver the same cuff pressure in each patient and the pressure exerted by the ETT cuff can lead to complications, with either over- or under-inflated cuffs. These can include a sore throat and cough, aspiration, volume loss during positive pressure ventilation, nerve palsies, tracheomalacia and tracheal stenosis. No objective means of ETT cuff pressure monitoring is available in the operating theatres of Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) and Chris Hani Baragwanath Academic Hospital (CHBAH). The ETT cuff pressure of patients undergoing general anaesthesia is therefore unknown.
Method: ETT cuff pressure of 96 adult patients undergoing general anaesthesia without nitrous oxide at CMJAH and CHBAH was measured by one researcher. A RUSCH Endotest™ manometer was used to measure ETT cuff pressure in size 7.0 – 8.5 mm ETTs. The cuff inflation technique that was used by the anaesthetist was also documented.
Results: The mean ETT cuff pressure recorded was 47.5 cm H₂O (range 10–120 cm H₂O). ETT cuff pressures exceeded 30 cm H₂O in 64.58% of patients. Only 18.75% of patients had ETT cuff pressures within the recommended range of 20–30 cm H₂O. There was no statistically significant difference between the ETT cuff pressures measured at the two hospitals. Minimal occlusive volume was the most frequent technique used to inflate the ETT cuff (37.5%); this was followed by inflating the ETT cuff with a predetermined volume of air in 31.25% of cases and palpation of the pilot balloon (27.08%). There was no statistically significant difference between the ETT cuff pressure measured and the inflation technique used by the anaesthetist.
Conclusion: ETT cuff pressures of the majority of patients undergoing general anaesthesia at two academic hospitals were higher than the recommended range. ETT cuff pressure should routinely be measured using a manometer.