Comparison of the Effect on the Cuff Pressure of the Endotracheal Tubes Following Cuff Inflation with Air and With Nitrous Oxide – Oxygen during General Anaesthesia - A Prospective, Randomised Study

Abstract

Background and aims: During general anaesthesia cuffed endotracheal tubes are used to provide airway seal and prevent aspiration. But it has been observed that use of nitrous oxide oxygen for ventilation during anaesthesia leads to rise in intracuff pressure which can be transmitted to the wall of trachea leading to complications. In this study we compared the effect on cuff pressure of Portex endotracheal tubes( high volume low pressure cuffs) and Armoured endotracheal tubes( low volume high pressure cuffs) when the cuffs were inflated with air and with nitrous oxide- oxygen mixture during general anaesthesia using nitrous oxide oxygen. Method:After institutional ethics committee approval 180 patients aged 18 -60 years of ASA status I & IIposted for elective surgeries were randomly allocated in four groups of 45 each. After taking consent and intravenous access general anaesthesia was given with endotracheal intubation. Group A1- Portexendotracheal tube cuff inflated with air. Group A2- Portex endotracheal tube cuff inflated with nitrous oxide- oxygen mixture. Group B1- Armoured endotracheal tube cuff inflated with air.Group B2- Armoured endotracheal tube cuff inflated with nitrous oxide- oxygen mixture. Controlled ventilation was done with nitrous oxide oxygen during the anaesthesia. Endotracheal tube cuff pressure was measured at inflation and at every 30 minutes interval till 90 minutes. Postoperatively patients were observed for any complications such as sore throat, difficulty in swallowing, hoarseness of voice, etc. Results: It was observed that the intracuff pressure in both the high volume low pressure and the low volume high pressure cuffed endotracheal tubes rises with time when the cuffs are inflated with air. The rise was not significant when nitrous oxide - oxygen was used for inflating the cuff in both the groups. Regardless of the type of inflating medium used for cuff inflation the incidence of complications was high in low volume high pressure cuffed endotracheal tubes as compared to high volume low pressure cuffed endotracheal tubes.