Comparison of four inflation techniques on endotracheal tube cuff pressure using a feline airway simulator

Abstract

Objectives The aim of this study was to compare four inflation techniques on endotracheal tube cuff (ETC) pressure using a feline airway simulator. Methods Ten participants used four different endotracheal cuff inflation techniques to inflate the cuff of a low-pressure, high-volume endotracheal tube within a feline airway simulator. The simulator replicated an average-sized feline trachea, intubated with a 4.5 mm endotracheal tube, connected to a circle breathing system and pressure-controlled ventilation with oxygen and medical air. Participants inflated the ETC: by pilot balloon palpation (P); by instilling the minimum occlusive volume (MOV) required for loss of airway leaks during mechanical ventilation; until a passive release of pressure with use of a loss-of-resistance syringe (LOR); and with use of a syringe with a digital pressure reader (D) specifically designed for endotracheal cuff inflation. Intracuff pressure was measured by a manometer obscured to participants. The ideal pressure was considered to be between 20 and 30 cmH2O. Data were analysed by Shapiro–Wilk, Kruskal–Wallis and χ2 tests, as appropriate. Results Participants were eight veterinarians and two veterinary nurses with additional training in anaesthesia. Measured median intracuff pressures for P, MOV, LOR and D, respectively, were 25 cmH2O (range 4–74 cmH2O), 41 cmH2O (range 4–70 cmH2O), 31 cmH2O (range 18–64 cmH2O) and 22 cmH2O (range 20–30 cmH2O). D performed significantly better ( P <0.001) than all other techniques, with no difference between the other techniques. Conclusions and relevance Use of D for cuff inflation achieved optimal cuff pressures. There may be high operator-dependent variability in the cuff pressures achieved with the use of P, MOV or LOR inflation techniques. As such, a cuff manometer is recommended when using any of these techniques.