Aspects of in vivo endotracheal tube intracuff pressure in cats.

OBJECTIVES: To determine the endotracheal tube cuff pressure produced with two inflation techniques, in two brands of endotracheal tube in cats. To determine the inspiratory pressure which produces an audible leak when the intracuff pressure is 30 cmH2 O.

STUDY DESIGN: Prospective, clinical, randomized study.

ANIMALS: A total of 40 client-owned healthy adult cats.

METHODS: Following induction of anaesthesia, endotracheal intubation was performed with a Parker Flex-Tip PFLP (Parker; n = 20) or Flexicare VentiSeal (Flexicare; n = 20) endotracheal tube. For each cat, the endotracheal tube cuff was inflated using two methods, minimum occlusive volume (MOV) and pilot balloon palpation (PBP). Intracuff pressure was recorded. Cuff pressure was then set at 30 cmH2 O and the pressure within the breathing system when a manual breath first caused an audible leak was measured.

RESULTS: PBP pressure was lower for Parker (36 ± 13 cmH2 O) compared with Flexicare (45 ± 13 cmH2 O, p = 0.048). MOV pressure was not different between tube types (56 ± 28 versus 66 ± 25 cmH2 O for Parker and Flexicare, respectively, p = 0.247). MOV produced a higher pressure than PBP for Parker (56 ± 28 versus 36 ± 13 cmH2 O, p = 0.001) and Flexicare (66 ± 25 versus 45 ± 13 cmH2 O, p = 0.007). When intracuff pressure was set at 30 cmH2 O, 95% of cats did not develop an audible leak until the inspiratory pressure was greater than 10 and 12 cmH2 O for Parker and Flexicare tubes, respectively.

CONCLUSIONS: PBP produced lower cuff pressures than MOV, although both techniques produced a cuff pressure above that at which mucosal blood flow is believed to be restricted. A cuff pressure of 30 cmH2 O may be sufficient to prevent audible leak in most cats if respiratory pressures are kept at 10-12 cmH2 O or below.

CLINICAL RELEVANCE: To ensure a safe endotracheal tube cuff pressure, use of a specifically designed pressure gauge is recommended.