Factors Affecting the Intracuff Pressure of Wire-reinforced Endotracheal Tubes during General Anesthesia Using Nitrous Oxide / 대한마취과학회지

ABSTRACT

BACKGROUND: We evaluated the factors affecting the need for cuff deflation to maintain intracuff pressure (P(cuff)) below 22 mmHg in two types of wire-reinforced endotracheal tubes; type A Safety-Flex(TM) (Mallinckrodt, Athlone, Ireland) and type B Insung(R) (Insung, Seoul, Korea). METHODS: Eighty patients were randomly divided into four groups (n = 20 for each); Group F-A female, type A; Group F-B female, type B; Group M-A male, type A; Group M-B male, type B. Sealing volume and sealing pressure (SP) were measured. Whenever Pcuff reached 22 mmHg during N2O administration, the cuff was deflated to SP. Elapsed time to first deflation (1-CP22) and deflation frequencies were recorded. RESULTS: Specific cuff compliance (C(cuff)) was higher in type A than that in type B (P < 0.05). More patients in Group F-B and M-B needed deflation than those in Group F-A and M-A, respectively (P < 0.05). 1-CP22 in patients intubated with type B was shorter than with type A (P < 0.05). In both tubes type A and B, SP was higher in patients who needed deflation compared to ones that did not (P < 0.05). CONCLUSIONS: Use of wire-reinforced tubes with high C(cuff) decreases the frequency of deflation. Low SP also reduces the need for cuff deflation to keep the P(cuff) below 22 mmHg during N2O anesthesia.