[Study of tracheal tube intra-cuff pressure.]

Since controlling tracheal tube cuffs internal pressure is unusual and there is no detailed description in the literature on how to maintain it below 30 cmH2O without manometer, this study aimed at checking tracheal tube intra-cuff pressures in intensive care unit and operating room patients. A maneuver was tested to keep intra-cuff pressure below 30 cmH2O, but at minimum levels needed for ventilator cycling with no tidal volume leakage.

Tracheal tube intra-cuff pressures were evaluated in 50 intensive care unit intubated patients (Group I) and 72 intubated patients in the operating room (Group II). A maneuver was tested to obtain the minimum tracheal tube intra-cuff pressure to maintain adequate ventilation with no air leakage. Initial tracheal tube intra-cuff pressure (P1) was recorded using a gaged digital manometer (cmH2O) coupled to a 15-ml syringe. Oropharynx secretion was aspirated. With the investigators external acoustic meatus positioned 10-20 cm apart from patients mouth and cuff connected to the manometer, cuff was slowly deflated until a murmur sound was heard, determined by tidal volume leakage during the inspiratory period of artificial ventilation. At this moment, cuff was slowly inflated until murmur disappearance. Final intra-cuff pressure (P2) and the remaining air volume in the manometer syringe (V) were recorded.

Mean P1 values in groups I and II were 85.3 and 56.2 cmH2O, respectively. Mean P2 values in groups I and II were 26.7 and 15.5 cmH2O, respectively. After the maneuver, standard deviation decreased from 56.3 to 8.2 in group I, and from 48 to 6.7 in group II. Maneuver has decreased cuff volume and pressure in 100% of group I patients, and in 97.3% of group II patients.

Both groups had intra-cuff pressures higher than necessary to keep ventilator cycling with no tidal volume leakage. Maneuver to keep intra-cuff pressure below 30 cmH2O was simple and cheap.