Appropriate cuff volumes of the Laryngeal Tube.

The manufacturer of the Laryngeal Tube (VBM, Germany) states that the cuffs should be inflated until the intracuff pressure reaches 60 cmH(2)O or with a certain volume of air (60 ml for the size 3 and 80 ml for size 4). We studied 100 patients to investigate this. In addition, we examined whether the patient's height or weight could be a predictor of the required volume. Following insertion of a laryngeal tube, the cuff volume at the intracuff pressure 60 cmH(2)O was measured. The mean (SD) volume was 62 (7.2) ml for size 3 and 84 (11.2) ml for size 4. There was a correlation between the height of the patient and the cuff volume (correlation coefficient = 0.64; p < 0.01; volume (ml) = -86.5 + 1.02 height (cm)), and between the patient's weight and the cuff volume (correlation coefficient = 0.37; p < 0.01; volume (ml) = 45.3 + 0.558 weight (kg)). The required volume for size 3 was < 60 ml in nine of 27 patients (33%), and for size, 4 < 80 ml in 20 of 73 patients (27%). Our results support the manufacturer's recommended cuff volumes, but if the cuff is inflated with these fixed volumes (60 ml and 80 ml), the cuff would be overinflated in one-third of patients, increasing the theoretical risk of ischaemic changes to the oropharynx. Since the cuff volume is correlated with the patient's height or weight, the cuff volume should be adjusted to the patients' stature.