The laryngeal tube compared with the laryngeal mask: insertion, gas leak pressure and gastric insufflation

Background. We have compared the laryngeal tube and laryngeal mask in 22 patients for the success rate of insertion, gas leak pressure and the incidence of gastric insufflation. Method. In a randomized, crossover design, the laryngeal tube and laryngeal mask were inserted in turn after induction of anaesthesia and neuromuscular block. The cuffs were inflated until the intracuff pressure reached 60 cm H2O. We measured adequacy of ventilation and the minimum airway pressure at which gas leaked around the cuff. The presence or absence of gastric insufflation was studied at an inflation pressure of 20 cm H2O. Results. It was possible to ventilate through the laryngeal tube in 21 patients and through the laryngeal mask in 21 patients. The mean leak pressure for the laryngeal tube (26 (SD 5) cm H2O) was significantly greater than that for the laryngeal mask (19 (4) cm H2O) (P<0.0 1; 95% confidence intervals for mean difference: 5.3-10.2 cm H2O). Gastric insufflation did not occur when the laryngeal tube was used and was noted in three patients when the laryngeal mask was used. Conclusion. The laryngeal tube provides a better seal in the oropharynx than the laryngeal mask.