The laryngeal tube compared with the laryngeal mask: insertion, gas leak pressure and gastric insuf¯ation

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 insuf¯ation. 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 in¯ated 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 gas-tric insuf¯ation was studied at an in¯ation 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 signi®cantly greater than that for the laryngeal mask (19 (4) cm H2O) (P<0.01; 95% con®dence intervals for mean difference: 5.3±10.2 cm H2O). Gastric insuf¯ation 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