Abstract:

 Objective   To evaluate the influence of head and neck position on oropharyngeal leak pressure with LMA-SupremeTM during intermittent positive pressure ventilation. Methods   Sixty anaesthetized adult female patients  were studied. The laryngeal mask airway  was inserted into each patient and the cuff was inflated to an intra-cuff pressure(ICP)of 60cm H2O. The oropharyngeal leak pressure(OLP), intra-cuff pressure, and leakage rate were determined at four different head and neck position (neutral, flexion, rotation and extension) at the time after the insertion and 60min after operation. Also, the anatomical position of the airway tube and drainage tube were also documented. Results   Compared with the neutral position, the oropharyngeal leak pressure and intracuff pressure were higher in flexion, but lower in extension in 0 and 60min. Changes in head and neck position did not alter the anatomical position of the airway tube, but the drainage rate was lower in extension than the others. Conclusion   Head flexion can improve airway sealing. Appropriate head flexion is an effective way to improve positive pressure ventilation. Caution should be warranted when using LMA-SupremeTM in extension as airway sealing is decreased in this position.

Key words:  LMA-SupremeTM；  Head and neck position； Oropharyngeal leak pressure;  Intracuff pressure