Effects of the laryngeal mask airway on the lower oesophageal barrier pressure in children.

The effects of laryngeal mask airway (LMA) insertion and cuff inflation on lower oesophageal sphincter, gastric and barrier pressure, and the relationship of the LMA cuff pressure and volume on the change in the barrier pressure were studied in 20 children. Subjects were aged one to five years, undergoing eye examination under general anaesthesia. There was no significant change in barrier pressure after insertion and inflation of the LMA compared with baseline measures. The cuff pressure and volume were not related to the change in barrier pressure. Two patients had marked decreases (10 to 15 mmHg) in barrier pressure after the LMA insertion. These decreases in barrier pressure would be expected to increase the risk of gastro-oesophageal reflux. We conclude that, although LMA use had little effect on barrier pressure in most children, occasional children will have potentially clinically significant decreases in barrier pressure with use of the LMA.