The effect of premedicants upon the lower oesophageal sphincter.

The barrier function of the lower oesophageal sphincter is of great practical importance in the prevention of regurgitation and aspiration. The action of seven most commonly used premedicants upon the lower oesophageal sphincter was studied in ten healthy volunteers. The results were compared with a placebo injection in eight volunteers. Sodium pentobarbital, droperidol and triflupromazine increased the presenting pressure of the lower oesophageal sphincter. Decreases were observed after promethazine, pethidine, the combination of droperidol plus fentanyl and atropine.