Preoperative drinking does not affect gastric contents

Summary: We have compared the effect of allowing free clear fluids until the time of oral premedication with conventional preoperative fasting. In a prospective, randomized trial, the residual volume and pH of gastric contents after induction of anaesthesia were measured in 100 elective surgical patients allocated randomly to a group in whom the intake of free clear fluids up to the time of premedication was measured (mean 388 ml in 6 h before surgery) or a control group who were fasted for 6 h. Preoperative drinking did not affect either mean (so) residual gastric volume (22 (21) ml in the study group vs 19 (16) ml in the control group) or pH (study group 2.64 (1.57) vs control group 2.26 (1.45)). The study group experienced less preoperative thirst. Problems with aspiration or regurgitation were not encountered. We believe that allowing elective surgical patients to drink clear fluids until 2 h before anaesthesia may enhance patient comfort without compromising safety. (Br. J. Anaesth. 1993; 70: 6-9)