RESUMEN
STUDY OBJECTIVE: To evaluate whether 360 ml of oral clear liquids consumed within 4 hours of elective surgery worsens gastric volume and acidity in patients given acid aspiration prophylaxis. DESIGN: Randomized, unblinded study. SETTING: Main operating room at a U.S. military hospital. PATIENTS: Eighty-three adult inpatients scheduled to receive general anesthesia for elective surgery. INTERVENTIONS: Nineteen patients (Group 1) were given 150 mg of oral ranitidine (two doses), 10 mg of metoclopramide, and 360 ml of apple juice 3 hours before the scheduled start of surgery. Thirty-four patients (Group 2) fasted before surgery but received acid aspiration prophylaxis identical to that given to Group 1. Twenty-three additional patients (Group 3) received no oral fluids or acid aspiration prophylaxis before surgery. MEASUREMENTS AND MAIN RESULTS: The residual gastric volume (RGV) and the pH of Group 1 patients were compared with measurements obtained in the two groups of patients who fasted. RGV measurements in Group 1 (14 +/- 3 ml) were similar to those in Group 2 (11 +/- 2 ml) and were significantly less than (p less than 0.05) those in Group 3 (26 +/- 4 ml). Gastric pH was significantly higher (p less than 0.001) in Group 1 (5.16 +/- 0.69) and Group 2 (5.78 +/- 0.43) than in Group 3 (1.97 +/- 0.27). CONCLUSIONS: Three hundred and sixty ml of apple juice consumed within 4 hours of elective surgery by patients given ranitidine and metoclopramide did not worsen gastric volume and acidity.