[Safety of preoperative oral rehydration therapy].

BACKGROUND: OS-1 is an oral rehydration solution that conforms with the principles of oral rehydration therapy. It may be useful for preoperative fluid management of surgical patients. While intake of clear fluids 2 hours before surgery is considered safe, it is not known if the same applies to OS-1. We therefore investigated the safety of OS-1 for preoperative patients as compared with clear fluids. METHODS: First, eight healthy adult volunteers were studied in a crossover manner. Volunteers ingested 500 ml of OS-1 or water (clear fluid). Gastric emptying time was measured using gastric ultrasonography. Gastric antral area as measured by ultrasonography correlates well with gastric volume in a close-to-linear manner. Next, we measured gastric volume of elective surgical patients who had drunk OS-1 until two hours before the induction of anesthesia. RESULTS: Gastric emptying time did not differ between OS-1 and water. The stomach was emptied 30 minutes after ingestion of both OS-1 and water. The fasting stomach was identified in all patients who had drunk OS-1 before surgery. CONCLUSIONS: We concluded that allowing elective surgical patients to drink OS-1 until two hours before anesthesia did not affect the volume of gastric contents.