Preoperative Oral Rehydration Therapy Mitigates Circulatory Suppression During Anesthesia Induction: A Retrospective Study of 1,000 Elective Surgery Cases Exploring Appropriate Preoperative Intake Volume

Background and objective Preoperative oral rehydration therapy has been introduced as an alternative to conventional IV fluid management. It helps shorten the preoperative fasting period, prevents and corrects dehydration before surgery, and supports circulatory stability during anesthesia induction. Appropriate preoperative oral rehydration solution (ORS) intake may help alleviate circulatory fluctuations. This study aimed to examine the relationship between ORS intake volume and circulatory fluctuations during anesthesia induction in 1,000 elective surgery cases. Methods We conducted a retrospective study at an independent administrative institution affiliated with the Kanagawa Prefectural Hospital Organization. We examined 1,000 patients who underwent elective surgery under general anesthesia between April 1, 2021, and December 27, 2021. Eligible patients were provided with three 500 mL bottles of ORS within 12-18 hours before surgery. Patients were classified into two groups: those who received vasopressors after anesthesia induction (V group) and those who did not (N group). Demographic and clinical data were obtained from electronic medical and anesthesia record systems. We examined whether differences in patient demographics and anesthesia-related factors influenced vasopressor administration. The primary outcome was the dose-response relationship between ORS intake volume and vasopressor administration, while secondary outcomes included identifying patient- and anesthesia-related factors influencing vasopressor use. Results Of the 1,000 patients enrolled, 473 (47%) received vasopressors between anesthesia induction and the start of surgery. ORS intake of