The Effect of Preoperative Oral Rehydration on Hemodynamic Changes during Induction of Anesthesia and Intraoperative Fluid Management

Preoperative oral rehydration solution (ORS) prevents dehydration before surgery. Therefore taking enough ORS possibly reduces the hemodynamic changes during induction of anesthesia, and reduces the amount of fluid needed during anesthesia.Forty patients undergoing elective surgery were randomly assigned to two groups: drinking 1,500 ml ORS 6 to 2 hours before anesthesia (ORS group) and nothing by mouth from 6 hours before anesthesia (Control group). Anesthesia induction was performed using propofol and remifentanil. To evaluate the hemodynamic changes, hemodynamic parameters including heart rate, blood pressure, cardiac index (CI), and stroke volume variation (SVV) were recorded before induction, after propofol administration, and after remifentanil administration. Total urine volume and the amount of fluid were also recorded at the end of the anesthesia.In ORS group, CI showed a significantly higher value after propofol administration (P = 0.046). SVV was significantly lower (P < 0.0001) and total amount of fluid during anesthesia was significantly reduced (P < 0.0001) in ORS group.Preoperative oral rehydration increases circulating blood volume, it keeps high CI during induction of anesthesia, and reduces the amount of intraoperative fluid.