Abstract: Objective To investigate the effects of drinking carbohydrate beverage 2 hours before surgery on gastric volume before anesthesia induction and perioperative hypotension in the elderly patients undergoing thoracic surgery. Methods Sixty elderly patients undergoing thoracoscopic lobectomy were randomly divided into two groups, with 30 patients in each group. Control group kept routine fasting before surgery, and experimental group received 5% glucose water 4 mL/kg 2 hours before anesthesia induction. Ultrasonography was performed in both groups after sectional examination, and cross-sectional area (CSA) under semi-recessed position was measured. Gastric volume (GV) and the ratio of gastric volume to body weight (GV/W) were calculated to evaluate the risk of reflux aspiration in the two groups. The systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) at T1(5 min after entry), T2(3 min after induction of anesthesia), T3(at the beginning of operation), T4(1 h after operation), T5 (at the end of operation), T6(2 h after operation) and T7 (6 h after operation) were detected by radial invasive arterial BP monitoring. The incidence rate of a perioperative SBP reduction > 20% for over 30 s, the dosage and the usage rate of ephedrine and norepinephrine in the perioperative period and the postoperative conditions of the patients were recorded and compared between the two groups. Results There were no significant differences in the risk of reflux aspiration, CSA and GV between the two groups (P>0.05). The levels of MAP at T2 and T5 were higher in experimental group than those in control group (P<0.05). The incidence rate of perioperative SBP reduction in control group was 75.86%, compared with 44.83% in experimental group ( P<0.05). The utilization rate and dosage of ephedrine and norepinephrine in experimental group were significantly lower than those in control group (P<0.05); Compared with control group, the first postoperative exhaust time was significantly shorter and the incidence rate of nausea and vomiting within 24 hours after surgery was significantly lower in experimental group (P<0.05). Conclusions Drinking 4 mL/kg carbohydrate beverage 2 hours before surgery will not increase the risk of reflux aspiration, but can better maintain the stability of perioperative blood pressure in the elderly patients undergoing thoracic surgery, and promote the recovery of the patients after surgery.

Key words: carbohydrate, aged, gastric volume, blood volume, hypotension