We studied the effects of different preoperative oral fluid protocols on preoperative discomfort, residual gastric fluid volumes, and gastric acidity. Two-hundred-fifty-two elective abdominal surgery patients (ASA physical status I-II) were randomized to preparation with a 12.5% carbohydrate drink (CHO), placebo (flavored water), or overnight fasting. The CHO and Placebo groups were double-blinded and were given 800 mL to drink on the evening before and 400 mL on the morning of surgery. Visual analog scales were used to score 11 different discomfort variables. CHO did not increase gastric fluid volumes or affect acidity, and there were no adverse events. The visual analog scale scores in a control situation were not different between groups. During the waiting period before surgery, the CHO-treated group was less hungry and less anxious than both the other groups (P < or = 0.05). CHO reduced thirst as effectively as placebo (P < 0.0001 versus Fasted). Trend analysis showed consistently decreasing thirst, hunger, anxiety, malaise, and unfitness in the CHO group (P < 0.05). The Placebo group experienced decreasing unfitness and malaise, whereas nausea, tiredness, and inability to concentrate increased (P < 0.05). In the Fasted group, hunger, thirst, tiredness, weakness, and inability to concentrate increased (P < 0.05). In conclusion, CHO significantly reduces preoperative discomfort without adversely affecting gastric contents.
Implications: Discomfort during the period of waiting before elective surgery can be reduced if patients are prepared with a carbohydrate-rich drink, compared with preoperative oral intake of water or overnight fasting. Visual analog scales can provide useful information about preoperative discomfort in elective surgery patients.