A Randomized Controlled Trial of Preoperative Carbohydrate Drinks on Postoperative Walking Capacity in Colorectal Surgery.

After approval by the Siriraj Institutional Review Board, patients aged greater than 18 years undergoing elective colorectal surgery at Siriraj Hospital will be approached and recruited in this study. Exclusion criteria are diabetes mellitus, any endocrine disorders or metabolic abnormalities, impaired renal function (GFR <60 ml/min), impaired hepatic function (Child-Pugh score class C), a history of delayed gastric emptying time, body mass index >30, inability to communicate and severe physical disability. Informed written consent will be obtained from each subject.

At the time of admission to the hospital, patients will be randomly allocated to one of the two groups using a computer-generated randomization schedule in a block of five. The carbohydrate (CHO) group will be given the carbohydrate drink (12.5% carbohydrates, 50 kcal/100 ml, 240 mOsmol/l, pH 5.0) while the control group will be given pure water. The pharmacy department is responsible for preparing the carbohydrate drink. The patients in the two groups will be given 800 mL of one of the drinks the night before surgery, between 1900 and 2400 h, and another 400 ml in the morning of the operation day. The last drink will be no later than 3 hours before the scheduled induction of anesthesia. Of note, the last meal on the day before the operation will be no later than 1800 h. Following this meal, no food or drink will be allowed except the carbohydrate drink or pure water.

Before induction of anesthesia, a thoracic epidural catheter will be inserted as routine in either the ninth or tenth thoracic intervertebral space in patients undergoing laparotomy colorectal surgery. Lidocaine 2% with epinephrine 1:200,000 3 mL will be injected in the epidural space to produce a bilateral segmental sensory block to ice and pinprick between T6 and T12 dermatomes. The neural blockade was maintained during surgery with additional infusion of bupivacaine 0.25% 4-8 mL/h.

General anesthesia will be induced in all patients with same protocol. Preoperative mechanical bowel preparation will be utilized in the case of left-sided colon cancer or rectal cancer. Intravenous prophylactic antibiotics will be administered to every patient. All operations will be performed by well-experienced surgeons. The choice of incision and operation will depend on tumor location and surgeon's discretion.

Primary outcomes are 2-minute walk test (2MWT) which will be measured before surgery to be a baseline, and then 2MWT will be measured at 72 hours after surgery. Patients will be asked to walk back and forth along a 15 m stretch of hallway as much as they can over a period of 2 minutes. To ensure safety, the evaluator walks behind the patient. Patients are told that they can rest if necessary, and they are allowed to use their regular walking aids.