Background: In Euroanaesthesia 2012, we reported that postoperative nausea vomiting (PONV) was significantly reduced in a group ingested high carbohydrate-rich drink (CHO group) compared with intravenous infusion group as preoperative oral rehydration therapy. We hypothesized that glucose metabolism due to carbohydrate load was involved in significant PONV reductions. We compared electrolyte ingest (EL group) and CHO group as preoperative oral rehydration therapy.
Methods: Subjects were 80 females with ASA/PS1-2 who were underwent mastectomies over the period from April, 2012 to November, 2012. CHO (250mL, 200Cal, carbohydrate 45g, protein 5g, phosphorus 450mg, zinc 20mg, copper 2mg)group (n=40) ingested up to CHO 250mL no later than 2 hours before the surgery. EL (500mL, 50Cal, carbohydrate 12.5g, sodium 575mg, potassium 390mg, magnesium 12mg, phosphorus 31mg) group (n=40) ingested up to EL 500mL no later than 2 hours before surgery. Both groups abstained from eating from 21 o'clock on previous day. Subjects can drink pure water freely by 2 hours before surgery. Both groups were managed by anesthesia using oxygen, air, sevoflurane, remifentanil and fentanyl. PONV was assessed for 24 hours following the operation based on subjective medical reports from the two groups. Statistical analyses were performed using the t test for the patient groups and the x2 test for PONV.
Results: There was no significant difference of age, BMI, operative duration, anesthesia duration, opioids, history of smoking and amount of pure water ingested before surgery. PONV occurred in 8 patients in CHO group and 14 patients in EL group indicating a tendency of lesser PONV in CHO group, but not reaching statistically-significant difference (p=0.13).
Discussion: Mechanism to improve PONV by preoperative oral rehydration therapy may include improvement of glucose metabolism and insulin resistance arising from carbohydrate load, normalization of digestive tract function and alleviation of psychological stress. This study on carbohydrate loads did arrive at no significant difference. However, further studies on increased number of cases are called for in reaching final conclusion.