Pre-operative intravenous fluid therapy with crystalloids or colloids on post-operative nausea & vomiting

Background & objectives: Post-operative nausea and vomiting (PONV) is a frequent complication and may be a reason for increased morbidity and cost of treatment Following elective surgery, it is believed to result from gut ischaemia consequent to hypovolemia from overnight fasting. This study was carried out to study the effects of pre-operative intravenous fluid supplementation, either crystalloids or colloids, on PONV. Methods: In this prospective randomized clinical trial, 60 female patients undergoing elective open cholecystectomy were randomly allocated to three equal groups A, B and C. All patients received preoperative fluid supplementation. Group A patients received 2 ml/kg Ringer lactate iv (intravenously) and served as control, Group B patients received 12 ml/kg Ringer lactate iv whereas Group C patients received 12 ml/kg of 4.5 per cent hydroxyethylstarch (Hetastarch) iv. All patients underwent cholecystectomy under standard anaesthesia technique with intraoperative fluid replacement by Ringer's lactate (6 ml/kg/h). An independent blinded observer assessed PONV during first 24 h following surgery using visual analogue scale (VAS.) score (0 = no nausea, 10 = worst imaginable nausea or vomiting). Rescue antiemetic was given whenever VAS was > 5. Results: The three groups were comparable in terms of age, body weight and duration of surgery. VAS scores in Groups B and C patients were less than that of Group A patients at all time intervals post-operatively and became significantly different at 4 h post-operatively. The VAS scores of Groups B and C patients were comparable throughout. A significantly large number (90%) of Group A patients required rescue antiemetic as compared to 50 and 55 per cent patients in Group B and Group C, respectively. Interpretation & conclusions: Pre-operative intravenous fluid supplementation using crystalloids and colloids results in significantly decreased incidence of PONV. Both, crystalloids as well as colloids were found to be equally effective in preventing PONV.