The effect of two different doses of remifentanil infusion on desflurane consumption at major abdominal surgery

Object: In this study, in patients undergoing major abdominal surgery, the effect of two different doses of remifentanil used during anaesthesia on desflurane consumption, postoperative pain and analgesic consumption were investigated. Material and Method: In this placebo controlled, double blinded, randomized study, 90 ASA I, II patients, aged 18-65, undergoing major abdominal surgery were recruited after approval of Cukurova University Medical faculty ethical committee and patient written consent. Following induction of anaesthesia with thiopental sodium (3-5 mg/kg, iv), anaesthesia maintainance was provided by desflurane (6%) in a mixture of oxygen (33%) and nitrous oxide (66%). After endotracheal intubation, patients were allocated into tree groups as to receive 0.5 ml/kg/h of salin (0,9%) infusion in group I, 0.125 mcg/kg/min of remifentanil in group II and 0,25 mcg/kg/min of remifentanil in group III, intravenously. Anaesthesia was maintained with desflurane (6%) in a mixture of oxygen (33%) and nitrous oxide (66%). The depth of anaesthesia was monitorized with bispectral index (BIS) technique. BIS levels were kept within 40-60 by changing the concentration of desflurane (1%). 30 minutes before the end of the operation 1mg/kg tramadol and 10mg metoclopramide was given. Patients' hemodynamic parameters, BİS values and desflurane concantrations was recorded at intraoperative 1,5, 15, 30, 60 , 90 and 120 min.intraoperatively. Haemodynamic parameters, pain scores, analgesic consuptions and side effects were recorded at 1,5, 10, 15, 20 and 30 min. postoperatively. Results: Desflurane concentration was found significantly higher in group 3 at time intervals between 1. and 60. min than in group 1 and 2 (p<0,05). Avarage desflurane consumption was 1,612 gr/min in the first group, 1,468 gr /min in the second group and 1,416 gr/min in the third group, and there was no significant difference between groups. Postoperative pain scores (VAS), analgesic requirements and side effects were significantly higher in group 3 than in group 1 and 2 (p<0.05). Conclusion: In this study, in patients undergoing major abdominal surgery, adding remifentanil infusion during desflurane anaesthesia resulted in lower desflurane consumption, better haemodynamic stability, but provided higher postoperative analgesic requirement and incidence of nausea-vomiting Key Words: Bispectral index, desflurane, remifentanyl.