Tiroidectomy operations comprasion of nitrous oxide and remifentanil effects

Routine use of Nitrous Oxide (N2O) has been questioned in the recent years because of its established toxicities and side effects 1,2 . Alternative agents are available and remifentanil has gained popularity in this regard, due to its similiar pharmacokinetics with N2O. The aim of our study is to compare the clinical effectiviness and the side effects of intraoperative remifentanil infusion and N2O. After ethics commitee approval and obtaining written informed consent, 75 patients udergoing thyroidectomy with desflurane-fentanil general anesthesia were randomly allocated to three groups (N2O, remifentanil and control). In the N2O-group flowmetre was set to give 2 lt/min N2O and 1 lt/min oxygen. In the remifentanil and control groups flowmetres were set to give 2 lt/min air and 1lt/min oxygen. In the Remifentanil group an infusion of 0.085 mcg/kg/min remifentanil was started (This is an infusion rate that will produce stable 2 ng/mL remifentanil whole blood concentration4. This concentration makes a similiar degree of MAC reduction in desflurane as expected with 70% N2O) in the N2O and control groups salin infusions were started. All of the other anesthetic procedures were the same for all groups and for extra analgesic needs fentanil was given in 0.001 mg/kg bolus doses as needed. Demographics, hemodynamics, time to eye opening, place and time orientation, nausea/vomiting and the drug doses, the first analgesic request time, and doses, patient, surgeon and anesthetist satisfaction scores; were recorded. Pain scores at resting, during neck movement and caughing were recorded at every ten minutes after extubation. Intraoperative maintanenece fentanyl doses (mg) for N2O, remifentanil and control groups were respectively 0,05±0,06 vs. 0,07±0,06 vs. 0,11±0,08. Fentanyl dose was significantly less than control group both in the N2O and remifentanyl groups (p=0,01 and p=0,03, respectively). There was no significant difference between N2O and remifentanyl groups for the intraoperative maintanence fentanyl doses (p=0,44). All other findings were unsignificantly different between groups (p>0.05 for all).We compared the clinical effectiviness and side effects of Remifentanil infusion with N2O during thyroidectomy. There were no difference regarding the intraoperative and postoperative analgesic use and side effects. Finding good alternatives to nitrous oxide anesthesia may be an important contribution to modern anesthesia practice.