Effect of Intraoperative Continuous I.V. Fentanyl on Tourniquet Induced Cardiovascular Changes and Postoperative Preemptive Analgesia in Total Knee Replacements / 대한통증학회지

ABSTRACT

BACKGROUND: It is difficult to treat tourniquet-induced hypertension despite adequate anesthesia, and the mechanism of that is not known. And it may be possible that intraoperative continuous infusion of opioid induces preemptive analgesia postoperatively. We investigated the effect of intraoperative continuous i.v. fentanyl on tourniquet induced cardiovascular changes and postoperative preemptive analgesia in total knee replacements. METHODS: Sixty patients were randomly assigned to two groups; In study group (1.5microgram/kg loading and 0.5microgram/kg/hr continuous infusion of fentanyl before skin incision and tourniquet inflation) and control group (no treatment). Anesthesia was maintained with enflurane (1-2 MAC) and 50% nitrous oxide in oxygen. Arterial pressure and heart rate were compared between two groups. They received postoperative pain treatment with patient-controlled analgesia (PCA) with fentanyl during the postoperative 48 hours after total knee replacement. Visual analog scale (VAS) scores at either rest or movement were used to assess pain. Total fentanyl dose delivered, number of PCA requests, supplemental analgesics, overall satisfaction score and adverse events were evaluated. RESULTS: There were no significant differences between the two groups on cardiovascular changes by tourniquet induced pain effect. VAS, PCA delivered dose and PCA demands at movement in the 24-48 hour decreased in study group compared with control group (P < 0.05). But there were no significant differences between the two groups on the other time periods except 24-48 hour's patient satisfaction and adverse events. CONCLUSIONS: We suggest that intraoperative continuous i.v. fentanyl infusion dose not affect cardiovascular change by tourniquet induced pain. But it may induce preemptive analgesia postoperatively.