Comparison of adenosine and remifentanil infusions as adjuvants to desflurane anesthesia

Background: Because adenosine has been alleged to produce both anesthetic a nd analgesic sparing effects, a randomized, double-blinded study was design ed to compare the perioperative effects of adenosine and remifentanil when administered as intravenous adjuvants during general anesthesia for major g ynecologic procedures. Methods: Thirty-two women were assigned randomly to one of two drug treatme nt groups, After premedication with 0.04 mg/kg intravenous midazolam, anest hesia was induced with 2 mu g/kg Intravenous fentanyl, 1.5 mg/kg intravenou s propofol, and 0.6 mg/kg intravenous rocuronium, and maintained with desfl urane, 2%, and nitrous oxide, 65%, in oxygen. Before skin incision, an infu sion of either remifentanil (0.02 mu g . kg(-1) . min(-1)) or adenosine (25 mu g . kg(-1) . min(-1)) was started and subsequently titrated to maintain systolic blood pressure, heart rate, or both within 10-15% of the preincis ion values. Results: Adenosine and remifentanil infusions were effective anesthetic adj uvants during lower abdominal surgery. Use of adenosine (mean +/- SEM, 166 +/- 17 mu g . kg(-1) . min(-1)) was associated with a significantly greater decrease in systolic blood pressure and higher heart rate values compared with remifentanil (mean +/- SEM, 0.2 +/- 0.03 mu g . kg(-1) . min(-1)). Tot al postoperative opioid analgesic use was 45% and 27% lower in the adenosin e group at 0-2 h and 2-24 h after surgery, respectively. Conclusions: Adjunctive use of a variable-rate infusion of adenosine during desflurane-nitrous oxide anesthesia was associated with acceptable hemodyn amic stability during the intraoperative period. Compared with remifentanil , intraoperative use of adenosine was associated with a decreased requireme nt for opioid analgesics during the first 24 h after operation.