Comparison of remifentanil and fentanyl in patients undergoing craniotomy for supratentorial space-occupying lesions

Background: Remifentanil hydrochloride is an ultra-short-acting, esterase-metabolized μ-opioid receptor agonist. This study compared the use of remifentanil or fentanyl during elective supratentorial craniotomy for space-occupying lesions. Methods: Sixty-three adults gave written informed consent for this prospective, randomized, double-blind, multiple-center trial. Anesthesia was induced with thiopental, pancuronium, nitrous oxide/oxygen, and fentanyl (n = 32; 2 μg · kg · ^-1min^-1) or remifentanil (n = 31; 1 μ · kg^-1 · min^-1). After tracheal intubation, infusion rates were reduced to 0.03 μg · kg^-1 · min^-1 (fentanyl) or 0.2 μg · kg^-1 · min^-1 (remifentanil) and then adjusted to maintain anesthesia and stable hemodynamics. Isoflurane was given only after specified infusion rate increases had occurred. At the time of the first burr hole, intracranial pressure was measured in a subset of patients. At bone flap replacement either saline (fentanyl group) or remifentanil (≃0.2 μg · kg^{- 1} · min^-1) were infused until dressing completion. Hemodynamics and time to recovery were monitored for 60 min. Analgesic requirements and nausea and vomiting were observed for 24 h. Neurological examinations were performed before operation and on postoperative days 1 and 7. Results: Induction hemodynamics were similar. Systolic blood pressure was greater in the patients receiving fentanyl after tracheal intubation (fentanyl = 127 ± 18 mmHg; remifentanil = 113 ± 18 mmHg; P = 0.004). Intracranial pressure (fentanyl = 14 ± 13 mmHg; remifentanil = 13 ± 10 mmHg) and cerebral perfusion pressure (fentanyl = 76 ± 19 mmHg; remifentanil = 78 ± 14 mmHg) were similar. Isoflurane use was greater in the patients who received fentanyl. Median time to tracheal extubation was similar (fentanyl = 4 min: range = -1 to 40 min; remifentanil = 5 min: range = 1 to 15 min). Seven patients receiving fentanyl and none receiving remifentanil required naloxone. Postoperative systolic blood pressure was greater (fentanyl = 134 ± 16 mmHg; remifentanil = 147 ± 15 mmHg; P = 0.001) and analgesics were required earlier in patients receiving remifentanil. Incidences of nausea and vomiting were similar. Conclusion: Remifentanil appears to be a reasonable alternative to fentanyl during elective supratentorial craniotomy.