We compared the effects of
remifentanil versus
fentanyl during surgery for intracranial space-occupying lesions. Patients were randomly assigned to receive either
remifentanil (0.5 microg. kg(-1). min(-1) IV during the induction of
anesthesia reduced to 0.25 microg. kg(-1). min(-1) after endotracheal intubation; n = 49) or
fentanyl (dose per usual practice of the anesthesiologist; n = 54).
Anesthesia maintenance doses of
isoflurane,
nitrous oxide, and
opioid were at the anesthesiologist's discretion for both groups. There were no differences between
opioid groups for the frequency of responses (hemodynamic, movement, and tearing) to intubation, pinhead holder placement, skin incision, or closure of the
surgical wound. Adverse event frequencies were similar between groups. Times to follow verbal commands (P < 0.001) and tracheal extubation (P = 0. 04) were more rapid for
remifentanil. The percentage of patients with a normal recovery score (were alert or arousable to quiet voice, were oriented, were able to follow commands, had motor function unchanged from their preoperative evaluation, were not agitated, and had modified Aldrete Scores of 9-10)
at 10 min after surgery was more for
remifentanil (45% vs 18%; P = 0.005). By 20 min, no difference between groups existed (P = 0.27). Anesthesiologists used more
isoflurane in the
fentanyl group (4.22 vs 1.93 minimum alveolar
anesthetic concentration hours). Neurosurgeons, blinded to treatment group, favored the use of
remifentanil. Similar frequencies of light
anesthesia responses and other adverse events suggest that intraoperative depths of
anesthesia were similar in the two groups. Under these conditions, emergence was more rapid with
remifentanil. This is consistent with the necessity for less
isoflurane use in the
remifentanil group and the intrinsic rapid clearance of this
opioid.
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