RESUMO
The purpose of this study was to determine if intrathecal fentanyl speeds the onset and prolongs the duration of sensory and motor block, prolongs the duration of postoperative analgesia, or increases the incidence of adverse effects in patients undergoing spinal anesthesia for outpatient knee arthroscopy. Fifty patients were randomized to receive 12 mg of hyperbaric bupivacaine 0.75% with 25 micrograms (0.5 mL) of fentanyl (group 1) or 12 mg of hyperbaric bupivacaine 0.75% with 0.5 mL of preservative-free normal saline (group 2). One-tailed t tests were used to determine differences in onset and duration of sensorimotor block and postoperative analgesia. No differences were found in onset and duration of sensory or motor block. Group 1 experienced significantly better postoperative analgesia lasting more than 3 hours longer than analgesia for group 2. Group 1 demonstrated significantly more pruritus, but there were otherwise no differences. We conclude that fentanyl does not enhance the onset and duration of sensory or motor block produced by 12 mg of intrathecal bupivacaine. Fentanyl, however, prolongs postoperative analgesia and increases the risk of pruritus.
