[Analgesia and sedation in the subarachnoid anesthesia technique: comparative study between remifentanil and fentanyl/midazolam].

OBJECTIVE: To assess the efficacy and safety of remifentanil in comparison with fentanyl-midazolam for analgesia and sedation during subarachnoid anesthesia. MATERIAL AND METHODS: Sixty ASA I-III patients between 25 and 75 years old and scheduled for inguinal hernia repair were enrolled. Before the subarachnoid block, the patients were randomly assigned to receive an intravenous infusion of 0.1 microgram.Kg-1.min.-1 of remifentanil (group R) or 1 microgram.Kg-1 of fentanyl and 0.02 mg.Kg-1 of midazolam (group F). Ten minutes later a subarachnoid block to L3-L4 was performed with 10 mg of hyperbaric bupivacaine. We recorded intensity of pain during performance of the block on a simple verbal scale, the observer's assessment of alertness/sedation (OAA/S), hemodynamic variables, respiratory frequency and SpO2, level of comfort and side effects. RESULTS: Over 70% of patients had no pain or slight pain during the subarachnoid puncture and absence of pain was significantly greater in group R than in group F (37% vs. 16%, p < 0.05). Sedation was adequate during surgery in both groups (OAA/S 2-3). There were no differences in level of comfort between the two groups. The incidences of hypoxemia, hypoventilation and excessive sedation were significantly higher in group R (40%, 20% and 16%, respectively; p < 0.05). CONCLUSIONS: Remifentanil is more effective for treating pain associated with a subarachnoid block and provides cardiovascular stability with a limited level of sedation per dose, but its use is associated with a high incidence of respiratory depression.