[Association of fentanyl or sufentanil an 0.5% isobaric bupivacaine in spinal anesthesia: a comparative study.]

Since the discovery of opioid receptors and the increase in spinal cord neuropharma- cological knowledge as to transmission and inhibition of nociceptive stimulations, there has been an increased interest in spinal drugs for anesthesiology and pain relief. This study aimed at prospectively evaluating the clinical efficacy of fentanyl (25 microg) and sufentanil (5 microg) with isobaric bupivacaine (10 mg), in patients submitted to spinal anesthesia for varicose vein surgery.

Participated in this study 60 patients, physical status ASA I and II, aged below 60 years, submitted to spinal anesthesia for varicose vein sugery, who were randomly distributed in three groups: B (10 mg isobaric bupivacaine), BF (10 mg isobaric bupivacaine and 25 microg fentanyl) and BS (10 mg isobaric bupivacaine and 5 microg sufentanil). Spinal anesthesia was induced in the left lateral position; lumbar puncture was performed at L3-L4, with 27G Quincke needles. The following parameters were evaluated after spinal anesthesia: onset time, sensory and motor block level. The following parameters were recorded during the procedure: arterial hypotension, bradycardia, respiratory depression, oxygen hemoglobin peripheral saturation decrease, nausea, vomiting, pruritus and shivering. Analgesia duration was evaluated in the post-operative period.

Groups were homogeneous. There were no significant differences in onset time, motor block and analgesia duration. There were differences in sensory block level between the control group and the opioid groups in all studied moments. Pruritus was the most frequent side-effect in the opioid groups.

The addition of fentanyl (25 microg) and sufentanil (5 microg) to isobaric bupivacaine (10 mg) in spinal anesthesia affects sensory block levels.