INTRATHECAL SUFENTANIL FOR LABOR ANALGESIA - DO SENSORY CHANGES PREDICT BETTER ANALGESIA AND GREATER HYPOTENSION

Sensory changes and hypotension occur after intrathecal sufentanil (IT S) is given during labor. The goal of this study was to determine whet her sensory changes are predictive of hemodynamic changes or duration of pain relief. We also examined whether sensory and hemodynamic chang es relate to the concentration of ITS administered. Forty-five ASA phy sical status I and II women in active labor were randomly assigned to receive 10 mu g ITS diluted in either 1, 2, or 3 mL of normal saline ( 15 in each group). An observer blinded to treatment recorded verbal pa in scores, blood pressure, and sensory changes to light touch, pinpric k, and cold at frequent intervals. Excellent analgesia was obtained in 42 of 45 patients. There were no differences among the groups with re spect to the number of patients with sensory changes, the duration of analgesia or sensory changes, the quality of analgesia, or the severit y of hypotension. The groups were therefore combined for further analy ses. Among this combined group, the duration of analgesia was 99 +/- 7 min (mean +/- SE). Cold, pinprick, and light touch sensation were dec reased in 66%, 50%, and 33% of patients, respectively. Motor block was absent in all patients. The duration and quality of analgesia were si milar in subjects with and without sensory changes. Systolic blood pre ssure decreased 23 +/- 2 mm Hg (P < 0.05) during the first 30 min afte r ITS, and six patients were given ephedrine. The magnitude of blood p ressure change was not affected by the diluent volume or the presence of sensory changes. Because sensory changes were not predictive of the duration or quality of analgesia or the degree of hemodynamic change, we conclude that analgesia with ITS is predominantly mediated via spi nal cord opioid receptors rather than by a local anesthetic-type condu ction blockade.