Photoplethysmographic evaluation of sympathectomy during lumbar epidural analgesia: A randomized comparison of 0.125% ropivacaine and 0.125% levobupivacaine

Background There are no data on the difference between the impact of ropivacaine and levobupivacaine on sympathetic nerve fibers during central neuraxial blocks. We hypothesized that there is no difference in the degree of sympathectomy between the two drugs during lumbar epidural analgesia for labor pain. Methods Sixty healthy parturients were randomized to the type of local anesthetic–opiod solution administered in the epidural space: 10 mL of 0.125% ropivacaine + 100 mcg of fentanyl or 10 mL of 0.125% levobupivacaine + 100 mcg of fentanyl. After the baseline measurement, photoplethysmography signal from the first toe of the leg was recorded 5, 10 and 20 minutes after administration of epidural analgesia. Results Area under the curve and the pulse transit time of the toe photoplethysmography increased in both groups during the first 20 minutes after administration of epidural analgesia (P