The influence of epidural volume extension on spinal block with hyperbaric bupivacaine for elective knee arthroplasty

Abstract

BackgroundEpidural volume extension (EVE) via a combined spinal–epidural is the enhancement of a small-dose intrathecal block by an epidural injection of physiological saline solution. The aim of this study was to investigate the sensory and motor block characteristics of spinal anesthesia after EVE. Eighty patients enrolled in this prospective, randomized, double-blind study. Group I (n=40) received 10 mg hyperbaric bupivacaine and group II (n=40) first received 10 mg hyperbaric bupivacaine intrathecally and subsequently 10 mL saline via epidural catheter.ResultsIn the first 30 min after combined spinal–epidural anesthesia, the maximum sensory block level was significantly higher in group II than in group I. The Bromage score was significantly higher in group II than in group I at 3–6 and 9 min of the intraoperative period. EVE increased the mean Smax significantly in group 2 than group 1 (p<0.05). Tmax was statistically similar between group 1 and group 2 (p>0.05). EVE significantly altered Time10 and Tadeq in group 2 (p<0.05).ConclusionsEVE with saline (10 mL) offer early onset of sensory and motor block and a high level of sensory block. And also delay supplemental epidural dose requirement intraoperatively.