Effect of epidural 0.25% bupivacaine on somatosensory evoked potentials to dermatomal stimulation
Lund, C.; Hansen, O.B.; Kehlet, H.
Regional Anesthesia 14(2): 72-77
1989
ISSN/ISBN: 0146-521X PMID: 2487667 Document Number: 331718
The effect of lumbar epidural analgesia with similar volumes (about 25 ml) of 0.25% and 0.5% bupivacaine on early (less than 0.5 seconds) somatosensory evoked potentials (SEPs) to electrical stimulation of the S1, L1, and T10 dermatomes was examined in two groups of ten patients. Level of sensory analgesia to pinprick was T5.7 +/- 0.8 and T6.4 +/- 0.7 in the 0.25% and 0.5% bupivacaine group, respectively. Motor blockade was more pronounced in the 0.5% bupivacaine group (p less than 0.05). Despite similar analgesia to pinprick, SEPs were more reduced during 0.5% bupivacaine than during 0.25%. These results support previous findings that quantitative assessment of neural blockade by SEP measurements may be more precise than pinprick analgesia.