[The effects of cervical epidural anesthesia on epidural somatosensory evoked potentials and phrenic nerve activities].
We have investigated the effects of cervical epidural anesthesia on-phrenic nerve activity (PNA), and epidural somatosensory evoked potential (SSEP) elicited by stimulation of the radial nerve in pentobarbital anesthetized cats. PNA was suppressed significantly to 72% of control value 10 min after injection of 1% lidocaine and recovered to control value within 30 min. Following 2% lidocaine injection, PNA tended to be more suppressed than with 1% lidocaine to 57% and recovered to control value within 30 min. Peak latencies of P1, N1, P2, N2, and P3 before injection of 1% lidocaine were 1.05 (0.24), 1.20 (0.11), 1.51 (0.20), 1.56 (0.34), 2.71 (0.33) (msec (SD)), respectively. Though these latencies did not increase after injection of 1% lidocaine, injection of 2% lidocaine increased them significantly and these elevations continued for 120 min. The amplitude of N2 increased significantly after injection of 1% lidocaine and the amplitude of N2 and N2-P3 increased after injection of 2% lidocaine. These results indicate that 2% lidocaine blocked the sensory nerve and the effects continued much longer than the depression of PNA by cervical epidural anesthesia.
Kasaba
T
T
Department of Anesthesiology, Miyazaki Medical College.
Inoue
T
T
D000200:Action Potentials / Q000187:drug effects; D000767:Anesthesia, Epidural / Q000009:adverse effects; D000779:Anesthetics, Local / Q000009:adverse effects; D000818:Animals; D002415:Cats; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D008012:Lidocaine / Q000009:adverse effects; D010791:Phrenic Nerve / Q000502:physiology*; D011826:Radial Nerve / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*
D000779:Anesthetics, Local; D008012:Lidocaine