Effects of repeated injection of local anesthetic on sciatic nerve blocks response

Abstract

In order to examine whether repeated sciatic nerve blocks showed tachyphylaxis and continuity of sciatic nerve with spinal cord affected development of tachyphylaxis when assayedin vivo by duration of depression compound action potentials (CAP), rats were anesthetized with halothane, ventilated, monitored and supported with stable hemodynamics and temperature. Posterior tibial nerve distally and sciatic nerve in thigh were exposed, placed on bipolar silver electrodes for stimulation and recording respectively. Three sequential sciatic nerve blocks were performed between these electrodes using 0.15 ml of 3% chloroprociane. Nine rats were chosen to observe the effects of repeated sciatic nerve blocks on CAP. In another 18 rats, a second investigator exposed the sciatic nerve near its origin at spinal cord and randomly performed nerve cut and sham (n=9). and closed the incision blinding the electrophysiologic investigator. The results showed that electrical stimulated tibial nerve induced sciatic nerve Aα/β, Aδ, C fiber mediated CAP waves. CAP amplitudes were remained stable during whole experimental procedure. CAP amplitudes were decreased completely with 3% chloroprocaine blocked sciatic nerve and recovered fully. The duration of CAP depression were reduced with repeated blocks. There were no selective blocked effects on Aα/β, Aδ, C fiber mediated CAP. With sciatic nerve cut proximally, there was no statistical significant tachyphylaxis with 3% chloroprocaine repeated blocked sciatic nerve, and the duration of first and third blocked Aδ fiber mediated CAP was 108±20 and 92±14 min respectively (P>0.05). In normal rats the duration of first and third blocked Aδ fiber mediated CAP was 110±20 and 75±16 min respectively (P<0.05). It was suggested that tachyphylaxis to local anesthetics can occur in rats repeated blocked sciatic nerve when assayedin vivo by duration of depression CAP. The continuity of sciatic nerve with spinal cord is one of the important factors affecting the development of tachyphylaxis.

Keywords

local anesthetic / tachyphylaxis / chloroprocaine / nerve block

References

[1] WilderR T, SholasM G, BerdeC B. NG-nitro-L-argine methyl ester (L-NAME) prevent tachyphylaxis to local anesthetic in a dose-dependent manner. Anesth Analg, 1996, 83: 1251-1251

[2] WangC, SholasM G, BerdeC B, et al.. Evidence that spinal segmental nitric oxide mediates tachyphylaxis to peripheral local anesthetic nerve block. Acta Anaesthesiol Scand, 2001, 45(8): 945-945

[3] ChioR H, BirknesJ K, Popitz-BergezF A, et al.. Pharmacokinetic nature of tachyphylaxis to lidocaine: peripheral nerve blocks and infiltration anesthesia in rats. Life Sci, 1997, 61: 177-177

[4] WilderR T, BerdeC B, GriggsC, et al.. Chronic exposure to lidocaine does not alter flux through sodium channels in cultured neuronal cells. Reg Anesth, 1993, 18: 283-283

[5] LipfertP, HolthusenH, ArndtJ O. Tachyphylaxis to local anesthetics does not result from reduced drug effectiveness at the nerve itself. Anesthesiology, 1989, 70: 71-71

[6] BromageP R, PettigrewR T, CrowellD E. Tachyphylaxis in epidural analgesia: I. Augmentation and decay of local anestehsia. J Clin Pharmacol J New Drugs, 1969, 9: 30-30

[7] LeeK, WilderR T, SmithR L, et al.. Thermal hyperalgesia accelerates and MK-801 prevents the development of tachyphylaxis to rat sciatic nerve blockade. Anesthesiology, 1994, 81: 1284-1284

[8] TrujilloK A, AkilH. Inhibition of morphine tolerance and dependence by the NMDA receptor antagonist MK-801. Science, 1991, 251: 85-85

[9] MaoJ, MayerD J. Spinal cord neuroplasticity following repeated opioid exposure and its relation to pathological pain. Ann N Y Acad Sci, 2001, 933: 175-175

[10] OzekM, UresinY, GungorM. Comparison of the effects of specific and nonspecific inhibition of nitric oxide synthase on morphine analgesia, tolerance and dependence in mice. Life Sci, 2003, 72: 1943-1943

[11] MogensenT, SimonsenL, ScottN B, et al.. Tachyphylaxis associated with repeated epidural injections of lidocaine is not related to changes in distribution or the rate of elimination from the epidural space. Anesth Analg, 1989, 69: 180-180

[12] BakerC E, BerryR L, ElstonR C. Effect of pH of bupivacalne on duration of repeated sciatic nerve blocks in the albino rat. Anesth Analg, 1991, 72: 773-773