The effects of medetomidine on radial nerve blockade with mepivacaine in dogs.
OBJECTIVE
To compare the sensory and motor effects of adding medetomidine to mepivicaine, administered either perineurally or systemically, for radial nerve block in dogs.


METHODS
Prospective randomized cross-over study.


METHODS
Six healthy Beagles, aged 18.7 +/- 6.3 months and weighing 10.4 +/- 1.3 kg.


METHODS
Dogs were anesthetized briefly with sevoflurane on three separate occasions and received each treatment administered in random order: mepivacaine 5 mg kg(-1) perineurally around the radial nerve with saline 0.01 mL kg(-1) intramuscularly (CONTROL); mepivacaine 5 mg kg(-1) and medetomidine 0.01 mg kg(-1) combined, perineurally with saline 0.01 mL kg(-1) intramuscularly (MEDPN); mepivacaine 5 mg kg(-1) perineurally around the radial nerve with medetomidine 0.01 mg kg(-1) intramuscularly (MEDIM). All nerve blocks were performed with the aid of a nerve locator. Motor effects were evaluated based on the ability to bear weight. Sensory effects were evaluated by the response to a graded-electrical stimulus. These were evaluated at 5-minute intervals for the first hour, and at 10-minute intervals thereafter. Mean intervals were calculated as follows: time to motor block onset, duration of motor block, time to peak sensory block, duration of peak sensory block (i.e. period of no response to maximal stimulus intensity), and duration of residual sensory block (i.e. time to return to baseline sensory function). Treatment means were compared using a one-way analysis of variance for repeated measures and, where significant differences were noted, a Student-Newman-Keuls test was applied; p < 0.05 was considered significant.


RESULTS
Medetomidine, administered either systemically or perineurally, significantly prolonged duration of peak motor block, peak sensory block, and residual sensory block compared with CONTROL.


CONCLUSIONS
Medetomidine prolonged sensory and motor blockade after radial nerve block with mepivacaine in dogs.


CONCLUSIONS
Medetomidine may prove to be a useful adjunct to peripheral nerve blockade with local anesthetics.
Lamont
Leigh A
LA
Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada. llamont@upei.ca
Lemke
Kip A
KA
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General / Q000662:veterinary; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D018592:Cross-Over Studies; D004285:Dogs / Q000502:physiology* / Q000601:surgery; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D008619:Mepivacaine / Q000008:administration & dosage*; D009407:Nerve Block / Q000662:veterinary*; D011446:Prospective Studies; D011826:Radial Nerve; D016896:Treatment Outcome
D000316:Adrenergic alpha-Agonists; D000779:Anesthetics, Local; D008619:Mepivacaine; D020926:Medetomidine