Effects Of Dexmedetomidine Combined With Bupivacaine On Sciatic And Femoral Nerve Blockade In Dogs

Although dexmedetomidine is an a-2-receptor agoinst which might combined with other local anesthesia in small animal clinical practice,the less published study were found that the dexmedetomidine combined with local anaesthesia on sciatic and femoral nerve blockade in dogs;Dexmedetomidine has been studied as an adjuvant to bupivacaine on peripheral nerve blocks in human and rats.Therefore,the research investigate the effects of dexmedetomidine combined with bupivacaine on femoral and sciatic nerve blockade in dogs,Compare with the effects on blockade of adding dexmedetomidine to bupivacaine or only bupivacaine,administered either perineurally or intramusculary(IM),for femoral and sciatic nerve blocks in dog.Six healthy mongrel dogs,three males and three females,aged 1.42(1.0-2.0)and weighing 4.90±0.88kg(3.8-6.0)were enrolled in this experimental study.All dogs were deemed healthy based on physical examination,complete blood count,biochemical serum test,neurologic and musculoskeletal examination;All dogs were randomly allocated to three femoral and sciatic nerve blockade treatments with a minimum washout period of 7 days between treatments,each dogs selected right pelvic limb.Ultrasound guided perpheral blocks were performed in anesthesia induced with bropophen and maintain anesthesiawith isoflurane.The three femoral and sciatic nerve btocks treatment:perineural dexmedetomidineTreatment(GDPN);Perineural dexmedetomidine,IM dexmedetomidine treatment(GDIM);control treatment(GCON);Each femoral and sciatic nerve block include:perineural treatment and intramusculory treatment,intramusculory treatment in the triceps muscular.Motor and sensory blockades were assessed at 10 minutes after the end of isoflurane administration until after 2 h of total recovery of limb activity;sensory blockade include:the innavation of the femoral/saphenous nerve,common fibular nerve and tibial nerve.Experimental result:all dog had normal sensory activity scores(score 1)at baseline;In the area innervated by the femoral/saphenious,common fibular nerve and tibial nerve,all dogs have complete blocks.(1)In the area innervated by the femoral/saphenious,onset time,total duration and complete duration of blockade did not diffe r significantly among treatments(P>0.05),total duration of blockade did not differ significantly among treatments(P>0.05);(2)In the area innervated by the common fibular nerve,onset time and complete duration of blockade did not differ significantly among treatments(P>0.05),in the total duration of blockade were longer in the GDPN than in the GCON and significant differences were detected between GDPN and GCON(P<0.05),and no significant difference were detected between GDPN and GDIm or between GCON and GDIM(P>0.05).(3)In the area innervated by the tibial nerve,onset time and complete duration of blockade did not differ significantly among treatments(P>0.05),in the total duration of blockade were longer in the GDPN than in the GCON and significant differences were detected between GDPN and GCON(P<0.05),and no significant difference were detected between GDPN and GDIM(P>0.05)or between GCONand GDIM(P>0.05).All dogs had normal proprioception scores(score 1)and no signs of ataxia at baseline.(1)In the proprioception blockade,all dogs with complete blockade.Onset time and complete duration of blockade did not differ significantly among treatments(P>0.05),in the total duration of blockade were longer in the GDPN than in the GCON and significant differences were detected between GDPN and GOON(P<0.05),and no significant difference were detected between GDPN and GDIM(P>0.05)or between GCON and GDIM(P>0.05);(2)In the walk to ability blockade,ataxia was observed in all dogs after perineural injections in three treatents(complete blocks).The onset time and duration of altered ability to walk were similar among treatments and no significant differences were detected(P>0.05).The results of the experimental indicate:(1)dexmedetomidine combined with bupivacaine for femoral and sciatic nerve blocks did not significantly decrease the onset time and prolong the duration time of the sensory and motor block;(2)Perineurally or intramuscularly dexmedetomid ine did not effect the bupivacaine blockade.