Comparison Of The Application Of Dexmedetomidine For Different Routes Of Administration In Replantation Of Severed Finger

Objective:the purpose of this study was to investigate the effect of dexmedetomidine administration in different ways under the guidance of ultrasound assisted interscalene brachial plexus block（Interscalene Brachial Plexus Block,IBPB）anesthesia downlink replantation,looking for more suitable for long time operation in brachial plexus block under dexmedetomidine regimen.Methods:60 patients who received the emergency of finger replantation hand surgery department of Southwest Medical University in the years of2016-2017 were selected.The patients were divided into three groups（n=20）,according to the order of hospitalization and online random number generator.Group B:mixed local anesthetic combined 1μg/kg dexmedetomidine（diluted with normal saline to 1ml）,30ml IBPB was performed.At the beginning of nerve block,20ml was injected with normal saline at the rate of120ml/h,then 0.1ml/kg/h was injected into normal saline（50ml）until the end of operation.Group IV:mixed local anesthetics combined normal saline（1ml）,30ml IBPB was performed.At the beginning of nerve block,1μg/kg dexmedetomidine（diluted with normal saline to 20ml）was injected at the speed of 120ml/h,then 0.1ml/kg/h was injected into normal saline（50ml）until the end of operation.Group CIV:the mixture of local anesthetics combined saline（1ml）,30ml IBPB was performed.At the beginning of nerve block,1μg/kg dexmedetomidine（diluted with normal saline to 20ml）was injected at the speed of 120ml/h,then 0.4μg/kg/h（0.1ml/kg/h）dexmedetomidine（plus saline diluted to 4μg/ml co 50ml）was injected until the end of operation;The preparation of local anesthetic:2%lidocaine 10ml+0.75%ropivacaine hydrochloride20ml+0.9%physiological saline 20ml,that meaned,0.4%lidocaine and 0.3%ropivacaine hydrochloride.All patients were treated with IBPB replantation under the guidance of ultrasound.Mean arterial pressure（MAP）,heart rate（HR）and oxygen saturation by pulse oximeter（SpO₂）were recorded at the following points:entered the operation room（T₀）,10min after injection block（T₁）,30min after injection block（T₂）,the beginning of surgery（T₃）,1H（T₄）,2h（T₅）,3h（T₆）,4H（T₇）,the end of surgery（T₈）.Ramsay sedation score was also recorded;recorded the time of brachial plexus nerve sensory and motor block onset and duration;recorded the duration of analgesia,the effect of anesthesia and complications.Result:1.There was no significant difference in age,weight,sex and operation time between the three groups（P>0.05）.2.Comparison of hemodynamics:T₁-T₅ time point compared with T₀,,the MAP and HR decreased in three groups,but in the T₁-T₅ time points,there were no statistical significance among three groups at the same point（P>0.05）;compared with T₅,T₆-T₈ time point,MAP and HR of B group and IV group increased,MAP,HR were stable at T₆-T₈ time point,in group CIV,there were no statistically significant of MAP,HR between B group and IV group（P>0.05）,there were statistically significant differences of MAP,HR between group CIV and group B and IV group（P<0.05）.3.the comparison of Ramsay sedation score:Compared with T₀,T₁-T₄ time,Ramsay sedation score of three groups increased,but Ramsay sedation score in the three groups had no statistical significance difference in T₁-T₄ time point（P>0.05）;at T₅-T₈ time point,CIV group Ramsay sedation score was highest,there were statistical significance differences between group B and group IV（P<0.05）.4.the effect of brachial plexus block:a comparison of the sensory and the movement onset time of the three groups,group B was the shortest（P<0.05）;compared with group IV,group B and group CIV feeling duration,exercise duration,duration of analgesia was significantly prolonged（P<0.05）.5.the comparison of the anesthetic effect:at T₅ time point,the effect of anesthesia in three groups were excellent;at T₅-T₈ time points,in the group B 6patients’anesthesia effect were good;6 patients in group IV anesthesia effect is good;and the anesthesia effect in group CIV all were excellent;compared with group B and IV,the anesthesia effect in group CIV were the best and the（P<0.05）.6.complications:three groups of patients during operation without hypotension,respiratory depression,local anesthetic poisoning and other complications,group CIV,one patient had dry mouth.Conclusion:The operation time in 2 hours in patients with replantation,dexmedetomidine 1μg/kg combined with 0.4%lidocaine and 0.3%ropivacaine for ultrasound-guided local IBPB sedation and anesthesia effect,and can shorten the onset time of sensory and motor nerve block,prolong the duration of analgesia.The operation time for more than 2 hours of replantation,dexmedetomidine 1μg/kg intravenous loading dose after continuous intravenous infusion of 0.4μg/kg/h assisted ultrasound guided IBPB significantly prolonged sedation of sensory and motor nerve block duration and the duration of analgesia and the operation effect is good,stable hemodynamics.