Effects Of Dexmedetomidine And Ropivacaine On Brachial Plexus Block And Their Influence On Th1/Th2

Objective:To observe the onset time,action time of different doses of Dexmedetomidine and ropivacaine on brachial plexus block and their influence on Th1/Th2,thus providing evidence for determining the doses of Dexmedetomidine for brachial plexus block.Methods:Sixty patients with upper limb surgery were selected from my hospital from December 2018 to September 2019 were randomly divided into RD₁ group（Dilute with0.9%NS to 20 ml of 0.4%ropivacaine 8 ml+Dexmedetomidine 0.4μg·kg-1）（n=20）,RD₂group（Dilute with 0.9%NS to 20 ml of 0.4%ropivacaine 8 ml+Dexmedetomidine 0.8μg·kg-1）（n=20）and R group（Dilute with 0.9%NS to 20 ml of 0.4%ropivacaine 8 ml）（n=20）.The onset time and maintaining time of brachial plexus movement and sensory block in the three groups were recorded.Mean arterial pressure（MAP）and heart rate（HR）at T₁（on admission）,T₂（25 min after brachial plexus block）,T₃（2 h after brachial plexus block）and T₄（6 h after brachial plexus block）.interleukin-4、interleukin-10 and interleukin-2、interferon-γlevels in serum were detected at T₁ and T₄,as well as Bispectral（BIS）in Dex values at T₁,T₂ and T₃ were recorded.Results:1.There was no significant difference in gender,age,ASA grade and BMI among the three groups（P>0.05）.2.Comparison of brachial plexus nerve block effect:Compared with the R group,the sensory and motor nerve block time of RD₁and RD₂was shortened,and the sensory and motor recovery time was prolonged.Compared with RD₁group,the onset time of nerve block was shorter and the recovery time was longer in RD₂ group,the difference was statistically significant（P<0.05）.3.Comparison of hemodynamic indexes MAP and HR:Compared with group R at T₂ and T₃,MAP and HR decreased in group RD₁,group RD₂ at T₂ and T₃,and the difference was statistically significant（P<0.05）.Compared with T₁ at the time points of T₂ and T₃,MAP and HR in the R group all decreased at T₂and T₃,but the decrease was only statistically significant at T₂（P<0.05）;In group RD₁,MAP and HR decreased at T₂,but only MAP decreased with statistically significant difference（P<0.05）,while MAP and HR decreased at T₃ with statistically significant difference（P<0.05）.MAP and HR decreased in RD₂group at T₂ and T₃,and the difference was statistically significant（P<0.05）;There was no statistical difference in MAP and HR between T₄and T₁ in each group（P>0.05）.At T₂ and T₃,the decrease of MAP and HR in RD₂ group was greater than that in R and RD₁ group,that is,RD₂group had the strongest inhibitory effect on stress stimulation.4.Comparison of immune stress response factor Th1/Th2:IL-2 and IFN-γrepresent Th1,and IL-4 and IL-10 represent Th2.Comparison of T₄ and T₁ in each group showed that IL-4and IL-10 increased,IL-2 and IFN-γdecreased,the difference was statistically significant（P<0.05）,but the level of IL-4 increased and IFN-γdecreased in RD₂ group was lower than that in other groups.RD₂ group has the least Th1/Th2 imbalance,It suppresses the immune stress response most strongly.5.Comparison of sedation levels by BIS:Compared with the R group,there was no significant difference in BIS at T₁in the RD₁and RD₂ groups（P>0.05）,and the BIS decreased at T₂ and T₃,the difference was statistically significant（P<0.05）.Compared with T₁Comparison between T₂,T₃ and T₁ in each group,BIS in group R at T₂ and T₃ showed no statistically significant difference（P>0.05）;BIS in group RD₁ decreased at T₂（P<0.05）,and also decreased at T₃,but the difference was not statistically significant（P>0.05）;BIS decreased at T₂and T₃ in RD₂ group,the difference was statistically significant（P<0.05）.that is,RD₂group had the best sedation degree.Conclusions:The onset time for block was shorter and the action time was longer in Dexmedetomidine 0.8μg·kg-1 and ropivacaine group,and It suppresses the immune stress response to some extent,The sedative effect was good.