Clinical Analgesic Effect Of Ropivacaine Combined With Dexmedetomidine In Different Administration Methods On Ultrasound-guided Serratus Anterior Plane Block

Objective:To observe and compare the effects of 50μg dexmedetomidine as an adjuvant of anterior serratus plane block on hemodynamics,postoperative analgesia and adverse reactions in patients undergoing video-assisted thoracic surgery,and to explore its mechanism.Method:Ninety patients who met the inclusion criteria for selective thoracoscopic surgery were selected and randomly divided into three groups of 30 patients in each group.After anesthesia induction,superficial serratus anterior plane block was performed under ultrasound guidance.Group C(ropivacaine group only):1ml normal saline+0.33%ropivacaine 19ml block,20ml normal saline intravenous infusion for l0min.DIV group(intravenous dexmedetomidine group):normal saline 1ml+0.33%ropivacaine 19ml block,50μg dexmedetomidine diluted to 20ml intravenous pumping for 10min;DP group(dextrometomidine group):dextrometomidine 50μg was diluted to 1ml+0.33%ropivacaine 19ml with saline solution for block,and 20ml normal saline was injected intravenously for 10min.The same methods of anesthesia induction and anesthesia maintenance were used in all the three groups.After the operation,the patient’s BIS value was>80,the eyes were opened and the spontaneous breathing function was completely recovered,and the tracheal tube was pulled out and sent to Postanesthesia Care Unit(PACU).The operation time,anesthesia time,infusion volume,blood loss and urine volume of the three groups were recorded.The Heart rate(HR)and Mean arterial pressure(MAP)of the three groups of patients were recorded before surgery(To),during skin resection(T1),15min(T2),30min(T3),60min(T4)after serratus anterior block,and after resuscitation(T5).The patient extubation time and the stay time in the PACU were recorded.Visual analogue scale(VAS)was recorded at rest for patients at 30min,4h,6h,8h,12h,24h and 48h postoperatively.The duration of effective analgesia after plane block of serratus anterior muscle was recorded.The number of effective compressions of the analgesic pump and the consumption of sufentanil were recorded.The number of cases with intraoperative hypotension and bradycardia was counted.The incidence of postoperative nausea,vomiting and respiratory depression was counted.Result:1.There was no statistically significant difference between the general data of the three groups and the comparison of the general conditions during the operation(p>0.05).2.Comparison of HR and MAP at various time points during operation:compared with group C,HR and MAP of div group were lower at T2 and T3 time points than that of group C,with significant difference(p<0.05).Compared with group C at T0,T1,T4 and T5 time points,there was no significant difference(p>0.05);Compared with DP group,HR and MAP of div group were significantly lower than DP group at T2 time point(p<0.01),and there was no significant difference at T0,T1,T3,T4,T5 time point(p>0.05);Compared with group C,HR and MAP of patients in DP group were significantly lower at T3 time point than those in C group(p<0.05),and there was no significant difference at T0,T1,T2,T4,T5 time point(p>0.05).3.There was no significant difference between the three groups of patients in terms of extubation time and anesthesia resuscitation time(p>0.05).4.Comparison of VAS scores at each postoperative time point in the three groups:compared with the C group,VAS scores in the DIV group at 6h after surgery were lower than those in the C group,showing a significant difference(p<0.01),and VAS scores at 30min,4h,8h,12h,24h and 48h after surgery showed no statistically significant difference(p>0.05);Compared with the C group,the DP group had lower VAS scores at the initial 6h,8h,and 12h than the C group,with significant differences(p<0.01).There was no significant difference in the VAS scores at 30min,4h,24h,and 48h.(p>0.05);Compared with the DIV group,VAS scores of the DP group were lower than those of the DIV group at 8h and 12h after surgery,showing a significant difference(p<0.01),and VAS scores of the DP group at 30min,4h,6h,24h and 48h after surgery showed no statistically significant difference(p>0.05).5.Compared with group C,the duration of effective analgesia in the DIV and DP groups was prolonged,and the difference was statistically significant(p<0.05;p<0.01);compared with the DIV group,the effective analgesia in the DP group The time was significantly prolonged,with a significant difference(p<0.01).6.Comparison of the number of analgesia pump compressions and sufentanil consumption among the three groups:Compared with group C,the number of effective analgesia pump compressions in the DIV group and the DP group was less than that in the C group,with significant differences(p<0.01).Compared with the DIV group,the number of effective compressions of the analgesia pump in the DP group was less than that in the DIV group,with a significant difference(p<0.01).Compared with the C group,the postoperative consumption of sufentanil in the DIV group and the DP group was less than that in the C group,with a significant difference(p<0.01).Compared with the DIV group,postoperative sufentanil consumption in the DP group was less than that in the DIV group,with a significant difference(p<0.01).7.There was no significant difference in the incidence of intraoperative hypotension and bradycardia among the three groups(p>0.05);there was no significant difference in the incidence of postoperative nausea,vomiting and respiratory inhibition among the three groups(p>0.05).Conclusion:Both peripheral nerve injection and intravenous injection of dexmedetomidine(50μg)can prolong the effective analgesia time and reduce the use of analgesics after anterior serratus plane block,and neither can increase the occurrence of intraoperative hypotension and bradycardia.Compared with intravenous injection,the analgesic time of dexmedetomidine is longer and the demand of opioids is less.