Application Of Different Concentrations Of Ropivacaine In Ultrasound-Guided Quadratus Lumborum Block In The Inguinal Hernia Repair Surgery

Objective:To investigate the analgesic effect of different concentrations of ropivacaine in the ultrasound-guided quadratus lumborum block in unilateral inguinal hernia repair surgery,to provide references for cliical selection of the optimal concentration of ropivacaine for quadratus lumborum block.Method:From January 2017 to November 2017,60 patients scheduled for the unilateral inguinal hernia repair surgery were selected,aged 50 to 82 years old（average 67.2±5.4）,ASAⅠ^Ⅰ.The body mass index was 18-25kg/m².The anesthetic method was combination of quadratus lumborum blockage and laryngeal mask airway（LMA）total intravenous general anesthesia（TIGA）.All patients were monitored with EKG,invasive blood pressure,SpO₂ and bispectral index（BIS）.Then the same senior anesthesiologist performanced the ultrasound-guided QL2 approach of quadratus lumborum block（Ropivacaine:volume 20ml,concentration according to different groups）.The anesthetic induction was performed after QLB took effect,and then the LMA was placed for ventilation.TCI to maintance anesthesia of the propofol and was adjusted according to the depth of anesthesia.All patients were randomly divided into three groups（n=20 respectively）:group L（0.2%Ropivacaine）,group M（0.35%Ropivacaine）,group H（0.5%Ropivacaine）.Record the time of QLB onset,the MAP and HR when patient intime of entered the operating room（T0）and the skin incision（T1）and separation of hernia sac（T2）and the the LMA was removed（T3）.The total dosage of sufentanil in operation and the time of recovery and the score of recovery in 10 min after LMA removed were analysisted.The plasma concentration of adrenocorticotrophic hormone（ACTH）and cortisol（COR）were measured in PACU;and VAS score at rest was recorded 6h、12h、24h、36h、48h postoperatively;The study also analysised the number of patient required additional flurbiprofen for analgesia postoperatively and the satisfaction of patients with analgesia and the occurrence of adverse reactions（include nausea,vomiting,respiratory depression,local anesthetic toxicity reaction,lower extremity motor block）.Results:The onset time of QLB in group M（10.5±1.9）and group H（9.9±1.3）were significantly shorter than that in group L（16.7±1.8,P<0.05 respectively）.The dosage of sufentanil in group M（6.8±2.0）and group H（6.5±1.7）were significantly lower than that in group L（15.4±2.6）during operation（P<0.05 respectively）.Compared with group L,The MAP and HR in T1 and T2 were less in group M and group H（P<0.05 respectively）.The plasma contents of ACTH and COR in group M（16.3±4.1、381.2±60.5）and group H（16.1±3.1、370.5±56.3）were significantly lower than those in group L（29.7±3.8、484.3±53.6）at 0.5h in recovery room（P<0.05respectively）.Compared with group L,the rest VAS scores at 6h,12h and 24h postoperatively were significantly decreased at each time point in group M and group H（P<0.05 respectively）.The cases of flurbiprofen additional analgesia in group M（25%）and group H（20%）were significantly lower than that in group L（90%）after operation（P<0.05 respectively）.The satisfaction of patients was significantly higher in group M（75%）and group H（80%）than that in group L（25%）,the differences were statistically significant（P<0.05 respectively）.The incidence of postoperative lower limb motor block in group H（15%）was significantly higher than that in group M（0.0%）and group L（0.0%,P<0.05 respectively）.Conclusion:The study shown that 0.35%ropivacaine is more suitable for ultrasound-guided QL2 quadratus lumborum block in open unilateral without tension hernia repair surgery.