Precision Superior Trunk Block Combined With Monitored Anesthesia Care Improves The Quality Of Anesthesia For Arthroscopic Shoulder Surgery: A Randomized Clinical Trial

Objective: To investigate whether the use of precision superior trunk block(STB)combined with monitored anesthesia care in patients undergoing shoulder arthroscopy could effectively provide surgical anesthesia,reduce the incidence of hemidiaphragmatic paralysis(HDP),and improve the safety and comfort of anesthesia.Methods: This was a single-center prospective,randomized controlled clinical trial.A total of 88 patients undergoing shoulder arthroscopy were enrolled and randomly allocated in a 1:1 ratio to the test group or the control group.Using our original ultrasound-guided precision three-step positioning method and the "sandwich" injection technique,all patients received STB with 0.25% ropivacaine 10 ml in the test group and 0.5% ropivacaine 15 ml in the control group.Intraoperative monitored anesthesia care under dexmedetomidine sedation(loading dose,0.6 μg/kg;maintenance dose,0.1-0.5 μg/kg/h)was used in both groups.The primary outcome was the incidence of HDP 3 h after the block.The secondary outcomes were the rate of successful surgical anesthesia,pain scores,opioid consumption,block duration,onset time,handgrip strength,satisfaction scores,and adverse effects,.Results: The two groups had no significant difference in patients’ demographic and morphometric characteristics.Patients all successfully completed the shoulder arthroscopy with a 100% success rate of surgical anesthesia without changing to general anesthesia or performing remedial analgesia.The incidence of HDP in the test group was significantly lower than that in the control group after 3 h of blocks(31.8% vs.84.1%)(P<0.001),the ratio difference was 52.3%(95%CI 34.8% to 69.8%)).All patients in the test group completed the surgery successfully without conversion to general anesthesia with tracheal intubation and remedial analgesia intraoperatively.Patients allocated to the test groups experience a much lesser reduction in grip strength(68.5±17.7% vs.80.8±14.9%)(P = 0.001).The overall satisfaction score of the test group was higher than that of the control group [8(8,9)vs.7(7,8)](P=0.003).Patients who were allocated to the test group had a higher pain score at 12 h after blocks [2(0,2)vs.0(0,2)](P=0.044),a shorter block duration(11.8±3.2h vs.14.5±4.3h)(P=0.001),and more opioid consumption in the hospital [10(0,20)mg vs.10(0,10)mg](P=0.041)when compared with the control group.No significant difference was found regarding the rate of block success,the onset time,the NRS scores at the other preset time,discharge opioid prescriptions,and adverse complications(P>0.05).Conclusion: Through this study,we further confirmed the effectiveness of precision STB in providing surgical anesthesia for patients undergoing shoulder arthroscopy without tracheal intubation for general anesthesia.Meanwhile,using a small dose of local anesthetic(10 ml of 0.25% ropivacaine)can effectively reduce the incidence of HDP,preserve more hand grip,and improve anesthesia safety and comfort,which has important clinical promotion value.