RT Journal Article SR Electronic T1 Reduced Hemidiaphragmatic Paresis With a “Corner Pocket” Technique for Supraclavicular Brachial Plexus Block: Single-Center, Observer-Blinded, Randomized Controlled Trial JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 720 OP 724 DO 10.1097/AAP.0000000000000795 VO 43 IS 7 A1 Ryung A. Kang A1 Yang Hoon Chung A1 Justin Sangwook Ko A1 Mi Kyung Yang A1 Duck Hwan Choi YR 2018 UL http://rapm.bmj.com/content/43/7/720.abstract AB Background and Objective Hemidiaphragmatic paresis is common after supraclavicular brachial plexus block (SCBPB). In this randomized trial, we compared the incidence of hemidiaphragmatic paresis in patients who had local anesthetic injected primarily in the corner pocket (defined as the intersection of the first rib and subclavian artery) during SCBPB with that of patients who underwent injection primarily inside the neural cluster.Methods Thirty-six patients scheduled for right elbow, forearm, wrist, or hand surgery under SCBPB (using 12.5 mL of 0.75% ropivacaine and 12.5 mL of 2% lidocaine with 1:200,000 epinephrine) were randomly assigned to 1 of 2 groups. In group CP, local anesthetic was injected primarily in the corner pocket (20 mL) and secondarily inside the neural cluster (5 mL). In group NC, local anesthetic was deposited primarily inside the neural cluster (20 mL) and secondarily in the corner pocket (5 mL). The primary outcome was the incidence of hemidiaphragmatic paresis, as measured by M-mode ultrasonography 30 minutes after SCBPB.Results The incidence of hemidiaphragmatic paresis was significantly lower in group CP than in group NC (27.8% vs 66.7%, P = 0.019). The median decreases in forced expiratory volume at 1 second (7.5% [interquartile range, 3.3%–17.1%] vs 24.4% [interquartile range, 10.2%–31.2%]; P = 0.010) and forced vital capacity (6.4% [interquartile range, 3.3%–11.1%] vs 19.3% [interquartile range, 13.7%–33.2%]; P = 0.001) were also lower in group CP than in group NC.Conclusions The incidence of hemidiaphragmatic paresis was effectively reduced when local anesthetic was injected primarily in the corner pocket during right-sided SCBPB. However, the 28% incidence of hemidiaphragmatic paresis associated with the corner pocket technique may still represent a prohibitive risk for patients with preexisting pulmonary compromise.Clinical Trial Registration This study was registered at Clinical Trial Registry of Korea, identifier KCT0001769.