title: Postoperative Analgesia by a Transversus Abdominis Plane Block Using Different Concentrations of Ropivacaine for Abdominal Surgery: A Meta-Analysis.
abstract: BACKGROUND
  Transversus abdominis plane block (TAPB) has been proven to be an effective means of postoperative anesthesia, but the optimum effective concentration of ropivacaine warrants further research.
  
  
  OBJECTIVE
  This study aimed to identify the optimal ropivacaine concentration of TAPB using a meta-analysis.
  
  
  METHODS
  This study consisted of a meta-analysis of randomized controlled trials (RCTs). We searched online databases, including PubMed, Embase, the Cochrane Database of Systematic Reviews, and Web of Science. RCTs investigating the 24-hour postoperative opioid consumption and the rest and dynamic pain scores 2, 12, and 24 hours after surgery were included in this analysis. We also assessed opioid-related side-effects and patient satisfaction 24 hours after surgery.
  
  
  RESULTS
  Nineteen RCTs (1217 patients) were included in this meta-analysis, which showed that only TAPB with 0.375% and 0.5% ropivacaine was able to reduce opioid consumption 24 hours after surgery by weighted mean differences of -6.55 and -4.44 mg (morphine IV equivalents), respectively (P<0.05). A meta-regression analysis did not reveal an association between the local anesthetic dose (in mg), surgery, anesthesia, block timing, and the TAPB effect on opioid consumption. Ropivacaine concentrations of 0.375% and 0.5% reduced the 2-hour postoperative pain score and reduced the incidence of nausea and vomiting, but this analgesic effect disappeared at 12 and 24 hours. Only TAPB with 0.375% ropivacaine improved the degree of satisfaction 24 hours after surgery (weighted mean difference of 0.87 [0.08-1.66], P=0.03).
  
  
  CONCLUSIONS
  In terms of efficacy and safety, the use of 0.375% ropivacaine for TAPB is preferred in the clinical work.
authors.affiliation: *Department of Anesthsioloy §Department of Intensive Care Unit, Binzhou People's Hospital, Binzhou, Shandong ¶Department of Anesthesiology, Weihai City Hospital, Weihai †Department of Anesthesiology, Children's Hospital of Chongqing Medical University ‡Chongqing Key Laboratory of Pediatrics, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chonqing ∥Department of Anesthsioloy, Sichuan Province People's Hospital, Sichuan, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Sun
authors.forename: Shouyong
authors.initials: S
authors.lastname: Wang
authors.forename: Pengpeng
authors.initials: P
authors.lastname: Ma
authors.forename: Shuting
authors.initials: S
authors.lastname: Liu
authors.forename: Aijie
authors.initials: A
authors.lastname: Shao
authors.forename: Ling
authors.initials: L
authors.lastname: Xiong
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000009:Abdominal Muscles / Q000187:drug effects / Q000294:innervation* / Q000601:surgery; D000577:Amides / Q000008:administration & dosage* / Q000009:adverse effects; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D009407:Nerve Block; D010149:Postoperative Pain / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D000077212:Ropivacaine
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine