title: Infusion Methods for Continuous Interscalene Brachial Plexus Block for Postoperative Pain Control after Arthroscopic Rotator Cuff Repair.
abstract: BACKGROUND
  Infusion methods during regional analgesia using perineural catheters may influence the quality of postoperative analgesia. This study was conducted to compare the effects of combined or bolus-only infusion of 0.2% ropivacaine on the postoperative analgesia in interscalene brachial plexus block (ISBPB) with perineural catheterization.
  
  
  METHODS
  Patients scheduled for arthroscopic rotator cuff repair were divided into two groups, one that would receive a combined infusion (group C, n = 32), and one that would receive intermittent infusion (group I, n = 32). A perineural catheter was inserted into the interscalene brachial plexus (ISBP) using ultrasound (US) and nerve stimulation, and 10 ml of 0.2% ropivacaine was administered. After the operation, group C received a continuous infusion of 4 ml/h, and a 4 ml bolus with a lockout interval of 60 min. Group I received only a 4 ml bolus, and the lockout interval was 30 min. Postoperative pain by the numeric rating scale (NRS) and the forearm muscle tone by the manual muscle test (MMT) were checked and evaluated at the following timepoints: preoperative, and postoperative 1, 4, 12, 24, 36, and 48 h. Supplemental opioid requirements, total consumed dose of local anesthetic, and adverse effects were compared between the two groups.
  
  
  RESULTS
  Sixty-four patients completed the study and the postoperative values such as operation time, time to discharge, and operation site were comparable. There were no differences in NRS scores and supplemental opioid requirements between the two groups. The MMT scores of group I at 4 and 12 h after surgery were significantly higher than those of group C (P < 0.05). The total consumed dose of local anesthetic was significantly lower in group I than in group C (P < 0.05). The adverse effects were not different between the groups.
  
  
  CONCLUSIONS
  The bolus-only administration of 0.2% ropivacaine provided a similar analgesic effect with a lower total volume of local anesthetic and decreased motor weakness compared to combined infusion. Therefore, bolus-only administration is an effective postoperative analgesic method in ISBPB with perineural catheterization after rotator cuff repair.
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Gyeong Jo
authors.initials: GJ
authors.lastname: Byeon
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Shin
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Ji Uk
authors.initials: JU
authors.lastname: Yoon
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Dental Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea. ; Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: Hyun Su
authors.initials: HS
authors.lastname: Ri
keywords: Arthroscopy; Brachial plexus block; Patient-controlled analgesia; Ropivacaine; Rotator cuff