title: A comparison of ultrasound alone vs ultrasound with nerve stimulation guidance for continuous femoral nerve block in patients undergoing total knee arthroplasty.
abstract: OBJECTIVE
  To compare analgesic efficacy of ultrasound (US) guidance alone and US guidance combined with nerve stimulation (NS) for continuous femoral nerve block (CFNB) in patients undergoing total knee arthroplasty (TKA).
  
  
  METHODS
  Prospective, randomized double-blind trial.
  
  
  METHODS
  Postanesthesia care unit and general ward.
  
  
  METHODS
  Fifty American Society of Anesthesiologist physical status I to II patients undergoing TKA under spinal anesthesia.
  
  
  METHODS
  In group A (n = 25), an 18-gauge Tuohy needle was directed at the lower mid-part of the femoral nerve, and a nonstimulating catheter was inserted through the needle under US guidance. In group B (n = 25), an 18-gauge Tuohy needle and stimulating catheter were directed to the lower part of femoral nerve under US guidance, and quadriceps muscle contraction was checked using NS. All patients received a 20-mL loading dose of 0.2% ropivacaine, a continuous infusion of 4 mL/h, and a 4-mL bolus of 0.2% ropivacaine with a lockout time of 60 minutes for patient-controlled analgesia.
  
  
  METHODS
  The primary outcome was resting and exercising pain quality assessed by numeric rating scale. Other outcomes included procedure time for correct catheter placement, block failure rate, patient satisfaction for postoperative pain control, total dose of local anesthetic, additional opioid requirement, and adverse effects postoperatively.
  
  
  RESULTS
  There were no significant differences between groups in resting and exercising numeric rating scale. Procedure times were longer in group B than group A (P < .05). There were no significant differences between groups in block failure rate or other outcomes.
  
  
  CONCLUSIONS
  US-guided CFNB was associated with similar analgesic efficacy and block failure rate and reduced procedure time compared to US with NS guidance for CFNB in patients undergoing TKA.
authors.affiliation: Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Republic of Korea; Research Institute for Convergence of biomedical science and technology Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea.
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Republic of Korea; Research Institute for Convergence of biomedical science and technology Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea. Electronic address: byeongj@pusan.ac.kr.
authors.forename: Gyeong-Jo
authors.initials: GJ
authors.lastname: Byeon
authors.affiliation: Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Republic of Korea.
authors.forename: Hyun-Jun
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Republic of Korea; Research Institute for Convergence of biomedical science and technology Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea.
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Republic of Korea; Research Institute for Convergence of biomedical science and technology Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea.
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Shin
authors.affiliation: Research Institute for Convergence of biomedical science and technology Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea; Department of Orthopedic Surgery, Pusan National University Yangsan Hospital, Yangsan, Gyeongnam, Republic of Korea.
authors.forename: Hyung-Jun
authors.initials: HJ
authors.lastname: Cho
mesh_terms: D000368:Aged; D000577:Amides / Q000008:administration & dosage; D016058:Analgesia, Patient-Controlled; D000779:Anesthetics, Local / Q000008:administration & dosage; D019645:Arthroplasty, Replacement, Knee; D004311:Double-Blind Method; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D005267:Femoral Nerve / Q000000981:diagnostic imaging / Q000187:drug effects*; D006801:Humans; D008297:Male; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies; D000077212:Ropivacaine; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine
keywords: Femoral nerve; Knee arthroplasty; Nerve block; Nerve stimulation; Patient-controlled analgesia; Ultrasonography