title: Effect of Local Anesthetic Concentration (0.2% vs 0.1% Ropivacaine) on Pulmonary Function, and Analgesia After Ultrasound-Guided Interscalene Brachial Plexus Block: A Randomized Controlled Study.
abstract: This study aims to assess diaphragmatic excursion and measure pulmonary functions as measures of the degree to which the phrenic nerve is blocked after ISB with two different concentrations of ropivacaine: 0.2% and 0.1%.
  
  
  
  Randomized, double-blinded study.
  
  
  
  Ambulatory surgical facility.
  
  
  
  Fifty patients undergoing shoulder arthroscopy for rotator cuff repair.
  
  
  
  Patients were randomized to receive ultrasound-guided ISB with 20 mL of either 0.2% or 0.1% ropivacaine. Diaphragmatic excursion was measured using M-mode ultrasound. Pulmonary functions were assessed by portable spirometer. Additional outcome data included oxygen saturation in post-anesthesia care unit (PACU), pain scores, quality of recovery scores (QOR), and opioid consumption over 72 hour period after surgery.
  
  
  
  Forced vital capacity (FVC) was significantly reduced 30 minutes after block placement and in PACU in the 0.2% group when compared with the 0.1% group (P = 0.04, P = 0.03, respectively). Forced expiratory volume (FEV1) was also significantly decreased in the 0.2% group in PACU when compared with the 0.1% group (P = 0.04). There were no significant differences in pain scores, length of stay, and total opioid consumption in PACU. Patients who received 0.2% ropivacaine had a longer block duration (18 vs 11.9 hours, P = 0.04) and used less opioid in the 72 hours after surgery (55 mg vs 102 mg codeine equivalents, P = 0.02), when they were compared to their counterparts who received 0.1% for their block.
  
  
  
  0.1% ropivacaine may impair pulmonary function less than 0.2% ropivacaine. The clinical significance of these differences needs to be further studied.
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Wong
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Lauren Georgiades
authors.initials: LG
authors.lastname: Keeney
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Liting
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Rebekah
authors.initials: R
authors.lastname: Williams
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA nabil.elkassabany@uphs.upenn.edu.
authors.forename: Nabil M
authors.initials: NM
authors.lastname: Elkassabany
mesh_terms: D000328:Adult; D000577:Amides / Q000008:administration & dosage* / Q000009:adverse effects*; D000772:Anesthesia, Local / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects*; D001182:Arthroscopy; D065527:Brachial Plexus Block / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008168:Lung / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D000077212:Ropivacaine; D000070636:Rotator Cuff Injuries / Q000601:surgery; D025321:Surgery, Computer-Assisted; D018084:Ultrasonography, Interventional
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine
keywords: Acute Pain; Nerve Block; Randomized Controlled Trial