Extrafascial injection for interscalene brachial plexus block reduces respiratory complications compared with a conventional intrafascial injection: a randomized, controlled, double-blind trial

Br J Anaesth. 2016 Apr;116(4):531-7. doi: 10.1093/bja/aew028.

Abstract

Background: Hemidiaphragmatic paresis after ultrasound-guided interscalene brachial plexus block is reported to occur in up to 100% of patients. We tested the hypothesis that an injection lateral to the brachial plexus sheath reduces the incidence of hemidiaphragmatic paresis compared with a conventional intrafascial injection, while providing similar analgesia.

Methods: Forty ASA I-III patients undergoing elective shoulder and clavicle surgery under general anaesthesia were randomized to receive an ultrasound-guided interscalene brachial plexus block for analgesia, using 20 ml bupivacaine 0.5% with epinephrine 1:200 000 injected either between C5 and C6 within the interscalene groove (conventional intrafascial injection), or 4 mm lateral to the brachial plexus sheath (extrafascial injection). The primary outcome was incidence of hemidiaphragmatic paresis (diaphragmatic excursion reduction >75%), measured by M-mode ultrasonography, before and 30 min after the procedure. Secondary outcomes were forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow. Additional outcomes included time to first opioid request and pain scores at 24 h postoperatively (numeric rating scale, 0-10).

Results: The incidences of hemidiaphragmatic paresis were 90% (95% CI: 68-99%) and 21% (95% CI: 6-46%) in the conventional and extrafascial injection groups, respectively (P<0.0001). Other respiratory outcomes were significantly better preserved in the extrafascial injection group. The mean time to first opioid request was similar between groups (conventional: 802 min [95% CI: 620-984 min]; extrafascial: 973 min [95% CI: 791-1155 min]; P=0.19) as were pain scores at 24 h postoperatively (conventional: 1.6 [95% CI: 0.9-2.2]; extrafascial: 1.6 [95% CI: 0.8-2.4]; P=0.97).

Conclusions: Ultrasound-guided interscalene brachial plexus block with an extrafascial injection reduces the incidence of hemidiaphragmatic paresis and impact on respiratory function while providing similar analgesia, when compared with a conventional injection.

Clinical trial registration: NCT02074397.

Keywords: analgesia; anesthesia, regional; brachial plexus block; diaphragm; postoperative pain.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anesthetics, Local
  • Brachial Plexus Block / methods*
  • Bupivacaine
  • Clavicle / diagnostic imaging
  • Clavicle / surgery
  • Double-Blind Method
  • Fascia / diagnostic imaging
  • Female
  • Humans
  • Intraoperative Complications / prevention & control*
  • Kaplan-Meier Estimate
  • Male
  • Pain Measurement / methods
  • Pain, Postoperative / epidemiology
  • Respiration Disorders / etiology*
  • Respiration Disorders / prevention & control*
  • Respiratory Mechanics / drug effects
  • Respiratory Paralysis / chemically induced
  • Respiratory Paralysis / epidemiology
  • Shoulder / diagnostic imaging
  • Shoulder / surgery
  • Treatment Outcome
  • Ultrasonography, Interventional

Substances

  • Anesthetics, Local
  • Bupivacaine

Associated data

  • ChiCTR/NCT02074397