title: Respiratory effects of low-dose bupivacaine interscalene block.
abstract: In this double-blind study, interscalene brachial plexus (ISBP) block was performed in 11 volunteers using 10 ml of either 0.25% (n = 6) or 0.5% (n = 5) bupivacaine with epinephrine 1:200,000. Diaphragmatic excursion, respiratory function and neural function were assessed for 90 min. Our results showed that hemidiaphragmatic excursion declined significantly after block in the 0.5% group and paradoxical movement during inspiration was more common than in the 0.25% group. Forced vital capacity and forced expiratory volume in 1 s declined significantly in the 0.5% group (mean 74.6 (SD 13.0)% and 78.2 (19.9)% of baseline, respectively) but not in the 0.25% group. Sensory anaesthesia in the upper limb was found consistently in both groups, although biceps paralysis occurred earlier after 0.5% bupivacaine. We conclude that ISBP block using 10 ml of 0.25% bupivacaine provided upper limb anaesthesia to pinprick in C5-6 dermatomes with only occasional interference with respiratory function.
authors.affiliation: Aintree Hospitals, Liverpool, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: al-Kaisy
authors.forename: V W
authors.initials: VW
authors.lastname: Chan
authors.forename: A
authors.initials: A
authors.lastname: Perlas
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000494:pharmacology*; D001917:Brachial Plexus; D002045:Bupivacaine / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000187:drug effects; D009407:Nerve Block; D015656:Respiratory Mechanics / Q000187:drug effects*; D012677:Sensation / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine