Cutaneous sympathetic vasoconstrictor reflexes for the evaluation of interscalene brachial plexus block
2000 (English)In: Acta Anaesthesiol Scand, Vol. 44, no 8, 946-52 p.Article in journal (Refereed) Published
BACKGROUND: Although signs of sympathetic blockade following interscalene brachial plexus block include Horner's syndrome, increased skin temperature and vasodilatation, the degree of sympathetic blockade is not easily determined. The aim of this study was, therefore, to use activation of cutaneous finger pad vasoconstrictor reflexes for description and quantification of the degree of sympathetic blockade following unilateral interscalene brachial plexus block. METHODS: Eight patients scheduled for acromioplasty under general anesthesia were studied. An interscalene plexus catheter was inserted preoperatively on the side to be operated upon and used postoperatively for administration of bupivacaine, given as a bolus (1.25 mg kg(-1)) followed by a continuous infusion (0.25 mg kg(-1) h(-1)). Skin blood flow (SBF) in the pad of the index finger was assessed by the laser Doppler technique, and regional skin vascular resistance (RVR) was calculated. The inspiratory gasp test (apnea at end-inspiration) or a local heat provocation were used as provocations of the cutaneous microcirculation. RESULTS: Interscalene brachial plexus block increased SBF and decreased RVR at rest, and produced satisfactory sensory and motor block. The inspiratory gasp test decreased SBF and increased RVR in the unblocked arm, while the opposite, increased SBF and decreased RVR, were observed during local heat provocation. In the blocked arm, these gasp-induced cutaneous vasoconstrictor and heat-induced vasodilator responses were attenuated. CONCLUSIONS: Interscalene brachial plexus block reduces regional sympathetic nervous activity, illustrated by increases in skin blood flow, skin temperature and attenuated vasoconstrictor responses to an inspiratory gasp. The inspiratory gasp vasoconstrictive response is a powerful and sensitive indicator for monitoring the sympathetic blockade following interscalene brachial plexus block.
Place, publisher, year, edition, pages
2000. Vol. 44, no 8, 946-52 p.
Adult, Aged, *Autonomic Nerve Block, Blood Pressure/drug effects, *Brachial Plexus, Female, Heart Rate/drug effects, Humans, Laser-Doppler Flowmetry, Male, Middle Aged, *Nerve Block, Regional Blood Flow, Respiratory Mechanics/physiology, Skin/blood supply/*drug effects/innervation, Vascular Resistance/physiology, Vasoconstriction/drug effects/*physiology
IdentifiersURN: urn:nbn:se:umu:diva-31430ISBN: 0001-5172 (Print)OAI: oai:DiVA.org:umu-31430DiVA: diva2:293017
Lehtipalo, S Winso, O Koskinen, L O Johansson, G Biber, B Clinical Trial Research Support, Non-U.S. Gov't Validation Studies Denmark Acta anaesthesiologica Scandinavica Acta Anaesthesiol Scand. 2000 Sep;44(8):946-52.2010-02-102010-02-102015-09-15