ABSTRACT
Introduction: The minimum volume of LA required toeffectively block the four main branches of the axillary brachialplexus is unknown. The main aim of the current study wasto determine the minimal volume of LA required to surroundeach branch of axillary brachial plexus and document its onsetand duration of sensory and motor effects.Material and methods: 20 patients with ASA I–II undergoinghand or forearm surgery were selected for this study. USG wasused to locate each of the 4 branches of axillary plexus. 1.5%of lignocaine with 1:200 000 of adrenaline was loaded into asyringe driver and deposited with a 22 G needle and injectioncommenced using the bolus function (600 ml h21).Results: The mean (95% of Confidence Interval) volumerequired for each nerve was: radial 3.32 (2.74–3.89) ml,median 2.65 (2.01–3.19) ml, ulnar 2.48 (2.04–2.93) ml, andmusculocutaneous 2.20 (1.86–2.54) ml. The mean (95% ofConfidence Interval) onset time for complete sensory blockwas: radial 21.5 (12.5–30.5) min, median 25.8 (17.5–34.0)min, ulnar 25.6 (16.8–34.4) min, and musculocutaneous 14.8(7.35– 23.2) min. The mean (95% of Confidence Interval) lastrecorded time with complete block was: radial 136.1 (104.6–158.7) min, median 143.7 (122.4–165.0) min, ulnar 182.2(157.1–207.2) min, and musculocutaneous 157.3 (130.8–183.9) min.Conclusions: We concluded that it is possible to deposit 2–4ml of local anaesthetic around each branch of axillary plexus.We also speculate that by increasing the amount of volumeof LA would produce anesthesia of quicker onset and withlonger.