Effects of age on minimum effective volume of local anesthetic for ultrasound-guided supraclavicular brachial plexus block

Autor: Jadranka Pavičić Šarić, Katarina Tomulić, Vinko Vidjak, Jelena Zenko
Rok vydání: 2013
Předmět:
Zdroj: Acta Anaesthesiologica Scandinavica. 57:761-766
ISSN: 0001-5172
Popis: Background Involutional changes of peripheral nervous system occur with aging. The aim of the study was to determine the minimum effective volume of local anesthetic required to offer an effective ultrasound-guided supraclavicular brachial plexus block in 50% of middle-aged ( 65 years) patients. We hypothesized reduced minimum effective volume of local anesthetic in elderly patients. Methods Middle-aged (n = 22) and elderly (n = 22) patients undergoing upper limb surgery received an ultrasound-guided supraclavicular brachial plexus block. Structural analysis of the brachial plexus in supraclavicular region was obtained by measuring the cross-sectional area. The prospective, observer-blinded study method is a previously validated step-up/step-down sequence model where the local anesthetic volume for the next patient is determined by the outcome of the previous block. The starting volume was 30 ml (50 : 50 mixture, 0.5%wt/vol levobupivacaine, 2%wt/vol lidocaine). The minimum effective volume of local anesthetic was determined using Dixon and Masey method. Results The minimum effective local anesthetic volume significantly differed between middle-aged and elderly [23.0 ml, 95% confidence interval (CI) 13.7–32.3 vs. 11.9 ml, 95% CI 9.3–14.6; 95% CI of the difference 1.6–20.6, P = 0.027]. The cross-sectional area of brachial plexus was 0.95 ± 0.15 in middle-aged and 0.51 ± 0.06 cm2 in elderly patients (P
Databáze: OpenAIRE
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