engleski

. Effect of age on anaesthetic volume for ultrasound guided supraclavicular brachial plexus block

Background and Goal of Study: The minimum volume required for effective ultrasound guided supraclavicular brachial plexus block (US-SCB) in 50% of patients is 23 ml, and in 95% of patients is 42 ml1 . The aim of study was to determine whether a 35 % reduction in anaesthetic volume of levobupivacaine in elderly patients (>70 years), due to involutive changes of brachial plexus (BP) assessed by measuring the cross-sectional area (CSA) of BP at the first rib, could accomplish an effective US-SCB for surgical anaesthesia in comparison with the control group (< 45 years). Materials and Methods: In this prospective, double-blind study 15 elderly patients undergoing upper limb surgery received a US-SCB with 27 ml of levobupivacaine, based on our previous clinical experience, whereas the control group (N=15) received 42 ml. Prior to the injection three measurements of the cross-sectional area (CSA) of BP were obtained and the mean was considered for the statistical analysis. Effective SCB was defined as complete sensory blockade in the distribution of the radial, ulnar, median and musculocutaneous nerve. Time to first postoperative analgesic request was recorded. Normal distribution of the variables was assessed using Kolmogorov-Smirnov test. Data are expressed as means ± standard deviations and Student’s t-test was used. Values of P< 0.05 were considered statistically significant. Results and Discussion: The mean age in elderly group was 80.60 (6.82) years and 42.73 (2.60) in the control group. Patients were comparable in terms of weight, height and duration of surgery. CSA of BP was 0.60 (0.08) cm2 in elderly and 0.91 (0.13) cm2 in the control group with significant difference ( P< 0.001). Effective US-SCB was achieved in 14 patients in each group.One patient (elderly group) had incomplete anaesthesia in the radial nerve, the other (control group) in the ulnar nerve distribution and had received supplemental local anaesthetic.Time to first analgesic request was 506 (335) minutes (elderly group) and 575 (255) minutes (control) with no significant difference (P=0.532). Conclusion: A 35% reduction in anaesthetic volume in elderly patients resulted in a effective US-SCB. CSA of BP was smaller in elderly patients.

Supraclavicular brachial plexus block ; Local anaesthetic

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