Procedural pain of an ultrasound‐guided brachial plexus block: a comparison of axillary and infraclavicular approaches

Abstract

BACKGROUND: Ultrasound (US)-guided infraclavicular (IC) and axillary (AX) blocks have similar effectiveness. Therefore, limiting procedural pain may help to choose a standard approach. The primary aims of this randomized study were to assess patient's pain during the block and to recognize its cause. METHODS: Eighty patients were randomly allocated to the IC or the AX group. A blinded investigator asked the patients to quantify block pain on a Visual Analogue Scale (VAS 0-100) and to indicate the most unpleasant component (needle passes, paraesthesie or local anaesthetics injection). Sensory block was assessed every 10 min. After 30 min, the unblocked nerves were supplemented. Patients were ready for surgery when they had analgesia or anaesthesia of the five nerves distal to the elbow. Preliminary scan time, block performance and latency times, readiness for surgery, adverse events and patient's acceptance were recorded. RESULTS: The axillary approach resulted in lower maximum VAS scores (median 12) than the infraclavicular approach (median 21). This difference was not statistically significant (P=0.07). Numbers of patients indicating the most painful component were similar in both groups. Patients in either group were ready for surgery after 25 min. Two patients in the IC group and seven in the AX group needed block supplementation (n.s.). Block performance times and number of needle passes were significantly lower in the IC group. Patients' acceptance was 98% in both groups. CONCLUSIONS: We did not find significant differences between the two approaches in procedural pain and patient's acceptance. The choice of approach may depend on the anaesthesiologist's experience and the patient's preferences.