{
  "abstract": "Background and Aims There is no consensus on the definition of a successful brachial plexus block or the best sensory assessment method for it, making it challenging to predict brachial plexus block success. 1 We attempted to identify early predictors of brachial plexus block success using the data from our published research studies.2 Methods We recruited 80 patients for two prospective-randomised axillary block studies and 70 for two prospective-randomised supraclavicular block studies (ethics committee-approved). Based on the data from the 10-minute assessment point after the block completion, we created four contingency tables (for each block type) to explore the association between the degree of sensory block of the ulnar, median, radial and musculocutaneous nerves and study outcomes ( table 1) and a binary logistic regression model to predict success based on the scores for cold testing alone for these nerves and study outcomes (four predictor variables, one outcome variable). (Cold assessment: alcohol-soaked swab, scored 0–10; Pinprick assessment: sterile needle, described as sharp, touch or absent)Results The studies generated the data for 150 blocks (Axillary: 66-successful/14-ineffective; Supraclavicular: 51-successful/19-ineffective). The contingency table analyses indicated a significant association between the degree of radial and ulnar nerve block and axillary and supraclavicular block success ( table 2). The regression model fit the data well and had 85% sensitivity for correct prediction. A cold assessment score of 0–3 for the ulnar and radial nerves at 10 minutes significantly increases the likelihood of a successful brachial plexus block, with odds ratios of 30.7 and 10.7, respectively (figure 1).Conclusions Early success at the radial and ulnar nerve is important for a successful axillary and supraclavicular brachial plexus block. The success of a nerve block depends on many factors, but these findings could help improve training for inexperienced anaesthetists, as the two nerves could be technically most challenging to access during these procedures. Abstract EP063 Table 1An example of a contingency table. The contingency tables were analysed using Fisher’s exact test, and for sensitivity, specificity, positive and negative predictive values, likelihood ratio, and effect size indices, i.e., odds ratio and relative risk. A complete block of a nerve was defined as a complete loss of sensation to cold, i.e. score=0/10 (0= no cold sensation and 10= as cold as the contralateral side), and loss of sensation to sharp in the sensory distribution of a nerve. A failure to achieve this criterion was labelled as an incomplete block of a nerveAbstract EP063 Table 2Main results of contingency table analyses indicating a significant association between the degree of radial and ulnar nerve block and the success of axillary and supraclavicular blocks. C.I.=confidence intervals. (Analysis conducted with GraphPad Prism v8)Abstract EP063 Figure 1A forest plot showing odds ratios (green dot) and their 95% confidence intervals (extended lines) for scores associated with increased odds of successful axillary and supraclavicular brachial plexus blocks. The x-axis is scaled at log 2 to accommodate upper limits of 95% confidence intervals. Scores on the y axis indicate score out of 10 when the nerve was tested for cold sensation at 10 minutes. The binary logistic regression was conducted with SPSS V. 29References 10.1097/AAP.0b013e3182583b00https://doi.org/10.1016/j.bjao.2025.100385",
  "authors": [
    {
      "affiliations": [
        "Department of Anaesthesia, Leeds General Infirmary, Leeds, UK"
      ],
      "name": "Anurag Vats"
    },
    {
      "affiliations": [
        "Department of Anaesthesia, Leeds General Infirmary, Leeds, UK"
      ],
      "name": "Pawan Gupta"
    },
    {
      "affiliations": [
        "Retired, Retired, Leeds, UK"
      ],
      "name": "Andrew Berrill"
    },
    {
      "affiliations": [
        "Heka, INRIA: Institut National de Recherche En Sciences Et Technologies Du Numérique, Paris, France"
      ],
      "name": "Sarah Zohar"
    },
    {
      "affiliations": [
        "Department of Anaesthesia, Leeds Teaching Hospitals NHS Trust, Leeds, UK",
        "Professor of Anaesthesia, University of Leeds, Leeds, UK"
      ],
      "name": "PM Hopkins"
    }
  ],
  "title": "EP063 Predicting brachial plexus block success based on early sensory assessment",
  "uid": "d6d1079c-fe08-5501-9da4-04879888587c"
}