UNASSIGNED: Successful brachial plexus blockade produces sympathetic blockade, resulting in increased skin temperature in the blocked segments. This study aimed to evaluate the accuracy of infrared thermography in predicting failed segmental supraclavicular brachial plexus block.
UNASSIGNED: This prospective observational study included adult patients undergoing upper-limb surgery under supraclavicular brachial plexus block. Sensation was evaluated at the dermatomal distribution of the ulnar, median, and radial nerves. Block failure was defined as absence of complete sensory loss 30 min after block completion. Skin temperature was evaluated by infrared thermography at the dermatomal supply of the ulnar, median, and radial nerves at baseline, 5, 10, 15, and 20 min after block completion. The temperature change from the baseline measurement was calculated for each time point. Outcomes were the ability of temperature change at each site to predict failed block of the corresponding nerve using area under receiver-operating characteristic curve (AUC) analysis.
UNASSIGNED: Eighty patients were available for the final analysis. The AUC (95% confidence interval [CI]) for the ability of temperature change at 5 min to predict failed ulnar, median, and radial nerve block was 0.79 (0.68-0.87), 0.77 (0.67-0.86), and 0.79 (0.69-0.88). The AUC (95% CI) increased progressively and reached its maximum values at 15 min (ulnar nerve 0.98 [0.92-1.00], median nerve 0.97 [0.90-0.99], radial nerve 0.96 [0.89-0.99]) with negative predictive value of 100%.
UNASSIGNED: Infrared thermography of different skin segments provides an accurate tool for predicting failed supraclavicular brachial plexus block. Increased skin temperature at each segment can exclude block failure in the corresponding nerve with 100% accuracy.

Regional anesthesia (RA) is an anesthetic technique essential for the performance of ambulatory surgery. Failure rates range from 6% to 20%, and the consequences of these failures have been poorly investigated. We determined the incidence and the impact of regional block failure on patient management in the ambulatory setting. This retrospective cohort study includes all adult patients who were admitted to a French University Hospital (Hôpital Saint-Antoine, AP-HP) between 1 January 2016 and 31 December 2017 for unplanned ambulatory distal upper limb surgery. Univariate and stepwise multivariate analyses were performed to determine factors associated with block failure. Among the 562 patients included, 48 (8.5%) had a block failure. RA failure was associated with a longer surgery duration (p = 0.02), more frequent intraoperative analgesics administration (p < 0.01), increased incidence of unplanned hospitalizations (p < 0.001), and a 39% prolongation of Post-Anesthesia Care Unit (PACU) length of stay (p < 0.0001). In the multivariate analysis, the risk factors associated with block failure were female sex (p = 0.04), an American Society of Anesthesiologists (ASA) score > 2 (p = 0.03), history of substance abuse (p = 0.01), and performance of the surgery outside of the specific ambulatory surgical unit (p = 0.01). Here, we have documented a significant incidence of block failure in ambulatory hand surgery, with impairment in the organization of care. Identifying patients at risk of failure could help improve their management, especially by focusing on providing care in a dedicated ambulatory circuit.