April 11, 2022
Abstract Infraclavicular nerve block, frequently preferred in upper extremity surgeries, provides additional advantages, such as reducing opioid consumption by providing an analgesic effect in the postoperative period. The success of peripheral nerve blocks is usually assessed by subjective feedback from the patient, and patient cooperation is needed. This study aims to determine whether the level of the perfusion index, which can be measured non-invasively, can predict the success of the infraclavicular block. Thirty patients who were operated on for carpal tunnel syndrome under infraclavicular brachial plexus block were included in the study. The perfusion index and skin temperature were measured 0–10–20–30 min after block- age and at 2, 4, and 6 h after surgery. The value of the perfusion index in the arm of patients with a successful block was significantly higher (p < 0.05) than in the unblocked arm at 10 min and afterward. The cutoff values for the perfusion index and the perfusion index ratio after local anesthetic injections were 12.55 and 2.175, respectively, at the 20th minute when a significant difference was detected in the sensory block and 14.63 and 2.72 at the 30th minute, when a significant difference occurred in motor block development. The perfusion index can be a reliable and objective method to assess the adequacy of an infraclavicular block. The perfusion index and cutoff values that we determined can be used as an accurate predictive value for the success of infraclavicular block in patients under general anesthesia or in patients whose block success is dif- ficult to evaluate. The study was retrospectively registered on clinicaltrials.gov (trial registration number, NCT04921891; date of registration, 09 June 2021). Keywords Infraclavicular block · Perfusion index · Ultrasound · Local anesthetic · Evaluation of the block.