Thermography in Anesthetic Peripheral Nerve Blocks When Using Different Local Anesthetics

Background: Peripheral nerve blocks in regional anesthesia are operator-dependent and are not always successful, leading to patient discomfort and postoperative pain. Current methods for assessing block failure rely on subjective patient reports of sensory and motor loss, which take time to appear and can be misleading. This study evaluates thermography as an objective, quantitative method for determining nerve block success and discusses its practical implications for clinical practice. Methods: This study was conducted at the Hospital of Traumatology and Orthopedics in Riga and included 55 patients undergoing sciatic nerve block with equipotent doses of different local anesthetics. Three local anesthetics—lidocaine, bupivacaine, and ropivacaine—were used in equipotent doses. After the block, the anesthetized region was imaged with a thermographic camera for 45 min to detect temperature changes. Results: Analysis showed no clinically significant differences among the local anesthetics in the timing or magnitude of skin temperature changes. At least 15 min must elapse before using thermography to judge nerve block success. Thermography is less reliable in acute bone fractures. Additionally, lower initial skin temperature was associated with a faster observable temperature increase, proving a strong negative correlation.