Thermal Imaging to Predict Failed Supraclavicular Brachial Plexus Block: A Prospective Observational Study

Area of Science:

• Anesthesiology and pain management
• Medical imaging and diagnostics
• Surgical procedures

Background:

• Successful brachial plexus blockade typically results in sympathetic blockade and increased skin temperature.
• Evaluating the accuracy of infrared thermography is crucial for identifying failed supraclavicular brachial plexus blocks.

Purpose of the Study:

• To assess the efficacy of infrared thermography in predicting failed segmental supraclavicular brachial plexus blocks.
• To determine the correlation between skin temperature changes and block success.

Main Methods:

• A prospective observational study involving adult patients undergoing upper-limb surgery with supraclavicular brachial plexus block.
• Skin temperature was monitored using infrared thermography at specific nerve distributions (ulnar, median, radial) at various time points post-block.
• Block failure was defined by the absence of complete sensory loss 30 minutes after block completion.

Main Results:

• Area under the receiver-operating characteristic curve (AUC) analysis showed increasing accuracy in predicting block failure over time, peaking at 15 minutes.
• At 15 minutes post-block, the AUC values for predicting ulnar, median, and radial nerve block failure were 0.98, 0.97, and 0.96, respectively.
• A 100% negative predictive value was achieved, indicating that increased skin temperature could reliably exclude block failure.

Conclusions:

• Infrared thermography is an accurate method for predicting failed supraclavicular brachial plexus blocks.
• Monitoring skin temperature changes can effectively identify and exclude block failures with high confidence.