Predicting successful supraclavicular brachial plexus block using pulse oximeter perfusion index

Area of Science:

• Anesthesiology
• Medical Devices
• Surgical Procedures

Background:

• Supraclavicular nerve block is a common anesthesia for upper limb surgeries.
• Traditional block success evaluations are time-consuming and require patient cooperation.
• A need exists for a more efficient and objective method to assess block success.

Purpose of the Study:

• To determine if perfusion index (PI) can predict ultrasound-guided supraclavicular nerve block success.
• To establish a cut-off value for PI to indicate successful block.
• To compare PI changes in blocked versus non-blocked limbs.

Main Methods:

• 77 patients undergoing elective orthopaedic procedures received ultrasound-guided supraclavicular nerve block.
• Sensory and motor block success assessed via pinprick and resistance tests.
• Perfusion index (PI) measured at baseline and 30 min post-injection in both limbs.
• PI ratio calculated (PI at 10 min / baseline PI).
• Receiver operating characteristic (ROC) curves used to determine accuracy.

Main Results:

• The blocked limb consistently showed higher PI and PI ratio compared to the unblocked limb.
• PI at 10 min demonstrated 100% sensitivity and specificity for block success at a cut-off of 3.3.
• PI ratio at 10 min showed 100% sensitivity and specificity at a cut-off of 1.4.

Conclusions:

• Perfusion index (PI) is a valuable tool for evaluating supraclavicular nerve block success.
• A PI ratio exceeding 1.4 reliably predicts successful block.
• This method offers a rapid and objective assessment, improving patient care.