Correlation Between Perfusion Index Ratio and End Diastolic Velocity Ratio After Supraclavicular Brachial Plexus Block as an Early Predictor of Successful Block in Superficialization Surgery of the Upper Limb

Regional anesthesia is fundamental for upper limb surgeries, with SCBPB providing dense anesthesia. However, early confirmation of successful block performance remains challenging. Traditional clinical methods (sensory/motor testing) are subjective and delayed. This study proposes using objective, noninvasive indices - PI (evaluated via pulse oximetry) and EDV (measured by Doppler ultrasound) - to determine their accuracy in detecting sympathetic blockade shortly after SCBPB. Early and reliable detection of block success is particularly important in superficialization surgeries such as arteriovenous fistula (AVF) superficialization in patients with compromised vascular status. The results are expected to enhance anesthesia practice by providing quantitative, reproducible, and rapid assessment tools.