Perfusion Index as an early indicator of successful ultrasound guided supraclavicular block in upper limb surgeries.

This is a prospective observational study that investigates whether the Perfusion index (PI) can serve as an early non-invasive indicator of a successful ultrasound-guided supraclavicular block in 78 patients undergoing upper limb surgeries. The research explores PI as a physiological alternative that reflects the vasodilation caused by sympathetic blockade. By recording PI values from two-minute intervals for the first ten minutes and five minute intervals thereafter, the study aims to establish a specific PI cut-off value and ratio that accurately predicts clinical success.