Peripheral Perfusion Index as a Predictor of Successful Supraclavicular Brachial Plexus Block

The PI (Perfusion Index) was measured using Masimo SET pulse oximetry applied on the index finger. The PI was recorded at baseline and at 10 , 20 , and 30 min after local anaesthetic injection in both the blocked limb and the contralateral unblocked limb using two separate oximeters. The PI ratio was calculated as the ratio between the PI at 10min after injection and the baseline PI. In every patient, a comparison between the blocked and unblocked limb was performed .