Perfusion index as an objective alternative to the Allen test, with flow quantification and medico legal documentation

Abstract

Aim:To evaluate the use of perfusion index for diagnosis of abnormal collateral hand circulation (CHC), in comparison with the modified Allen test and pulse oximetry using Doppler ultrasonography as a reference test.

Methodology: Forty two (84 hands) healthy volunteers were randomly selected for our study. Adequacy of the collateral hand circulation during occlusion of the radial artery was assessed in each hand using four tests by four expert investigators, one for each test: (I) Modified Allen test (2) Perfusion index (3) Pulse oximetry, and (4) Doppler ultrasonography being the standard test.

Results: The Doppler ultrasonography (the standard test) diagnosed abnormal CHC in 3 hands (3.5%). The modified Allen test showed abnormal CHC in 16 hands (19%), with sensitivity100%, specificity 78% and positive predictive value 18.7% when compared with the standard Doppler ultrasonography. Also pulse oximetry method indicated abnormal CHC in 4 hands (4.7%) with sensitivity100% specificity 98% and 75% positive predictive value. ROC analysis showed that > 65.7% reduction in the perfusion index diagnosed abnormal CHC with 100% sensitivity, 98.8% specificity and 75.5% positive predictive value using Doppler ultrasonography as a reference test.

Conclusion: Using Doppler ultrasonography as a reference test, perfusion index is a reliable objective test for diagnosis and prediction of abnormal CHC, with high sensitivity, specificity, and accepted positive predictive value.

Citation:Al-metwalli RR. Perfusion Index as an Objective Alternative to the Allen Test, with Flow Quantification and Medico legal Documentation. Anaesth Pain & Intensive Care 2014;18(3):245-249