Comparison of VOP and Doppler ultrasound in measuring forearm blood flow during direct heating

Abstract

PURPOSE Venous occlusion plethysmography (VOP) is the gold standard for measuring forearm blood flow to obtain maximal skin blood flow. We sought to compare this method to Doppler ultrasound. METHODS Seven subjects (four female, three male; BMI = 23±3 kg.m−1) underwent a ramped local heating protocol. Local heating was achieved by heating the forearm with a water spray device. Doppler ultrasound of the brachial artery and forearm VOP were measured during five stages: under thermoneutral conditions (33oC), after 15 minutes of heating at 36oC, 39oC, and 42oC, and after 30 minutes of heating at 42oC. The protocol aimed to produce a linear rise in blood flow with each subsequent stage. Doppler ultrasound and VOP blood flow measurements were compared by linear regression analysis. RESULTS The protocol was successful in covering a wide range of blood flow, from normal baseline to near maximal values. Measurement of forearm blood flow using Doppler ultrasound and VOP were shown to be highly correlated, with a regression coefficient of R2 = 0.773. CONCLUSION Comparable changes in forearm blood flow can be measured using either Doppler ultrasound or VOP.