Laser Doppler Measurements of Systolic Blood Pressure on the First and Second Toe in Patients with Peripheral Arterial Disease.

Abstract

Laser Doppler was used to measure toe blood pressure (TBP) in 40 consecutive patients with various degree of peripheral arterial disease. The aim of this methodological study was to increase the usefulness of TBP by exploring the interchangeability between TBP from the first and second toe and by investigating daily routine reproducibility and measurement variability. According to our study design pressure values were based on three measurements that were averaged. At simultaneous measurements, TBP of the first toe was 71 mm Hg (standard deviation [SD] 25) compared with 70 mm Hg (SD 25) on the second toe. The correlation ( r ) between first and second toe pressure measurements was 0.84 and intraclass correlation coefficient (ICC) was 0.84. The difference between TBP on the first and second toe was not related to gender, diabetes, or magnitude of the pressures. Repeated TBP measurements of the right first toe after disconnection of cuffs, 5 to 10 minutes rest, and reconnection of cuffs had a coefficient of variation (CV) of 9% and an ICC of 0.93. CV for toe-brachial index (TBI) was 8%. Our results show that measurements of TBP from the second toe to a large extent are interchangeable with those assessed from the first toe and can be used in clinical situations where measurements from the first toe are not feasible. Flow detection with three averaged laser Doppler measurements generates TBP and TBI with low variability.