Pulse oximetry index: a simple arterial assessment for patients with venous disease

To provide additional safety data comparing ankle brachial pressure index (ABPI) and pulse oximetry (Lanarkshire Oximetry Index, LOI) as measures of arterial circulation in patients with venous disease of the leg.

A total of 107 (195 legs) attending hospital leg ulcer clinics participated in this prospective open study. We attempted to measure brachial and foot arterial pressures in all patients using both the handheld Doppler method (ABPI) and pulse oximeter method (LOI). Features of patients with limbs in which either the ABPI or LOI could not be assessed were documented. ABPI and LOI values were compared, and agreement between the two assessment methods was assessed.

We found the LOI measurement to be a simpler technique than Doppler ABPI measurement, with an endpoint less prone to the subjective variability associated with the Doppler method. Of the 195 legs assessed,we obtained LOI in 10 in which an ABPI could not be recorded. LOI could not be recorded in only one leg. There was a linear association (p<0.001) and fair agreement (kappa=0.303) between LOI and ABPI in the 184 legs in which both ratios could be measured. There was no evident tendency for LOI to read either low or high compared with ABPI.

Pulse oximetry LOI is a simple alternative to Doppler ABPI in the screening of patients for arterial disease that could be a contraindication to, or require modification of, compression therapy. It can be measured in some legs that cannot be assessed by Doppler ultrasound.