RELIABILITY OF TRANSCUTANEOUS OXIMETER ELECTRODE HEATING POWER DURINGEXERCISE IN PATIENTS WITH INTERMITTENT CLAUDICATION

The purposes of this study were to (1) compare the reliability of tran scutaneous oximeter electrode power with the reliability of oxygen ten sion and (2) compare the relationship of the oximetry measures with ex ercise performance in claudicants. One hundred ten PAOD patients with stable claudication symptoms performed a treadmill test and had the fo llowing exercise measures obtained: foot transcutaneous oxygen tension , oximeter electrode heating power, exercise duration, and peak oxygen consumption. A subset of 30 patients were tested once per week over t hree successive weeks to assess the reliability of the oximetry measur es. The coefficient of variation of foot transcutaneous oxygen tension at peak exercise was 32.8%, whereas the variability of the oximeter e lectrode heating power was only 5.1%. Oximeter electrode heating power at peak exercise was related to maximal claudication pain time (r=0.4 4, P < 0.001) and peak oxygen consumption (r=0.36, P < 0.001), whereas foot transcutaneous oxygen tension was not related to either (r=0.15, P=0.119; r=0.13, P=0.189; respectively). Thus, transcutaneous oximete r electrode heating power was six to seven times less variable than tr anscutaneous oxygen tension, and the oximeter electrode power at peak exercise was more closely related to exercise capacity. It ss conclude d that the measurement of transcutaneous oximeter electrode heating po wer during exercise is more reliable and better correlated with exerci se capacity in PAOD patients with intermittent claudication than the m easurement of transcutaneous oxygen tension.