Criteria Predictive of Limb Viability at 1 Year in Patients with Chronic Severe Ischemia-TcPO 2 and Demographic Parameters

Abstract

Following an earlier study, the investigators sought to identify and define objective prognostic criteria of viability at 1 year of a limb with severe chronic ischemia. A study was undertaken in 116 patients (118 limbs) (74 men and 42 women), with a mean age of 71.9 years for men and 81.6 years for women. Static transcutaneous oxygen pressure (TcPO2) was measured with a verticalization sensitization test and inhalation of oxygen on JO and viability of the limb noted 1 year later. Logistic analysis was made of 13 oximetry parameters and two demographic parameters (age and gender). Results were analyzed in absolute terms and by tissue oxygenation ratio (TOR) (ratio between absolute TcPO2 at the foot and at a chest reference electrode). Six factors appeared to be prognostic factors of limb viability at 1 year, statistically significant at 6% according to threshold values: age, verticalization TcPO2, TcPO2 after 1 minute's inhalation of oxygen, TcPO2 after 4 minutes' inhalation of oxygen, and slope of TcPO2 and slope of TOR between 1 and 4 minutes' inhalation. A 1 year viability index integrating these criteria is suggested.

Reference Probe for TcpO2 at Rest: A Systematic Review

“…A potentially important point is the lack of precision in the exact location of the reference probe on the chest in the majority of studies that used this site [14, 15,22,26,27,[29][30][31][32]. However, Orenstein et al, investigated the variability of TcpO 2 measurements over 23 different locations in healthy volunteers (including above and below the nipple) [33].…”

“…RPI should not be affected by age, and this could therefore be pertinent. However, Chomard et al, found there was no advantage in using RPI rather than TcpO 2 as an absolute value to predict limb viability at 1 year [31].…”