Dependence of Transcutaneous Oxygen Tension on Local Arteriovenous Pressure Gradient in Normal Subjects

Abstract

1. We studied the relationship between transcutaneous oxygen tension at the foot and local arteriovenous pressure difference in 15 normal men and women; arteriovenous pressure difference was varied by changing the height of the foot with respect to the heart and by applying external pressure to the foot. 2. Control transcutaneous oxygen tension was 67 +/- 9 SD mmHg (8.9 +/- 1.2 kPa) at a control arteriovenous pressure difference of 80 +/- 6 SD mmHg (10.6 +/- 0.8 kPa). 3. In every subject transcutaneous oxygen tension fell non-linearly with a decrease in arteriovenous pressure difference; transcutaneous oxygen tension was relatively insensitive to changes in arteriovenous pressure difference when arteriovenous pressure difference was high, but always fell sharply to zero at some positive arteriovenous pressure difference [range 13-34 mmHg (1.7-4.5 kPa)]. 4. An analysis of the data indicated that transcutaneous oxygen tension varied with arteriovenous pressure difference approximately as the oxygen tension of cutaneous venous blood under the sensor varied (in the absence of changes in cutaneous vascular resistance and oxygen consumption). 5. This analysis was supported by studies in three subjects in whom the oxygen tension of superficial venous drainage from a warmed hand or foot was measured along with transcutaneous oxygen tension while arteriovenous pressure difference was varied.

Preamputation evaluation of limb perfusion with laser Doppler imaging and transcutaneous gases

“…In this case, age may explain the higher values since it has been found to negatively correlate with TcPO 2 [31]. The same finding may apply to other studies of younger populations [32][33]. The ROC data indicated that although the accuracy of TcPO 2 and LDI flux ratio at discriminating between the two subject groups did not statistically differ over the full range of specificity values (estimated by the area under the curve of the ROC plot) at the high specificity (≥0.9) range, LDI flux ratio was significantly more sensitive that TcPO 2 .…”

Circulatory and mechanical response of skin to loading

“…TcPo, measurement reflects the local oxygen delivery in relation to local metabolic consumption and thus gives a measure of local blood flow and arterial oxygen content (19,26). TcPo, values are diminished in the limbs of patients with peripheral vascular deficiency (4,8-10, 21,23,24,28).…”

“…This study addresses the latter. Previous studies have shown the relationship between elevated tissue pressures and diminished tissue oxygenation (6,19,20,26). Transcutaneous partial pressure of oxygen (TcPo,) measurements reflect local circulation (3,4,(8)(9)(10)21,23,24,27) and have shown close correlation with healing in the below-knee amputee (16,17,25,28).…”

Transcutaneous Oxygen and Carbon Dioxide during Treatment of Critical Limb Ischemia with Iloprost, a Prostacyclin Derivative

“…The large scattering of tcpC>2 values during iloprost could have been influenced by the extent of the residual individual leg blood flow reserves, although the missing statistical association with pretreatment oxygen and ankle pressure levels did not seem to support this hypothesis. However, both measurements are relatively poor indices of the regional perfusion, since positive arte riovenous pressure differences may coexist with undetect able tcpCb levels [21], and Doppler sonographic systolic pressure values for the ankle reflect poorly those recorded more distally [22]. The data do not permit further infer ences, since even minute flow changes may markedly influence tcpOi, due to the hyperbolic shape of the func tion relating blood flow and tcpCb in maximally pre- heated skin of underperfused areas [1], The question may also arise as to whether the individual tcpCT response to iloprost might help to predict limb outcome [11], but we did not address this issue in our study.…”