A comparative analysis of transcutaneous oximetry (tcPo2) during oxygen inhalation and leg dependency in severe peripheral arterial occlusive disease

Abstract

Transcutaneous oximetry (tcPO2) performed during either oxygen inhalation or leg dependency was intra-individually compared in 64 patients suffering from a peripheral arterial occlusive disease, with and without critical limb ischemia. Among the 81 extremities investigated, 29 had a moderate peripheral arterial occlusive disease (6 in stage I, 23 in stage II) and 52 were initially affected by rest pain or ulceration (stage III/IV). Thirty-seven legs out of the latter improved under conservative treatment. In the remaining 15 limbs, vascular surgery or an amputation became necessary. The tcPO2 was measured at the forefoot with the patient in supine and sitting positions while breathing room air and in the supine position while inhaling 100% oxygen. In limbs with a tcPO2 below 15 mm Hg of patients in the supine position breathing room air, leg dependency generally provoked larger tcPO2 increases than oxygen inhalation. This difference between oxygen inhalation while supine and room air breathing leg dependency tcPO2 values exhibited an approximately linear correlation with the resting tcPO2. Responses of tcPO2 to leg dependency and oxygen inhalation seemed to reflect different mechanisms, that is, microvascular flow redistribution and supine perfusion reserve, respectively. The best discrimination of critical limb ischemia was observed for the tcPO2 of patients breathing room air while in the supine position, which was not surpassed by either the oxygen inhalation or the leg dependency test. Satisfactory results were achieved by combining limits for, first, supine (10 mm Hg) and sitting (45 mm Hg) tcPO2, as well as, second, ankle arterial pressure (60 mm Hg) and supine tcPO2 (10 mm Hg).

Functional Microcirculatory Impairment: A Possible Source of Reduced Skin Oxygen Tension in Human Diabetes Mellitus

“…Transcutaneous oxygen tension (TcPO2) measured on the lower extremity of patients with or without diabetes mellitus (DM) has been used to provide diagnostic and prognostic information in several clinically important areas (Oh et al, 1987;Rooke and Osmundson, 1990;Fronek, 1991;Bacharach et al, 1992;Scheffler and Rieger, 1992;Mayrovitz, 1994). However, in patients with DM, reduced levels of TcPO2 have been reported to be present even in young individuals thought to be free of other hemodynamically compromising factors (Breuer et al, 1988;Railton et al, 1983;Uccioli et al, 1994) but the source of the diabetes associated TcPO2 deficit has been illusive to pin down.…”

Measurement of transcutaneous oxygen pressure in patients with post-thrombotic syndrome: Findings and possible clinical applications

“…23 Definitive tcPO2 cut-off values cut-off point values have been established in PAD according to the severity of the disease. 24 tcPO2 measurement has been used as a method to determine amputation level and to estimate wound healing; 23 it has become a standard tool in the evaluation of diabetic patients. 25 In Meijer et al 23 and Quigley and Faris, 26 a tcPO2 reference value for wound healing to occur is >40 mm Hg.…”

In vivo assessment of peripheral vascular function by tcpo2 and skin blood flow modelling

“…Normally, it involves production of reactive oxygen species which reduces the nitric oxide bioavailability, or modifies the release of local endotelins and vasodilator prostaglandins, resulting in typical vasoconstriction following hyperoxia (42). The tcpO 2 variation measured in the foot of a normal individual, breathing an atmosphere with O 2 saturation, ranges from 238 to 500% (43,44). Results from peripheral vascular failure are strikingly insufficient and even controversial, with studies reporting a tcpO 2 rise (43,45), while others suggest exactly the opposite (41,43,45).…”

“…The tcpO 2 variation measured in the foot of a normal individual, breathing an atmosphere with O 2 saturation, ranges from 238 to 500% (43,44). Results from peripheral vascular failure are strikingly insufficient and even controversial, with studies reporting a tcpO 2 rise (43,45), while others suggest exactly the opposite (41,43,45). The atmosphere with 100% oxygen saturates the haemoglobin (the excess remains dissolved in the plasma), and it will be used by the tissue.…”