A New Method for the Assessment of Tissue Hemoglobin Oxygenation in Patients with Chronic Venous Insufficiency

Abstract

Venous incompetence often leads to ulceration of the skin of the lower limb due to a disturbance of skin microcirculation. We investigated 10 healthy subjects and 18 patients with chronic venous insufficiency by means of a fast scanning reflection photometer and determined noninvasively the hemoglobin oxygen saturation (SHB) and the relative concentration of hemoglobin (CHB) in the skin of the forefoot and at the calf, 10 cm proximal of the inner malleolus during positional changes. In supine position no significant differences were found. During sitting and standingSHBdropped and was significantly lower in patients at both locations (calf, standing, patients 22.2 ± 10.6% vs controls 48.2 ± 13.5%,P< 0.001).CHBincreased in patients during standing from 0.71 to 2.13 ± 0.33 aU (in controls from 0.69 to 1.49 ± 0.28 aU,P< 0.001). Activation of the muscle pump decreasedCHBand increasedSHBin patients and in controls. After the movements were stopped,SHBdecreased again and fell to the initial low values eight times faster in patients (7.4 ± 5.3 vs 57.5 ± 19.6 sec,P< 0.001).CHBincreased four times faster in patients (7.2 ± 6.1 vs 29.9 ± 13.6 sec). In sitting and standing positions hemoglobin oxygenation in the skin of the lower limb was markedly reduced in patients, but normal perfusion conditions were restored in supine position, indicating reversibility of the changes. Reflection oxymetry seems a valuable tool for the assessment of chronic venous insufficiency. The substantially reduced oxygenation of dermal hemoglobin in standing patients may contribute to the development of venous ulcers.