Effect of Carbon Dioxide-Enriched Water and Fresh Water on the Cutaneous Microcirculation and Oxygen Tension in the Skin of the Foot

Abstract

The effects of immersion of the lower leg and foot in fresh water and in carbon dioxide (CO₂ )-enriched water (1200 mg CO₂ per kg water; succinate + sodium bicarbonate: Actibath®, KAO Tokyo) on cutaneous circulation, vasomotion and oxygen tension (PO₂) were measured by laser Doppler flowmetry and transcutaneous oximetry. On the first of two consecutive days patients were randomly assigned to have the lower extremities immersed in either fresh water or CO₂-enriched water under standardized conditions (temperature, 34°C; depth, 35 cm; immersion time, twenty minutes) with concurrent measurement. On the second day patients were switched to the other bath type. For both sets of measurements probes were attached symmetrically to the dorsum of each foot. Included in the study were 18 patients with mild, bilateral, peripheral, occlusive arterial disease (intermittent claudication, femoral or iliac type). During immersion in CO₂ enriched water the Doppler laser signal and vasomotion amplitude rose by 300%, while PO₂ increased by 10%. These increases were still apparent during the latter part of the measurement period, following withdrawal of the limbs from the bath, while patients were seated and supine. During immersion in fresh water and thereafter the Doppler laser signal was unchanged and the PO₂ increase was considerably less marked. The authors were thus able to demonstrate vasodilation and increased oxygen utilization (Bohr effect) resulting from topical CO₂ application, and hence, that the use of topical CO₂ has an objective basis.