EFFECT OF CARBON DIOXIDE-ENRICHED WATER AND FRESH-WATER ON THE CUTANEOUS MICROCIRCULATION AND OXYGEN-TENSION IN THE SKIN OF THE FOOT

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; succ inate + sodium bicarbonate: Actibath(R), KAO Tokyo) on cutaneous circu lation, vasomotion and oxygen tension (Po-2) were measured by laser Do ppler flowmetry and transcutaneous oximetry. On the first of two conse cutive days patients were randomly assigned to have the lower extremit ies immersed in either fresh water or CO2-enriched water under standar dized conditions (temperature, 34 degrees C; depth, 35 cm; immersion t ime, twenty minutes) with concurrent measurement. On the second day pa tients were switched to the other bath type. For both sets of measurem ents probes were attached symmetrically to the dorsum of each foot. In cluded in the study were 18 patients with mild, bilateral, peripheral, occlusive arterial disease (intermittent claudication, femoral or ili ac type). During immersion in CO2-enriched water the Doppler laser sig nal and vasomotion amplitude rose by 300%, while Pot increased by 10%. These increases were still apparent during the latter part of the mea surement period, following withdrawal of the limbs from the bath, whil e patients were seated and supine. During immersion in fresh water and thereafter the Doppler laser signal was unchanged and the Po-2 increa se was considerably less marked. The authors were thus able to demonst rate vasodilation and increased oxygen utilization (Bohr effect) resul ting from topical CO2 application, and hence, that the use of topical CO2 has an objective basis.