Short-term effect of cold provocation on single-breath carbon monoxide diffusing capacity in subjects with and without Raynaud's phenomenon.

The lung diffusing capacity for carbon monoxide was determined by the single breath method (DLCOsb) before, during, and after immersion of the left hand in cold water in four groups of subjects: (i) normal individuals; (ii) subjects with idiopathic Raynaud's disease; (iii) patients with progressive systemic sclerosis without associated Raynaud's phenomenon; and (iv) patients with connective tissue disease associated with Raynaud's phenomenon. Our results showed significant differences in the evolution of DLCOsb after cold stimulation between the groups. Control subjects (group one) showed a transient but significant reduction in DLCOsb at the end of two minutes of cold stimulation, normalizing ten minutes later. Subjects with primary Raynaud's phenomenon (group two) showed on the contrary a transient but significant rise in DLCOsb after 2 minutes, while subjects with an isolated connective tissue disease without Raynaud's phenomenon (group three) showed a significant decrease in DLCOsb at both observation times. Patients with Raynaud's phenomenon associated with a connective tissue disease (group four) showed a delayed decrease in DLCOsb ten minutes after cold stimulation. This latter result appeared as an addition to the effects of cold stimulation observed in groups two and three.