Increase in pulmonary blood flow during cold stimulation of the mouth in patients with systemic lupus erythematosus.

To determine whether pulmonary blood flow is altered by cold stimulation of the mouth, a cold stimulus was induced by having 11 systemic lupus erythematosus patients without pulmonary fibrosis hold ice in their mouths. Lung perfusion was measured by continuous venous infusion of Krypton-81m. During the period in which the ice was held in the mouth, 2 patients showed 32% and 41% increase in pulmonary blood flow. After the cold stimulus was removed, pulmonary blood flow recovered in these patients to within the control range by a margin commensurate with the increase in the duration of the cold stimulus, suggesting that the response may be due to an abnormal reflex of the autonomic nervous system.