Effect of cold pressor test on carbon monoxide diffusing capacity in normal subjects.
We investigated changes in the pulmonary carbon monoxide diffusing capacity (DLco) during the cold pressor test (CPT) on 25 normal subjects. In 10 of them we also observed changes in circulatory parameters by a computerized dual cadmium telluride detector system, using an equilibrium radionuclide blood-pool label. DLco and DLco per unit of alveolar volume (DLco/VA) averaged in the control period were 29.4 +/- 4.1 ml/min/mm Hg, 6.1 +/- 0.8 ml/min/mm Hg/l (mean +/- SD). During the 2nd minute of CPT, DLco increased by 3.6 +/- 1.5% and DLco/VA by 5.1 +/- 1.5% (mean +/- SE). The systemic blood pressure increased by 17% (mean increase) whereas the heart rate and the stroke volume remained unchanged. The increases were small but significant (p less than 0.05, p less than 0.01, respectively). We conclude that the increase in DLco is due to cold-induced systemic vasoconstriction followed by a passive shift of blood into the pulmonary vasculature.
Kuwahira
I
I
Department of Medicine, Tokai University School of Medicine, Kanagawa, Japan.
Ide
M
M
Suzuki
Y
Y
Ohta
Y
Y
Yamabayashi
H
H
D000328:Adult; D001794:Blood Pressure; D001810:Blood Volume; D002248:Carbon Monoxide / Q000378:metabolism*; D003080:Cold Temperature; D005541:Forced Expiratory Volume / Q000502:physiology; D015637:Gated Blood-Pool Imaging; D006339:Heart Rate; D006801:Humans; D008297:Male; D011652:Pulmonary Circulation; D011653:Pulmonary Diffusing Capacity; D013318:Stroke Volume; D014661:Vasoconstriction; D014797:Vital Capacity
D002248:Carbon Monoxide