VASOCONSTRICTION IN THE HAND FROM A DEEP INSPIRATION

Abstract

A study of the vascular reaction of the hand and forearm to a deep breath was made by the use of 5 methods. 1. The pressure plethysmograph method of Hewlett (Heart 1: 87, 1909), which measures total flow into the hand and fore-arm, showed a complete stoppage of flow in 66 per cent of 48 subjects. 2. The plethysmograph showed a fall in hand volume from a deep breath varying from 1 to 13 cc. with an avg. fall of 6.7 cc. 3. The thermopile showed an avg. drop in skin temp, of 0.78[degree] C. (0.13[degree] to 257[degree] C). 4. The skin calorimeter measures skin blood flow in terms of temp, changes. A drop in the heat output of the skin following a deep breath was obtained in 88% of the cases. 5. Microscopic observation of the nail fold capillaries showed that following a deep breath there was a complete standstill of the blood in the tufts lasting from 3-5 seconds in 83 per cent of the subjects. These results showed that a deep breath of air caused a constriction of the arterioles of the forearm and hand but was especially marked in the skin of the fingers.