Digital blood pressure in normal subjects and patients with peripheral arterial disease.

Systolic toe blood pressure was measured in 10 normal subjects and 17 patients with peripheral arterial disease during a warming and a cooling period, in which the skin temperature on the first toe was changed from 33 degrees C to 24 degrees C. In normal subjects systolic toe blood pressure increased from an average of 110 mm Hg to 120 mm Hg during cooling (P less than 0.01), while the systolic arm blood pressure was unchanged during the study (125 mm Hg). Among the patients systolic toe blood pressure increased from an average of 56 mm Hg to an average of 70 mm Hg (P less than 0.01), while arm blood pressure increased from an average of 167/79 mm Hg during warming to 175/83 mm Hg during the cooling period. It is emphazised that despite the small, but significant, increase in digital blood pressure during the cooling period, changes in distal temperature will only have a small influence on the digital blood pressure, when one is evaluating patients with suspected or manifest peripheral arterial disease. In general, measurement during vasodilatation is to be preferred, since curves are easily obtainable.