抄録
Plethysmography is a volumetry method for the study of the peripheral blood circulation, which can be used to measure the blood flow by combination of the venous occlusion method. For this purpose the classic mechanical plethysmography and recently advanced mercury-in-gauge plethysmograph are the most available, but the former is not conveniently to be handled and both can only be used on finger or hand.
The photoelectric or impedance plethysmograph is easy to handle and can be used on any portion of the skin, but has a deficit of being incapable of recording the absolute volume changes. They are adapted, however, to observe the comparative vascular responses characteristic to various physiological and pathological conditions.
