抄録
The reflection photoelectric plethysmograph has been modified to record volume changes in the different vascular layers in the human skin. It was found that pulse amplitude of the skin measured with this device increased as the pressure applied on the skin increased and it became maximum under a pressure of 50-70 mmHg. Three different and significant plethysmographic traces were identified during the Valsalva maneuver by compressing the skin surface with pressures of 0-20 mmHg, 30-50 mmHg and 50-120 mmHg respectively. There was a great difference between the plethysmographic traces of the finger and those of the ear lobe under a pressure of 30 mmHg. However, it was almost impossible to find any difference under a pressure of 80 mmHg. These plethysmographic traces corresponded with the arterial blood pressure changes recorded sphygmomanometrically. This may prove to be a useful device for continuous recording of the blood pressure in man.
