Postprandial decrease in vascular resistance correlated with change in second derivative of finger plethysmogram in young subjects.

Abstract

The second derivative of the finger plethysmogram (SDPTG) comprises five waves termed a to e. The magnitudes of waves b-e are normalized by that of wave a for within- and between-patient comparison. In the present study, affects of meal ingestion for SDPTG in young and elderly subjects are examined. Mean arterial pressure and SDPTG before and after meal ingestion in young and elderly subjects were measured. For young subjects, stroke volume and pulse rate were also measured, and the total peripheral resistance (TPR) of the blood vessels was analyzed. Relationship between TPR and the ratio of the peak of SDPTG in young subjects was also analyzed. In young subjects, postprandial d/a was significantly larger and TPR was smaller than before intake and was linearly and significantly correlated with TPR. An increase in the postprandial d/a was also observed in the elderly subjects who were not undergoing hypertension treatment. However, this increase was not observed in elderly subjects who were treated for hypertension. Change in d/a is considered to be an index of change in TPR. TPR is considered to be decreased by agents for treatment of hypertension, and meal ingestion does not appear to further decrease TPR. These results are considered to be useful for understanding cardiodynamics surrounding meal ingestion.