Studies Made by Simulating Systole at Necropsy. X. State of Peripheral Circulation in Cadaver Preparations

Abstract

The state of the peripheral circulations of cadaver preparations, when perfused with blood, was examined by a study of the falling curves of diastolic pressure before and after the simulation of systole. In 43 experiments in 5 cadavers, the presystolic pressures fell at a rate which never exceeded that of many end-diastolic pressure curves secured on normal subjects. The long falling pressure curves secured after systole were essentially exponential in form. Two of Gomez' criteria, the pressure level of the asymptote of the falling pressure curve and the exponential fall rate of this curve, were calculated for our 43 experiments; the average values were close to the averages secured by Gomez in normal subjects. A method of estimating stroke volume, suggested by Gomez, is not supported by our data. The falling diastolic pressure curves level off at a value much above atmospheric pressure, a finding which supports the conception of the ‘critical closing pressure’ suggested by Burton. The values for critical closing pressure secured in our five cadavers are well within the range of those which have been secured during life on men and animals. In three arteriosclerotic subjects this pressure did not differ significantly from that of two younger subjects with essentially normal vessels. Submitted on January 4, 1957