research program
There is a research program at the Uniformed Services University of the Health Sciences in Bethesda, MD in which oxygen consumption and debt are measured in pigs that are acutely bled to a predetermined mean blood pressure and held at that pressure for about 4 hours or until the animal dies. We measured PPV in the forelimb of one such animal. We found that in this one animal that changes in PPV tracked very closely with changes in cardiac output.
Anecdotal data obtained from one pig at the Uniformed Services Medical School, Bethesda, MDl