Effect of tourniquet-shock on the circulation of rats bearing Guerin carcinoma.

Blood pressure, cardiac output (Evans blue dilution) and its fractions (Sapirstein's indicator dilution technique), nutritive organ and tumour blood flow and circulatory resistance were studied under anaesthesia 1.5 hour post-release of both hind limbs constricted for 2.5 hours in rats bearing Guérin carcinoma. In tourniquet-shock the redistribution of cardiac output was essentially similar in normal and tumour bearing rats: e.g. skin and kidney fractions of cardiac output were diminished in both instances. In tumour bearing animals the circulatory resistance of tumour vasculature was more markedly enhanced than that of organ vessels, thus tumour fraction of cardiac output was decreased accordingly. It appears that the tumour might also contribute considerably to the development of a circulatory redistribution in shock.