Peripheral circulatory changes as criteria for hemorrhagic shock therapy.

This study of hemorrhagic shock syndrome in dogs evaluates commonly used therapeutic procedures on the basis of ability to correct specific vascular decompensatory episodes associated with progressive refractoriness to blood transfusion. Using specific criteria (vasomotion, responsiveness to vasoconstrictor stimuli, tone of arterioles and venules and capillary blood flow), it was found that pressor drugs improved blood pressure only at the expense of peripheral circulation. However, drugs such as angiotonin and especially pitressin, when added to the transfusion medium in subpressor concentrations sufficient to produce only a tonic narrowing of the terminal arterioles, brought sustained improvement in blood flow through the omental vessels. That the prognosis for successful treatment of the circulatory collapse closely parallels the sequential changes which occur in the terminal vascular bed, adds further significance to the probable causal relationship between the observed vascular derangements and the ultimate collapse of the peripheral circulation.