Studies on Starling's law of the heart. I. The circulatory response to acute hypervolemia and its modification by ganglionic blockade.

Abstract

The application of Starling's law of the heart to the circulation of man has been the subject of intensive interest and investigation. Infusions of intravenous fluids have been employed in attempts to simulate in man the increase in venous return to the Starling heart-lung preparation. A variety of fluids has been utilized in such studies in man, including saline (1-4), dextran (4-6), glucose solutions (4), and human serum albumin (2, 7). In general, the results have been conflicting, with a few investigators noting an increase both in filling pressure and cardiac output (1, 5), while in the majority of studies no consistent relationship between these parameters was noted (2-4, 6, 7). Indeed, in most human subjects the augmentation of the total blood volume has failed to be associated with a rise in cardiac output, even in the face of a decline in hematocrit (2-4, 6, 7). The possibility was considered that the presence of an actively functioning autonomic nervous system in the intact state and its absence in the heart-lung preparation accounts for the difference in the cardiac response to infusion in man and increased venous return to the heart-lung preparation. The present study was therefore designed to determine whether the circulatory response to acutely induced hypervolemia is modified by reducing the activity of the autonomic nervous system by means of ganglionic blockade.