Effect of l-Arterenol Infusion on "Central Blood Volume" in the Dog

Abstract

Infusion of 1-arterenol into anesthetized dogs increased the volume of blood in the heart and lungs, as indicated by an increase in "central blood volume," estimated lung volume and pressure changes in the heart and lungs. An analysis of pressure and flow data in the systemic venous bed during infusion of the drug suggests that important sources of the shifted blood are the peripheral veins and venules.F OWLER AND COWORKERS have demonstrated that both pulmonary artery and "pulmonary capillary pressures" increase during the continuous infusion of 1-arterenol, in the human.1 These workers concluded that the pulmonary hypertension was secondary to an increased pulmonary venous pressure; however, the mechanism of this pressure rise was not investigated. With a constant cardiac output, changes in pulmonary vascular pressures occurring during 1-arterenol infusion could be due to either vasomotor activity in the pulmonary vascular bed, or a volume increase in the pulmonary circuit due to the shift of blood from the systemic circuit. Since the resistance across the pulmonary vascular bed did not change in any consistent manner during 1-arterenol infusion, Fowler concluded that the rise in pulmonary artery pressure was not due to constriction of the pulmonary arteries. These data, together with the general lack of evidence for active pulmonary vasomotor changes, make the second possibility the more likely explanation for the increased pulmonary artery pressure.2 '' Work from various laboratories indicates that systemic vasomotor activity can change the volume of blood contained in the heart and lungs. Johnson observed a decrease in this

The Effect of Norepinephrine on Cardiac Output, Arterial Blood Pressure, and Heart Rate in Dogs Treated With Chlorothiazide*†

“…This observation is in agreement with the generally accepted view that norepinephrine does not increase output in intact dogs or normal men (8)(9)(10)(11)(12)(13). Increases in cardiac output with norepinephrine have been reported in men and dogs, however, when the regulatory reflexes mediated over the vagi are inhibited (9,14).…”

The Effects of Exercise on Central Blood Volume in Man

“…An augmentation of central blood volume has been demonstrated when an erect subject assumes the recumbent position (1-3), after the inflation of an antigravity suit (3,4), following immersion of the body in water (4), after the administration of sympathomimetic amines (5)(6)(7), and when large volumes of blood are transfused to subjects under ganglionic blockade (8). A shift of blood out of the thorax occurs when the erect position is assumed (1,2,9), following the application of spinal and general anesthesia (10), positive pressure breathing (7,11), the Flack maneuver (12), venous tourniquets to the extremities (3), and after the administration of ganglionic blocking agents (13,14).…”

Norepinephrine Induced Pulmonary Congestion in Patients With Aortic Valve Regurgitation*

“…The chamber size and elasticity factors during the infusion of norepinephrine are, in all probability, opposite in direction to those associated with the large error alluded to above for the following reasons. Epinephrine in the dog has been shown with a cinefluorographic technique to increase the left ventricular diastolic area (10), and a similar change may be inferred for norepinephrine from the rise in left ventricular diastolic pressures associated with its use (11). Similar pressure changes occur in man, judged by left atrial mean pressures (12).…”

“…The. cardiopulmonary location of this blood has been further evidenced by increased Hamilton central volumes and left ventricular enddiastolic pressure (11). That a translocation of blood from the periphery is involved in this process would appear to be the case, since limb volumes measured plethysmographically indicate a decline (2,22).…”