Fig. 2.

Hemodynamic responses to octreotide, and to tilting before and after octreotide, while cardiac output (CO; D) is maintained constant. Octreotide raised mean arterial pressure (MAP; A) and right atrial pressure (RAP; B). Because CO was constant, total vascular conductance (TVC; A) mirrors MAP, and heart rate (HR; C) and stroke volume (SV; C) mirror one another. Head-up tilt (HUT) reduced RAP and SV and increased HR similarly before and after octreotide. Heart-shaped symbols indicate that the tendency for an increase in afterload (MAP; A) to reduce SV and an increase in preload (RAP; B) to augment SV offset one another such that octreotide did not alter SV (C). White line in B highlights the sustained increase in RAP induced by octreotide. Heart symbols denote the expected effect of the change in each variable on stroke volume.