<unk>  <unk>  is the blood pressure in the venae cavae, near the right atrium of the heart.<unk>  reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system.<unk>  is often a good approximation of right atrial pressure (RAP), although the two terms are not identical, as a pressure differential can sometimes exist between the venae cavae and the right atrium.<unk>  and RAP can differ when arterial tone is altered. This can be graphically depicted as changes in the slope of the venous return plotted against right atrial pressure (where<unk>  increases, but right atrial pressure stays the same; VR =<unk>  − RAP).<unk>  has been, and often still is, used as a surrogate for preload, and changes in<unk>  in response to infusions of intravenous fluid have been used to predict volume-responsiveness (i.e. whether more fluid will improve cardiac output). However, there is increasing evidence that<unk> , whether as an absolute value or in terms of changes in response to fluid, does not correlate with ventricular volume (i.e. preload) or volume-responsiveness, and so should not be used to guide intravenous fluid therapy. Nevertheless,<unk>  monitoring is a useful tool to guide hemodynamic therapy. The cardiopulmonary baroreflex responds to an increase in<unk>  by decreasing systemic vascular resistance while increasing heart rate and ventricular contractility in dogs.
Central venous pressure
Mean arterial pressure
Mean systemic pressure
Segmental blood pressure
Pulmonary wedge pressure
Arteriovenous oxygen difference
Cerebral perfusion pressure
Pulse pressure