CENTRAL VENOUS PRESSURE (CVP)
Central venous pressure is the pressure within the superior vena cava and is an approximation of right atrial pressure and is measured in mmHg.
Prior to CO monitoring, circulatory status and fluid management were commonly assessed and guided through surrogate parameters, including: CVP, HR, MAP, haematocrit, and urine output. CVP, it was assumed, positively reflected intravascular volume and could therefore be used to guide fluid management.
However, In the 1980’s Shippy et al.  demonstrated no relationship between individual blood volume deficit or excess, and the corresponding CVP. Despite this, it wasn’t until the 2000’s that the inability of CVP to assess blood volume and guide fluid management was more widely accepted. In the review by Marik et al. , the authors concluded that neither CVP, nor the change in CVP, are able to predict the haemodynamic response to a fluid challenge and therefore, CVP should not be used to make clinical decisions regarding fluid management.
- Shippy, C.R., P.L. Appel, and W.C. Shoemaker, Reliability of clinical monitoring to assess blood volume in critically ill patients. Crit Care Med, 1984. 12(2): p. 107-12.
- Marik, P.E., M. Baram, and B. Vahid, Does central venous pressure predict fluid responsiveness? A systematic review of the literature and the tale of seven mares. Chest, 2008. 134(1): p. 172-8.