The use of central venous pressure monitoring in the intensive care and acute care setting is increasing. This is a measure of the venous pressure where the superior and inferior vena cava join prior to entering the right auricle of the heart.
Central Venous Pressure monitoring is more accurate then blood pressure monitoring because changes in circulating volume will be reflected in changes in CVP. The normal CVP is between 5 and 15 CMS of water.
When there is overloading of the circulatory system or there is heart failure the CVP rises. However, when there is dehydration (e.g. diabetes insipidus), fluid loss due to bleeding or shifting of fluids within the body compartments (e.g. shock) than the CVP will fall.
Generally, when the CVP is rising to unhealthy levels the patient may display difficulty with breathing. Conversely, when the CVP is falling there may be a decrease in urinary output and the patient may complain of feeling excessively thirsty. To correct over hydration, as illustrated by a rising CVP the physician may choose to restrict fluids or to administer a diuretic. To deal with a falling CVP the physician might choose to give the patient more fluids or blood as the case may be.
Most institutions have Policies and Procedure manuals which state the indications for the insertion of a CVP monitoring line.