Central venous pressure

The central venous pressure ( CVP) is the blood pressure in the right atrium of the heart and in the superior vena cava ( SVC ). The central part of the expression refers to the valveless space in the center of the circulatory system (especially before or in the right atrium ) at heart.

Importance

The CVP was long used as a measure of intravascular volume, ie the blood and amount of liquid that is inside the vessels, which is now regarded as largely obsolete. Numerous studies have shown that the connection with the intravascular volume status is very poor.

About the central venous catheter can also determine the central venous oxygen saturation. Under a number of conditions, among others, that the arterial oxygen saturation is normal, the patient has no oxygen utilization disorder has (as can be for example in the case of sepsis ) and no arteriovenous shunt is present, it can be used as guidance for a sufficient cardiac output. The determination of the mixed venous saturation using a pulmonary artery catheter has the advantage that the blood from the upper and lower half of the body ( therefore gemischtvenös ) originates.

Measurement

The CVP is measured invasively via the central venous catheter ( CVC ) on the flat-lying patient. You can determine it by a manometer or the height of a liquid column above the specific means of Thoracic Schublehre zero. The zero point is approximately 2/5 of the thorax level below the sternum. The permanent measurement of the CVP may be just as direct measurement of blood pressure ( IBP) through a monitor done. Here, instead of the arterial catheter connected to a pressure sensor of the central venous catheter.

The plausibility of the CVP measurement can be estimated from the width of the inferior vena cava in the ultrasound.

Normal values

The central venous pressure is measured in mm Hg.

  • 3-8 mmHg which corresponds to 4-10 cm of water column [ cmH2O ] (conversion factor: 1 mmHg ≈ 1.36 cmH2O )
  • SI - Compliant: 0.199 to 1.197 kPa (conversion factor: 1 mmHg ≈ 133.3 Pa)

Deviations

The central venous pressure may be lowered in acute or chronic volume depletion. Increases he can in the right heart or global heart failure, high positive end-expiratory be with pressure (PEEP ) in overhydration, with a tension pneumothorax, pulmonary embolism or pulmonary edema.

Possibilities of error

  • The catheter is present and is incorrectly too high measured.
  • The zero point is set incorrectly.
  • The patient is not in a horizontal position.
  • In the measuring system or in the transducer for air bubbles.
  • The tube of the measuring system is pressed.
  • Patient pressed during measurement with the abdomen or thorax
  • Infusion line is open and fluid is running during the measurement of the system
Monitoring (medicine)
835909
de