CENTRAL VENOUS AND/OR

PULMONARY OCCLUSION

PRESSURE IN A

HEMORRHAGIC SHOCK, IS IT

LOW, NORMAL, OR HIGH?

Abdulrhman M AljoherS 62 (8)

Outline

Introduction

Concepts

Central venous pressure (low, normal, high)?

Pulmonary occlusion pressure (low, normal, high)?

Conclusion

References

1

2

3

4

5

6

•Central venous pressure

•Pulmonary occlusion pressure

Introduction

Central venous pressure

• describes the pressure in the thoracic vena cava near the right atrium (therefore CVP and right atrial pressure are essentially the same).

• CVP is a major determinant of the filling pressure and therefore the preload of the right ventricle, which regulates stroke volume through the Frank-Starling mechanism.

"central venous pressure" (CVP)

Central venous pressure

Pulmonary occlusion

pressure

• Also known as pulmonary capillary wedge pressure or PCWP

• provides an indirect estimate of left atrial pressure (LAP). Although left ventricular pressure can be directly measured by placing a catheter within the left ventricle

Pulmonary occlusion pressure

•Focused on the CVP

Concepts

Central venous pressure

Examination of internal jugular venous pulsations has generally been preferred for estimating central venous pressure as

well as right-sided hemodynamics.

ΔCVP = ΔV / Cv

Reduction CVP

leading to a decrease in venous pressure.

The reduction in the vascular volume observed with hypovolemia occurs primarily

in the venous circulation(which normally contains 70 percent of the

blood volume),

Factor increasing the CVP

Decreased cardiac output

Increased blood volume

Venous constriction

Changing from standing

to supine body posture

Arterial dilation

Forced expiration

(e.g., Valsalva)

Muscle contraction (abdominal and limb)

So, what would happen to the CVP when the

volume decrease?

The CVP

will

decrease

s

How about the PWCP?!

Yeah!

Conclusion

Central venous pressure estimates the

right atrial pressure

Pulmonary capillary wedge pressure

estimates the left atrial pressure.

The values reflect end-diastolic volume, or

preload, of the right and left ventricles,

respectively.

Central venous pressure and pulmonary

capillary wedge pressure both would have

been decreased because of the loss of

blood volume from the venous side of the

circulation.

Conclusion

CVP

• measured in the vena cava.

• Its value is related to the volume of blood in the veins and is approximately equal to the right atrial pressure.

PCWP

• measured by advancing a catheter through the pulmonary artery until it “wedges” in the artery’s smallest branch.

• At that point, the catheter senses pulmonary capillary pressure, which is nearly equal to the left atrial pressure.

References

http://www.uptodate.com/contents/pulmon

ary-artery-catheterization-interpretation-of-

tracings?source=search_result&search=Pu

lmonary+Artery+Wedge+Pressure+and+We

dging&selectedTitle=1~150#H14

Physiology: Cases and Problems

http://cvphysiology.com/Heart%20Failure/H

F008.htm

http://cvphysiology.com/Blood%20Pressur

e/BP020.htm

Be always enlightened!

Be always shiny!

Thank You