Central venous pressure (CVP) measures pressure in the vena cava, reflecting preload and right atrial pressure, and is crucial in assessing hemodynamic status in critical care. Normal CVP is between 8 to 12 mmHg and can be affected by factors such as cardiac function and blood volume; various causes for high or low CVP are identified. Additionally, CVP readings, along with their waveform patterns, provide insights into possible pathological conditions during procedures like cardiopulmonary bypass.

1. CENTRAL VENOUS
PRESSURE
By,
D. E. Nirman Kanna, BS. PT(AHS),
Perfusionist,
Cardio Thoracic and Vascular Surgery.

2. Central venous pressure is defined as the measure of pressure in the vena cava,
can be used as an estimation of preload and right atrial pressure.
 CVP is also defined as pressure of blood returning to or filling in the Right
atrium (Filling pressure).
Central venous pressure is often used as an assessment of hemodynamic
status, particularly in the intensive care unit.
 Pressure in IVC and SVC = Pressure in Right Atrium

3. The central venous pressure can be measured using a central venous
catheter advanced via the internal jugular vein and placed in the
superior vena cava near the right atrium.
A normal central venous pressure is between 8 to 12 mmHg.

4. SITES OF CENTRAL VENOUS CATHETER
PLACEMENT
• Superior vena cava
• Inferior vena cava
• Brachiocephalic veins
• Internal jugular veins
• Subclavian veins
• Iliac veins
• Common femoral veins

5. FACTORS AFFECTING CVP
Cardiac Function
Blood Volume
Capacitance of Blood vessel
Intrathoracic Pressure
Intraperitoneal Pressure

6. CAUSES FOR HIGH CVP
• Volume over load
• Right sided heart failure
• Cardiac Tamponade
• Constrictive Pericarditis
• Pulmonary Hypertension
• Tricuspid Stenosis and Regurgitation
• High stoke volume

7. INTRAOPERATIVE CVP

8. CAUSES FOR LOW CVP
• Hypovolemia
• Decreased venous return
• Excessive vasodilation
• Shock
• Arrhythmia
• During CPB

9. CVP WAVEFORM
Prominent positive a wave – Atrial contraction
Smaller, Positive c wave – Closure of tricuspid valve during
isovolumetric contraction
x descent – Atrial relaxation (Decreased in atrial pressure)
v wave- Filling of atrium
Negative Y descent –Ventricular filling (Tricuspid valve opens)

11. PATHOLOGICAL CONDITIONS
Irregular rhythm with loss of a wave = AF/ Afl
Cannon a wave = Complete heart block, VT, VF, TS, RVH ,PS,
Pulmonary Hypertension
Early/ Holosystolic cannon v wave = Significant TR
Large v wave = RVF
Prominent a and v waves = Pericardial constriction
Steep x and y descents = Decreased venous return
Tall a and v waves, Steep x and y descents = RV ischemia
Dominant x descent, attenuated y descent = Cardiac tamponade

13. INTERPRETATION

15. EFFECT OF CPB IN CVP
• CVP should be maintained 8 to 12 mmHg (minimum 6mmHg should be
maintained)before Cardiopulmonary bypass.
• During bypass, CVP will be equal to zero or in negative value
• During Steep Trendelenburg position, CVP will be decreased and during reverse
Trendelenburg position CVP will be increased.
• After weaning from CPB, CVP should be maintained in normal value,
• if CVP is high, Blood volume should be reduced and vasodilator drugs can be
administered.
• If CVP is low, Volume should be added and vasoconstrictive drugs can be administered.