Central Venous Pressure (CVP)

It is best estimated in the right internal jugular vein.

The maximum pulsation is observed when the trunk is inclined by less than 30 degrees.

In Patients with low CVP the trunk shouln't be inclined and the legs should be elevated.

In Patients with elevated CVP it may be necessary to elevate the trunk further to as much as 90 degrees.

Shinning a beam of light tangentially across the skin overlying the vein will expose the pulsations.

The top limit of the normal pulsation is 4cm above the sternal manubrium and corresponds to a CVP of 9cm of water (The center of the right atrium is 5cm below the sternal manubrium).

The CVP is subnormal when the neck veins are collapsed or in horizontal position.

JVP Waveform

'a' wave Positive presystolic, is the right atrial contraction.
Large 'a' waves = contraction against an increased resistance.
'a' wave is absent in atrial fibrillation.

'c' wave Ventricular isovolumetric systole, is positive, produced by bulging of the tricuspid valve into the right atrium and impact of the carotid artery.

'x' wave Descent, is the atrial relaxation and the downward displacement of the tricuspid valve.
Accentuated in constrictive pericarditis

'v' wave Positive, late systolic, results from the increasing amount of blood in the vena cava and right atrium.
Prominent in tricuspid regurgitation, if joined to the 'x' wave is called the 'ventricularization wave'.

'y' wave Descent, by the tricuspid opening and rapid outflow of blood.
Rapid and deep in tricuspid regurgitation.
Slow in obstruction to the right ventricular filling.