Correlation between clinical assessment of jugular venous pressure and direct measurement of central venous pressure has an overall accuracy of 56% (Cook DJ).
Best estimated by identifying the right internal jugular venous pulse when the patients is in the lying position at 30-45 degrees or sitting upright.
When jugular venous pressure is greater than 20 cm the venous pulse may not be visualized, as it would be above the angle of the jaw.
When elevated suggests elevated right atrial pressure and right heart failure.
The jugular venous pressure, referred to as jugular venous pulse, is the indirectly observed pressure over the venous system via visualization of the internal jugular vein.
It is useful in the differentiation of different forms of heart and lung disease.
Waves include three upward deflections and two downward deflections.
The upward deflections include: the “a” standing for atrial contraction, “c” for ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole and “v” deflection reflecting atrial venous filling.
The downward deflections of the wave are the “x” when the atrium relaxes and the tricuspid valve moves downward) and the “y” descent with the filling of ventricle after tricuspid opening.
Observing the veins of the neck the patient is positioned under 45°, and the filling level of the jugular vein is determined.
The internal jugular vein is visualized to look for the pulsation.
The filling level of the jugular vein should be less than 3 centimetres vertical height above the sternal angle as observed along the surface of the sternocleidomastoid muscle.
Pulses in the JVP are signs of the state of the right atrium.
Differentiation from the carotid pulse is necessary: the JVP beats twice in quick succession in the cardiac cycle.
There are two waves in the JVP for each contraction-relaxation cycle by the heart.
The first beat represents that atrial contraction termed a.
The second beat represents venous filling of the right atrium against a closed tricuspid valve, termed v, and not the commonly mistaken ventricular contraction.
The carotid artery only has one beat in the cardiac cycle.
The JVP cannot be palpated, so that If one feels a pulse in the neck, it is generally the common carotid artery.
The JVP can be stopped by occluding the internal jugular vein by lightly pressing against the neck, and it will fill from above.
JVP varies with head-up-tilt.
JVP varies with the angle of neck.
When standing the JVP appears to be lower on the neck, or it may not be seen at all, because it is below the sternal angle.
The carotid pulse’s location does not vary with head up tilt.
JVP usually decreases with deep inspiration, and is a consequence of the Frank–Starling mechanism as inspiration decreases the thoracic pressure and increases blood movement into the heart by increasing venous return, which then moves into the pulmonary circulation.
The jugular venous pulsation has a biphasic waveform.
The ” a ” wave corresponds to right atrial contraction and ends synchronously with the carotid artery pulse.
The peak of the ‘a’ wave demarcates the end of atrial systole.
The ” c ” wave corresponds to right ventricular contraction causing the tricuspid valve to bulge towards the right atrium.
The ” x ” descent follows the ‘a’ wave and corresponds to atrial relaxation and rapid atrial filling due to low pressure.
The ” x’ ” descent follows the ‘c’ wave and occurs as a result of the right ventricle pulling the tricuspid valve downward during ventricular systole.
The x’ descent can be used as a measure of right ventricle contractility.
The ” v ” wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return – this occurs during and following the carotid pulse.
The ” y ” descent corresponds to the rapid emptying of the atrium into the ventricle following the opening of the tricuspid valve.
The waveform that is seen immediately after the arterial pulsation is felt is the ‘v wave’ of the JVP.
Abdominojugular test or hepatojugular reflux: compression of the liver resulted in “reflux” of blood out the hepatic sinusoids into the great veins thereby elevating right atrial pressure and visualized as jugular venous distention.
The abdominojugular test was shown to correlate best with the pulmonary arterial wedge pressure.
Patients with a positive response had lower left ventricular ejection fractions and stroke volumes, higher left ventricular filling pressure, higher mean pulmonary arterial, and higher right atrial pressures.
The abdominojugular test correlates with the pulmonary arterial wedge pressure, and therefore, is probably a reflection of an increased central blood volume.
A positive abdominojugular test suggests a pulmonary artery wedge pressure of 15 mm Hg or greater.
Cannon a-waves, or increased amplitude ‘a’ waves, are associated with AV dissociation, that is, third degree heart block, when the atrium is contracting against a closed tricuspid valve, or even in ventricular tachycardia.
C-V waves can be a sign of tricuspid regurgitation.
The absence of ‘a’ waves may be seen in atrial fibrillation.
An elevated JVP is the classic sign of venous hypertension reflecting right-sided heart failure.
The paradoxical increase of the JVP with inspiration is referred to as the Kussmaul sign, and indicates impaired filling of the right ventricle, with a differential diagnosis of Kussmaul’s sign includes constrictive pericarditis, restrictive cardiomyopathy, pericardial effusion, and severe right-sided heart failure.
Jugular venous pressure can assess the central venous pressure in the absence of invasive measurements.