Jugular venous pressure

The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system. It can be useful is the differentiation of different forms of heart and lung disease.

The interpretation of JVP findings can be challenging and is becoming a lost art, as much of the subtle information previously obtained by careful observation of the JVP can now be gained easily with echocardiography and/or EKG. "Cannon a-waves", which result when the atrium contracts with the tricuspid valve still closed, (due to an arrhythmia) is one such example.

An elevated JVP is the classic sign of venous hypertension (e.g. right-sided heart failure). The paradoxical increase of the JVP with inspiration (instead of the expected decrease) is referred to as the Kussmaul sign.

Causes of an elevated JVP

Bradycardia
Constrictive pericarditis
Fluid overload (intravenous fluid)
Right heart failure
Hyperdynamic circulation (e.g. in extreme anemia)
Obstruction of the superior vena cava
Pericardial effusion
Tricuspid valve disease (stenosis or regurgitation)

Hepatojugular reflex

The hepatojugular reflex is an expanded form of the JVP measurement. By pressing on the liver (hepato-) for 15-30 seconds, venous blood is advanced into the circulation. The JVP increases in a normal person. However, a slow decrease of the JVP after checking the hepatojugular reflex can indicate right ventricular failure.

Method

A classical method for quantifying the JVP was described by Borst & Molhuysen in 1952. It has since been modified in various ways.

The patient is positioned under 45°, and the filling level of the jugular vein determined. In healthy people, it is maximum several (3-4) centimetres above the sternal angle. Some doctors employ a venous arc, an instrument to measure the JVP more accurately. A pen-light can aid in discerning the jugular filling level.

Visualization of the JVP

The JVP is easiest to observe if one looks along the surface of the sternocleidomastoid muscle, as it is easier to appreciate the movement relative the neck when looking from the side (as opposed to looking at the surface at a 90 degree angle). Like judging the movement of an automobile from a distance, it is easier to see the movement of an automobile when it is crossing one's path at 90 degrees (i.e. moving left to right or right to left), as opposed to coming toward one.

Differentiation of the JVP from the carotid pulse

Pulses in the JVP are rather hard to observe, but trained cardiologists do try to discern these as signs of the state of the right atrium.

The JVP and carotid pulse can be differentiated several ways:

multiphasic - the JVP "beats" twice (in quick succession) in the cardiac cycle. In other words, there are two waves in the JVP for each contraction-relaxation cycle by the heart. The first beat represents that atrial contraction (termed a) and second beat the ventricular contraction (termed v). The carotid artery only has one beat in the cardiac cycle.
non-palpable - the JVP cannot be palpated. If one feels a pulse in the neck, it is generally the common carotid artery.
occludable - the JVP can be stopped by occluding the internal jugular vein by lightly pressing against the neck.
varies with head-up-tilt (HUT) - the JVP varies with the angle of neck. If a person is standing their JVP appears to be lower on the neck (or may not be seen at all because it below the sternal angle). The carotid pulse's location does not vary with HUT.
varies with respiration - the JVP usually descreases with deep inspiration. Physiologically, this is a consequence of the Frank-Starling mechanism as inspiration decreases the thoracic pressure and increases blood movement into the heart (venous return), which a healthy heart moves into the pulmonary circulation.
abdominal jugular reflex (AJR) (also hepatojugular reflex) - the JVP changes with abdominal pressure. If the JVP is elevated 4 cm, it usually returns to its baseline level within 10 seconds. If the JVP remains elevated for a longer period of time it suggests heart failure.

Reference

Borst JG, Molhuysen JA. Exact determination of the central venous pressure by a simple clinical method. Lancet 1952;2(7):304-9. PMID 14955978.

External links

Clinical Examination page on JVP
JVP (GPnotebook)
JVP - may not be very useful

Cardiology | Physical examination