Jugular venous pressure

From Wikipedia, the free encyclopedia

You have new messages (last change).

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 in 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. Certain wave form abnormalities, include "Cannon a-waves", which result when the atrium contracts against a closed tricuspid valve, due to complete heart block (3rd degree heart block), or even in ventricular tachycardia. Another abnormality, "c-v waves", can be a sign of tricuspid regurgitation.

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, and indicates impaired filling of the right ventricle. The differential diagnosis of Kussmaul's sign includes constrictive pericarditis, restrictive cardiomyopathy, pericardial effusion, and severe right-sided heart failure.

Contents

[edit] Causes of an elevated JVP

[edit] Hepatojugular reflux

Main article: Abdominojugular test

Hepatojugular reflux, sometimes incorrectly referenced as a "reflex",[1] 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, and distention should appear more pronounced. However, a slow decrease of the JVP after checking for hepatojugular reflux can indicate right ventricular failure.

[edit] Method

A classical method for quantifying the JVP was described by Borst & Molhuysen in 1952.[2] 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.

[edit] 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. Remember, tangential light is critical.

[edit] 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 reflux (AJR) (also hepatojugular reflux) - 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.

[edit] References

  1. ^ Aronson J (1999). "Hepatojugular reflux". BMJ 318 (7192): 1172. PMID 10221938.  Free Full Text.
  2. ^ Borst J, Molhuysen J (1952). "Exact determination of the central venous pressure by a simple clinical method.". Lancet 2 (7): 304-9. PMID 14955978. 

[edit] External links

v • d • e
Physical examination

Neurology | Mental state | Eyes | Jugular venous pressure | Respiratory system | Precordium | Abdomen | Peripheral vascular | Hip | Knee

Retrieved from "http://en.wikipedia.org../../../j/u/g/Jugular_venous_pressure.html"