Jugular venous pressure
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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.
Method
The patient is positioned under 30°, 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-torch can aid in discerning the jugular filling level.
The JVP is elevated in venous hypertension (e.g. right-sided heart failure) and paradoxically increased in Kussmaul's sign (see there).
The hepatojugular reflex is an expanded form of the JVP measurement. By pressing on the liver (hepato-) for 10-15 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.
Causes of an elevated JVP include:
- 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)
Jugular 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. There are two pulse waves in the JVP for each contraction-relaxation cycle by the heart. The first is the pressure wave after contraction of the atrium (termed a), and the second one is at the end of the filling of the atrium (termed v).
Interpretation of JVP findings can be even more difficult. Some classics are "cannon a-waves" (when the atrium contracts with the tricuspid valve still closed, e.g. due to arrhythmia).
External links
- Clinical Examination (http://www.clinicalexam.com/pda/c_ref_jvp.htm) page on JVP
- JVP may not be very useful (http://www.eboncall.org/CATs/2035.htm)