Jugular Venous Pressure

Overview

The jugular venous pressure (JVP) provides a window into the pressure in the right atrium. When a patient is positioned appropriately, the internal jugular vein acts as a blood-filled manometer, providing an estimate of venous pressure close to the heart, which can be a helpful diagnostic tool. In right-sided heart failure, for example, the heart cannot efficiently pump venous blood into the pulmonary circulation and so it “backs up” in the venous system, increasing JVP. Similarly, if a patient has been given too much fluid, the JVP will also rise as the heart hasn’t got the pumping capacity to shift the increased venous load. By contrast, in a patient with hypotension (e.g. in sepsis or haemorrhage) the JVP will fall or may be near-impossible to estimate.

Measuring the JVP

JVP is generally measured in centimetres of blood (rather than millimetres of mercury), as the vertical distance from the sternal angle (or angle of Louis) to the furthest point in the neck where venous pressure (or pulsation) are noticeable (Figure 1). The patient should be sitting at an angle of 45° (as is standard for a cardiac examination); JVP is higher when supine and lower when sitting upright. These differences occur due to the relative position of the heart and the jugular veins. In the supine position, the heart and jugular veins are in line with each other. By contrast, when sitting the heart is below the jugular veins and so pressure builds up in them, causing distention. Estimating JVP is a clinical skill that requires some practice, and it is often difficult in young, healthy subjects.

Figure 1: Estimating JVP in a patient positioned in the usual 45° incline for a cardiac examination. The sternal angle is the palpable border between the manubrium (Man.) and the sternum, near to the point where the second costal cartilage meets the sternum. JVP is measured in centimetres above the sternal angle to the height where the internal jugular vein is clearly distended and/or pulsatile. JVP should be <4 cm in a healthy individual, but will be elevated when the heart cannot efficiently pump the venous return into the pulmonary circulation, such as in right-sided heart failure.