JVP and assessment of intravascular volume
An important part of the physical examination that requires a lot of experience and practice. Jugular venous pressure (JVP) gives you a direct indication of the filling pressure of the right side of the heart, central venous pressure, CVP. It is determined by a combination of filling (intravascular volume), power of the heart, and resistance to flow out of the right side of the heart (pulmonary artery pressure). And possibly venous tone, see below. It is an important clinical sign when combined with other evidence of what is going on in the lungs, cardiovascular system, and knowledge of history and drugs. It requires a lot of practice and even an expert can't get it right all the time, but it is risk-free, low-tech, and you can repeat it as often as you like.
A couple of simple things:
|A really nice simple description (YouTube) from Dr Thomas Heywood, Scripps - but we don't usually add 5cm to report it (or use a ruler), we usually estimate and say 'above the sternal angle'. Or watch it on YouTube - M N C||Equally good: watch from 1.20 mins. Measuring from the sternal angle is probably a bit less accurate of course, but then the mid-axilla isn't always accurately at the level of the right atrium either. - M N C|
Key: resources good for: M medical students; N renal nurses; C primary care, clinical officers; P postgraduate medicine
Some really excellent advanced films are linked from further down the page.
- Volume - it is raised by sudden transfusion of blood to a healthy individual, or by excess intravascular salt and water as found in renal failure or in heart failure
- Pulmonary artery pressure - so it is raised in pulmonary embolism, left ventricular failure which raises pulmonary artery pressure, pulmonary hypertension (caused by lung disease or as a primary condition)
- Pumping strength of the heart - so it is raised in congestive biventricular or right-sided heart failure; and rarely but importantly in pericardial disease, including pericardial tamponade from effusion or haemorrhage.
- Abdominal pressure - It may be a bit higher than normal if you have raised intra-abdominal pressure, including pregnancy
- Occluded veins - Veins will be 'stuck up' if neck veins are occluded
If you can't see a JVP despite lying someone completely flat, or if you can only start to see it then, it implies inadequate intravascular volume. However it can sometimes be difficult to see when it is so high that you can't see the top of it, so remember to look out for that too.
- Turning the neck too far so that neck muscles are in tension, hiding the pulsation. Often best to look while the patient is talking to you first.
- Missing a very high pressure (as above). Sitting them right up can help.
- In fat or breathless patients, JVP is just more difficult
Magic hospital beds - with electric beds you can vary the angle at which your subject is sitting from flat to 90°, up and down till you see the JVP appear. Amusing as well as useful.
Other ways to estimate CVP, or correlates of it
- Measure it directly via a central venous catheter. Invasive, some risks, not always as reliable as you'd like
- Ultrasound collapse pressure enables you to see the height at which the internal jugular vein collapses even in an obese patient.
- IVC diameter - use of ultrasound to show the diameter of the IVC and whether it collapses on inspiration. Qualitative rather than quantitative as there is variation in normal diameter.
- Echocardiography can give some impression of pulmonary artery pressure, right ventricular contraction and filling, but qualitative rather than quantitative and uses a number of assumptions.
A complication: is JVP the same as CVP?
Interestingly, no it's not.
- The correlation of JVP with measured CVP, however you measure it, isn't at all that good.
- JVP is also consistently a bit lower than catheter-measured CVP
These differences are not caused by observer error, because JVP measured by ultrasound collapse pressure agrees closely with clinically assessed JVP. (e.g. see Chest 2011 139:95-100). It is likely that venous tone, which varies in different physiological and pathological states of course, is one of the things that complicates the picture.
Nevertheless, distinguishing high venous pressure versus low, and seeing changes in a patient whose condition shouldn't have changed much, are valuable signs.
Good further info about JVP from the renalfellow blog
The Wellcome film by Paul Wood from 1957 is an absolute classic - beautifully filmed, showing outstanding, severe examples of little-modified rheumatic and other heart disease of a type that you will rarely find in developed nations now - M P (but mostly P)
|[[YouTube?id=OuG-Ru7fryE&width=300&height=225]]||This is the first film of 4 short parts. Or watch them all linked together in a new window - P (postgraduate)|
Have you seen our tutorial on fluid compartments and IV fluid prescription? It is part of our Edren Textbook.
Coming soon - home experiments in JVPology. You should try some too.