- The JVP gives an indication of the pressure in the right atrium – it is not a direct measure of volume. We can infer some information regarding the volume status based on the pressure, but must remember that there are other influences at play.
- The JVP should be measured with the patient at 45 degrees to the horizontal. In this position, the sternal angle is a vertical distance of ~5cm above the right atrium
- By convention the JVP is measured as the vertical height from the sternal angle, but many people add the additional 5cm when reporting it – the important thing is to state the reference point, i.e. RA or sternal angle
- A measurement of >3cm from sternal angle (>8cm from RA) is taken as evidence of high RA pressure in normal patients
- Points helpful in distinguishing the JVP from the carotid:Visible, not palpableComplex waveform – see here for more detailsVaries with respiration – usually decreases on inspirationFills from aboveIncreases with pressure on the abdomen – the hepatojugular reflux
Most importantly, there are many conditions that can result in an elevated JVP:
1. Right ventricular failure2. Tricuspid regurgitation or stenosis3. Pericardial effusion or constrictive pericarditis4. SVC obstruction – usually no waveform as transmission from the RA is blocked5. Volume overload
In the next post I’ll try to cover some of the previous studies that have the examined the use of the JVP in clinical assessments and trials. Hopefully this has provided some useful review for trainees in one of the common everyday clinical practices.