Right ventricle systolic pressure
From Echocardiography in ICU
Calculation of right ventricle systolic pressure (RVSP)
The right ventricle systolic pressure can be non-invasively measured by echocardiography.
It is obtained by the addition of the pressure gradient between the right ventricle and the right atrium, to the pressure in the right atrium.
Measurement of the pressure gradient between right ventricle (RV) and right atrium (RA)
The RV-RA pressure gradient is measured using the maximum velocity of the tricuspid regurgitation jet.
The maximum velocity measured as the peak regurgitation (systolic) is converted to pressure with Bernouilli law:
P = 4 V2
The maximum velocity of the tricuspid regurgitation can be measured from the parasternal short axis view or from the apical 4 chamber view. It is crucial to get a good envelope of the regurgitant jet, which means that the measurement is accurate.
Estimation of right atrium (RA) pressure
In patients with central venous lines, the RA pressure is easily measured: it is the central venous pressure (CVP).
In spontaneously breathing patients, the RA pressure is estimated from the measurement of the IVC size and collapsibility index:
(maximum diameter - minimum diameter) / maximum diameter.
Apical 4 chamber view, color Doppler on tricuspid valve. Visualization of trace tricuspid regurgitation
Apical 4 chamber view, CW-Doppler aligned on tricuspid regurgitation. Measurement of maximum velocity: 228 cm/sec, translated into maximum pressure gradient between RV and RA: 21mmHg.
Subcostal view, Mmode on IVC. Measurement of maximum and minimum diameter.
--> Collapsibility index = (25.4-23.7)/25.4 = 7 %--> RA pressure estimated at 20mmHg
Result: RVSP = 21 + 20 = 41 mmHg
Evaluation of size and dynamics of the inferior vena cava as an index of right-sided cardiac function. Moreno F.L., Hagan A.D., Holmen J.R., Pryor T.A., Strickland R.D., Castle C.H. Am J Cardiol (1984) 53 : pp 579-585