Measure TR Vmax.
Bernoulli equation transforms this into pressure gradient (gradient = 4 x V2). Machine will calculate this. This is the difference between RVSP and RAP.
Gradient = RVSP – RAP
RSVP = gradient + RAP
Assuming no PS then
PASP = RSVP
If PS then peak gradient across the valve will be the difference between RSVP and PASP so
PASP = RSVP – PS gradient
Normal PASP 15-30mmHg
Measure PR Vmax to get pressure gradient between PA and RV
Gradient = PADP – RVDP
PADP = gradient + RVDP
RVDP assumed to be the same as RAP so
PADP = gradient + RAP
Normal PADP 5-15mmHg
MPAP = ((PASP – PADP) / 3) + PADP
Normal MPAP is 15mmHg
Pulmonary hypertension when MPAP >25 (this will usually mean a PASP of >40)
Full BSE guideline for pulmonary hypertension (2010):
You won’t need to know the full pulmonary hypertension guideline in the table but I add it for completeness. It just goes to show how 30mins (fairly standartd for a depatmental study) is not long enough for a full echo unless the scan is normal.