Thread by @GUH_ICU_Anaesth

1/13 - GUH Echo tweetorial:

The tricuspid regurgitation jet velocity shown was used in a critical care patient to estimate RV systolic pressure:
Vol control – tvol 420ml PEEP 10cmH20
Cardiovascular: MAP 67mmHg on Noradrenaline 0.3mcg/kg/min

2/13
His TRVmax is high:
Why should I not diagnose this patient with pulmonary hypertension in my echo report?

2 are correct:
a. not steady state
b. Off axis cursor
c. Echo cannot diagnose it
d. Poor 2D view

3/13
Answer:
a, c and possibly b!

Lets start with what TR vmax means and how it is calculated

4/13
First we need a TR jet
Fortunately 65-85% of population have TR which makes things easier!

doi.org/10.1093/eurhea…

5/13
The blue TR jet is blood flowing away from the probe into the RA from the RV during systole

6/13
Cursor is lined up through the TR Jet (red arrow on left image)

Continuous wave doppler then measures the fastest red blood cell traveling along the arrow as the blood is ejected back into the right atrium

Maximum speed of the TR jet’ (on right) = 2.0m/s

7/13

Here is a real-life example of the cursor line on top and CWD waveform below

8/13

But how does this relate to the RV systolic pressure?

Enter this guy!

Unsurprising achievement - given his father helped develop Calculus, and his uncle discovered the mathematical constant e!

9/13
Here is his simplified equation:

∆P = Pressure
V= max velocity

So the trvmax of 2.0m/s = 4(2)2 = 16mmHg - EASY!

We then add the estimated RA pressure to get the RV systolic pressure

10/13

So why cant it be used to diagnose pulmonary hypertension?

Poor agreement between pressures estimated by echo compared to invasive (R heart catheterization) because:

11/13
So PHTN can only diagnosed by invasive measurement.

If TR Vmax cannot be used to diagnose pulmonary HTN what is it used for?

It is used as the first step in assessing the PROBABILITY of pulmonary hypertension with 3 defined categories in steady state
:

12/13
What about critical illness?

So many other factors impact pulmonary artery pressures in critical care

Critical illness = disrupted steady state so ‘probability of pulmonary hypertension’ should not be reported as it does not reflect steady state!

doi:10.1530/ERP-17-0071

13/13

So is estimation of RVSP useful in critical care?
YES!

We can
1.Identify high right sided pressures
2.Assess how the RV function has responded
3.Determine the cause
4.Adjust treatments accordingly

@AnaesTrainees @COAIrl @ICSIreland @AndyNeill @cianmcdermott @POCUSClub @NixLimerick @iceman_ex @GoughCJ @drjimday @pnolan99 @cmc47802929
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