GUH-ICU&Anaesthesia Profile picture
Sep 14, 2021 14 tweets 7 min read Read on X
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

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More from @GUH_ICU_Anaesth

Apr 5, 2022
1/9
Tuesdays Tweetorial:
You are in cardiothoracic theatre doing a mitral valve replacement for severe MR

The anaesthetic consultant is doing a TOE and keeps saying 'PISA'

U know its in Italy but have no idea why he keeps saying it

What is PISA and why is it used?
2/9
PISA = Proximal Isovelocity Surface Area

Blood is ejected -> LA

It converges at the mitral regurgitant orifice it forming hemispheres -> different blood velocity in each hemisphere

RCCs that are equidistant from the orifice(in each hemisphere) travel at similar speed
3/9
Each hemisphere has a radius

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Remember:
Blue: RCCs moving Away from probe
Red: Towards the probe
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Quiz answer:

1.Sir Austin Bradford Hill

2.The Bradford Hill Criteria – 1965

Guidelines to help assess whether an observed association between an exposure and an outcome is likely to be causal.

#FOAMed #MedTwitter
1.TEMPORALITY:

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ANSWER:
A patient is admitted hypotensive with E. Coli sepsis.

The consultant asks for gentamycin and adds:

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Gentamycin, like other aminoglycosides exhibit concentration dependent killing

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Sep 28, 2021
1/8
You are asked to preoperatively assess a patient with known primary severe mitral regurgitation for an hip replacement

Which of the following new findings might result in you postponing surgery:

Dilated LV
Impaired LV sys fxn
Pulmonary HTN
New Afib Image
2/8

Answer:

Any/all of the above

If known severe MR – these are the NEW findings that should prompt you to speak to you friendly cardiologist colleagues Image
3/8

Valvular Heart Dx (VHD) AHA guidelines : Image
Read 9 tweets
Sep 14, 2021
GUH Images in Anaesthesia and ICU:

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
His TR Vmax suggests his RV systolic pressure is 51mmHg + RA pressure = HIGH

I am conscious that I should not diagnose this patient with pulmonary hypertension in my echo report:

Why?
Read 4 tweets
Jun 24, 2021
1/14
GUH - Echo Tweetorial - Aortic Stenosis:

How do they calculate:
1. Valve area
2. Mean AV gradient
3. Max AV gradient
2/14
Essential Principles:
1. The effective orifice area is always smaller than the anatomical orifice area
This effective orifice area is what is calculated
It is the key determinant of survival
2. Continuity equation
Conservation of mass
3/14
Continuity equation:
A2 X V2 = A1 x V1
(AVA) x (AV VTI) = (LVOT CSA) x (LVOT VTI)
AVA = [(LVOT CSA) x (LVOT VTI)]/ AV VTI
Read 15 tweets

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