NZRUS Flashcards
(54 cards)
How to calculate CO with echo
CO= LVOT area x VTI (using pulse wave doppler) x HR.
Ejection fraction calculation
EF(%) = SV/EDV x 100
SV:Stroke Volume
EDV:End Diastolic Volume
How to calculate EF using the fractional shortening method?
Normal to severe values
- Obtain PSLA view
- Select M-mode and place the cursor in the middle of the LV being careful to not include the mitral valve or papillary muscle.
- Freeze the M-mode image.
- Measure the LVEDD (max diameter) and LVESD (minimum diameter)
The ultrasound will give you an ejection fraction reading
In PSAX How can you calculate EF ?
Fractional Area Change
1. Obtain PSSAx view at the level of the papillary muscles.
2. At the end of diastole (maximum area), measure the area of the left ventricle to obtain the LVEDA.
- At the end of systole (minimum area), measure the area of the left ventricle to obtain the LVESA.
Insert values into the equation to obtain fractional area change.
Fractional Area Change values compared with EF?
Key limitation
Regional wall disfunction can alter measurement, and may over- or under-estimate global function.
How to calculate pulmonary artery systolic pressure using echo
- 4 chamber view
- Identify regurgitant jet over tricuspid using colour doppler
- CW doppler over the tricuspid regurg jet
- Calculate peak velocity (see image)
- Insert this into formular.
Pressure gradient = 4 x peak velocity (in m/s) - Add right atrial pressure (Approx 10mmHg
How to calculate right atrial pressure on echo
Measure IVC
Rocking vs fanning
“Rocking” is movement along the same direction of the beam long axis (think a pizza wheel moving).
“Fanning” is perpendicular to “rocking” where the beam angle is varied.
What is EPSS ? Used for
E-Point Septal Separation
- Used to estimate LVF
- EPSS is obtained by placing the M-mode tracer over the distal tip of the anterior leaflet of the mitral valve
EPSS > 7 mm is evidence of reduced LVEF. Of note, EPSS ≥ 13 mm correlates with severely decreased function, with an estimated LVEF of ≤ 35%.
L normal - R abnormal
What is a normal TASPE
> 1.6cm
Pressure velocity equation
change in pressure = 4 x Volume squared
What is continuous wave doppler?
Key uses?
Tells us the maximum velocity using 1 crystal to send impose and another to sense it
Used for EG measurement of TR/MR and can calculate the Max velocity
What is pulse wave doppler? Key uses
Uses 1 crystal to generate sound and receive it
Measuring VTI
How to measure Aortic stenosis
Measure LVOT in PLAX
Get apical 5 chamber and look at LVOT
-> Continuous wave doppler to measure max velocity
(image)
-> Then pulse wave doppler at valve to get velocity at valve
???
Locations for Lung US
- 2nd inter costal space mid clav line (Depth 10cm)
- 4/5th at anterior axillary line
- Mid axilary at costoprenic angle (use xiphisterum as guide)
- Posterolateral wall
(move posterior and fan anterior from position 3.)
When thinking about lung US detection of PTX what are you looking for
Lung sliding
A lines
Lung pulse
lung point
B-lines
What do the arrows show
Pleural line
A line
A line
Lung sliding and A lines - is there a PTX?
No - Lung sliding rules out PTX
Key DDx for lack of lung sliding
PTX
Single bronchi intubation
Apnea
penumonia / atelectasis
pleural scarring
What is the lung point
Whats shown here
Sub cut air
What is a false lung point
Area of insufflating sliding lung next to the cardiac structures which appears not to slide
The lung here parenchyma is decompressed between the heart and chest wall, yielding this funding.
What happens where A and B lines meet?
B lines ablate A lines
What do B lines represent? Where do they start?
Where do they go?
Do they move with lung sliding?
Interstitial thickening
Start at pleural line
Extend down the pleural field
Move with lung sliding
