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Ultrasound in cardiac arrest
1. UTILITY OF ECHO
IN RESUS
Sinéad Taylor
Emergency Registrar
Sir Charles Gairdner Hospital
2. Outline
1. Refresher on basic echocardiography views
2. Use of echocardiography in arrest and peri-arrest situations
1. Where does it fit in the ALS/ACLS algorithm?
2. Re-evaluating PEA
3. Finding a cause
4. When do we terminate CPR?
19. What can an echo exam in
cardiac arrest achieve?
1. Identify the cause of the arrest
1. Treatable vs. non-treatable
2. Can rapidly change management
2. Assess PEA – is the patient truly pulseless?
3. Early detection of myocardial activity and ROSC
20. Where does echo fit in the ACLS
algorithm?
• Challenges of echo during cardiac arrest:
• Little space
• Little time
• Need to minimise interruptions to chest compressions/ACLS algorithm
• How do we overcome these obstacles?
• Pre-plan with ultrasound machine settings
• FEEL protocol (Focused Echocardiographic Evaluation in Life Support)
23. Pulse Check
• It’s one of the first things we’re taught when we learn basic CPR/first aid,
but how useful is it?
• Problems:
• Takes time (sometimes even longer than 5 seconds in healthy people)
• Accuracy can be as low as 78%
• Lower in arrest – 45% of healthcare providers can’t accurately detect a central pulse!
• No palpable pulse
• (Semi) Organised electrical activity on monitor
• Organised cardiac activity on echo Pseudo PEA
26. Hypovolaemia
Zafiropoulos A, Asrress K, Redwood S, Gillon S, Walker D. CRITICAL CARE ECHO ROUNDS: Echo in cardiac arrest. Echo Research and Practice. 2014;1(2):D15-D21.
30. Hypovolaemia - IVC
• To determine hypovolaemia, we look at 2 different IVC parameters:
• Size
• Collapsibility index
• This then gives us an idea of right atrial pressure/CVP.
• 𝐶𝐼 % =
(𝐼𝑉𝐶𝐷 max − 𝐼𝑉𝐶𝐷 min) 𝑥100
𝐼𝑉𝐶𝐷 𝑚𝑎𝑥
• Probable non-fluid responders:
• <50% collapsibility index
• >2cm IVC diameter
• Probable fluid responders (i.e., hypovolaemic)
• >50% collapsibility index
• <1cm IVC diameter
37. Tamponade
• Remember… tamponade is a clinical diagnosis.
• BUT if your patient is in cardiorespiratory arrest and you see the
following features, think of tamponade:
• RA collapse
• RV collapse
• IVC dilation
• Swinging heart
• Best views for tamponade:
• Subcostal – good for cardiac arrest, and you can assess IVC
• PLAX – is the fluid pericardial or a pleural effusion?
• Apical 4CV – look for RA and RV collapse
38. Tamponade
• How much fluid matters?
• It’s more about how quickly the fluid builds up, rather than the absolute
volume.
• Correlate what you’re looking at on echo with the patient’s clinical and
haemodynamic status.
42. Thrombosis - PE
• Sensitivity of echo for detecting PEs of any severity – approx 60%.
• However if your patient is unstable, an absence of echo evidence for RV
overload/dysfunction can exclude a PE(*)
• PE causing arrest
• 2/3 pulmonary vascular bed obstructed
• sudden increase in afterload dilation of right ventricle
• On echo:
• PLAX: Increase in RV diameter >30mm
• A4CV: increase in area of RV as compared to LV to 90%
• PSAX: D-shaped septum, paradoxical movement
(*) Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galie` N, Pruszczyk P, Bengel F, Brady AJ,
Ferreira D, Janssens U et al. 2008 Guidelines on the diagnosis and management of acute
pulmonary embolism: the Task Force for the diagnosis and management of acute pulmonary
embolism of the European Society of Cardiology (ESC). European Heart Journal 29 2276–2315.
43. PE Echo features
1. Echo dense thrombus – in RA or RV, IVC or pulmonary artery
2. RV strain
• Dilated RV
• Poorly contracting RV
• Reduced TAPSE
• Hyperdynamic LV
• RV free wall hypokinesis
3. RV overload
• D-shaped ventricle
• Dilated non-collapsing IVC
54. References
1. Carbonatto G. Point of Care Ultrasound Module 6: Echo. Lecture presented at; 2018; Sydney University Medical School.
2. Beraud A, Burkett T. Introduction to transthoracic echocardiography [Internet]. Koninklijke Philips; 2015 [cited 15 August 2018].
Available from: http://viewer.zmags.com/publication/3c9e5062#/3c9e5062/1
3. ANZCOR Adult Cardiorespiratory Arrest Flowchart [Internet]. Australian Resuscitation Council. 2016 [cited 15 August 2018].
Available from: https://resus.org.au/guidelines/flowcharts-3/
4. Zafiropoulos A, Asrress K, Redwood S, Gillon S, Walker D. CRITICAL CARE ECHO ROUNDS: Echo in cardiac arrest. Echo Research
and Practice. 2014;1(2):D15-D21.
5. Neskovic A, Hagendorff A, Lancellotti P, Guarracino F, Varga A, Cosyns B et al. Emergency echocardiography: the European
Association of Cardiovascular Imaging recommendations. European Heart Journal - Cardiovascular Imaging. 2012;14(1):1-11.
6. Breitkreutz R, Walcher F, Seeger F. Focused echocardiographic evaluation in resuscitation management: Concept of an
advanced life support–conformed algorithm. Critical Care Medicine. 2007;35(Suppl):S150-S161.
7. 7. Bystrzycki A. Ultrasound Village: ED Basic Echo - where does it fit? [Internet]. 2017 [cited 15 August 2018]. Available from:
https://www.youtube.com/watch?v=125wM8DrbNI
8. 8. Carbonatto G. Sepsis – Critical Care Sonography [Internet]. Criticalcare-sonography.com. 2016 [cited 15 August 2018].
Available from: https://www.criticalcare-sonography.com/2016/09/15/sepsis/
9. UOTW #36 Answer - Ultrasound of the Week [Internet]. Ultrasound of the Week. 2015 [cited 15 August 2018]. Available from:
https://www.ultrasoundoftheweek.com/uotw-36-answer/
10. 10. Thavanathan R, Hoang R. Look Deep Inside Yourself: Echo in Cardiac Arrest - EMOttawa [Internet]. EMOttawa. 2017 [cited 15
August 2018]. Available from: https://emottawablog.com/2017/09/look-deep-inside-yourself-echo-in-cardiac-arrest/
11. Tibballs, J., & Russell, P. (2017). Reliability of pulse palpation by healthcare personnel to diagnose paediatric cardiac arrest.
Resuscitation, 80(1), 61–64
12. Ochoa, F. J., Ramalle-Gómara, E., Carpintero, J. ., Garcı́a, A., & Saralegui, I. (1998). Competence of health professionals to check
the carotid pulse. Resuscitation, 37(3), 173–175
13. 11. Long B, Alerhand S, Maliel K, Koyfman A. Echocardiography in cardiac arrest: An emergency medicine review. American
Journal of Emergency Medicine. 2018;36:488-493.
14. 12. Blyth L, Atkinson P, Gadd K, Lang E. Bedside Focused Echocardiography as Predictor of Survival in Cardiac Arrest Patients: A
Systematic Review. Academic Emergency Medicine. 2012;19(10):1119-1126.
Editor's Notes
I’m sure a lot of you already know what these are, but for those of you who are a bit rusty here’s a brief refresher. I’m not going to spend a lot of time on this as echo is a huge topic, and I’m by no means an expert by any stretch of the imagination.
Start with the probe at 10 o’clock, towards the patient’s right shoulder. Ideally the patient will be in a steep left lateral decubitus.
Start with the probe high up on the chest, then come down rib space by rib space until you see the view that you want
It’s here in the parasternal long axis that you do most of your calculations.
By using M-mode you can measure the left ventricle end diastolic diameter, left ventricular end systolic diameter, and the machine can then calculate the fractional shortening and ejection fraction from these.
We can then use the ejection fraction to assess myocardial function.
You can also look at the aortic root and ascending aorta.
BUT this starts to get into some pretty advanced echo stuff, which is a bit beyond me. So here’s a very quick way to “eyeball” LV contraction and RV size.
To get from long axis to parasternal short axis is really easy. When you’re in long axis get the mitral valve in the middle of the screen, then rotate 90 degrees to get to the short axis. You can then use really small movements of your wrist and fan up and down the heart, to look at all these different levels:
Mitral valve
Mid ventricular level (through the papillary muscles)
Apex
Aortic root level
Pulmonary bifurcation
Aortic valve level
Right atrium
Tricuspid valve
Right ventricular outflow tract (RVOT)
Pulmonary valve
Pulmonary artery
Aortic valve
Left atrium
There are lots of different apical views like 2 chamber, 3 chamber, but today we’re just going to focus on 4 chamber and 5 chamber views.
You can achieve this by:
Rolling the patient into a left posterior oblique position
Placing the probe over the apical pulse (5th intercostal space, mid-axillary line)
Index marker between 2 and 3 o’clock
Tilt the probe anteriorly to transect all chambers
To get to this from the apical 4 chamber view, just tilt the probe slightly anteriorly until you see the aortic valve. This view is useful for assessing aortic motion and regurg, but beware if you’re using this view to assess the chambers themselves as they’ll be foreshortened.
You can use the subcostal window to look both a long and short axis view, and it can sometimes be the only window that you’ll get. This is a really important view to master for echo in a cardiac arrest, as if the lucas is on you won’t be able to place your probe in the spots needed for the other views.
To achieve this view, you look at the heart using the liver as a sonographic window.
You can also use the subcostal view to look at the IVC, and it’s here that you measure the IVC from inner wall to inner wall, making sure that you’re measuring 0.5-3cm from the right atrium. You can use the middle hepatic vein as a landmark and measure just distal to it, in inspiration and expiration.
It can be a bit of a fight for space in a resus scenario, especially if the patient has arrested!
You’ve got:
People doing CPR (or the lucas on),
nurses trying to cut the patient’s clothes off and attach monitoring
A stressed intern trying to get access
Another doctor trying to examine the patient
And then someone comes in with the massive ultrasound machine, trying not to run over people’s toes, and throws a probe on as well. You only have a few seconds in between compressions to get your views.
So given we’re so short on space AND time, the patient’s already arrested, and that we’re following a very clear ACLS guideline, how much can an echo really add?
The FEEL protocol was developed to help physicians fit echo into a cardiac arrest algorithm.
In an arrest scenario, the subcostal view might be the best, especially if the lucas is on.
Alternatively, a very experienced practitioner might be able to het parasternal or apical view whilst compressions are ongoing.
Here you’ve got a normal heart, and a hypovolaemic heart.
In a normal heart, the left ventricular cavity narrows by half in each cardiac cycle.
But as you can see in the second image, the ventricular walls are kissing – so posterior wall of LV and interventricular septum come together in systole, and the left ventricle at the end of systole is obliterated.
There are some pitfalls to be noted – particularly inotropic support, severe valvular regurg, or left ventricular hypertrophy.
The other thing to note that this method of assessment requires a beating heart, which limits its applicability in a cardiac arrest scenario.
There are also static measurements such as LV end diastolic area or diameter and ejection fraction that can be taken, but they need a bit of time to measure, and if you don’t get the image just right then they can also be very prone to error. So if you’re like me and you’re not an expert in echo, it’s best to avoid this in an emergency situation.
PSAX at level of papillary muscle with kissing walls and cavity obliteration due to hypovolaemia
Apical 4 chamber view – small LV cavity
Tamponade is a clinical diagnosis that you need to make based on BP, HR and respiratory status.
TAPSE (tricuspid annular plane systolic excursion) – measures right ventricular function. Again, this is advanced and difficult to obtain during CPR, unless you’re doing transoesophageal echo.
Again, a lot of these echo features are a bit more advanced.