The TTE questions are increasing in their number and the expected level of detail. Somehow, the college has focused their echocardiographic interest on aortic stenosis. Of the past paper questions which concern TTE data interpretation, three are about AS. Question 17.1 and Question 17.2 from the second paper of 2014 are perhaps more relevant, as the discussion revolves around the identification of peri-arrest findings on TTE images. Assessment of valve dysfunction (eg. severity staging of aortic stenosis) is covered in greater detail in the Cardiothoracic Intensive Care section, and no further time will be spent here on the TTE assessment of valvular disease.
Past SAQs have included:
Question 8 from the second paper of 2022 asked for a comparison of a dodgy bedside echo by an intensivist with a formal echo assessment by a trained sonographer. An excellent paper by Andrus & Dean (2013) has most of the answers. This probably would have benefited from a tabular format:
|Focused bedside TTE||Formal TTE|
Investigations for murmurs
Investigation of syncope and arrhythmias
LV systolic function
RV dilatation (PE)
Cardiac activity during cardiac arrest
Myocardial ischemia (i.e. regional wall motion abnormalities)
RV systolic function
Diastolic function assessment
Specific, not sensitive
Usually done on smaller machines with poor resolution.
Windows and probe orientation are not always standardised.
Staff performing this assessment may be variably trained, increasing error.
Trained staff may be unfamiliar with the limitations of the technique, and may underestimate its accuracy.
Poor windows or views may result in inaccurate chamber size comparisons, leading to the wrong diagnosis.
Defined scope of practice, limited to specific views (i.e. not a diagnostic investigation)
Requires a skilled sonographer or TTE-trained accredited ICU staff.
Time-consuming; may not be suitable for rapidly making decisions
More difficult to perform serial assessments within a short timeframe.
Otherwise static: a snapshot assessment in a dynamically changing ICU scenario.
For many ICU patients, all classic views may not be possible.
Not cost-effective (usually requires dedicated staff)
|Limitations of both||
Question 17.1 from the second paper of 2014 asked about the utility of TTE in cardiac arrest, and particularly which the most appropriate view is. The answer to the latter is inevitably the subcostal view; it would be insane to interfere with CPR by trying to shove the probe on the chest. The former is best answered in a "critically evaluate" pattern, even though the college question itself did not demand such depth.
An ideal resource for answering such a question would have to be this 2012 article by Price et al. In addition to this earlier article, Berg (2018) is worth reading for the pros and cons, as the paper comes from the more modern era during which the enthusiasm for intra-arrest ultrasound has somewhat cooled.
Question 17.2 from the second paper of 2014 asked for the candidates to identify characteristic abnormalities seen on the TTE during a cardiac arrest. A picture is worth a thousand words:
In answer to Question 16 from the second paper of 2020, the single best view to assess the pericardial tamponade is through a subxiphoid view. At least that's what it sounds like the examiners wanted ("which view", they asked, implying one view). Most echosavvy people will agree that to fully appreciate the effusion and its haemodynamic effects you would need to image it in at least a couple of different planes. Loculated effusions could have disproportionate regional effects, and limited views can give rise to the misidentification of all kinds of sonolucent friendlies (eg. ascites, pericardial cysts). If there is an effusion, it is also very easy to overestimate its size. D'Cruz & Constantine (1993) detail these pitfalls in their paper, for the interested reader with infinite time.
The subxiphoid view, however, has a couple of benefits:
Echocardiographic features of cardiac tamponade are listed elsewhere.
Price, Susanna, Shahana Uddin, and Tom Quinn. "Echocardiography in cardiac arrest." Current opinion in critical care 16.3 (2010): 211-215.
Zafiropoulos, Andreas, et al. "Critical Care Echo Rounds: Echo in cardiac arrest." Echo Research and Practice 1.2 (2014): D15-D21.
Flato, Uri Adrian Prync, et al. "Echocardiography for prognostication during the resuscitation of intensive care unit patients with non-shockable rhythm cardiac arrest." Resuscitation 92 (2015): 1-6.
Anderson, Kenton L., et al. "Ultrasound Guided Chest Compressions Over the Left Ventricle During Cardiopulmonary Resuscitation Increases Coronary Perfusion Pressure and Return of Spontaneous Circulation in a Swine Model of Traumatic Cardiac Arrest." Circulation 130.Suppl 2 (2014): A15853-A15853.
Memtsoudis, Stavros G., et al. "The usefulness of transesophageal echocardiography during intraoperative cardiac arrest in noncardiac surgery." Anesthesia & Analgesia 102.6 (2006): 1653-1657.
Blyth, Lacey, et al. "Bedside focused echocardiography as predictor of survival in cardiac arrest patients: a systematic review." Academic Emergency Medicine 19.10 (2012): 1119-1126.
Labovitz, Arthur J., et al. "Focused cardiac ultrasound in the emergent setting: a consensus statement of the American Society of Echocardiography and American College of Emergency Physicians." Journal of the American Society of Echocardiography 23.12 (2010):
in't Veld, Maite A. Huis, et al. "Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions." Resuscitation 119 (2017): 95-98.
Clattenburg, Eben J., et al. "Point-of-care ultrasound use in patients with cardiac arrest is associated prolonged cardiopulmonary resuscitation pauses: a prospective cohort study." Resuscitation 122 (2018): 65-68.
Michels, Guido, and Roman Pfister. "Point-of-care ultrasound use in patients with cardiac arrest: More harmful than useful?." Resuscitation 124 (2018): e21.
Atkinson, Paul R., et al. "Does Point-of-care Ultrasound Use Impact Resuscitation Length, Rates of Intervention, and Clinical Outcomes During Cardiac Arrest? A Study from the Sonography in Hypotension and Cardiac Arrest in the Emergency Department (SHoC-ED) Investigators." Cureus 11.4 (2019).
D'CRUZ, IVAN A., and ARTHUR CONSTANTINE. "Problems and pitfalls in the echocardiographic assessment of pericardial effusion." Echocardiography 10.2 (1993): 151-166
.Berg, Katherine M. "Finding a window: Timing of cardiac ultrasound acquisition during cardiac arrest." Resuscitation 124 (2018): A11-A12.
Link, Mark S., et al. "Part 7: adult advanced cardiovascular life support: 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care." Circulation 132.18_suppl_2 (2015): S444-S464.
Luis, Sushil A., Jonathan Chan, and Patricia A. Pellikka. "Echocardiographic assessment of left ventricular systolic function: an overview of contemporary techniques, including speckle-tracking echocardiography." Mayo Clinic Proceedings. Vol. 94. No. 1. Elsevier, 2019.
Mitchell, Carol, et al. "Guidelines for performing a comprehensive transthoracic echocardiographic examination in adults: recommendations from the American Society of Echocardiography." Journal of the American Society of Echocardiography 32.1 (2019): 1-64.
Andrus, Phillip, and Anthony Dean. "Focused cardiac ultrasound." Global Heart 8.4 (2013): 299-303.
Johnson, Benjamin K., et al. "Internal medicine point‐of‐care ultrasound assessment of left ventricular function correlates with formal echocardiography." Journal of Clinical Ultrasound 44.2 (2016): 92-99.