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Just the facts: point-of-care ultrasound in cardiac arrest

Clinical scenario

A 58-year-old man presents to the emergency department for sudden-onset chest pain and dyspnea. Shortly after being brought to a room, he has a cardiac arrest. Chest compressions are initiated. You wonder whether ultrasound could assist with managing this patient in cardiac arrest.

Key clinical questions

What is the best approach to using ultrasound in cardiac arrest?

Ultrasound is a valuable adjunct to the management of cardiac arrest among properly trained clinicians (as defined by the individual society but typically consisting of a training course with completion of > 25 reviewed ultrasound examinations in a given application). The use of ultrasound during cardiac arrest can be split into core (subxiphoid and parasternal cardiac views), supplementary (lung and inferior vena cava views), and additional (pulse check, endotracheal tube placement, deep venous thrombosis [DVT], aorta and FAST views) [1]. While either a subxiphoid or parasternal view can be used, one recent study of experienced ultrasound users found that the parasternal long view demonstrated significantly better cardiac image quality with a shorter time to image acquisition compared with subxiphoid [2]. When performing a cardiac ultrasound, it is critical to minimize delays in chest compressions. Strategies to reduce delays include: placing the probe in position prior to the pulse check (to help landmark the view of the heart and reduce image acquisition time); recording the image prospectively and analyzing it after resumption of compressions; using structured protocols to assess one aspect (e.g., cardiac tamponade, right ventricular dilation) per pulse check; having a separate clinician than the code team leader perform the ultrasound when possible; and having a dedicated timer to limit image acquisition time. Doppler ultrasound can also be useful to detect arterial flow as an adjunct to manual arterial pulse checks.

What diagnoses can be assessed with ultrasound during cardiac arrest?

There are several diagnoses that can be identified using focused ultrasound during a cardiac arrest. As part of the cardiac assessment, clinicians can evaluate for pericardial effusion with cardiac tamponade, right ventricular dysfunction suggestive of pulmonary embolism, presence of a clot in transit (i.e., visible thrombus in the heart), and ventricular fibrillation [1]. The lungs could be evaluated for pneumothorax, hemothorax, or massive pleural effusion. Endotracheal tube placement can be assessed, which can be particularly valuable as quantitative capnography is less accurate for confirmation in patients without return of spontaneous circulation [3, 4]. Finally, additional examinations of the lower extremity veins (e.g., DVT), aorta (e.g., aortic aneurysm or dissection), or FAST examination (e.g., hemoperitoneum from trauma, ruptured ectopic pregnancy) can be performed based upon the clinical scenario.

How reliable is right ventricular dilation for suspected pulmonary embolism in cardiac arrest?

While focused cardiac ultrasound can be used to identify the presence of right ventricular dilation in the setting of shock secondary to pulmonary embolism, current evidence suggests it may be less reliable among patients in cardiac arrest. Both animal and human studies have demonstrated that right ventricular dilation is frequently seen in patients with cardiac arrest from an array of causes, including arrhythmias, respiratory failure, and circulatory failure in the absence of pulmonary embolism [5]. Right ventricular dilation appears to be progressive as cardiac arrest continues, and should not be used in isolation to diagnose pulmonary embolism in the later stages of cardiac arrest. However, right ventricular dilation may be more suggestive of pulmonary embolism if performed early in the cardiac arrest with a consistent history (e.g., sudden onset chest pain or dyspnea) or in the presence of a DVT. As right ventricular dilation can also be seen with chronic pulmonary hypertension, clinicians should also evaluate for right ventricular free wall thickness. A thin wall (diameter < 5 mm) is suggestive of an acute etiology [6].

What is the role of ultrasound in suspected cardiac tamponade?

Ultrasound can be valuable for the diagnosis and management of cardiac tamponade. Cardiac tamponade should be considered in the context of any patient with a pericardial effusion in cardiac arrest. Ultrasound findings suggestive of cardiac tamponade include a pericardial effusion in the context of diastolic right ventricular collapse (high specificity), systolic right atrial collapse (high sensitivity), or a plethoric inferior vena cava (high sensitivity) [7]. It is important to note that cardiac tamponade is primarily dependent upon the rate of fluid accumulation, rather than the total volume, and can occur with relatively smaller effusions if acute [7]. Once diagnosed, ultrasound is the preferred method for guiding drainage and has been demonstrated to be highly successful with a low rate of complications [8].

How accurate is cardiac ultrasound for predicting post-arrest outcomes?

Despite widespread use for intra-arrest prognostication, there is a lack of high-quality evidence supporting the independent use of cardiac ultrasound for this purpose. Although cardiac activity seen on ultrasound is associated with improved odds for return of spontaneous circulation and survival in non-traumatic, non-shockable cardiac arrest, and may provide valuable information in the management of non-traumatic pulseless electrical activity (PEA) or asystole, ultrasound should not be viewed as the sole predictor in determining outcome. Patients with traumatic cardiac arrest without cardiac activity on ultrasound have a high likelihood of death and negligible chance of survival [9]. Importantly, cardiac activity should involve visualized motion of the cardiac walls (e.g., isolated valve movements would not qualify as cardiac activity). To improve the reliability of ultrasound as a prognostic tool in cardiac arrest, future research should focus on standardizing the definition of cardiac motion, strengthening study quality, and assessing transesophageal versus transthoracic echocardiography during CPR. Currently, a Bayesian approach is reasonable, including ultrasound as one tool in the prognostic process.

Case resolution

You perform a cardiac ultrasound during the first pulse check, being conscious to not delay resumption of compressions. You identify a dilated right ventricle with a thin right ventricular free wall and no pericardial effusion. Based upon the preceding symptoms and POCUS findings, you initiate intravenous thrombolysis. The patient achieves return of spontaneous circulation and is transferred to the intensive care unit.

References

  1. Atkinson P, Bowra J, Milne J, et al. International federation for emergency medicine consensus statement: sonography in hypotension and cardiac arrest (SHoC): an international consensus on the use of point of care ultrasound for undifferentiated hypotension and during cardiac arrest. CJEM. 2017;19(6):459–70.

    Article  Google Scholar 

  2. Gaspari RJ, Gleeson T, Alerhand S, et al. A multicenter, prospective study comparing subxiphoid and parasternal views during brief echocardiography: Effect on image quality, acquisition time, and visualized anatomy [published online ahead of print, 2022 Jan 19]. J Emerg Med. 2022;S0736–4679(21)00769–1. https://doi.org/10.1016/j.jemermed.2021.10.032

  3. Gottlieb M, Holladay D, Burns KM, Nakitende D, Bailitz J. Ultrasound for airway management: an evidence-based review for the emergency clinician. Am J Emerg Med. 2020;38(5):1007–13.

    Article  Google Scholar 

  4. Gottlieb M, Holladay D, Peksa GD. Ultrasonography for the confirmation of endotracheal tube intubation: a systematic review and meta-analysis. Ann Emerg Med. 2018;72(6):627–36.

    Article  Google Scholar 

  5. Wardi G, Blanchard D, Dittrich T, Kaushal K, Sell R. Right ventricle dysfunction and echocardiographic parameters in the first 24h following resuscitation in the post-cardiac arrest patient: A retrospective cohort study. Resuscitation. 2016;103:71–4.

    Article  Google Scholar 

  6. Alerhand S, Sundaram T, Gottlieb M. What are the echocardiographic findings of acute right ventricular strain that suggest pulmonary embolism? Anaesth Crit Care Pain Med. 2021;40(2): 100852.

    Article  Google Scholar 

  7. Alerhand S, Carter JM. What echocardiographic findings suggest a pericardial effusion is causing tamponade? Am J Emerg Med. 2019;37(2):321–6.

    Article  Google Scholar 

  8. Salem K, Mulji A, Lonn E. Echocardiographically guided pericardiocentesis - the gold standard for the management of pericardial effusion and cardiac tamponade. Can J Cardiol. 1999;15(11):1251–5.

    CAS  PubMed  Google Scholar 

  9. Lalande E, Burwash-Brennan T, Burns K, Harris T, Thomas S, Woo MY, Atkinson P. Is point-of-care ultrasound a reliable predictor of outcome during traumatic cardiac arrest? A systematic review and meta-analysis from the SHoC investigators. Resuscitation. 2021;1(167):128–36.

    Article  Google Scholar 

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Correspondence to Michael Gottlieb.

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Gottlieb, M., Sundaram, T., Olszynski, P. et al. Just the facts: point-of-care ultrasound in cardiac arrest. Can J Emerg Med (2022). https://doi.org/10.1007/s43678-022-00336-7

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Keywords

  • Emergency medicine
  • Resuscitation
  • Ultrasound