PoCUS – Measurements and Quick Reference

Developed by Dr. Heather Flemming as part of her PG PoCUS Elective at SJRHEM.

A useful Point of Care Ultrasound (PoCUS) guide to common normal values, measurements, pathological values and quick reference tips. A pdf version is also provided in this post which can be downloaded, printed and attached to your ultrasound machine for easy access.

 

 

 


 


Download (PDF, 1017KB)

 

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SJRHEM associated publication – The Reason Study

The Reason Study group, which included researchers from SJRHEM and involved may of SJRHEM physicians contributing data, has just published the results of the biggest prospective study to determine whether cardiac activity on ultrasound during ACLS is associated with improved survival.

The paper: Emergency department point-of-care ultrasound in out-of-hospital and in-ED cardiac arrest, was published in Resuscitation (http://dx.doi.org.ezproxy.library.dal.ca/10.1016/j.resuscitation.2016.09.018) reported that “Cardiac activity on ultrasound was the variable most associated with survival following cardiac arrest. Ultrasound during cardiac arrest identifies interventions outside of the standard ACLS algorithm.”


Abstract

Background

Point-of-care ultrasound has been suggested to improve outcomes from advanced cardiac life support (ACLS), but no large studies have explored how it should be incorporated into ACLS. Our aim was to determine whether cardiac activity on ultrasound during ACLS is associated with improved survival.

Methods

We conducted a non-randomized, prospective, protocol-driven observational study at 20 hospitals across United States and Canada. Patients presenting with out-of-hospital arrest or in-ED arrest with pulseless electrical activity or asystole were included. An ultrasound was performed at the beginning and end of ACLS. The primary outcome was survival to hospital admission. Secondary outcomes included survival to hospital discharge and return of spontaneous circulation.

Findings

793 patients were enrolled, 208 (26.2%) survived the initial resuscitation, 114 (14.4%) survived to hospital admission, and 13 (1.6%) survived to hospital discharge. Cardiac activity on US was the variable most associated with survival at all time points. On multivariate regression modeling, cardiac activity was associated with increased survival to hospital admission (OR 3.6, 2.2–5.9) and hospital discharge (OR 5.7, 1.5–21.9). No cardiac activity on US was associated with non-survival, but 0.6% (95% CI 0.3–2.3) survived to discharge. Ultrasound identified findings that responded to non-ACLS interventions. Patients with pericardial effusion and pericardiocentesis demonstrated higher survival rates (15.4%) compared to all others (1.3%).

Conclusion

Cardiac activity on ultrasound was the variable most associated with survival following cardiac arrest. Ultrasound during cardiac arrest identifies interventions outside of the standard ACLS algorithm.

 


A very good critique of this paper has been published on the well-known EM Blog – St. Emlyns – JC: Is this the REASON to use USS in cardiac arrest? St.Emlyn’s

St. Emlyn’s Bottom Line: A lack of cardiac activity on initial USS is very probably associated with a worse prognosis. The role of USS in improving outcome as an intervention in cardiac arrest is less certain

 


We will be asking our Research Director (Dr Paul Atkinson), who was closely involved in this study, for his take on the results and how they should be interpreted/incorporated into practice. This has been posted here.

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Resident Clinical Pearl – PoCUS for ETT Placement Confirmation

ETT Placement Confirmation During Cardiac Arrest: US for the Win!

Resident Clinical Pearl – November 2015

Kalen Leech-Porter, PGY 1, iFMEM, Saint John NB, Dalhousie University

Reviewed by: Dr Jay Mekwan and Dr David Lewis

 

The AHA has updated their guidelines for CPR and emergency cardiovascular care this year (2015)[i].  Previously, there were insufficient studies to warrant a recommendation for Point of Care Ultrasound (PoCUS) for ETT confirmation, however, a new study has emerged to suggest that PoCUS can be a useful adjunct for ETT placement confirmation.  A 96 patient observational study done on patients during cardiac arrest, found that PoCUS had a sensitivity of 98.9% and a specificity of 100%[ii].  ETT placement was determined by placing the ultrasound transducer transversely above the suprasternal notch to identify endotracheal or esophageal intubation.  It was determined during the study that in using this method ultrasound could be completed without interrupting chest compressions.

As the above study has yet to be replicated, end-tidal CO2 remains the gold standard for ETT placement confirmation (an observational, prospective study of 566 patients found colorimetric to be 95.6% sensitive, 99.8% specific[iii]) during cardiac arrest.  However, AHA has added ultrasound as an additional method for confirmation of endotracheal tube placement, with the caveat that ultrasound should never interfere with the continuous conduction of high-quality CPR.


 

How to confirm ETT with PoCUS:

Video by Haney Mallemat

 

Video by Joseph Minardi


 

Abridged Instructions from ACEP Tips and Tricks [iv]

  • Place the high frequency linear probe transversely just above the sternal notch (Image A); note normal airway anatomy (Image B), prior to ETT placement (if time permits)
Image A

Image A

From: Joseph Minardi’s Video [see above]

 

Image B

Image B

From: Halley Mallemat’s video [see above]

 

Trachea: Hyperechoic, curvilinear with comet-tail artifact

Esophagus: more distal, oval with heyperchoic wall and hypoechoic center


 

  • PoCUS ETT confirmation can be done in real time, as ETT is placed, or done post placement. Successful ETT: there will be a slight increase in artifact/shadowing in trachea region only, known as the “Bullet Sign” (Image C) [v].  The operator should see reverberations in the trachea’s anterior lumen.  To further confirm can slightly shake the ETT, this should only show trachea movement.
Image C

Image C

From: Mark Favot [v]


 

 

  • Esophageal Intubation: will cause a second ‘trachea’ appear (Image D and E), referred to as the “double tract sign”
Untitled4

Image D

From: Halley Mallemat’s video [see above]

Image E

Image E

From ACEP Tips and Tricks [iv]


 

  • Pitfalls: the esophagus may be located directly posterior to the trachea, therefore esophageal intubation may be missed if inadequate depth is used.
  • Additionally, observing bilateral lung sliding while bagging a paralyzed patient also suggest ETT confirmation.

References

[i] Web-based Integrated 2010 & 2015 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care; Part 7: Adult Advanced Cardiovascular Life Support.  (Nov. 25, 2015) https://eccguidelines.heart.org/index.php/circulation/cpr-ecc-guidelines-2/part-7-adult-advanced-cardiovascular-life-support/

[ii] Sun, Jen-Tang, Sim, Shyh-Shyong, et al. “Ultrasonography for proper endotracheal tube placement confirmation in out-of-hospital cardiac arrest patients: two-center experience.”  Critical Ultrasound Journal 6 (2014): A29 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4101346/

[iii] Hayden, SR., and Sciammerella, J., et al. “Colorimetric end-tidal CO2 detector for verification of endotracheal tube placement in out-of-hospital cardiac arrest.” Acad Emerg Med 6 (1995): 499-502 http://www.ncbi.nlm.nih.gov/pubmed/7497049

[iv] Chao, Alice and Ghrahbaghaian, Laleh. “Tips and Tricks: Airway Ultrasound.” American College of Emergency Physicians Emergency Ultrasound Section Newsletter (June, 2015). http://www.acep.org/Content.aspx?ID=102309

[v] Favot, Mark. “Ultrasound for Verification of Endotracheal Intubation.” FOAM EM (March, 2015). http://www.foamem.com/2015/03/02/ultrasound-for-verification-of-endotracheal-tube-location/

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