The REASON Trial: POCUS in Cardiac Arrest

Background: For many emergency providers, POCUS has become a critical modality in the resuscitation of patients with cardiac arrest. The authors of this paper (The REASON Trial) state that <8% of all OHCA’s survive to hospital discharge; a dismal number. We already know that shockable rhythms, early defibrillation, early bystander CPR, and ROSC in the field are all associated with increased survival. What we don’t have is large scale evidence that the use of POCUS improves survival with good neurologic outcomes.

Clinical Question: Is detection of cardiac activity on POCUS in patients with PEA or asystole associated with improved survival from cardiac arrest?

What They Did:

• Multicenter, Non-randomized, prospective, protocol-driven observational study at 20 hospitals across the United States and Canada
• Performance of bedside cardiac ultrasound at the beginning and end of ACLS

Outcomes:

• Primary Outcome: Survival to Hospital Admission
• Secondary Outcomes: Survival to Hospital Discharge, ROSC

Inclusion:

• Patients with non-traumatic, Out-of-Hospital arrest or in-ED arrest with pulseless electrical activity or asystole

Exclusion:

• Resuscitation not continued after initial ultrasound
• Resuscitation efforts discontinued due to a DNR order
• Resuscitation lasted < 5 minutes

Results:

• 793 patients enrolled
  • 208 (26.2%) survived initial resuscitation (95% CI 23.3 – 29.4)
  • 114 (14.4%) survived to hospital admission (95% CI 12.1 – 17.0)
  • 13 (1.6%) survived to hospital discharge (95% CI 0.9 – 2.8)
  • 263 (33%) of patients had cardiac activity on initial US
    • 54% of PEA patients had cardiac activity on initial US
    • 134 (51.0%) achieved ROSC
    • 76 (28.9%) survived to hospital admission
    • 10 (3.8%) survived to hospital discharge
  • 530 (67%) of patients had NO cardiac activity on initial US
    • 76 (14.3%) achieved ROSC
    • 38 (7.2%) survived to hospital admission
    • 3 (0.6%) survived to hospital discharge
  • Cardiac activity on US:
    • Associated with Increased Survival to Hospital Admission (OR 3.6; 2.2 – 5.9)
    • Associated with Increased Survival to Hospital Discharge (OR 5.7; 1.5 – 21.9)
  • No Cardiac Activity on US:
    • Associated with Non-Survival
    • 0.6% still survived to discharge
  • Ultrasound identified findings that respond to non-ACLS interventions
    • Pericardial Effusion: 34 patients
      • Pericardiocentesis Increased survival to discharge rates 15.4% vs all others 1.3%
    • Pulmonary Embolism: 15 patients
      • Thrombolytics
        • Survival to discharge 6.7%

Strengths:

• Kappa statistic was used to evaluate the strength of agreement of bedside ultrasound
• First large, multicenter study evaluating use of ultrasound during ACLS
• All providers who Performed US weren’t RDMS or fellowship trained which makes this more generalizable than many other studies

Limitations:

• Treating physicians were unblinded to US results, but this would be expected as US performed in real time. But does this create a self-fulfilling prophecy for patients who had no cardiac activity? In other words when we see no cardiac activity on US, do we end resuscitation efforts early?
• The primary endpoint was not patient centered. A primary outcome of neurologically intact or neurologically functional survival would have been superior.
• Very low survival rate, but may be due to the selection bias created by excluding patients without the use of ultrasound at the beginning of resuscitation and patients with resuscitations lasting <5minutes

Discussion:

• Previous published rates of ROSC in cardiac arrest with cardiac activity range from 24 – 73%. This study found a ROSC rate of >50% if cardiac activity detected. This is amazing considering that all patients in this study were patients with PEA/Asystole and no VF/VT patients
• The overall survival rate to hospital discharge in patients with cardiac activity was 3.8% in this study which is a bit higher when compared to other large OHCA studies (i.e. 1.4% – 2.7%)
• 54% of PEA patients had cardiac activity on initial US, further emphasizing the fact that using fingers to check for a pulse in cardiac arrest is not optimal
• The absence of cardiac activity on presentation is not 100% sensitive for non-survivors though the rate of survival to discharge was vanishingly low (0.6%)

Author 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.”

Clinical Take Home Point: The use of bedside ultrasound in PEA/Asystolic cardiac arrest can help identify pathologies that require a specific intervention, used as an adjunct to discontinue resuscitation efforts, and identify cardiac activity that is not appreciated with traditional finger pulse checks. It is unclear from this study whether the use of bedside ultrasound in cardiac arrest is an intervention that improves neurologically intact outcomes.

References:

1. Gaspari R et al. Emergency Department Point-Of-Care Ultrasound in Out-Of-Hospital and in-ED Cardiac Arrest. Resuscitation 2016; 109: 33 – 39. PMID: 27693280

For More Thoughts on This Topic Checkout:

• Simon Carley at St. Emlyn’s: Is this the REASON to use USS in Cardiac Arrest?
• Matt and Mike at Ultrasound Podcast: State of the Evidence Cardiac Arrest Echo. REASON Trial with Romolo Gaspari
• Matt and Mike at Ultrasound Podcast: Cardiac Arrest Echo from REASON trial Part 2 with Romolo Gaspari

Post Peer Reviewed By: Anand Swaminathan (Twitter: @EMSwami)

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