US Journal Club July, 2019: Cardiac Arrest

Case 1

Emergency Department Point-Of-Care Ultrasound in Out-Of-Hospital and in-ED Cardiac Arrest: The REASON Trial

Gaspari R et al. Resuscitation 2016; 109: 33 – 39. PMID: 27693280

Full Text

  • Introduction and background information 
    • In 2014 there were 424,000 out-of-hospital cardiac arrests (OHCA) in the US1
    • 60% were treated by emergency medical services (EMS)
      • Among those, 23% had initial shockable rhythm (ventricular tachycardia (VT) or ventricular-fibrillation)
    • 10.6% of all patients survived to discharge 
    • Of those with shockable rhythms, 31% survived to discharge
    • Survival with good neurological outcome was 8.3%
  • What was the primary objective of this study?
    • To detect if cardiac activity in patients with OHCA in pulseless electrical activity (PEA) or asystole is associated with improved survival to hospital admission
  • Methods and study design
    • Multicenter, non-randomized prospective observational trial
    • Across 20 centers in the US and Canada
    • US performed initially and at the end of resuscitation to determine cardiac activity  
      • Subxiphoid and parasternal long views
    • Cardiac activity defined as any visible movement of the myocardium excluding movement of blood within ventricle or isolated valve movements 
    • Performed by EM physicians who were US credentialed
    • Inclusion criteria:
      • OHCA or in-ED arrest with PEA or asystole
      • Patients in v-fib or VT who were defibrillated into PEA/asystole in the field
    • Exclusion criteria:
      • Traumatic arrest
      • If resuscitation stopped after initial US or lasted < 5 mins
  • What was the primary outcome of the study?
    • Survival to hospital admission
    • Secondary outcome was survival to hospital discharge
  • Results
    • A total of 793 patients enrolled
      • 26.2% of patients survived initial resuscitation 
      • 14.4% survived to hospital admission
      • 1.6% survived to discharge
    • 33% of patients had cardiac activityon initial US, of these:
      • 51% achieved ROSC
      • 28.9% survived to admission, 3.8% to discharge
    • 67% of patients had no cardiac activity on initial US, of these:
      • 14.3% achieved ROSC
      • 7.2% survived to admission, 0.6% to discharge
  • Discussion
    • Lack of cardiac activity on US in patients with asystole or PEA had a 99% positive predictive value for non-survival
    • No difference between OHCA and in-ED arrests in survival to discharge
    • Cardiac activity on US associated with survival to admission/discharge → OR 3.6/5.7
    • US found “non-ACLS” interventions:
      • Pericardial effusions found in 34 patients
        • Pericardiocentesis increased survival to discharge to 15.4%
      • Pulmonary embolism were found in 15 patients
        • Patients had survival to discharge 6.7%
  • Were there any limitations?
    • Primary outcome measured survival to hospital discharge, a more patient centered outcome would have included neurologically intact survival
  • Take home points
    • Patients with OCHA without a shockable rhythm have a poor prognosis and US can help to determine survivability
    • No cardiac activity seen on the initial US has very high predictive value for non-survival
    • US was able to find “non-ACLS” interventions including pericardial effusions and PE which, if acted on, increases survivability
    • Further studies evaluating neurologic outcomes would be beneficial  

References

  1. Go AS, Mozaffarian D, Roger VL, et al. Heart disease and stroke statistics–2013 update: a report from the American Heart Association [published correction appears in Circulation. 2013 Jan 1;127(1):doi:10.1161/CIR.0b013e31828124ad] [published correction appears in Circulation. 2013 Jun 11;127(23):e841]. Circulation. 2013;127(1):e6–e245. doi:10.1161/CIR.0b013e31828124ad

Case 2

Variability in Interpretation of Cardiac Standstill Among Physician Sonographers

Hu, Kevin et al. Annals of Emergency Medicine, Volume 71, Issue 2, 193 – 198

Full Text

  • Introduction
    • No current consensus exists regarding definition of cardiac standstill on ultrasound
    • US is used commonly during cardiac arrest to help determine termination of resuscitation
  • What was the primary objective of the study?
    • To determine how much variability exists in the interpretation of cardiac standstill on US
  • Methods and study design
    • Cross sectional, convenience sample survey performed at various residency conferences
    • Survey given to EM residents, EM attendings, US, ICU and cardiology fellows
    • Participants were shown 15 seperate 6 second US clips of PEA in subxiphoid or parasternal long views
    • Were given 20 seconds to answer if image showed standstill or cardiac activity
    • Were asked to rank their US skills as basic, advanced or expert
  • What was the primary outcome?
    • Validity in interpretation of standstill among the respondents
    • Secondary outcome of variability among subgroups based on speciality/training level
  • Results
    • Total of 127 participants
    • Physician sonographers were composed of:
      • 74% Emergency medicine
      • 12% Critical care
      • 3% Cardiology
    • Training level:
      • 63% residents
      • 9% fellows
      • 19% attendings
    • Ranked on scale of 0 – 1 with 0 being no agreement and 1 being complete agreement
      • Moderate agreement (score of 0.47) in interpretation of US
      • Moderate agreement across speciality/training level/US experience 
  • Were there any weaknesses in the study?
    • Selection bias due to selecting residents at conferences who may be more interested and therefore skilled at ultrasound than others
    • Concern for how well images were interpreted on computer screen
  • Take home points
    • No current consensus exists regarding cardiac standstill on ultrasound
    • After surveying EM residents, attendings and various fellows with US clips to determine standstill versus cardiac activity, there is poor agreement 
    • This persists across both training speciality and training level 
    • Likely a universal definition of cardiac arrest in ultrasound would benefit cardiac arrest management 

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