US Journal Club July, 2019: Cardiac Arrest

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

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

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

Variability in Interpretation of Cardiac Standstill Among Physician Sonographers

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

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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