Background

Cardiac arrest is common occurrence effecting > 300,000 Americans each year and with a generally dismal prognosis (survival rate 7-9%). Currently, there is an absence of evidence or guidelines to aid physicians’ regarding the timing of resuscitation termination when patients do not obtain return of spontaneous circulation (ROSC). Point-of-care ultrasound (POCUS) has been useful in other critical patients such as in trauma or undifferentiated shock. Bedside echocardiography is readily available and can be used during cardiac arrest resuscitation to rapidly assess cardiac activity as well as elucidate potential etiologies. This is the first systematic review to look at the existing evidence for the use of POCUS in cardiac arrest management.

Clinical Question

“Does detection of cardiac contractility on bedside echocardiography predict return of spontaneous circulation (ROSC) during cardiac arrest?”

Design

Systematic review with QUADAS tool and meta-analyses

Literature Search

MEDLINE via PubMed, EMBASE, CINAHL, and Cochrane Library databases

Outcomes

Primary: Test characteristics of point-of-care echo in cardiac arrest for predicting ROSC (sensitivity, specificity, likelihood ratios)

Inclusion

Diagnostic accuracy studies looking at TTE performed during cardiac arrest. Studies had to report the findings of the TTE as well as the outcome of the cardiac arrest case.

Primary Results

  • Search identified 2,539 relevant titles which were screened
  • Ultimately, 8 studies were included for this analysis

Test Characteristics of Cardiac Activity Found on POCUS for predicting ROSC (Primary Outcome)

  • Sensitivity 91.6% (95% CI: 84.6% to 96.1%)
  • Specificity 80% (95% CI: 76.1% to 83.6%)
  • Positive LR 4.26 (95% CI 2.63 to 6.92)
  • Negative LR 0.18 (95% CI 0.1 to 0.31)

Strengths

  • Meta-analyses
  • Low heterogeneity for the (-) LR
  • Conclusion based on low heterogeneity

Limitations

  • Not based on patient centered outcome (not all studies reported outcomes past ROSC)
  • Small sample size despite being meta-analyses, sample sizes were too small for sub-group analysis
  • Does not differentiate the types of cardiac arrest (V fib vs. PEA vs. asystole and traumatic vs. non-traumatic)
  • Some studies only included expert sonographers, may not be applicable to all providers
  • There is lack of uniformity in definition of “cardiac activity” in studies and not all studies clearly defined what is considered “cardiac activity”
  • Unclear inter-rater reliability in assessment of cardiac activity in individual studies

Author's Conclusions

"Echocardiography performed during cardiac arrest that demonstrates an absence of cardiac
activity harbors a significantly lower (but not zero) likelihood that a patient will experience ROSC. In selected patients with a higher likelihood of survival from cardiac arrest at presentation, based on established predictors of survival, echo should not be the sole basis for the decision to cease resuscitative efforts. Echo should continue to be used only as an adjunct to clinical assessment in predicting the outcome of resuscitation for cardiac arrest.”

Our Conclusions

Point-of-care ultrasound can be extremely helpful in guiding resuscitation of a patient in cardiac arrest. Lack of cardiac activity in a cardiac arrest patient can help guide termination of resuscitation efforts in the right clinical context but should not be used in isolation. More studies are required to elucidate the value of point-of-care ultrasound in predicting meaningful patient outcomes.

Potential Impact To Current Practice

Point-of-care ultrasound has been incorporated into many aspects of practice in Emergency Medicine; resuscitation of the cardiac arrest patient is no different. The addition of limited echocardiography in cardiac arrest can only augment the clinical assessment of the patient’s prognosis though should not be the lone decision instrument.

Bottom Line

Point-of-care echocardiography can be a useful tool to aid clinical assessment during resuscitation of the patient in cardiac arrest where lack of cardiac activity portends poor prognosis.