Management of Comatose Adults With OHCA: Key Points

The following are key points to remember from an American Heart Association (AHA) Scientific Statement on cardiac catheterization laboratory management of the comatose adult patient with an out-of-hospital cardiac arrest (OHCA):

1. Approximately 350,000 patients in the United States experience OHCA each year, with a survival rate of 6-10%. OHCA accounts for 15-20% of natural deaths and 50% of cardiovascular deaths. A coordinated systems of care approach to OHCA, including emergency access to the cardiac catheterization laboratory and extracorporeal membrane oxygenation (ECMO), positively impacts survival.
2. Risk factors for OHCA include atherosclerotic coronary artery disease, atrial fibrillation, cardiomyopathy, chronic kidney disease, substance abuse, and obstructive sleep apnea. Underlying mechanisms for sudden cardiac arrest from primary cardiac causes fall into three broad categories: 1) ischemic (accounting for 70% of cardiac arrests), 2) structural (including cardiomyopathies, aortic stenosis, and pulmonary embolism), and 3) electrical (including channelopathies, electrolyte disturbances, and drug toxicity). Prearrest chest discomfort and history of myocardial infarction are associated with fivefold higher odds of acute coronary lesions.
3. Following return of spontaneous circulation (ROSC), the electrocardiogram (ECG) is an important tool but lacks sensitivity and specificity for acute coronary occlusion. ST elevation has an 85% positive predictive value and 65% negative predictive value for an acute or subacute coronary lesion. In ambiguous situations, serial ECGs performed >30 minutes after ROSC can provide clarity and guide the timing of coronary angiography.
4. Following OHCA, findings of the initial neurologic examination are not well-correlated with eventual neurologic outcome. Therefore, determination of neurologic prognosis should be delayed >72 hours after ROSC and should involve a multimodal approach. Clinical factors associated with poor neurologic outcome of OHCA include advanced age, unwitnessed arrest, absence of bystander cardiopulmonary resuscitation (CPR), nonshockable rhythm on initial assessment, prolonged duration of arrest before ROSC, blood lactate >7 mmol/L, pH <7.2, and diffuse cerebral edema on computed tomography.
5. In the past several years, six randomized controlled trials have evaluated the role of immediate or early coronary angiography in patients with ROSC after OHCA, without ST elevations. Collectively, these studies did not show a survival benefit of early coronary angiography. However, patients with cardiogenic shock or electrical instability were excluded from most of these trials. Some subsets of patients, such as those with chest pain preceding arrest, marked ST-segment depressions, and favorable post-arrest prognostic features, may benefit from early coronary angiography and/or hemodynamic support.
6. Particularly when features strongly associated with adverse neurologic outcomes are present following OHCA, the potential risks and benefits of coronary angiography and mechanical circulatory support (MCS) should be considered carefully, taking into account the patient’s previously expressed wishes, the family’s perspective, and the possibility of medical futility.
7. Following cardiac arrest due to massive pulmonary embolism (PE), rapid decision-making by a multidisciplinary PE response team is invaluable. Treatment options may include systemic fibrinolytics, catheter-based thrombolysis or mechanical thrombectomy, and venoarterial (VA)-ECMO.
8. Emergent deployment of VA-ECMO following failed CPR (ECPR) may be considered for selected OHCA patients if the suspected cause of cardiac arrest is reversible (AHA Class 2a recommendation). Factors associated with successful outcomes of ECPR include patient age <70 years, rapid mobilization of ECMO teams, and short no-flow times.
9. In hemodynamically stable patients, radial artery access for coronary angiography is preferred. If MCS is planned, ultrasound-guided femoral artery access is recommended. If percutaneous coronary intervention is performed, reliable P2Y12 inhibition in the post-arrest setting could consist of ticagrelor (possibly crushed) or intravenous cangrelor.
10. Important considerations for post-arrest intensive care unit management are summarized in the 2020 AHA guidelines for CPR and emergency cardiovascular care. These include targeted temperature management, or cooling, for patients with ROSC after OHCA who do not follow commands, maintaining a constant temperature between 32°C and 36°C for ≥24 hours.

https://www.ahajournals.org/doi/10.1161/CIR.0000000000001199