Eyal Herzog1, Lee Herzog2, Emad F. Aziz3, and Stephan A. Mayer4
1 Hadassah Medical Center Jerusalem, Israel
2 Icahn School of Medicine at Mount Sinai, New York, NY, USA
3 Rutgers New Jersey Medical School, Newark, NJ, USA
4 New York Medical College, Valhalla, NY, USA
Background
Definition of disease
Cardiac arrest is the cessation of cardiac activity resulting in the abolition of circulation.
Disease classification
Cardiac arrest is traditionally categorized as being of cardiac or non‐cardiac origin (e.g. driven by respiratory failure, sepsis, or trauma).
The type of arrest is defined by the initial cardiac rhythm:
Ventricular fibrillation (VF) or ventricular tachycardia (VT), the two shockable rhythms: 20%.
Pulseless electrical activity (PEA): 35%.
Asystole: 45%.
Incidence/prevalence
Each year 326 000 people experience EMS‐assessed out‐of‐hospital cardiac arrests in the USA.
Approximately 50% of out‐of‐hospital cardiac arrests are witnessed, and 60% are treated by EMS providers.
In 2013 survival to discharge was 10% overall, but 33% for patients with witnessed VF or VT.
About half of cardiac arrest survivors regain consciousness and have a good neurologic outcome.
Etiology
Coronary artery disease resulting in acute myocardial infarction or ischemic cardiomyopathy is the most common cause of sudden cardiac arrest.
Primary cardiac conduction abnormalities.
Non‐ischemic cardiomyopathy.
Drug intoxication, including opioid overdose.
End‐stage renal failure patients on dialysis.
Prevention
Diagnosis
Patients with sudden cardiac arrest present with sudden collapse and loss of consciousness.
In an unmonitored setting, the key to diagnosis is to establish unresponsiveness to verbal and tactile stimuli, apnea, and pulselessness.
In a monitored setting, or as soon as a cardiac monitor can be placed, the diagnosis can be established by demonstrating VF, VT, or asystole.
PEA is established when cardiac monitoring shows organized electrical activity but the patient is pulseless and unresponsive.
Basic cardiac life support
The 2019 AHA guidelines for performing high quality CPR for out‐ of‐ hospital cardiac arrest patients without an advanced airway is shown in the box.
Chest compressions
Untrained lay rescuers should provide compression‐only (hands‐only) CPR for adult victims of cardiac arrest.
In addition, if a trained rescuer is able to perform rescue breaths, he or she should add rescue breaths in a ratio of 30 compressions to 2 breaths.
The rescuer should continue CPR until an AED arrives and is ready for use, EMS providers take over care of the victim, or the victim starts to move.
The 2015 AHA guidelines suggest against the routine use of automated mechanical chest compression devices to replace manual chest compressions
Chest compression rate
In most studies, longer durations of chest compressions are associated with higher survival rates, and fewer compressions are associated with lower survival rates.
The 2019 AHA guidelines recommend a manual chest compression rate of 100–120 bpm.
Chest compression depth
During manual CPR, rescuers should perform chest compressions to a depth of at least 5 cm (2 inches) for an average adult, while avoiding excessive chest compression depths (greater than 6 cm (2.4 inches)).
Rescuers should avoid leaning on the chest between compressions to allow full chest wall recoil for adults in cardiac arrest.
Compression : ventilation ratio
The 2015 AHA guidelines suggest a compression : ventilation ratio of 30:2 in patients in cardiac arrest.
If an advanced airway is in place (e.g. if the patient has arrested while on mechanical ventilation or if a bag‐valve‐mask is applied) it may be reasonable for the provider to deliver 1 breath every 6 seconds (10 breaths per minute) while continuous chest compressions are being performed.
Bystander naloxone in opioid‐associated life‐threatening emergencies
For patients with known or suspected opioid addiction who are unresponsive with no normal breathing but a pulse, it is reasonable for appropriately trained lay rescuers and BLS providers to administer intramuscular or intranasal naloxone in addition to providing standard BLS care.
Shock first versus CPR first
For witnessed adult cardiac arrest when an AED is immediately available, it is reasonable that the defibrillator be used as soon as possible.
For adults with unmonitored cardiac arrest or for whom an AED is not immediately available, it is reasonable that CPR be initiated while the defibrillator equipment is being retrieved and applied and that defibrillation, if indicated, be attempted as soon as the device is ready for use.
Advanced cardiac life support
Epinephrine
The 2019 AHA guidelines suggest that for cardiac arrest with an initial non‐shockable rhythm, epinephrine should be given as soon as possible.
These guidelines suggest vasopressin should not be used instead of epinephrine in cardiac arrest.
These guidelines suggest considering use of vasopressin in combination with epinephrine, but note that this does not confer an advantage compared to alone.
These guidelines suggest against the routine use of high‐dose epinephrine (5 mg) as opposed to standard‐dose epinephrine (1 mg), in cardiac arrest.
Use of Advanced Airways
The 2019 AHA guidelines suggest that either bag mask ventilation or an advanced airway strategy (supraglottic airway device or endotracheal intubation) may be considered during CPR.
When delivering ventilation, chest compressions should not be interrupted. Verntilation should be provided during chest compressions at a rate of 10 breaths per minute.
Antiarrhythmic drugs
The 2015 AHA guidelines suggest the use of amiodarone 150 mg in repeated doses in adult patients with refractory VF/VT to improve rates of return of spontaneous circulation (ROSC).
These guidelines also suggest the use of lidocaine or nifekalant (for both give 1 mg/kg, repeat twice for a maximum dose of 3 mg/kg) as an alternative to amiodarone in adult patients with refractory VF/VT.
These guidelines recommend against the routine use of magnesium in adult patients.
Resuscitative TEE is an emerging advanced technique for imaging the heart during or immediately after CPR. Its main advantage is that imaging the heart via the esophagus does not interfere with chest compressions.
TEE can diagnose two syndromes during cardiac arrest that can influence management:
Pseudo‐PEA: pulseless due to profound shock with preserved LV contractility. Treatment is to give inotropes and high dose vasopressors.
Fine VF: cardiac monitor appears to show asystole but heart is shown to be fibrillating. Treatment is repeated attempts at cardioversion.
Cardiocerebral resuscitation
Diagnosis and management of acute coronary syndromes
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