Cardiac Arrest

Cardiac arrest is the sudden, complete cessation of cardiac output with hemodynamic collapse. Patients present as pulseless, unresponsive, and apneic. Rhythms associated with cardiac arrest are ventricular fibrillation Ventricular fibrillation Ventricular fibrillation (VF or V-fib) is a type of ventricular tachyarrhythmia (> 300/min) often preceded by ventricular tachycardia. In this arrhythmia, the ventricle beats rapidly and sporadically. The ventricular contraction is uncoordinated, leading to a decrease in cardiac output and immediate hemodynamic collapse. Ventricular Fibrillation/tachycardia, asystole, or pulseless electrical activity. The treatment of cardiac arrest begins with basic life support (BLS) when out-of-hospital and advanced cardiac life support (ACLS) when in-hospital. Basic life support comprises checking the patient’s mental status, activating the emergency response system, and cardiopulmonary resuscitation (CPR). An automated external defibrillator (AED) should be used once available. High-quality CPR (with early defibrillation in shockable rhythms) is crucial to survival in cardiac arrest. Advanced cardiac life support includes CPR, securing the airway, administering medications (such as epinephrine), and identifying and treatment of the cause of cardiac arrest. Post-cardiac arrest care follows return of spontaneous circulation (ROSC).

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Overview

Definition

Sudden cardiac arrest (SCA) is the abrupt cessation of cardiac activity.

Epidemiology

  • Approximately 350,000 SCAs per year occur in the United States.
    • 60% occur out-of-hospital, with a 10% survival rate (up to 30% when witnessed by a bystander).
    • 40% occur in-hospital, with a 20% survival rate.
  • Incidence of cardiac arrest increases linearly with age.
  • 57% of patients are men.
  • Survival rate is 10% for non-shockable rhythms and > 30% for shockable rhythms.

Risk factors

  • Smoking 
  • Family history of SCA
  • Heavy alcohol intake (6 or more drinks/day) or binge drinking
  • Elevated free fatty acids Fatty acids Fatty acids are integral building blocks of lipids, and can be classified as unsaturated or saturated based on the presence/absence of carbon-carbon double bonds within their nonpolar chains. Fatty Acids and Lipids (associated with sudden cardiac death ( SCD SCD Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease) and ventricular arrhythmia after a myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction)

Etiology and Clinical Presentation

Cardiac causes of cardiac arrest

  • Structural heart disease: 
    • Coronary heart disease Coronary heart disease Coronary heart disease (CHD), or ischemic heart disease, describes a situation in which an inadequate supply of blood to the myocardium exists due to a stenosis of the coronary arteries, typically from atherosclerosis. Coronary Heart Disease (CHD): associated with up to 70% of SCAs
    • Congenital heart diseases
    • Cardiomyopathies
    • Valvular heart diseases
    • Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis
    • Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a "false lumen." Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection
    • Acute pericardial tamponade
  • No structural heart disease:
    • Complete heart block
    • Brugada syndrome
    • Idiopathic ventricular fibrillation Ventricular fibrillation Ventricular fibrillation (VF or V-fib) is a type of ventricular tachyarrhythmia (> 300/min) often preceded by ventricular tachycardia. In this arrhythmia, the ventricle beats rapidly and sporadically. The ventricular contraction is uncoordinated, leading to a decrease in cardiac output and immediate hemodynamic collapse. Ventricular Fibrillation
    • Long QT syndrome Long QT syndrome Long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization that produces QT prolongation on electrocardiogram (ECG). Long QT syndrome is associated with an increased risk of developing life-threatening cardiac arrhythmias, specifically torsades de pointes. Long QT Syndrome
    • Preexcitation syndrome
    • Familial sudden cardiac death
    • Chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall trauma (commotio cordis)

Non-cardiac causes of cardiac arrest

  • Trauma
  • Electrocution 
  • Excessive hemorrhage
  • Hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia
  • Pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism
  • Drowning Drowning Drowning occurs due to respiratory impairment from submersion or immersion in a liquid medium. Aspiration of water leads to hypoxemia, which affects all organ systems, resulting in respiratory insufficiency and acute respiratory distress syndrome (ARDS), cardiac arrhythmias, and neuronal damage. Drowning
  • Sudden infant death syndrome Sudden Infant Death Syndrome Sudden infant death syndrome (SIDS) describes the sudden death of an otherwise healthy infant (< 1 year of age) with no identifiable cause. Sudden infant death syndrome is the leading cause of death in children between 1 and 12 months of age in the United States. Sudden Infant Death Syndrome (SIDS)
  • Sudden unexplained death in epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy (SUDEP)

Mnemonics

The 5 Hs and 5 Ts of the common reversible causes of SCA:

  • 5 Hs:
    1. Hypoxia
    2. Hypovolemia
    3. Hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia or hyperkalemia Hyperkalemia Hyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia
    4. Hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
    5. Hydrogen ion (acidosis)
  • 5 Ts:
    1. Toxins
    2. Tamponade
    3. Tension pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax
    4. Thrombosis ( myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction)
    5. Thrombosis (pulmonary embolism)

Clinical presentation

  • Unresponsive (loss of consciousness)
  • Pulseless
  • Apneic (may have agonal respirations)
  • Some have warning symptoms
    • Most common symptoms:
      • Chest pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain
      • Dyspnea
    • Up to 80% of patients have symptoms 1 hour before and 50% have symptoms 1 month before the SCA.

Cardiac Rhythms

Four major cardiac rhythms are associated with SCA. These rhythms are divided into shockable and non-shockable rhythms.

Shockable rhythms

Shockable rhythms are usually caused by primary cardiac disease (most commonly ischemia). Less commonly, they are caused by systemic conditions (electrolyte disturbances, toxins, autoimmunity Autoimmunity Autoimmunity is a pathologic immune response toward self-antigens, resulting from a combination of factors: immunologic, genetic, and environmental. The immune system is equipped with self-tolerance, allowing immune cells such as T cells and B cells to recognize self-antigens and to not mount a reaction against them. Defects in this mechanism, along with environmental triggers (such as infections) and genetic susceptibility factors (most notable of which are the HLA genes) can lead to autoimmune diseases. Autoimmunity).

  • Ventricular fibrillation (VF):
    • Disorganized high-frequency electrical activity in the ventricles
    • No mechanical contraction, which means no pulse
  • Pulseless ventricular tachycardia Ventricular tachycardia Ventricular tachycardia is any heart rhythm faster than 100 beats/min, with 3 or more irregular beats in a row, arising distal to the bundle of His. Ventricular tachycardia is the most common form of wide-complex tachycardia, and it is associated with a high mortality rate. Ventricular Tachycardia (VT):
    • Rapid, regular ventricular rate with a wide QRS complex
    • More than 100/min on rhythm strip

Non-shockable rhythms

  • Asystole:
    • No discernible electrical activity
    • Flatline on electrocardiogram Electrocardiogram An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG) (P waves and QRS complexes are not present)
  • Pulseless electrical activity (PEA): 
    • Electrocardiogram ( ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG)) shows a cardiac rhythm without a palpable pulse.
    • May be organized (with normal-appearing ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG) complexes) or unorganized (no discernible complexes on ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG))
    • From electromechanical dissociation, or no cardiac filling (“empty heart”)

Management with Basic Life Support (BLS)

Chain of survival

  1. Recognize an arrest and confirm scene safety. 
    • Attempt to rouse the patient verbally and physically.
    • Observe for signs of breathing (patients may have agonal breathing in cardiac arrest).
    • Check the patient’s pulse within 10 seconds:
      • Use the carotid artery in adults.
      • Use the brachial or femoral artery in children.
  2. Activate the emergency response system.
    • Call for help/call other people for assistance.
    • Call 911.
    • Have someone get an automated external defibrillator (AED), if available.
  3. Start cardiopulmonary resuscitation (CPR) immediately.
    • Ideally done simultaneously with calling for help
    • Important addition: If opioid overdose is suspected, give naloxone if available.
  4. Check the cardiac rhythm with an AED once it arrives.
  5. When shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock is indicated, continue chest compressions until just before shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock is ready to be given.
  6. Resume chest compressions immediately after delivery of shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock, continuing until emergency responders are available.

High-quality CPR

  • Single most important intervention for cardiac arrest; should be provided promptly!
  • No serious harm from CPR found in patients determined not to be in cardiac arrest
  • 30 chest compressions followed by 2 rescue breaths (30:2) in adults
  • 15:2 in child/infant victim if with 2 rescuers
  • Principal components: 
    • Rate: 100–120 compressions/min
    • Compression depth: 5–7.6 cm (2–3 in) (child: 5 cm (2 in), infant: 3.8 cm (1.5 in))
    • Continuity: Limit pauses during CPR.
    • Allow full chest recoil.
    • Avoid excessive ventilation (1 breath every 5–6 seconds).
  • Airway access:
    • Head tilt/chin lift to establish an airway.
    • For cervical injury: jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint thrust without head extension
    • Deliver breath mouth-to-mouth or via bag-mask ventilation.
General cardiopulmonary resuscitation (cpr) cycle

General CPR cycle: (start: bottom image)
1. Upon recognition of cardiac arrest, give 30 firm chest compressions.
2. Follow the compressions with 2 rescue breaths.
3. When an AED arrives, place pads in appropriate areas.
4. When prompted by the AED, check rhythm and deliver the shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock when indicated (after making sure that no one is in physical contact with the patient).
Resume CPR cycle after shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock delivery.

Image: “Aed ablauf” by Jörg Rittmeister. License: Public Domain

Management with Advanced Cardiac Life Support (ACLS)

Circulation, airway, breath (CAB)

Circulation, airway, breath is the advanced cardiac life support mantra. Since 2010, management has focused on starting chest compressions first to address circulation, then airway access and rescue breathing.

  • C (circulation):
    • High-quality CPR
    • Determine rhythm; in PEA/asystole, continue CPR.
    • Defibrillate shockable rhythms:
      • Shock at 120–200 joules on a biphasic defibrillator (lower peak electric current efficient in terminating ventricular tachyarrhythmias).
      • Shock at 360 joules on a monophasic defibrillator. 
    • Establish intravenous (IV) or intraosseous (IO) access.
    • Epinephrine 1 mg IV and repeat every 3–5 minutes for all rhythms.
    • Medications for shockable rhythms ( ventricular tachycardia Ventricular tachycardia Ventricular tachycardia is any heart rhythm faster than 100 beats/min, with 3 or more irregular beats in a row, arising distal to the bundle of His. Ventricular tachycardia is the most common form of wide-complex tachycardia, and it is associated with a high mortality rate. Ventricular Tachycardia/fibrillation):
      • Amiodarone 300 mg IV with repeat dose of 150 mg IV as indicated
      • Consider lidocaine.
      • For torsades de pointes: magnesium sulfate (not for routine use)
  • A (airway): 
    • Bag-mask device (if not intubated)
    • Use of an advanced airway (endotracheal tube or ETT): 10/min
  • B (breathing): 
    • Oxygenate patient with 100% oxygen.
    • Use quantitative waveform capnography (check end-tidal (ETCO₂)): If ETCO₂ is low or decreasing, check CPR quality.
  • Differential diagnosis: 5 Hs and 5 Ts; treat accordingly
Adult cardiac arrest diagram

Adult cardiac arrest diagram
Upon recognition of cardiac arrest, rapid evaluation of breathing, pulse and rhythm (once cardiac monitor is available) is done and cardiopulmonary resuscitation (CPR) is initiated. Defibrillate shockable rhythms, ventricular fibrillation Ventricular fibrillation Ventricular fibrillation (VF or V-fib) is a type of ventricular tachyarrhythmia (> 300/min) often preceded by ventricular tachycardia. In this arrhythmia, the ventricle beats rapidly and sporadically. The ventricular contraction is uncoordinated, leading to a decrease in cardiac output and immediate hemodynamic collapse. Ventricular Fibrillation (VF) or pulseless ventricular tachycardia Ventricular tachycardia Ventricular tachycardia is any heart rhythm faster than 100 beats/min, with 3 or more irregular beats in a row, arising distal to the bundle of His. Ventricular tachycardia is the most common form of wide-complex tachycardia, and it is associated with a high mortality rate. Ventricular Tachycardia (VT). If with pulseless electrical activity/asystole, CPR continues. Simultaneously through the process, intravenous (IV) access (or intraosseous access) is obtained to administer needed medications. IV epinephrine is given every 3–5 minutes.
Endotracheal intubation (advanced airway) is performed. Quantitative waveform capnography (which shows end-tidal (et)CO₂) is monitored. If (et)CO₂ is low, reassess CPR quality.
Cycle of steps (defibrillation and/or CPR with minimal interruption + airway support → rhythm, pulse and blood pressure check → IV medication administration) continues until return of spontaneous circulation (ROSC). Continuation of the cycle is also assessed if there is no ROSC. Signs of ROSC are: pulse and blood pressure present, abrupt sustained increase in etCO₂ (about ≥ 40 mm Hg) and spontaneous arterial pressure waves with intra-arterial monitoring.

Image by Lecturio.

Special populations

  • Pediatric advanced life support (PALS): 
    • In asystole/PEA, administer epinephrine as soon as possible (within 5 min).
    • Use cuffed ETT to reduce air leaks.
    • Respiratory rate increased to 20–30/min
    • Medications and shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock energy are given based on weight.
  • Pregnant patient in-hospital ACLS:
    • More prone to hypoxia: oxygenation and airway management Airway management An airway, breathing, and circulation (ABC) assessment is the mainstay for evaluating and treating critically ill individuals. The airway assessment helps identify individuals with potential obstruction of the airway, which may benefit from airway management techniques to ensure adequate ventilation and oxygenation. Airway Management prioritized during resuscitation from cardiac arrest 
    • Adult ACLS + IV placement above the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm (ensures the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Posterior Abdominal Wall does not obstruct IV administration)
    • If receiving IV magnesium: Stop and give calcium chloride or gluconate.
    • Provide lateral uterine displacement to relieve aortocaval compression.
    • Obstetric and neonatal care:
      • If no ROSC in 5 minutes: immediate perimortem cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery
      • Neonatal team to receive neonate
    • Consider etiologies of maternal cardiac arrest (A, B, C, D, E, F, G, H):
      • Anesthetic complications
      • Bleeding
      • Cardiovascular
      • Drugs
      • Embolic
      • Fever
      • General nonobstetric causes (5 Hs and 5 Ts)
      • Hypertension
  • Coronavirus disease 2019 Coronavirus disease 2019 Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that mainly affects the respiratory system but can also cause damage to other body systems (cardiovascular, gastrointestinal, renal, and central nervous systems). ( COVID-19 COVID-19 Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that mainly affects the respiratory system but can also cause damage to other body systems (cardiovascular, gastrointestinal, renal, and central nervous systems). ):
    • Whenever possible, patients are placed in negative pressure rooms.
    • Don appropriate personal protective equipment (PPE) prior to entry.
    • Limit personnel performing CPR.
    • Oxygenation, preferably with low aerosolization risk
    • Pause chest compression for endotracheal intubation.
    • When possible, connect patient to a ventilator with inline HEPA (high-efficiency particulate air) filter.

Outcomes

Return of spontaneous circulation signs

  • Pulse and blood pressure
  • Abrupt sustained increase in ETCO₂ level (about ≥ 40 mm Hg)
  • Spontaneous arterial pressure waves with intra-arterial monitoring

Criteria for termination of resuscitation:

  • Several factors considered in making the decision to stop:
    • Duration of resuscitation (> 30 minutes without perfusing rhythm)
    • Initial rhythm: asystole
    • Absence of brainstem function
    • Long interval between arrest and resuscitation
    • Patient age and comorbidities
    • Normothermia
  • In out-of-hospital resuscitation, the criteria are:
    • Arrest not witnessed by emergency medical services (EMS)
    • Asystole/PEA (no shocks delivered)
    • No ROSC before the 3rd dose of epinephrine
  • ETCO₂ level:
    • Indicates CO₂ production, which increases with perfusion and pulmonary circulation (↑ in ROSC)
    • When low, confirm endotracheal tube placement first.  
    • A confirmed low EtCO₂ (< 10 mm Hg) in > 20 min of resuscitation: absent circulation and predicts acute mortality

Post-resuscitation Care

Goals

  • Brain injury mitigation
  • Manage ischemia-reperfusion injury and support multi-organ systems.
  • Determine and treat cause of SCA.
  • Involve a multidisciplinary medical team given complexity of post-arrest patient care.

Critical care

  • Hemodynamic support:
    • Use of crystalloid and/or vasopressor or inotropic support
    • Maintain systolic blood pressure > 90 mm Hg or mean arterial pressure Mean Arterial Pressure Mean arterial pressure (MAP) is the average systemic arterial pressure and is directly related to cardiac output (CO) and systemic vascular resistance (SVR). The SVR and MAP are affected by the vascular anatomy as well as a number of local and neurohumoral factors. Vascular Resistance, Flow, and Mean Arterial Pressure > 65 mm Hg.
    • Emergent cardiac intervention in cases of ST-segment elevation myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction and/or cardiogenic shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
  • Mechanical ventilation:
    • Titrate fraction of inspired oxygen (FiO2) for oxygen saturation (SPO2) > 94%.
    • Titrate to partial pressure Partial pressure The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. Gas Exchange of carbon dioxide (PaCO2) 35–45 mm Hg.
    • Start at 10/min.
  • Targeted temperature management for comatose patient:
    • Improves neurologic outcome 
    • Use of cooling device with feedback loop, beginning at 32–36ºC (89.6–96.8ºF) for 24 hours
    • ↑ risk of death for each degree rise above 37ºC (98.6ºF)
  • Other critical care management:
    • Continuous temperature monitoring
    • Maintenance of normoxia and normocapnia
    • Lung-protective ventilation
    • Maintenance of euglycemia ( insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin therapy to maintain a blood glucose of 150–180 mg/dL)
    • Electroencephalogram (EEG) monitoring
  • Evaluation and treatment of causes:
    • Obtain brain computed tomography (CT) scan
    • Other imaging studies depending on the clinical picture
    • Laboratory tests
    • Remember the 5 Hs and Ts.

Prevention

Primary prevention

  • Screen for risk factors for CHD ( lipid disorders Lipid disorders An abnormal amount of lipid in blood is called dyslipidemia, which includes abnormal levels of cholesterol, triglycerides, and/or lipoproteins. Dyslipidemia may be primary (familial) or secondary (acquired). Both primary and secondary causes can lead to the development of premature cardiovascular (atherosclerosis) disease. Lipid Disorders, hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension).
  • Screen for CHD (in appropriate patients).
  • Reduce risk factors:
    • Control hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension.
    • Treat hypercholesterolemia.
    • Treat diabetes.
    • Smoking cessation
    • Moderate alcohol consumption
    • Heart-healthy diet and regular exercise

Secondary prevention

  • Implantable cardioverter-defibrillator (ICD):
    • Terminates ventricular arrhythmias when they recur
    • Recommended in the following:
      • Survivors of SCA (from VT/VF) with heart failure and cardiomyopathy Cardiomyopathy Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Overview of Cardiomyopathies
      • Patients with structural heart disease (associated with hemodynamically unstable VT or spontaneous sustained VT)
  • Antiarrhythmic therapy:
    • Drugs (adjunctive treatment):
      • Amiodarone (preferred)
      • Sotalol
      • Mexiletine
    • Catheter ablation (adjunctive treatment)

Clinical Relevance

The following conditions are causes of cardiac arrest:

  • Pericardial tamponade: a clinical syndrome caused by the accumulation of fluid in the pericardial space; results in reduced ventricular filling and subsequent hemodynamic compromise. Patients present with Beck’s triad ( hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension, distended jugular veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins, and muffled heart sounds Heart sounds Heart sounds are brief, transient sounds produced by valve opening and closure and by movement of blood in the heart. They are divided into systolic and diastolic sounds. In most cases, only the first (S1) and second (S2) heart sounds are heard. These are high-frequency sounds and arise from aortic and pulmonary valve closure (S1), as well as mitral and tricuspid valve closure (S2). Heart Sounds). Tamponade can cause cardiac arrest. Treatment is with pericardiocentesis.
  • Tension pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax: an abnormal collection of air in the pleural space due to laceration of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs. Types of pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax include simple (spontaneous) and tension. Physical exam findings include decreased breath sounds, hyperresonance on percussion, and tracheal deviation. Treatment includes needle decompression and chest tube placement.
  • Coronary heart disease Coronary heart disease Coronary heart disease (CHD), or ischemic heart disease, describes a situation in which an inadequate supply of blood to the myocardium exists due to a stenosis of the coronary arteries, typically from atherosclerosis. Coronary Heart Disease: acute anginal pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain because of partial or total occlusion of 1 or more coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries due to advanced coronary heart disease. Three clinical entities can be identified: unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina, non-ST-segment elevation myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction ( MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction), and ST-segment elevation MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction. Diagnosis is by ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Normal Electrocardiogram (ECG) and cardiac enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body's constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes. Treatment is with percutaneous coronary intervention and/or medical management.
  • Cardiomyopathies: a group of myocardial diseases associated with impaired systolic and diastolic function. Classified into dilated, hypertrophic, and restrictive cardiomyopathies. Potential complications include heart failure, arrhythmias, and sudden death. Treatment varies based on type and includes medications and/or surgery.

References

  1. Marine, J., Russo, A., Knight, B., Levy, S., Yeon, S. (2020) Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy. UpTodate. Retrieved December 19, 2020, from https://www.uptodate.com/contents/secondary-prevention-of-sudden-cardiac-death-in-heart-failure-and-cardiomyopathy
  2. Panchal, A. et al. (2020). Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 142 (16): S366–S468. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000916
  3. Podrid, P. (2019). Overview of sudden cardiac arrest and sudden cardiac death. UpToDate. Retrieved December 5, 2020, from https://www.uptodate.com/contents/overview-of-sudden-cardiac-arrest-and-sudden-cardiac-death
  4. Rittenberger, J and Callaway, C. (2020). Post-cardiac arrest management in adults. UpToDate. Retrieved December 5, 2020, from https://www.uptodate.com/contents/post-cardiac-arrest-management-in-adults
  5. Podrid, P. (2019). Pathophysiology and etiology of sudden cardiac arrest. UpToDate. Retrieved December 5, 2020, from https://www.uptodate.com/contents/pathophysiology-and-etiology-of-sudden-cardiac-arrest
  6. Rittenberger, J and Callaway, C. (2020). Post-cardiac arrest management in adults. UpToDate. Retrieved December 5, 2020, from https://www.uptodate.com/contents/post-cardiac-arrest-management-in-adults
  7. Topjian, A. et al. (2020). Part 4: Pediatric Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 142(16):S469–S523.

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