Cardiac arrest is a sudden, life-threatening condition where the heart stops beating effectively, leading to loss of blood flow to the brain and vital organs. Unlike a heart attack, which involves blocked blood flow, cardiac arrest is an electrical malfunction that requires immediate CPR and defibrillation to prevent death.

Introduction: Definition and

Cardiac arrest is a critical medical emergency characterised by the sudden and unexpected cessation of effective cardiac mechanical activity, resulting in the loss of circulation, consciousness, and spontaneous breathing. Unlike a heart attack (myocardial infarction), which refers to compromised blood flow to the heart muscle, cardiac arrest involves the abrupt failure of the heart’s pumping function, leading to immediate cessation of blood flow to vital organs. If not treated within minutes, cardiac arrest can lead to irreversible organ damage and death.

Epidemiology of Cardiac Arrest

Globally, cardiac arrest remains a significant cause of morbidity and mortality. It is estimated that out-of-hospital cardiac arrest (OHCA) occurs in approximately 55–113 per 1 lakh population annually, with survival rates ranging from 2% to 10% depending on the region, access to emergency services, and the timeliness of intervention. In-hospital cardiac arrest (IHCA) also contributes substantially to healthcare burden, with varied outcomes based on hospital resources and protocols.

Pathophysiology:

At the cellular and organ level, cardiac arrest is the result of a sudden disruption in the heart’s electrical activity, mechanical function, or both. The majority of cases are due to arrhythmias—abnormal heart rhythms—that compromise the heart’s ability to pump blood. The most common arrhythmias leading to cardiac arrest are ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). Less commonly, asystole (total absence of electrical activity) or pulseless electrical activity (PEA) may be the cause.

Underlying these arrhythmias are a variety of pathological processes including acute ischaemia (often due to coronary artery disease), electrolyte imbalances (such as hyperkalaemia or hypokalaemia), severe hypoxia, acidosis, and structural heart diseases like cardiomyopathies. Cardiac arrest can also result from non-cardiac causes, such as massive pulmonary embolism, severe trauma, or drug overdose, which either directly impair cardiac function or disrupt the electrical conduction system.

Causes and Risk Factors

Common Causes

• Coronary Artery Disease (CAD): The leading cause, responsible for up to 80% of cases in adults. Acute myocardial infarction may precipitate fatal arrhythmias.
• Cardiomyopathy: Conditions such as hypertrophic, dilated, or arrhythmogenic right ventricular cardiomyopathy may predispose to arrhythmias.
• Inherited Channelopathies: Genetic conditions like Long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic VT.
• Structural Heart Defects: Congenital anomalies, valvular diseases, and previous cardiac surgeries.
• Electrolyte Imbalances: Abnormal potassium, calcium, and magnesium levels can destabilise cardiac electrical activity.
• Respiratory Causes: Severe hypoxia due to airway obstruction, drowning, or asphyxiation.
• Other Causes: Major trauma, massive pulmonary embolism, drug toxicity (especially antiarrhythmics, tricyclic antidepressants, opioids), severe infections (sepsis), and metabolic derangements.

Risk Factors

• Age: Incidence increases with age, particularly beyond 45 years.
• Gender: Males have a higher risk compared to females.
• Family History: Sudden cardiac death in first-degree relatives.
• Personal History: Previous myocardial infarction, heart failure, or arrhythmias.
• Lifestyle Factors: Smoking, sedentary lifestyle, poor diet, excessive alcohol intake.
• Chronic Diseases: Diabetes mellitus, hypertension, obesity, chronic kidney disease.
• Drug Use: Use of stimulants, illicit drugs, or medications that prolong QT interval.

Clinical Presentation

Cardiac arrest is distinguished by its abrupt and dramatic presentation. The classic signs and symptoms include:

• Sudden Collapse: The individual may suddenly lose consciousness and fall to the ground.
• Absence of Pulse: No palpable central pulse (carotid or femoral) can be detected.
• No Normal Breathing: The person is not breathing or is only gasping (agonal respiration).
• Unresponsiveness: The patient does not respond to verbal or painful stimuli.
• Cyanosis: Bluish discolouration of the lips and extremities due to hypoxia.
• Occasional Seizure-like Activity: Brief convulsive movements may occur immediately following collapse.

Recognition of cardiac arrest in any healthcare or community setting is a critical step in initiating prompt life-saving interventions.

Diagnosis

Diagnostic Criteria

Cardiac arrest is diagnosed clinically based on three cardinal features:

1. Unresponsiveness
2. Absence of normal breathing
3. Absence of central pulse

Diagnostic Tests

• Electrocardiogram (ECG): Essential for identifying the underlying rhythm (VF, VT, asystole, or PEA).
• Blood Tests: Arterial blood gases, electrolytes, cardiac enzymes, and markers of organ dysfunction.
• Imaging: Chest X-ray, echocardiography, or CT scan may be considered post-resuscitation to identify reversible causes.

During the acute event, diagnosis is primarily clinical; investigations are pursued after return of spontaneous circulation (ROSC).

Differential Diagnosis

• Syncope: Temporary loss of consciousness due to transient cerebral hypoperfusion, with spontaneous recovery.
• Seizure: May mimic cardiac arrest but usually accompanied by post-ictal confusion and preserved breathing.
• Stroke: Sudden neurological deficit, but without loss of pulse or breathing.
• Respiratory Arrest: Absence of breathing but pulse may be present initially.

Emergency Management

Immediate Response

Prompt recognition and immediate action are crucial. The recommended steps, summarised by the “Chain of Survival”, include:

1. Early recognition of cardiac arrest and activation of emergency medical services (EMS).
2. Immediate initiation of high-quality cardiopulmonary resuscitation (CPR).
3. Rapid defibrillation when appropriate (especially for VF/VT).
4. Effective advanced life support (ALS) and post-resuscitation care.

Cardiopulmonary Resuscitation (CPR)

CPR is the cornerstone of emergency cardiac arrest management. Current guidelines emphasise:

• Chest compressions at a rate of 100–120 per minute, with a depth of at least 5 cm but not more than 6 cm in adults.
• Allowing full chest recoil between compressions.
• Minimising interruptions in compressions.
• Providing rescue breaths at a ratio of 30:2 compressions to breaths (for trained rescuers).
• Use of automated external defibrillators (AEDs) as soon as available.

In settings where advanced airway management is feasible, continuous chest compressions with asynchronous ventilation can be provided.

Defibrillation

Defibrillation is indicated for shockable rhythms (VF/VT). Early defibrillation significantly improves survival rates. AEDs are designed for use by laypersons and professionals alike, and their widespread availability in public spaces is a key factor in improving outcomes.

Advanced Life Support (ALS)

ALS includes advanced airway management, intravenous or intraosseous access, administration of medications (such as adrenaline, amiodarone), and identification of reversible causes (the “Hs and Ts”: hypoxia, hypovolaemia, hydrogen ion (acidosis), hypo/hyperkalaemia, hypothermia, toxins, tamponade, tension pneumothorax, thrombosis—pulmonary or coronary).

ALS requires a coordinated team approach and is typically performed by trained healthcare professionals.

Hospital Treatment

Following successful resuscitation (ROSC), comprehensive post-resuscitation care is critical to optimise neurological recovery and prevent recurrence. Key elements include:

• Airway and Breathing: Secure airway, optimise oxygenation and ventilation. Avoid hyperoxia.
• Haemodynamic Support: Maintain adequate blood pressure and perfusion, often requiring vasopressors or inotropes.
• Targeted Temperature Management (TTM): Induced hypothermia (32–36°C) for comatose survivors to reduce neurological injury.
• Coronary Reperfusion: Emergent coronary angiography and percutaneous coronary intervention (PCI) if myocardial infarction is suspected.
• Neurological Monitoring: Serial neurological assessments, EEG, and neuroimaging as indicated.
• Organ Support: Renal replacement therapy or mechanical ventilation as needed.
• Continuous Cardiac Monitoring: Detection and management of recurrent arrhythmias.
• Psychological Support: Early involvement of rehabilitation and mental health services for patients and families.

Prevention

Primary Prevention

The primary goal is to reduce the incidence of first-time cardiac arrest through modification of risk factors:

• Control of hypertension, diabetes, and hyperlipidaemia through medication and lifestyle changes.
• Smoking cessation and reduction of alcohol intake.
• Regular physical activity and healthy diet (rich in fruits, vegetables, whole grains, and low in saturated fats).
• Weight management to prevent obesity.
• Management of underlying heart diseases and regular follow-up for high-risk individuals.
• Education regarding the warning signs of cardiac disease and the importance of timely medical consultation.

Secondary Prevention

For individuals with known heart disease or previous cardiac events:

• Use of implantable cardioverter-defibrillators (ICDs) in high-risk patients.
• Optimisation of heart failure therapy and arrhythmia management.
• Regular cardiac monitoring and prompt treatment of arrhythmias.
• Patient and family education regarding CPR and emergency response.

Public Health Measures

• Widespread training of laypersons and healthcare workers in basic life support (BLS) and CPR.
• Strategic placement of AEDs in public areas (airports, railway stations, malls, workplaces).
• Development of robust emergency medical services (EMS) systems, especially in rural and semi-urban regions.
• Public awareness campaigns to reduce stigma and encourage prompt action during cardiac emergencies.

Prognosis and Outcomes

The prognosis following cardiac arrest depends on multiple factors, including the cause, time to initiation of CPR, availability of defibrillation, quality of post-resuscitation care, and patient comorbidities. Key points include:

• Overall survival to hospital discharge after OHCA remains low (2–10%), but early CPR and defibrillation can double or triple survival rates.
• Neurological outcome is closely linked to the duration of cerebral hypoxia. Delayed resuscitation increases the risk of hypoxic-ischemic brain injury, leading to cognitive deficits or persistent vegetative state.
• Complications such as multi-organ dysfunction, infections, and recurrent arrhythmias may occur in survivors.
• Long-term follow-up is essential for rehabilitation and management of physical, emotional, and cognitive sequelae.

In India and other resource-limited settings, delayed access to emergency care, lack of public awareness, and limited availability of AEDs further worsen prognosis.

Impact

Impact on Patients

Survivors of cardiac arrest often face significant physical, psychological, and social challenges. Physical sequelae can include reduced functional capacity, chronic fatigue, and neurological impairment. Psychological effects such as anxiety, depression, post-traumatic stress disorder (PTSD), and cognitive dysfunction are common. Long-term rehabilitation, including physiotherapy, occupational therapy, and psychiatric support, is essential for optimal recovery.

Impact on Families

Cardiac arrest is a traumatic event for families, who may experience emotional distress, grief, and anxiety regarding the patient’s prognosis and future. Caregivers often require support to cope with the demands of long-term care and the uncertainty of outcomes.

Impact on Healthcare Systems

Cardiac arrest imposes a substantial burden on healthcare resources, encompassing pre-hospital emergency services, intensive care units, advanced diagnostics, and rehabilitation programmes. The direct costs include emergency care, hospitalisation, and interventions such as ICD implantation. Indirect costs arise from lost productivity, long-term disability, and the need for ongoing support services. In India, the strain on public health infrastructure is exacerbated by disparities in access, awareness, and resources, highlighting the need for integrated, system-wide approaches to prevention and management.

Nursing Care of Patients with Cardiac Arrest

Nursing care required for patients with cardiac arrest, encompassing emergency management, ongoing assessment, post-resuscitative care, support for families, and the importance of education and prevention.

Immediate Nursing Response to Cardiac Arrest

Recognition and Activation

The first step is immediate recognition. Signs include sudden collapse, loss of consciousness, absence of pulse, and abnormal or absent breathing. The nurse should initiate the following actions rapidly:

• Check for responsiveness and breathing.
• Activate emergency response system (call for help, code blue, etc.).
• Obtain an automated external defibrillator (AED) or crash cart.

Basic Life Support (BLS)

Nurses trained in BLS should provide high-quality chest compressions and ventilations:

• Place the patient on a firm, flat surface.
• Begin chest compressions at a rate of 100–120 compressions per minute, with a depth of 5–6 cm (2–2.5 inches) in adults.
• Allow full chest recoil between compressions.
• Minimize interruptions in compressions.
• Provide rescue breaths at a ratio of 30:2 compressions-to-breaths with a bag-mask device or mouth-to-mask.
• Use a barrier device to protect both patient and provider.

Advanced Life Support (ALS)

Once the code team or advanced responders arrive, nurses should assist in advanced interventions:

• Attach cardiac monitor/defibrillator pads for rhythm analysis.
• Prepare for defibrillation if indicated (e.g., ventricular fibrillation or pulseless ventricular tachycardia).
• Establish intravenous (IV) or intraosseous (IO) access for medication administration.
• Administer emergency drugs as ordered (e.g., epinephrine, amiodarone).
• Assist with airway management, including endotracheal intubation if necessary.
• Document events, medications, and time intervals accurately.

Post-Resuscitation (Post-Cardiac Arrest) Care

Once spontaneous circulation returns (return of spontaneous circulation – ROSC), the focus shifts to optimizing recovery and preventing recurrence.

Hemodynamic Stabilization

• Monitor vital signs continuously (heart rate, blood pressure, oxygen saturation).
• Maintain systolic blood pressure above 90 mmHg and mean arterial pressure (MAP) above 65 mmHg.
• Administer IV fluids or vasopressors as ordered.
• Monitor heart rhythm for recurring arrhythmias.

Airway and Breathing Management

• Maintain airway patency; ensure endotracheal tube placement if intubated.
• Monitor arterial blood gases (ABGs) and adjust oxygen settings to maintain SpO2 ≥ 94%.
• Avoid hyperoxia (excessive oxygen) as well as hypoxia.
• Suction airway as needed to prevent aspiration and maintain airway clearance.

Neurological Assessment and Protection

• Perform frequent neurological assessments (level of consciousness, pupillary response, motor function).
• Monitor for seizures and initiate anticonvulsants if indicated.
• Consider targeted temperature management (therapeutic hypothermia) to reduce neurological injury, following hospital protocols.

Management of Metabolic and Other Complications

• Monitor blood glucose levels; treat hypo- or hyperglycemia.
• Correct electrolyte imbalances (potassium, calcium, magnesium).
• Monitor renal function and urine output.
• Assess for and treat acidosis or alkalosis.

Infection Prevention

• Practice strict aseptic technique with lines and catheters.
• Monitor for signs of sepsis or infection, such as fever, leukocytosis, or local inflammation.
• Administer prophylactic antibiotics as prescribed.

Skin Integrity and Pressure Ulcer Prevention

• Perform regular skin assessments, especially in unconscious or immobile patients.
• Reposition patient every two hours, or as tolerated, to prevent pressure ulcers.
• Use pressure-relieving devices as indicated (specialized mattresses, cushions).

Ongoing Monitoring and Support

Vital Signs and Hemodynamics

Continuous monitoring of vital signs is essential. Nurses should promptly report any deviations to the medical team and intervene as appropriate.

Pain, Comfort, and Sedation

• Assess for and manage pain or discomfort; use validated pain scales where possible.
• Administer sedation or analgesia as ordered for intubated or agitated patients.
• Provide non-pharmacological comfort measures (e.g., positioning, quiet environment).

Psychological Support

• Communicate with the patient, even if unconscious; hearing may be preserved.
• Support and educate the patient’s family, explaining interventions and prognosis compassionately.
• Offer resources such as chaplaincy, counseling, or social work.

Nutrition and Hydration

• Assess nutritional status and collaborate with dietitians.
• Provide enteral or parenteral nutrition as appropriate for comatose or intubated patients.
• Monitor fluid balance and correct any imbalances.

Documentation and Communication

Accurate and timely documentation is crucial during cardiac arrest and after resuscitation.

• Record the timeline of events (onset, interventions, medications given, ROSC, etc.).
• Document assessments, findings, and any changes in the patient’s condition.
• Ensure all members of the healthcare team are informed of updates and care plans.

Family Involvement and Support

Nurses often serve as a vital link between the medical team and the patient’s family.

• Inform family members promptly and clearly about the patient’s condition.
• Offer comfort, presence, and information in a supportive, non-judgmental manner.
• Allow family to be present during resuscitation if appropriate and in line with hospital policy.
• Address questions and concerns, and provide educational materials about cardiac arrest and recovery.

Prevention

Nurses play a pivotal role in educating patients and families about cardiac arrest prevention and post-arrest rehabilitation.

Patient and Family Education

• Teach risk factors for cardiac arrest (e.g., underlying cardiac conditions, lifestyle).
• Discuss the importance of medication adherence and regular follow-up.
• Train family members in basic life support and how to use an AED.
• Promote healthy lifestyle modifications: proper diet, exercise, smoking cessation, and stress reduction.

Rehabilitation

Post-cardiac arrest patients may require rehabilitation:

• Physical therapy for mobility and strength.
• Speech and occupational therapy for neurological deficits.
• Psychological support for emotional recovery (anxiety, depression, PTSD).

Ethical and Legal Considerations

Nurses must be familiar with ethical dilemmas that can arise in cardiac arrest situations, including:

• Respecting advance directives or do-not-resuscitate (DNR) orders.
• Balancing aggressive life-sustaining treatment with patient wishes and quality of life.
• Ensuring informed consent for interventions and procedures.

REFERENCES

1. American Heart Association. About Cardiac Arrest. https://www.heart.org/en/health-topics/cardiac-arrest/about-cardiac-arrest. Last reviewed 11/9/2023.
2. Elmer J, Rittenberger JC, Coppler PJ, et al. Long-term survival benefit from treatment at a specialty center after cardiac arrest . https://pubmed.ncbi.nlm.nih.gov/27650862/. Resuscitation. 2016 Nov;108:48-53.
3. Fugate JE, Rabinstein AA. Life after cardiac arrest: better with time. http://pubmed.ncbi.nlm.nih.gov/24291509/). Resuscitation. 2014 Feb;85(2):157-8.
4. Merck Manual Consumer Version. Cardiac Arrest and CPR.https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/cardiac-arrest-and-cpr/cardiac-arrest-and-cpr. Revised 4/2023.
5. National Heart, Lung, and Blood Institute (U.S.). What Is Cardiac Arrest?. https://www.nhlbi.nih.gov/health/cardiac-arrest Last updated 5/19/2022.
6. Sawyer KN, Camp-Rogers TR, Kotini-Shah P, et al. Sudden Cardiac Arrest Survivorship: A Scientific Statement From the American Heart Association. https://pubmed.ncbi.nlm.nih.gov/32078390/. Circulation. 2020 Mar 24;141(12):e654–e685.
7. Sudden Cardiac Arrest Foundation. Latest Statistics. https://www.sca-aware.org/about-sudden-cardiac-arrest/latest-statistics.
8. Tsao CW, Aday AW, Almarzooq ZI, et al. Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association. https://pubmed.ncbi.nlm.nih.gov/36695182/ [published correction appears in Circulation. 2023 Feb 21;147(8):e622]

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