Cardiac arrest - Clinicals, Diagnosis, and Management

Emergency Medicine

Clinicals - History

Fact Explanation
Sudden loss of consciousness Cardiac arrest is the sudden and complete cessation of cardiac output which is a medical emergency. Loss of consciousness is due to disrupted blood supply to the brain. The most common causes are catastrophic arrhythmias or mechanical causes such as cardiac rupture or aortic dissection. Ventricular fibrillation, ventricular tachycardia and asystole are arrhythmias that can lead to cardiac arrest. Pulse-less electrical activity is the absence of cardiac output in spite of normal electrical activity in the heart. Causes include cardiac tamponade, pulmonary thrombosis, hypovolaemia etc. Sudden loss of consciousness
Cardiac arrest is the sudden and complete cessation of cardiac output which is a medical emergency. Loss of consciousness is due to disrupted blood supply to the brain. The most common causes are catastrophic arrhythmias or mechanical causes such as cardiac rupture or aortic dissection. Ventricular fibrillation, ventricular tachycardia and asystole are arrhythmias that can lead to cardiac arrest. Pulse-less electrical activity is the absence of cardiac output in spite of normal electrical activity in the heart. Causes include cardiac tamponade, pulmonary thrombosis, hypovolaemia etc.
Cessation of normal breathing Breathing usually continues for sometime after cessation of cardiac function. Agonal breathing describes the labored breathing or gasping associated with cardiac arrest. Cessation of normal breathing
Breathing usually continues for sometime after cessation of cardiac function. Agonal breathing describes the labored breathing or gasping associated with cardiac arrest.
History of previous cardiac disease. Various cardiac diseases such as coronary artery disease, cardiomyopathies, valvular heart disease etc can lead to cardiac arrest and sudden cardiac death. Coronary heart disease is a common cause of cardiac arrest and the patient may have a history of chest pain, previous myocardial infarction and previous cardiac arrest. Risk factors for cardiac disease such as diabetes mellitus, smoking, hypertension, hyperlipidaemia etc may also be present. History of previous cardiac disease.
Various cardiac diseases such as coronary artery disease, cardiomyopathies, valvular heart disease etc can lead to cardiac arrest and sudden cardiac death. Coronary heart disease is a common cause of cardiac arrest and the patient may have a history of chest pain, previous myocardial infarction and previous cardiac arrest. Risk factors for cardiac disease such as diabetes mellitus, smoking, hypertension, hyperlipidaemia etc may also be present.

Clinicals - Examination

Fact Explanation
Examination should be meticulous and rapid. Initiation of patient resuscitation is the main priority in cardiac arrest. Resuscitation should be prompt and started inn the out-hospital setting. Maintaining adequate cerebral perfusion prevents cerebral ischemia and damage. Use the A- airway, B- breathing, C- circulation approach when examining the patient. Examination should be meticulous and rapid.
Initiation of patient resuscitation is the main priority in cardiac arrest. Resuscitation should be prompt and started inn the out-hospital setting. Maintaining adequate cerebral perfusion prevents cerebral ischemia and damage. Use the A- airway, B- breathing, C- circulation approach when examining the patient.
Cardiovascular examination – Inability to feel the pulse, No blood pressure recording Lack of cardiac output will lead to absence of pulse and unrecordable blood pressure. It is important to note that examination of patient and investigations should not delay the initiation of emergency resuscitation. Cardiovascular examination – Inability to feel the pulse, No blood pressure recording
Lack of cardiac output will lead to absence of pulse and unrecordable blood pressure. It is important to note that examination of patient and investigations should not delay the initiation of emergency resuscitation.
Respiratory examination - Absence of spontaneous breathing Look, listen and feel for spontaneous breathing. Respiratory examination - Absence of spontaneous breathing
Look, listen and feel for spontaneous breathing.

Investigations - Diagnosis

Fact Explanation
The diagnosis is clinical Make a quick assessment of the unresponsive patient to check the pulse and breathing. Once suspected quickly start cardiopulmonary resuscitation (CPR) without delaying for other investigations. The diagnosis is clinical
Make a quick assessment of the unresponsive patient to check the pulse and breathing. Once suspected quickly start cardiopulmonary resuscitation (CPR) without delaying for other investigations.
Serum electrolytes Metabolic changes such as hyper/hypo-kalaemia may lead to cardiac arrest. Serum electrolytes
Metabolic changes such as hyper/hypo-kalaemia may lead to cardiac arrest.
Arterial blood gas analysis (ABG) Cardiac arrest will lead to the development of metabolic acidosis due to lactic acidosis. Degree of ventilation may causes changes in this. ABG can also be used to monitor the pH and PaCO2 which correlate with coronary perfusion pressure and cardiac output. Arterial blood gas analysis (ABG)
Cardiac arrest will lead to the development of metabolic acidosis due to lactic acidosis. Degree of ventilation may causes changes in this. ABG can also be used to monitor the pH and PaCO2 which correlate with coronary perfusion pressure and cardiac output.

Investigations - Management

Fact Explanation
Post resuscitation care Continue monitoring the patient after successful resuscitation. Monitor vital parameters. Observe for features of cerebral injury or myocardial dysfunction. ECG, echocardiography can be used to assess cardiac function. Monitor blood glucose levels to prevent either hyper/ hypoglycemia. Post resuscitation care
Continue monitoring the patient after successful resuscitation. Monitor vital parameters. Observe for features of cerebral injury or myocardial dysfunction. ECG, echocardiography can be used to assess cardiac function. Monitor blood glucose levels to prevent either hyper/ hypoglycemia.
Rehabilitation Patients who survive the acute episode should investigated for an aetiology. ECG, echocardiography, caridac enzyme levels can be used to identify cardiac diseases. Risk factors for coronary heart disease can be investigated with blood glucose level, HbA1c level, lipid profile etc. Coronary angiography may be required to visualize the coronary vessels. Rehabilitation
Patients who survive the acute episode should investigated for an aetiology. ECG, echocardiography, caridac enzyme levels can be used to identify cardiac diseases. Risk factors for coronary heart disease can be investigated with blood glucose level, HbA1c level, lipid profile etc. Coronary angiography may be required to visualize the coronary vessels.

Management - Supportive

Fact Explanation
Call for help Call out for help. Management of cardiac arrest should ideally be done by a specific team of professionals with each member of the team designated with a specific task. Call for help
Call out for help. Management of cardiac arrest should ideally be done by a specific team of professionals with each member of the team designated with a specific task.
Set up monitors Monitors/ defibrillator should be quickly attached to the patient with minimum interference to CPR. the use of the capnography - end-tidal CO2 trace is currently recommended. Set up monitors
Monitors/ defibrillator should be quickly attached to the patient with minimum interference to CPR. the use of the capnography - end-tidal CO2 trace is currently recommended.

Management - Specific

Fact Explanation
Management of cardiac arrest The latest guidelines used for management of cardiac arrest are the American Heart Association (AHA) guidelines for Cardiopulmonary resuscitation and emergency cardiovascular care science published in 2010. Algorithms have being developed for basic life support and advanced life support. Management of cardiac arrest
The latest guidelines used for management of cardiac arrest are the American Heart Association (AHA) guidelines for Cardiopulmonary resuscitation and emergency cardiovascular care science published in 2010. Algorithms have being developed for basic life support and advanced life support.
Basic life support (BLS) Basic life support is recommended in the out of hospital setting where one rescuer is present. First ensure safety for the rescuer before approaching the victim. Check for responsiveness and if the patient is not responding shout out for help. Proceed to open the airway with the head tilt and chin lift. Look, listen and feel for breathing for no more than 10 seconds. If the patient's breathing has ceased or is labored proceed to administering cardiopulmonary resuscitation. Basic life support (BLS)
Basic life support is recommended in the out of hospital setting where one rescuer is present. First ensure safety for the rescuer before approaching the victim. Check for responsiveness and if the patient is not responding shout out for help. Proceed to open the airway with the head tilt and chin lift. Look, listen and feel for breathing for no more than 10 seconds. If the patient's breathing has ceased or is labored proceed to administering cardiopulmonary resuscitation.
Cardiopulmonary resuscitation (CPR) CPR is used to maintain the circulation as much as possible until definitive care administered. Chest compressions with intermittent rescue breaths are administered repeatedly. Chest compressions are administered at the lower sternum with interlocked hands. A rate of 100-120 compressions per minute and a depth of 5 - 6 cm is used. After completion of 30 compressions, correct the airway before administering 2 rescue breaths. Continue with chest compressions and rescue breaths in a ratio of 30:2. Cardiopulmonary resuscitation (CPR)
CPR is used to maintain the circulation as much as possible until definitive care administered. Chest compressions with intermittent rescue breaths are administered repeatedly. Chest compressions are administered at the lower sternum with interlocked hands. A rate of 100-120 compressions per minute and a depth of 5 - 6 cm is used. After completion of 30 compressions, correct the airway before administering 2 rescue breaths. Continue with chest compressions and rescue breaths in a ratio of 30:2.
Advanced life support As with BLS start CPR after calling for help. Connect the patient to the monitor/ defibrillator. Assess the cardiac rhythm. Ventricular fibrillation/ pulseless ventricular tachycardia are considered shockable rhythms while asystole, pulse-less electrical activity are non-shockable rhythms. Management defers depending on the type of rhythm identified. Advanced life support
As with BLS start CPR after calling for help. Connect the patient to the monitor/ defibrillator. Assess the cardiac rhythm. Ventricular fibrillation/ pulseless ventricular tachycardia are considered shockable rhythms while asystole, pulse-less electrical activity are non-shockable rhythms. Management defers depending on the type of rhythm identified.
Management of Ventricular fibrillation/ pulseless ventricular tachycardia These rhythms are managed with defibrillation. The charge used is a 150-200 J biphasic for the first shock and followed by 150-360 J biphasic shocks for subsequent attempts. CPR is continued with minimum interruption. After the shock, the rhythm is assessed and up to 3 shocks are given initially. After the 3rd shock adrenaline 1 mg IV and amiodarone 300 mg IV is administered. If VF/VT persists continue administering shocks while giving further adrenaline 1 mg IV after each alternate shock (approximately
every 3-5 min).
Management of Ventricular fibrillation/ pulseless ventricular tachycardia
These rhythms are managed with defibrillation. The charge used is a 150-200 J biphasic for the first shock and followed by 150-360 J biphasic shocks for subsequent attempts. CPR is continued with minimum interruption. After the shock, the rhythm is assessed and up to 3 shocks are given initially. After the 3rd shock adrenaline 1 mg IV and amiodarone 300 mg IV is administered. If VF/VT persists continue administering shocks while giving further adrenaline 1 mg IV after each alternate shock (approximately
every 3-5 min).
Management of asystole and pulse-less electrical activity These are considered non-shockable rhythms. Management includes continued cardiopulmonary resuscitation while adrenaline IV is administered at intervals of 3-5 minutes. Management of asystole and pulse-less electrical activity
These are considered non-shockable rhythms. Management includes continued cardiopulmonary resuscitation while adrenaline IV is administered at intervals of 3-5 minutes.
Rule out reversible causes of cardiac arrest. Hypothermia, hypovolaemia, hypoxia, metabolic changes(hyperkalaemia), toxins, tension pneumothorax, thrombosis etc are reversible causes of cardiac arrest. Exclusion of these should be carried out during the resuscitation process with minimum interference to administration of cardiopulmonary resuscitation. Rule out reversible causes of cardiac arrest.
Hypothermia, hypovolaemia, hypoxia, metabolic changes(hyperkalaemia), toxins, tension pneumothorax, thrombosis etc are reversible causes of cardiac arrest. Exclusion of these should be carried out during the resuscitation process with minimum interference to administration of cardiopulmonary resuscitation.
Precordial thump Precordial thump has a low success rate and is effective only when administered close to the onset of the cardiac arrest. Currently the use of precordial thump is de-emphasised. It may be used under medical supervision in the setting of emergency department resuscitation room, ICU etc. Precordial thump
Precordial thump has a low success rate and is effective only when administered close to the onset of the cardiac arrest. Currently the use of precordial thump is de-emphasised. It may be used under medical supervision in the setting of emergency department resuscitation room, ICU etc.
Post-resuscitation care Following return of spontaneous circulation it is important to ensure continued care to the patient. Avoid hyperoxaemia by maintaining a SaO2 of 94-98%. Monitor and control blood glucose level of the patient. It is also recommended to use primary percutaneous coronary intervention in appropriate patients. Post cardiac arrest syndrome developing following cardiac arrest comprises of cerebral injury, myocardial dysfunction, ischaemia/reperfusion response. Post-resuscitation care
Following return of spontaneous circulation it is important to ensure continued care to the patient. Avoid hyperoxaemia by maintaining a SaO2 of 94-98%. Monitor and control blood glucose level of the patient. It is also recommended to use primary percutaneous coronary intervention in appropriate patients. Post cardiac arrest syndrome developing following cardiac arrest comprises of cerebral injury, myocardial dysfunction, ischaemia/reperfusion response.
Use of therapeutic hypothermia Hypothermia has shown to be neuroprotective. Cooling suppresses neural pathway transmission and lowers brain metabolic rate. Currently hypothermia is used in patients who are comatose. Use of therapeutic hypothermia
Hypothermia has shown to be neuroprotective. Cooling suppresses neural pathway transmission and lowers brain metabolic rate. Currently hypothermia is used in patients who are comatose.
Rehabilitation Patients who survive cardiac arrest need thorough investigation for the aetiology. Management should be tailored according to the cause. Patients with coronary heart disease need proper evaluation of disease extent, pharmacological management, optimization of cardiac risk factors. Further evaluation is required to routinely recommend an intensive early intervention service. Rehabilitation
Patients who survive cardiac arrest need thorough investigation for the aetiology. Management should be tailored according to the cause. Patients with coronary heart disease need proper evaluation of disease extent, pharmacological management, optimization of cardiac risk factors. Further evaluation is required to routinely recommend an intensive early intervention service.

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