Cardiac Arrest

Question 1

Define cardiac arrest

Answer 1

Acute cessation of cardiac function

Shockable rhythms
o VF
o Pulseless VT

Non-shockable rhythms
o Pulseless electrical activity (PEA)
o Asystole

Question 2

What are the causes/risk factors of cardiac arrest?

Answer 2

• Ischaemic heart disease
• Cardiomyopathy
• Dysrhythmias

Reversible causes: 4Hs and 4Ts
• Hypoxia
• Hypothermia
• Hypovolaemia
• Hyper/hypokalaemia
• Tamponade
• Tension pneumothorax
• Thromboembolism (PE)
• Toxins

Question 3

What are the symptoms of cardiac arrest?

Answer 3

• Unconscious

* Not breathing

Question 4

What are the signs of cardiac arrest?

Answer 4

• Absent carotid pulse

Question 5

What are the investigations for cardiac arrest?

Answer 5

• ECG - may show QT interval, ST-segment or T-wave changes; conduction abnormalities; ventricular hypertrophy
• FBC - low haematocrit in haemorrhage
• serum electrolytes -may show electrolyte abnormalities
• ABG -may show respiratory acidosis; metabolic acidosis; respiratory acidosis with renal compensation; metabolic acidosis with respiratory compensation; mixed metabolic and respiratory acidosis; can also reveal hyperkalaemia
• cardiac biomarkers - positive/elevated
• toxicology screen - posistive in illicit drug use
• CXR - may show pneumothorax or other disorders of the lungs or thoracic cage may show causes of, or complications from, cardiac arrest
• echocardiogram - may show valvular abnormalities, myocardial scarring, cardiomyopathy, pericardial effusion
• coronary angiography - may show signs of coronary disease; may also reveal acute coronary artery occlusion with thrombus

Question 6

What is the management plan for cardiac arrest?

Answer 6

1st line treatment - CPR

Acute:
shockable rhythm - CPR and defibrillation, adrenaline, magnesium and anti-arrhythmic
non-shockabke rhythm - CPR and adrenaline and atropine

Treatment of REVERSIBLE causes
• Hypothermia - warm slowly
• Hypokalaemia and Hyperkalaemia - correction of electrolyte levels
• Hypovolaemia - IV colloids, crystalloids and blood products
• Tamponade - pericardiocentesis
• Tension Pneumothorax - aspiration or chest drain
• Thromboembolism - treat as PE or MI
• Toxins - use antidote for given toxin