Cardiac Arrest

Question 1

What is the definition of cardiac arrest?

Answer 1

Acute cessation of cardiac function

Question 2

What is the aetiology of cardiac arrest?

Answer 2

The REVERSIBLE causes of cardiac arrest can be summarised as the 4 Hs and 4 Ts

FOUR Hs

• Hypothermia
• Hypoxia
• Hypovolaemia
• Hypokalaemia/Hyperkalaemia

FOUR Ts

• Toxins (and other metabolic disorders (drugs, therapeutic agents, sepsis))
• Thromboembolic
• Tamponade
• Tension pneumothorax

Question 3

What is the epidemiology of cardiac arrest?

Answer 3

None available

Question 4

What are the presenting symptoms of cardiac arrest?

Answer 4

Management precedes or is concurrent to history

Cardiac arrest is usually sudden but some symptoms that may preceded by fatigue, fainting, blackouts, dizziness

Question 5

What are the signs of cardiac arrest upon physical examination?

Answer 5

Unconscious

Not breathing

Absent carotid pulses

Question 6

What are the appropriate investigations for cardiac arrest?

Answer 6

Cardiac Monitor = Allows classification of the rhythm

Bloods

• ABG
• U&E
• FBC
• X-match
• Clotting
• Toxicology screen
• Blood glucose

Question 7

What BLS is involved in the management of cardiac arrests?

Answer 7

If the arrest is witnessed and monitored, consider giving a precordial thump (thump the sternum of the patient with the ulnar aspect of your fist)

Clear and maintain the airway with head tilt, jaw thrust and chin lift

Assess breathing by look, listen and feel -> If they are not breathing, give two rescue breaths

Assess circulation at carotid pulse for 10 seconds

• If absent - give 30 chest compressions at around 100/min
• Continue cycle of 30 chest compressions for every 2 rescue breaths

Proceed to advanced life support as soon as possible

Question 8

What ALS is involved with the management of cardiac arrests?

Answer 8

1. Attach cardiac monitor and defibrillator
2. Assess rhythm
   A)I f pulseless ventricular tachycardia or ventricular fibrillation (shockable rhythms)
   - Defibrillate once (150-360 J biphasic, 360 J monophasic) Make sure no one is touching the patient or the bed
   - Resume CPR immediately for 2 minutes and then reassess rhythm, and shock again if still in pulseless VT or VF
   - Administer adrenaline (1 mg IV) after second defibrillation and again ever 3-5 mins
   - If shockable rhythm persists after 3rd shock - administer amiodarone 300 mg IV bolus (or lidocaine)

B) If pulseless electrical activity (PEA) or asystole (non-shockable rhythms)

• CPR for 2, and then reassess rhythm
• Administer adrenaline (1 mg IV) every 3-5 mins
• Atropine (3 mg IV, once only) if asystole or PEA with rate < 60 bpm

During CPR:

• Check electrodes, paddle positions and contacts
• Secure airway
• Once secure, give continuous compressions and breaths
• Consider magnesium, bicarbonate and external pacing
• Stop CPR and check pulse only if change in rhythm or signs of life

Question 9

How are the REVERSIBLE causes of cardiac arrest treated?

Answer 9

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

Question 10

What are the possible complications of cardiac arrest?

Answer 10

Irreversible hypoxic brain damage

Death

Question 11

What is the prognosis for patients with cardiac arrest?

Answer 11

Resuscitation is less successful if cardiac arrest happens outside the hospital

Increased duration of inadequate effective cardiac output –> poor prognosis