Cardiac arrest

Question 1

Define cardiac arrest

Answer 1

Acute cessation of cardiac function

Question 2

Aetiology/risk factors for cardiac arrest

Answer 2

(REVERSIBLE CAUSES)

4 Hs

• Hypothermia
• Hypoxia
• Hypovolaemia
• Hypokalaemia/hyperkalaemia

4 Ts

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

Question 3

Epidemiology of cardiac arrest

Answer 3

.

Question 4

Presenting symptoms of cardiac arrest

Answer 4

• Management precedes or is concurrent to history

- Usually sudden but some symptoms that may precede: fatigue, fainting, blackouts, dizziness

Question 5

Signs of cardiac arrest on physical examination

Answer 5

• Unconscious
• Not breathing
• Absent carotid pulses

Question 6

Appropriate investigations for cardiac arrest (& their results)

Answer 6

CARDIAC MONITOR
- Allows classification of rhythm

BLOODS

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

Question 7

Management of cardiac arrest

Answer 7

Safety:

• Approach scene w/ caution as cause of arrest may pose threat
• Defibrillators & O2 are hazards

Basic life support:

• Consider PRECORDIAL THUMP (ulnar aspect of fist to sternum) if arrest is witnessed & monitored
• Clear & maintain airway w/ HEAD TILT, JAW THRUST, CHIN LIFT
• Assess breathing by LOOK, LISTEN, FEEL (2 rescue breaths if not breathing)
• Assess circulation at CAROTID PULSE for 10 secs (30 chest compressions at 100/min in cycle of 30 to 2 rescue breaths)
• Proceed to advanced life support ASAP

Advanced life support:

Attach cardiac monitor & defibrillator

Assess rhythm…

1) If pulseless ventricular tachycardia or ventricular fibrillation (shockable rhythms)
- Defib once 150-360 J biphasic, 360 J monophonic (no one touching patient or bed)
- Resume CPR immediately for 2 mins, reassess rhythm, shock again if still pulseless VT/VF
- Administer adrenaline (1mg IV) after 2nd defibrillation & again every 3-5 mins
- If shockable rhythm persists after 3rd shock administer amiodarone 300mg IV bolus (or lidocaine)

2) If pulseless electrical activity (PEA) or systole (non-shockable rhythms)
- CPR for 2 & reassess rhythm
- Administer adrenaline (1mg IV) every 3-5 mins
- Atropine (3mg IV once only) if systole or PEA w/ rate <60bpm

During CPR…

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

Treatment of reversible causes:
Hypothermia - warm slowly
Hypo/hyperkalaemia - correction of electrolyte levels
Hypovolaemia - IV colloids, crystalloids & blood products
Tamponade - pericardiocentesis
Tension pneumothorax - aspiration or chest drain
Thromboembolism - treat as PE or MI
Toxins - use antidote for given toxin

Question 8

Complications & management of cardiac arrest

Answer 8

• Irreversible hypoxic brain damage

- Death

Question 9

Prognosis for cardiac arrest

Answer 9

Resuscitation is less successful outside hospital

Inc. duration of inadequate effective cardiac output -> poor prognosis