45. Cardiac arrest/sudden death

Question 1

Causes of sudden cardiac death/arrest.

Answer 1

• Acute CV events: acute MI, massive PE, aortic dissection, ruptured aortic aneurysm
• Cardiomyopathies: HCM, DCM, ARVCM
• Channelopathies: Long QT, Short QT, Brugada, catecholaminergic polymorphic ventricular tachycardia
• Coronary heart disease: MI, congenital anomalies
• Structural heart disease: LVOT (e.g. critical AS),
• Congenital heart disease: Fallot’s tetralogy, PDA
• Arrhythmias: WPW, etc.

Question 2

Cardiac arrest: reversible causes (with treatment)

a) 4 Ts
b) 4 Hs

Answer 2

a) Thromboembolism: coronary or pulmonary (PCI/ thrombolysis), tension pneumothorax (needle decompression), tamponade (pericardiocentesis), toxins
b) Hypoxia (high-flow O2), hypovolaemia (fluid resus), hypothermia (warming), hypoglycaemia (glucose/glucagon)/ hypo/hyperkalaemia (KCl/ insulin + dex)

Question 3

Sudden cardiac death: management of relatives

Answer 3

• ECG and Echo of first-degree relatives

- If life-threatening arrhythmia picked up - offer ICD

Question 4

Resuscitation guidelines.

a) When to begin CPR?
b) Adults: initial sequence of actions
c) Paediatrics: initial sequence of actions

Answer 4

a) Unresponsive and not breathing normally (i.e. after having assessed responsiveness, opened airway and assessed breathing)
b) Call resus team, commence CPR (30:2), attach defib pads and monitor, assess rhythm (also manage airway, oxygenate and ventilate where possible)
c) If alone first do 1 minute of CPR (5 initial breaths, then 15:2), call resus team, start/continue CPR, attach defib pads and monitor, assess rhythm (also manage airway, oxygenate and ventilate where possible)

Question 5

Cardiac arrest.

a) How to confirm
b) Shockable and non-shockable rhythms - causes?
c) If shock delivered, how long should CPR be ceased for?
d) Shockable rhythms - after three shocks, do what?

Answer 5

a) Check breathing and pulse simultaneously

b) Shockable: VT/VF - causes:
Non-shockable: PEA, aystole - causes: Hs and Ts

c) No more than 5 seconds

d) Give 1mg IV adrenaline and 300mg IV amiodarone
- 1mg IV adrenaline should then be repeated every alternate CPR cycle (every 3-5 mins)

Question 6

Non-shockable rhythms: management

a) PEA - define
b) Management of PEA/asystole

Answer 6

a) Cardiac arrest in the presence of electrical activity (other than ventricular tachyarrhythmia) that would normally be associated with a palpable pulse

b) - Consider the reversible causes of PEA/asystole (The 4 Hs and Ts)
- Start CPR 30:2 (effective compressions with minimal interruption)
- Oxygenate at 100%, use airway adjunct where possible
- Give adrenaline 1 mg IV as soon as intravascular access is achieved
- Continue CPR 30:2 until the airway is secured – then continue chest compressions without pausing during ventilation
- Recheck the rhythm after 2 mins
- Always be checking for signs of life (pulse, breathing, movement, eye opening, rise in etCO2)
- If no signs of life/electrical activity compatible with life/shockable - continue CPR 30:2, re-check rhythm every 2 minutes and give 1mg IV adrenaline every 3-5 mins (during alternate CPR cycles)

Question 7

ROSC.

a) management

Answer 7

• A-E approach
• Aim for SpO2 94 - 98%
• Aim for normal PaCO2
• 12 lead ECG
• Treat precipitating cause
• Targeted temperature management

Question 8

Aortic dissection.

a) Risk factors
b) Clinical features
c) vs. acute MI
d) Management of suspected dissection

Answer 8

a) Typical patient is man in his 60s with HTN. Other RFs include smoking, atherosclerosis, pre-existing aortic disease (e.g. aneurysm), Marfan’s/EDS
b) Sudden onset of severe tearing chest/back pain; pain may migrate as the dissection progresses; other symptoms related to blood loss (e.g. syncope, weakness, collapse and arrest)
c) MI - more gradual onset of pain, ECG changes (note: it may co-exist)

d) - A-E approach (may be arrest, collapse, etc.) - oxygen, IV access, bloods, fluids, analgesia (morphine)
- IV beta-blockers (reduce BP and blood loss)
- Surgical graft repair (e.g. EVAR)