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Common cardiac arrest and advanced life support (ALS) questions for medical finals, OSCEs and MRCP PACES


Question 1: Recognising cardiac arrest

Outline your initial approach to an unconscious individual

  • On finding an unconscious individual, follow the three SSS’s: safety, shake, sho
    • Safety: ensure it is safe to approach
    • Shake: ask the patient “Are you alright?” whilst gently shaking their arm
    • Shout: if the patient responds, assess them from an ABCDE perspective; if they do not respond, shout for help and put out a cardiac arrest call

What would you do if there was no response?

  • Open the airway with a head tilt/chin lift manoeuvre, palpate the carotid pulse and look, listen and feel for breathing for 10 seconds
  • If there is a risk of a cervical spine injury, open the airway using a jaw thrust whilst an assistant applies manual in-line stabilisation (MILS)
  • If there is no pulse, no signs of life, or if in any doubt, commence cardiopulmonary resuscitation (CPR) immediately in a ratio of 30 compressions to 2 ventilation

Question 2: Initial cardiac arrest management

Once cardiac arrest has been identified, what procedure should be initiated without delay?

  • If the patient is in cardiac arrest (or there is any suspicion that they might be in cardiac arrest) CPR should be started immediately.

Question 3: compressions in advanced life support (ALS)

In what ratio are compressions and ventilations initially performed during CPR in ALS?

  • 30 chest compressions to 2 breaths (30:2)

How does the ratio of compressions to breaths change after establishment of a definitive airway in ALS?

  • Once a definitive airway has been established, compressions and ventilation can occur simultaneously with no break in compressions.

Question 4: timings in advanced life support (ALS)

During advanced life support, what duration should CPR continue for between rhythm checks?

  • Two minutes.
    • Do not stop CPR to do a rhythm check before 2 minutes is up.

Question 5: rhythms in advanced life support (ALS)

Which are the shockable rhythms?

  • Shockable rhythms in cardiac arrest are ventricular tachycardia (VT) and ventricular fibrillation (VF)

Which are the non-shockable rhythms?

  • Any other rhythm is not shockable. This includes asystole, p-wave asystole, and a rhythm compatible with life but with no pulse (PEA)

Question 6: adrenaline in advanced life support (ALS)

What is the dose of adrenaline given in cardiac arrest?

  • 1mg adrenaline 1:10,000 (10ml) iv. Follow immediately with a 20 ml flush.

When is adrenaline given in shockable rhythms?

  • Immediately after the third shock

When is adrenaline given in non-shockable rhythms?

  • As soon as intravenous (IV) or intraosseus (IO) access has been obtained

Question 7: other medications in advanced life support (ALS)

When, and at what dose, is amiodarone given in cardiac arrest?

  • Immediately after the third shock in a shockable rhythm – at the same time as adrenaline. It is not indicated in a non-shockable rhythm.
  • The dose is 300mg iv

Question 8: reversible causes of cardiac arrest

What are the reversible causes of cardiac arrest?

  • The reversible causes are remembered by the “4 Hs and 4 Ts”
    • Hypoxia: ensure a patent airway and give high flow oxygen
    • Hypovolaemia: commence IV fluid resuscitation
    • Hypo/hyperkalaemia and other metabolic derangements: check the VBG for any metabolic derangements and correct accordingly. Look at previous bloods for likely magnesium concentrations or correct empirically.
    • Hypothermia: check the patient’s temperature and if low re-warm to 32-34 oC
    • Tension pneumothorax: auscultate the patient’s lung fields during ventilations and perform needle decompression if required
    • Tamponade (cardiac): obtain a beside echocardiogram (echo) and perform pericardiocentesis as indicated
    • Toxins: check the patient’s drug chart and/or enquire about recent medications or overdoses in the collateral history
    • Thrombosis (pulmonary or cardiac): obtain a bedside ultrasound and identify symptoms and risk factors in the collateral history

Question 9: Hyperkalaemia in cardiac arrest

How would you alter the management of cardiac arrest in a patient with hyperkalaemia?

  • The management of the immediate arrest would essentially be the same as for any arrest. However, as soon as hyperkalaemia was suspected, treatment should be commenced:
    • Calcium chloride 10 ml of 10% IV
    • Insulin-dextrose IV infusion (10 units of actrapid in 50 ml of 50% dextrose)
    • Sodium bicarbonate 50 ml of 8.4% IV
  • The reasons for the hyperkalaemia should be sought and treated post-arrest.

Click here to download free teaching notes on advanced life support: Emergency – Cardiac arrest

Perfect Advanced Life Support revision for medical students, finals, OSCEs and MRCP PACES