Cardiorespiratory Arrest

Question 1

What is a cardiac arrest?

Answer 1

A sudden circulatory failure due to loss of cardiac systolic function

Question 2

What are the 4 main arrhythmias classified as a cardiac arrest?

Answer 2

1. Pulseless VT

Ventricles beating to fast to be effective

2. Ventricular Fibrillation (VF)

Quivering of ventricles severely reducing CO

3. Pulseless Electrical Activity

ECG shows electrical activity but there is no pulse

4. Asystole

Heart ceases to beat

Question 3

What are shockable and non-shockable arrhythmias?

Answer 3

Shockable arrhythmias are those that can be treated by use of defibrillator - pulseless VT or VF

Non-shockable arrhythmias are those which cannot be treated in this way - PEA or Asystole

Question 4

How does Ventricular Tachycardia present on an ECG?

Answer 4

Rate - 180 to 190 bpm
Rhythm - Irregular
QRS - Prolonged
P wave - Absent

Question 5

How does Ventricular Fibrillation present on an ECG?

Answer 5

Rate - 300+
Rhythm - Irregular
QRS - Unrecognisable
P wave - Absent

Way to remember higher rate in VF than VT -

A quiver occurs faster than a whole contraction, more quivers in a min compared to contractions so faster rate

Question 6

What are the risk factors of cardiac arrest?

Answer 6

• Cardiomyopathy
• LV hypertrophy
• CAD
• Arrhythmogenic RV dysplasia

Question 7

What are the clinical features of cardiac arrest?

Answer 7

Patient is unconscious, apnoiec, and lacks arterial pulse

Within 3 mins, damage done to brain is irreversible

Question 8

What are the causes of Cardiac arrest?

Answer 8

Main cause: Coranary Artery Disease

• Hypoxia
• Hypovolemia
• Hypo/ hyperkalemia
• Hypothermia
• Trauma
• Tension Pneumothorax
• Cardiac Tamponade
• Toxins

Question 9

What is the management of cardiac arrest?

Answer 9

• Basic Life Support

- Advanced Life Support

Question 10

What does Basic Life Support involve?

Answer 10

• Maintaining adequate blood circulation
• Manually preserving brain via cardiorespiratory resuscitation

ABD approach

A - Airway:
Open airway by turning patient on their back, tilting head back and lifting chin

B - Breathing:
Look (chest movement)
Listen (breath sounds)
Feel (patients expired air on your cheek)
If breathing normally, put in recovery position
Assess fro 10 seconds

C - Circulation:
External chest compressions 5-6 cm down the sternum

D - Defibrillate
Attach electrodes to chest. One on right pericardium under clavicle and one on left pericardium below pec major

During defibrillation, no one should be touching the patient and CPR should be resumed immediately after

Question 11

What does Advanced Life Support involve?

Answer 11

Once in hospital, get IV access and record ECG to administer drugs and determine if arrhythmia is shockable or not

CPR until defibrillator is attached. If the rhythm is shockable, administer a shock and continue CPR. Reassess rhythm

If arrhythmia is not shockable, proceed with CPR

ALS involves:

• Ratio of chest compressions to ventilation 30:2
• For VF/ pulseless VT (shockable rhythms) IV Adrenaline and IV Amiodarone are given once CPR is restarted after the 3rd shock
• Shock -> 2 mins CPR -> Shock
• For asystole/PEA (non-shockable rhythms) IV Adrnaline is given ASAP

Question 12

What is the difference between cardioversion and defibrillation?

Answer 12

• Cardioversion is an electric shock timed with the cardiac cycle
• Defibrillation is an electric shock given randomly

Both techniques aim to restore sinus rhythm

Question 13

What criteria make DNAR a valid decision?

Answer 13

• Patient is mentally competent
• Signed advanced directive forbidding resuscitation
• Quality of life following resuscitation would be poor
• Resuscitation unlikely to be successful