Science of Resuscitation

Question 1

Cardiac Arrest Definition

Answer 1

Absence of mechanical movement of the heart, primarily an electrical issue. NOT a heart attack

Question 2

What is the 3 Phase Model of Resuscitation?

Answer 2

1. Electrical - 0-4 mins post cardiac arrest
2. Circulatory - 4-10 mins post cardiac arrest
3. Metabolic - 10+ mins post cardiac arrest

Question 3

What Interventions are done at each Phase?

Answer 3

1. Defib
2. Chest compressions to maintain blood perfusion pressure
3. Drug therapy as the breakdown of tissues due to lack of O2/anaerobic respiration is causing unhealthy metabolite production

Question 4

Basic Resuscitation Steps

Answer 4

1. Recognise patient is unresponsive/not breathing during A to E assessment
2. Call for Backup
3. 30 Chest Compressions
4. 2 Rescue Breaths
5. Continue CPR at ratio of 30:2 compressions to breathes
6. Switch paramedics when necessary

Question 5

Downward pressure to ______ increases _________ pressure

Answer 5

sternum, intrathoracic

Question 6

Compression of the heart is mostly to the ____ and less so the ________

Answer 6

Atria, ventricles

Question 7

Compression of the great ______ increases flow and pressure on the ________

Answer 7

vessels, vasculature

Question 8

As blood moves forward, the heart _____ and vasculature stop ________

Answer 8

valves, backflow

Question 9

______ of the chest generates a ______ pressure by recoil increasing ______ refilling

Answer 9

Rebound, negative, vascular

Question 10

Filling of the cardiac arteries increases negative pressure in turn increasing ______ pressure by _____ blood into the cardiac arteries

Answer 10

perfusion, drawing

Question 11

Ways of Optimising Chest Compressions

Answer 11

• Perfect rate
• Perfect depth
• Full recoil
• No distractions
• Regular changes

Question 12

What is the Best Depth and Rate for Chest Compressions?

Answer 12

Depth - 4.5cm Rate - 100-120bpm as should pump faster as chest compressions are only 30% as effective as a normal hear

Question 13

Definition of Chest Compression Fraction

Answer 13

The amount of time during cardiac arrest the patient receives chest compressions. E.g. high fraction = most of cardiac arrest the time spent was doing chest compressions

Question 14

What is the relationship between Perfusion Pressure and Defib?

Answer 14

The higher the perfusion pressure the more likely you are to have a successful defibrillation

Question 15

What is the Difference in Pressure in Ventilation compared to normal Breathing? And what is its effect on CPR?

Answer 15

Normal breathing = negative pressure system whereas ventilation is a positive pressure system. AAR it puts pressure on the arteries reducing the efficiency of CPR performed

Question 16

Ways of Optimising Ventilation

Answer 16

• Perfect rate
• Good tidal volume
• Good O2 amount
• Perfect depth
• No distractions

Question 17

What is the best Rate and Tidal Volume for Ventilation?

Answer 17

Rate - 12-20 breathes or when you breath, they breath Tidal Volume - 100kg male = 600ml ref but good volume is a slight rise/fall in the chest

Question 18

Things to note on ECG’s

Answer 18

• Is there an electrical activity?
• Is there normal/fast/slow rate?
• Is QRS complex narrow? 3 squares
• Are there P waves?
• Are there T waves?

Question 19

4 Different ECG’s During Cardiac Arrest

Answer 19

• Asystole
• Ventricular Fibrillation
• Ventricular Tachycardia
• Pulseless Electrical Activity

Question 20

What does a Defibrillation do?

Answer 20

Stops/depolarises all parts of the heart to allow the SAN (pacemaker) to start again at a normal rhythm. Should do highest energy on first shock

Question 21

Which types of ECG Cardiac Arrests do you Shock and not Shock and Why?

Answer 21

Shock = ventricular tachycardia and ventricular fibrillation because those rhythms need to be stopped and reset in hopes for the SAN to reinstate regular heart beats Not Shock = asystole as they don’t need a reset and pulseless electrical activity