Defbibrillation

Question 1

What is the relationship between time from collapse to defibrillation and survival?

Answer 1

For every minute that passes, mortality increases by 7–10% in the absence of defibrillation

Question 2

What is the pre-shock pause and its effect on defibrillation success?

Answer 2

Pre shock is time from stopping CPR and shock- every 5-second increase almost halves the chance of success.

Question 3

How does bystander CPR affect survival rates from witnessed cardiac arrest?

Answer 3

Bystander CPR doubles survival rates.

Question 4

What are the three common features of all defibrillators?

Answer 4

• A power source capable of providing direct current
• A capacitor that can be charged to a pre-determined energy level
• Two electrodes placed on the patient’s chest

Question 5

What defines successful defibrillation?

Answer 5

The absence of VF/pVT at 5 seconds after shock delivery.

Question 6

What should be done to ensure good contact between defibrillator pads and the patient’s skin?

Answer 6

Remove any transdermal drug patches and excessive hair from the area.

Question 7

What is the recommended standard electrode position for defibrillation?

Answer 7

One electrode to the right of the upper sternum and the apical pad in the mid-axillary line.

Question 8

Where should the electrodes be placed if the patient has an ICD?

Answer 8

Electrodes should be placed at least 10–15 cm away from the device to avoid damage.

Question 9

What is the recommended shock strategy for defibrillation?

Answer 9

Single shocks are recommended to minimize interruptions to chest compressions.

Question 10

What is the minimum energy for the first shock in defibrillation?

Answer 10

At least 150 J.

Question 11

What safety measures should be taken during defibrillation?

Answer 11

Ensure no contact with the patient and clear any areas of wetness.

Question 12

What precautions should be taken regarding oxygen during defibrillation?

Answer 12

Remove oxygen masks or cannulae at least 1 m away from the patient’s chest.

Question 13

What are automated external defibrillators (AEDs) designed to do?

Answer 13

Guide lay rescuers and healthcare professionals to attempt defibrillation safely.

Question 14

Fill in the blank: The chance of successful defibrillation decreases with every _______ increase in the pre-shock pause.

Answer 14

5-second

Question 15

True or False: Continuous chest compressions during shock delivery increase the chance of ROSC.

Answer 15

False

Question 16

What is the optimal shock strategy for witnessed VF/pVT cardiac arrest?

Answer 16

Consider a three-shock strategy if the patient is connected to a manual defibrillator.

Question 17

What is the goal for healthcare providers performing CPR in hospitals?

Answer 17

The goal is to provide the first shock within 3 minutes of collapse anywhere in the hospital.

Question 18

What is the CPR ratio to be used if no shock is indicated?

Answer 18

30 compressions to 2 rescue breaths.

Question 19

What are the advantages of manual defibrillators over AEDs?

Answer 19

They enable rapid rhythm diagnosis and shock delivery, minimizing interruptions in chest compressions and often have additional functions like synchronized shocks and external pacing facilities.

Question 20

What is a key disadvantage of manual defibrillators?

Answer 20

They require the operator to be skilled in ECG rhythm recognition, necessitating extra training compared to AEDs.

Question 21

What is the maximum pause allowed in chest compressions for rhythm analysis?

Answer 21

No longer than 5 seconds.

Question 22

What energy setting should be chosen for the first shock with a defibrillator?

Answer 22

At least 150 J.

Question 23

What should be done immediately after delivering a shock?

Answer 23

Restart CPR using a 30:2 ratio.

Question 24

What should be administered if VF/pVT persists after the second shock?

Answer 24

Adrenaline 1 mg IV and amiodarone 300 mg IV.

Question 25

What is recommended for defibrillation of children between 1 and 8 years?

Answer 25

Use special pediatric electrodes with integral energy attenuators.

Question 26

True or False: Synchronised cardioversion is required for VF and pVT.

Answer 26

False.

Question 27

What must be done before attempting synchronised cardioversion on conscious patients?

Answer 27

They must be anaesthetised or sedated.

Question 28

What is the risk of leaving the synchronisation switch 'on' after use?

Answer 28

It will inhibit discharge of the defibrillator for treating VF/pVT.

Question 29

What should be the distance between defibrillator electrodes and implanted devices like pacemakers?

Answer 29

At least 10–15 cm.

Question 30

What is the energy requirement for internal defibrillation using biphasic shocks?

Answer 30

10–20 J.

Question 31

What is the key learning regarding defibrillation for patients in VF/pVT?

Answer 31

Early defibrillation is the only effective means of restoring spontaneous circulation.

Question 32

Fill in the blank: For manual defibrillators, consider _______ energy levels for refractory and recurrent VF.

Answer 32

[escalating]

Question 33

What should be done if an ICD has not delivered a shock during cardiorespiratory arrest?

Answer 33

Attempt external defibrillation in the usual way.

Question 34

What is the purpose of implantable event recorders?

Answer 34

To record the heart's rhythm at the time of an event such as transient loss of consciousness.

Question 35

What should be done if ROSC is achieved after using an implantable event recorder?

Answer 35

Arrange to have the device interrogated for valuable information about the cardiac rhythm.

Question 36

What is a potential risk of delivering a shock through a defibrillation pad placed over an implanted device?

Answer 36

Damage to the device itself or the myocardium due to excess current flow.