Defibrillation of Adults using a Zoll Semi Automated Defibrillator - by Suitably Qualified Healthcare Professionals

Publication: 19/01/2009  --
Last review: 25/03/2019  
Next review: 01/03/2022  
Clinical Guideline
ID: 1472 
Approved By: Clinical Guidelines Committee 
Copyright© Leeds Teaching Hospitals NHS Trust 2019  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Defibrillation Of Adults by Suitably Qualified Healthcare Professionals using a Zoll Semi Automated Defibrillator

1. Clinical Guidance - Zoll Semi Automated Defibrillator
1.1 Summary
1.2 Definition
1.3 Indication for use
1.4 Guidelines
1.4.1 Procedure
1.5 Training and implementation plan
1.6 Review
1.7 References

1. Clinical Guidance - Zoll Semi Automated Defibrillator

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1.1 Summary

Following the onset of ventricular fibrillation / pulseless ventricular tachycardia (VF / VT), cardiac output ceases and cerebral hypoxia injury starts within 3 minutes. If complete neurological recovery is to be achieved, early successful defibrillation with a return of spontaneous circulation is needed. Early defibrillation has been proven to improve outcome from VF / VT cardiac arrest. The probability of successful defibrillation and subsequent survival to hospital discharge declines rapidly with time and the ability to deliver early defibrillation is one of the most important factors in determining survival from cardiac arrest.

A semi-automated external defibrillator is designed to be used by all health care professionals regardless of their background.

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1.2 Definition

Defibrillation is the passage of current of sufficient magnitude across the myocardium to depolarise a critical mass of the cardiac muscle simultaneously, to enable the natural pacemaker tissue to resume control.

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1.3 Indication for use

For use in adult patients who are unresponsive, apnoeic, and pulseless.

For use by any Leeds Teaching Hospitals NHS Trust employee who fulfils the criteria outlined in the Resuscitation Services Training and Education document.

Operators should practice within the boundaries outlined in this document.

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1.4 Guidelines

These guidelines have been produced to support the use of the Zoll semi-automated defibrillator in the event of an adult having a cardiorespiratory arrest within the Leeds Teaching Hospitals NHS Trust.

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1.4.1 Procedure

Upon discovering a collapsed person the following sequence of events should occur:



1. Ensure the area is safe

Safety of the rescuer is paramount.
The rescuer must not endanger their own life

2. Shake the victim gently by his shoulders and ask loudly ‘are you all right’

This will determine if the victim is responsive

3. If the person is unresponsive either:

a) Pull the emergency bell located in some hospital areas
b) Shout for help

Summoning help quickly to fulfil subsequent tasks e.g. calling 2222 and bringing the cardiac arrest trolley to the victim.

4. Turn the victim on his back. Open the airway by tilting the
head and lifting the chin.

Avoid head tilt if injury to the neck is suspected

This will hopefully achieve a patent airway for the victim and allow further assessment.

Head tilt may worsen a neck injury. Instead chin lift only or use jaw thrust.

5. Assess for any signs of life. This will involve checking for signs of adequate breathing and circulation simultaneously.

To assess breathing keep the airway open and: Look for any chest movements

In the first few minutes after cardiac arrest a victim may be barely breathing, or taking infrequent, noisy gasps (agonal breathing).

6. Listen for any breath sounds at the victims mouth, feel for any warmth of expired air on your cheek.
At the same time attempt to feel for a carotid pulse. Assessment of breathing and circulation should take no more
than 10 seconds.

This is abnormal breathing and should be treated as if the person is not breathing at all.

It is recognised that locating a carotid pulse can be difficult. If any doubt exists as to the presence of a circulation and no breathing is apparent then commence chest compressions

7. If there are no signs of life

Send an assistant to summon the cardiac arrest team by dialling 2222. Ask the assistant to return with the cardiac arrest trolley and defibrillator whilst chest compressions are commenced.
If you are on your own leave the victim to call 2222 returning to the patient with the cardiac arrest trolley and defibrillator

To ensure the cardiac arrest team arrives as soon as possible

Defibrillation may reverse the cause of the arrest. Cardiac compressions alone will not reverse the arrest but simply buys time until advanced interventions can be applied.

8. Immediately the defibrillator arrives it should be attached to the victim via the single use defibrillator pads. This is performed by placing one beneath the right clavicle, to the right of the sternum and the other in the left mid-axillary line

If more than one rescuer is present chest compressions should be continued whilst the defibrillator pads are attached

To enable a quick and accurate assessment of the patients rhythm (by the defibrillator) resulting in defibrillation, if required, being performed without delay. Pictures on the pads allow correct placement of pads. Each pad MUST be placed onto the victims bare chest

Interruptions to chest compressions should be kept to a minimum to maximise blood flow to the heart

9. If not already performed turn the defibrillator on, ensuring the defibrillator pads are connected.

Once connected correctly the defibrillator will say `stand clear’

The defibrillator will determine whether or not a shock is required and direct you accordingly

To allow the defibrillator to accurately analyze the rhythm. All cardiopulmonary resuscitation must stop until further instructed by the defibrillator

Please refer to the subsequent sections on shock required and no shock required


10. If the defibrillator identifies a heart rhythm that may benefit from defibrillation it will start to charge automatically. This is indicated by an audible tone .

The defibrillator, having analysed the rhythm, will automatically charge to pre-set energy levels.

11. As the defibrillator is charging commence safety checks
Give the command `stand clear, oxygen away’ loudly and clearly
Ensure fluid is not connecting any individual to the patient
Perform a visual sweep of the area

Defibrillation delivered to a non arrested heart caused by inadvertent touching of the victim or equipment during the shocking process may result in death or injury of the operator or assistants.

12. When charging is complete a command of `press shock’ is given by the defibrillator.

The operator should deliver the shock only if they are confident it is safe to do so.

Pressing the shock button delivers the shock to the victim

The defibrillator will disarm itself after 15 seconds if the shock is not delivered

13. Following the delivery of a shock the defibrillator will instruct personnel to `perform CPR’ this instruction should be
followed without exception

Interruptions to CPR, particularly chest compressions should be kept to an absolute minimum.

14. Perform CPR at a ratio of 30:2 until further instructions are
given by the defibrillator or until the patient shows obvious signs of life e.g. spontaneous movement, regular breathing, coughing. If obvious signs of life are detected stop CPR and re assess the victims airway, breathing and circulation

After each shock, 2 minutes of CPR should be performed, this is
timed by the defibrillator

CPR and/or defibrillation will not be required if obvious signs of life are shown by the victim


15. If the defibrillator detects a rhythm that is non-shockable it will state 'no shock advised, check pulse’ wait 10 seconds then states 'if no pulse start CPR’
Stop CPR if a pulse is detected and reassess the victim

Defibrillation will not benefit the patient in this instance

Check carotid pulse and other signs of life for no longer than 10 seconds. CPR required if no pulse.
Victims condition has changed therefore a full reassessment of the victim is required

16. Upon arrival of the emergency team
Report the sequence of events to the cardiac arrest Team Leader
Assist with further resuscitation procedures under the instruction of the cardiac arrest Team Leader


17. Immediately post cardiopulmonary arrest
Document events in the nursing notes or on an incident form if the victim is a visitor or member of staff.
Clean, restock and check the emergency trolley.


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1.5 Training and implementation plan

All training will be provided or facilitated by Resuscitation Services.

Level 2 resuscitation courses, covering defibrillation, should be accessed through the Organisational Learning Training Calendar.
All resuscitation courses carry a mandatory annual requirement.

All staff has a responsibility of maintaining and updating their skills by accessing the appropriate course as stated above.

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1.6 Review

These guidelines will be reviewed with the introduction of the next planned Resuscitation Council (UK) guideline review in October 2020 or such time before that, should new national guidelines be produced.


Record: 1472

These guidelines have been produced to support the use of the Zoll semi automated defibrillator in the event of an adult having a cardiorespiratory arrest within the Leeds Teaching Hospitals NHS Trust.

Clinical condition:

Adults in cardiopulmonary arrest and in either Ventricular Fibrillation or Pulse-less Ventricular Tachycardia

Target patient group: All adults
Target professional group(s): Allied Health Professionals
Clinical Physiologists
Secondary Care Nurses
Secondary Care Doctors
Adapted from:

Evidence base

1.7 References
Resuscitation Council (UK) Adult Cardiopulmonary Resuscitation Guidelines 2015

Approved By

Clinical Guidelines Committee

Document history

LHP version 1.0

Related information

Not supplied

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