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Chain of survival
The chain of survival refers to a series of actions that, properly executed, reduce the mortality associated with cardiac arrest. Like any chain, the chain of survival is only as strong as its weakest link.
The four interdependent links in the chain of survival are:
Early recognition and call for help
Early advanced cardiac life support
1. Ensure personal safety
Check the patient’s surroundings are safe before approaching (if you injure yourself, you will not be able to help the patient, so take this seriously)
Put on gloves (and other personal protective equipment) as soon as possible
Be careful with sharps during resuscitation
2. Check the patient for a response
The first step is to assessforaresponse.
Gently shake the patient’s shoulders and askloudly “Hello can you hear me?” or “Are you alright?”.
Shout for help: This is absolutely essential, as you will not be able to effectively assess and treat the patient alone.
Position the patient and inspect the airway
Position the patient on their back
Open their airway using a head-tilt and chin-lift manoeuvre
Inspect the airway for obvious obstruction. If an object is seen to be obstructing the airway, use a fingersweep or suction to remove obstructions that are in lineofsight.
Assess for signs of life
With the airwayheldopen (using the head-tilt and chin-lift manoeuvre), positionyourhead looking down towards the chest, with your cheek above the patient’s mouth.
If the patient is suspected to have suffered significanttrauma (with potential spinal involvement) perform a jaw-thrust rather than a head-tilt chin-lift manoeuvre.
In addition, you should place twofingers over the carotidartery to assess for a pulse at the same time.
Look, listen and feel to assess if the patient is breathing for 10 seconds (ideally, you should expose the chest to assess breathing):
Observe for chest rising and falling
Listen for any evidence of breath sounds
Feel for air blowing against your cheek
Look for any other signs of life (e.g. movement)
If the patient has occasional, irregulargasps of breath, this does not qualify as a sign of life as it commonly occurs in cardiac arrest and is referred to as agonalbreathing.
A pulse is present, but the respiratory rate is low
If the respirationrate is below12 – assist ventilation with bagvalvemask (BVM) to maintain 10 breaths/min (re-checking the pulse every minute to ensure it is still present).
You will likely need twopeople to perform effectiveventilation with a BVM (one ensuring a good seal over the face and the other compressing the bag to deliver the oxygen).
The BVM should ideally be connected to high-flow oxygen as soon as possible.
A pulse is present and respiratory rate is acceptable
If you feel a pulse or evidence of genuinebreathing, the patient would need urgent medical assessment (using an ABCDE approach) to stabilise them before further deterioration.
4. No signs of life
Call the resuscitation team (a.k.a. “crash team”)
If there are nosignsoflife, you need to callforhelp from the resuscitation team and commence CPR.
If more than one person is present, you can do these tasks simultaneously, however, if you are alone, you should leavethepatient and gethelpfirst (as this will ensure the resuscitation team attend and can commence advanced life support).
In a hospital, calling for help involves calling2222 to request urgent input from the resuscitationteam
When calling2222 it is important to clearly state your location (e.g. ward) and the typeofcardiacarrest (e.g. adult or paediatric) as this will inform which team members attend.
Perform chest compressions
The patient needs to be positioned on a flat, hardsurface for effective compressions to be possible.
Deliver 30 chest compressions followed by 2 ventilations and repeat.
Place one hand on top of the other in the centre of the lowerhalfofthesternum.
Aim to compress the chest by approximately one-third of the depth of the chest wall (5-6cm), as this allows for sufficient emptying of the cardiac ventricles.
Perform compressions at approximately 100-120 compressions per minute.
Make sure to allow the chest to fullyrecoil (this allows enough time for the heart’s chambers to refill before the next compression).
It is absolutely essential to minimiseinterruptions to chest compressions.
Alternate the person performing chest compressions at 2-minute intervals (if enough team members are present)
If trachealintubation is performed, chestcompressions should then be continued without any interruption at a rate of 100-120 a minute.
Ventilate the patient
Perform a head-tilt chin-lift manoeuvre to opentheairway and allow effectiveventilation.
Pinch the nostrils closed with your thumb and index finger.
Place your mouth tightly over the patient’s mouth (or use a pocket-mask or bag-valve-mask if available)
Deliver 2 breaths (with an inspiratorytime of approximately 1 second) and watch for the patient’s chest rising (which confirms you are ventilating them).
Releasethenostrils and observe for the patient’s chestfalling as the air is exhaled.
You should then begin performing another 30 chest compressions.
Add supplementaloxygen as soon as you are able to.
In clinical settings, mouth-to-mouth ventilation is not often used because of clinical reasons (e.g. concerns regarding infections) or because airway equipment is available (e.g. pocket-mask, bag-mask or anaesthetic input for tracheal intubation).
If there are clinical reasons to avoid mouth-to-mouth ventilation, perform chest compressions until help and airway equipment arrives.
Attach the AED
Once an automatedexternaldefibrillator (AED) arrives, it is import to attach the 2 self-adhesive pads immediately to the patient’s chest (as labelled):
ADHESIVE PAD 1: To the rightof the sternum below the clavicle
ADHESIVE PAD 2: In the mid-axillary line with its long axis vertical and sufficiently lateral
If the patient is hairy, you may need to shave the areas to allow adequate contact between the pads and the skin
Check for piercings and remove as these can cause burns to the patient during defibrillation (however doing this should not significantly delay defibrillation)
Turn on the AED
TurnontheAED and follow the audio-visual instructions:
Typically the AED will ask you to pausechestcompressions whilst it performs a rhythmcheck.
It will then indicate if the rhythm is shockable or non-shockable and instruct you to deliverashock if it is the former.
If a shock needs to be delivered, ensure you and no one else is in contact with the patient and press the deliver shockbutton on the AED
Re-commence CPR after the shock is delivered and follow further instructions from the AED (which will typically involve another rhythm check in 2 minutes).
Advancedlifesupport would be commenced once the resuscitation team arrives.
If signs of life present or the patient responds to treatment
Arrange an urgent medical assessment
Call for urgentmedicalassessment which may be the same resuscitationteam as for cardiac arrest, or a dedicated medicalemergencyteam.
Re-assess the patient using a structured ABCDE approach:
Airway: Ensure airway patent
Breathing: Give oxygen and monitor with pulse oximetry
Circulation: Record blood pressure, obtain venous access, attach ECG monitoring
Disability: Assess AVPU/GCS and check a capillary blood glucose
Exposure: Inspect for evidence of trauma or other clues as to a diagnosis (e.g. rash or bleeding)