22nd April 2019 Friday Resus Ready First Aid Trivia

Where to place defibrillator pads?

Automated External Defibrillators (AEDs) are a piece of life saving equipment. If you haven’t used one before they can seem very intimidating. As we discussed in a previous trivia question an AED can be used by anyone, even with no training because the machine will tell you what to do.

With everything that goes on in a resuscitation attempt, it can be confusing where to place the pads on the adult casualty’s chest.

The question:

Where would you place the pads on an adult casualty’s chest who has collapsed, unconscious and not breathing.


Option 1: One pad just below the collar bone on their right and one pad just below the arm pit on their left side


Option 2: One pad just below the collar bone on thier left and one pad just below the arm pit on their right side


Results from the facebook poll are:

  • Option 1 – Top right & left onside 86% 86%
  • Option 2 – Top left & right onside 14% 14%

If you answered Option 1 – One pad just below the collar bone on their RIGHT and one pad just below the arm pit on their LEFT side then you would be correct!!

Why do we place the pads the same way on every person you may ask?  We do this for a couple of reasons. Lets explain.

The first reason has to do with the natural conduction pathway of the heart.  The what? You might say.  In order for our heart to pump we need an electrical signal to be sent from the brain to the heart muscle to tell it to contract.  We also need the muscle to contract when it receives the signal.  If both of these are working correctly then we have a normal heart beat.  When one or both of these are not working correctly that is when the heart goes into distress and blood flow out of the heart is effected.

Our heart is made up of 4 chambers, 2 atriums (right and left) and 2 ventricals (right and left), see the diagram. During a normal heart beat the atriums contract first pushing blood from the atrium into the ventrical. After this, the ventricals then contract forcing blood from the ventrical to lungs or the body. As the ventrical is contracting the atrium is relaxing allowing blood to fill up again ready for the next contraction.

The atriums know when to contract when they receive an electrical impulse from the brain to what we medically call the sinoatrial node (SA node) which is located in the top right atrium of the heart, the signal then travels down close to the center of the heart through the atrioventricular node (AV node).  There the impulse is slowed down and then continues down the conduction pathway via the bundle of His and into the purkinje fibers at the base of the heart.  Take a look at the picture.  In which direction does the current flow?

From right to left! This is the main reason we place our defibrillator pads on the top right and then on the left side of our casualty.  We are trying to mimic the natural electrical pathway of the heart.


The second reason has to do with internal pacemaker/defibrillator devices that are placed in the chest of a person with a failing heart.  Some people require these devices to regularly send the impulse to the Sinus Node to stimulate the heart beat because their signal from the brain to the heart is getting mixed up along the way.  Some people have these because their heart sometimes goes into abnormal rhythms are requires a reset from a defibrillator.  What ever the reason they have them implanted they will always be placed in the exact same position in almost every country in the world.  Can you guess where?  They will always be located just below the collar bone on the left side. This is to make sure that the right side below the collar bone is always free to place defibrillator pads on.

You should never defibrillate over an implanted device, you will clearly be able to see if someone has one of these as there will be a small bulge under the skin under the left collar bone, kind of looking like an egg shape under the skin. (If you ever watched The Mummy and that scene when the sacarbs go under that guys skin, it kind of looks like that but without the movement or the bugs lol). It also goes without saying, DON’T try and remove the implanted device.  If the casualty has an internal defibrillator and they require defibrillation then their implant is not working and they require resuscitation.


How do you remember where to place the pads?

I like to use an analogy.  Pretend you are sitting in the drivers seat of your car.  Now place your seat belt on.  Which way does the strap sit across your chest?  Top right and then clips into the buckle on your bottom left side.

Easy- top right, bottom left side.  Imagine where the seatbelt strap would sit on the casualty as if they were sitting in the drivers seat.


Defibrillators can seem intimidating if you haven’t practiced with one before.  If you are interested in learning more and practice using an AED then why not attend one of my upcoming public courses or get some friends and family together for an in-home CPR training session for only $59pp. 

Classes are fun and interactive and you leave with the confidence that you know what to do in an emergency.  And the best part is, that you don’t need any prior experience.  Contact me or use the book a course button below. 


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