first responder

Cardiac arrest for first responders

  1. Cardiac arrest for first responders – February 2016

Arguably the most serious call of all for any pre-hospital responder is to the patient in cardiac arrest. The alternative for the patient is irreversible brain damage then death within a few minutes on one hand to resuscitation and restoration of normal life at the other. The critical difference between the two is the responder doing just the right things in a very timely manner.

The cells of the human body have a few non negotiable needs. These include oxygen in particular and a fuel source such as sugar for energy. When they suddenly stop arriving because the heart stops beating, death is only minutes away. Effective resuscitation can prolong this time and, in some cases, restore the patient’s own effective circulation.

So what constitutes ‘effective resuscitation’?

There have been lots of simple ways to answer this question for many years. ABC for airway, breathing, circulation has been taught for a long time. This changed to DRABC. In the last few years the order was reversed to CAB. There is good reason for this and that will be explained. To do this now a slightly longer mnemonic will be used: DRSabCD.

The first ‘D’ is dangers. It must be safe for the rescuer before resuscitation is attempted. If something has overwhelmed the patient, can that overwhelm the rescuer too? Think gases, electricity, chemicals and so forth. Any danger to the rescuer means resuscitation is not safe. Can the patient be safely moved away? Can the hazard be removed? If it isn’t safe, you simply shouldn’t proceed into the danger.

If the scene is safe, does the patient respond? This is the ‘R’. All that is being checked for is any sign of life. Give the patient a shake, not too rough, to see if they can be somehow roused or woken. If they can, they are alive. Sick perhaps but alive. If they cannot, they are unresponsive. Move to the next letter.

S is send for help. This can include getting help from anyone nearby. It should also include calling professional help. First responders should provide a situation report to confirm help is needed. It is better to get the help early and without delay.

This is small ‘a’. Small ‘a’ denotes that it isn’t as important as the capital letters. This means don’t spend a lot of time on it at the moment. This ‘a’ stands for airway but not complex airway. This will be returned to later in the resuscitation. At this point simply place the patient’s head in a flat, lying on the back position with the face upward. This is meant to best open the airway without any other action. In this position the patient will not be mechanically blocking their own airway as they might with their chin pushed down onto their chest. Don’t roll the patient onto their side or use suction or spend any other time on the airway just yet. There are more important things right now so this will have to wait.

The next letter is small ‘b’. Small ‘b’ stands for breathing. It is important to discover if the patient is breathing or not. A patient can be unresponsive and not breathing. Drug overdose, for example, can cause this to happen. So this step is simply to check if the patient is breathing or not. Look at the chest rise and fall, listen for breath and feel for breathing.

Some patients in cardiac arrest may take an occasional gasp or move their chest now and then as if they are breathing. This can be confusing. These occasional gasps or noises don’t help and don’t count as breathing. The breathing you are looking for is normal, every few seconds breathing that gets repeated regularly. Only then is it effective breathing. If there is no effective breathing present, it will be important to breathe for the patient. But not just yet. If there is no breathing present there might be bigger priorities right now so move to the next step,

This is ‘C’. Capital not small. This is an action step. Feel for a pulse. The carotid is likely the best in this situation. If a pulse can be felt, the patient who is unconscious and not breathing can now have their breathing managed by regular ventilation using a bag/valve/mask device. However if there is no pulse to be felt, full resuscitation is critical. If there is any uncertainty in feeling the pulse, you must assume there is no pulse. A pulse check should only take a few seconds, no more than ten at the absolute most. Where there is no pulse, chest compressions must be started. Delays starting chest compressions reduce the chances of success.

Compressions have a few simple rules if they are to work. They must be fast at around 100 per minute and no more than 120. Too slow and the blood doesn’t flow. However too fast and they won’t work either as blood won’t have enough time to come back and refill the heart. The compressions must be hard. About one third of the chest diameter, or five to six centimetres in adults, must be pushed down. Finally, they must be continuous. It takes several compressions to get blood moving. If you keep stopping, so does the blood flow. Then they don’t work. If there are a lot of interruptions then there is no effective movement of blood. Once it is identified that there is no pulse, effective compressions must be commenced and stopped for only the briefest moments for essential reasons. Survivors have chest compressions performed. Without them, there is much less chance of survival.

It is most important that the chest compressions don’t just start effective, but stay that way. To help do this, the person doing the compressions should be changed every couple of minutes. In this way the compression person doesn’t tire as readily.

With compressions ongoing and effective, the next critical item is to apply a defibrillator. Automatic external defibrillators are very commonly encountered now and a standard first responder option. Defibrillation along with compressions are the two most critical elements in a cardiac arrest resuscitation. The defibrillator is the application of electricity through the patient’s chest designed to ‘re-set’ the natural electricity within the heart that controls the heart beats. This is the dramatic bit seen on television that almost always has an immediate resounding success. In real life it isn’t exactly like that.

The defibrillator works best when used as early as possible then every couple of minutes whilst the patient remains in cardiac arrest. The beauty of the modern automatic external defibrillator is that it provides all the instructions needed to make it work and it decides when it is the right time to use it or not. Defibrillation is further discussed in a more detailed separate post.

Once the defibrillator has been attached and its instructions followed, then it is time to turn back to the airway and breathing that were originally pretty much ignored.

Firstly, the airway is revisited. Now is the time to get a little more involved. This would be the time to use any other airway device or technique that might be needed. Of course nothing at all might need to be done in some cases. Airway is also better discussed in a separate post. Likely it will be the person who used the defibrillator who turns to the airway at this point.

Finally, breathing is revisited. In cardiac arrest, breathing means ventilation. In first aid speak this might mean mouth to mouth. For first responders it means ventilation with a bag/valve/mask device. An effective face seal with the mask is needed. This can be a challenge where there is a lot of facial hair or the cheeks are sunken. It can also be a challenge if the false teeth have been taken out. These are not usually a problem for the airway so if someone has taken them out of the mouth, it might be a good idea to put them back in. They can be important to keeping the face in shape.

The patient is ventilated slowly with two ventilations after each thirty compressions. The compression person stops very briefly to allow this. If they didn’t then all of the air would simply be pushed out of the lungs and there would be no ventilation. It is important not to overdo the ventilation. If the air overfills the lungs and stomach it can cause a few problems. Overfilling the stomach with air can force the patient’s lunch back out and cause airway problems. Overfilling the lungs can ‘pump up’ the pressure in the chest making it hard for blood to come back from the head and feet. This makes the compressions not work well so is not helpful at all. Stick to the resuscitation formula.

The rest of the cardiac arrest for now is lots of compressions, very brief stop every two minutes to check pulse and let the defibrillator do its stuff, change over the compression person then go again. Straight after the shock (and no shock when that occurs) immediately return to the next two minutes of compressions.

Jeff Kenneally

Jeff is the author of the 2014 – 2016 Ambulance Victoria First Responder clinical practice protocols and accompanying education program. This post is based on the 2015 ILCOR basic life support guidelines.

Gavid D Perkins, Anthony J Handley, Rudolph W Koster, Maaret Castren, Michael A Smyth, Theresa Olasveengen, Konraad G Monsieurs, Violett Raffay, Jan-Thorsten Grasner, Volker Wenzel, Giuseppe Ristagno, Jasmeet Soar, on behalf of the adult basic life support and automated external defibrillation section collaborators. European resuscitation council guidelines for Resuscitation 2015. Section 2: Adult basic life support and automated external defibrillation. Resuscitation 95. 2015;81-99

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