5. Airway care for first responders – June 2015
Most patient care clinical guidelines or protocols start with a sentence along the lines of ‘ensure the patient has a patent airway’. Fair enough that would seem. What constitutes a patent airway then and what can be done by a medical first responder to fix any problems?
Firstly, what is a patent airway? The airway has but one role in life. It is nothing more than a tube between the opening to the outside world, the mouth, and the alveoli at the end of the lungs. Air, in particular oxygen, needs to be able to move from outside all the way to the alveoli. In return, waste carbon dioxide flowing from the blood into the alveoli needs to be able to be blown back out again. Where this happens freely, there is a patent airway.
To help maintain the airway, the human body has a number of built in protective mechanisms. These are the airway reflexes and include gagging, coughing, sneezing and even swallowing. All seek to move things away from the upper airway in the mouth. When the patient loses consciousness though, these protections either weaken or stop working completely. Hence the first responder must step up to the plate and take over the airway protection.
Perhaps to best understand what a patent airway is, consider what a non patent airway is. What sort of things make an airway not patent? In a sense these can be all grouped together into one word – obstruction. An obstruction is a blockage and this is the one thing that can stop an airway being patent. Fortunately there are only a few types of blockage to consider.
What is the most common airway problem to manage? As simple as it sounds, it is the patient’s own tongue. The tongue is a big muscle designed to help move food out of the mouth and into the oesophagus (food pipe). The mouth forms a sort of funnel leading food to the oesophagus at the back of the throat. This works will except the trachea (windpipe) is also at the back of the throat. But nature gave the body one neat trick. At the very back of the tongue is a little cartilage flap called the epiglottis. During swallowing the tongue moves backward. When this happens it pushes that little flap closed sealing off the trachea. Voila, no food can enter the lungs. This works very well.
However if the control of the tongue is lost as it is during unconsciousness, a patient flat on their back may not have a patent airway. The tongue can fall backward and push that flap over the trachea. Enter the first responder. There are three tricks to help here. The patient can be rolled onto their side causing the tongue to fall forward again. This is the lateral position and is taught in first aid courses. But this isn’t helpful in cardiac arrest with chest compressions being performed.
Trick two is another simple mechanical method – jaw thrust or chin lift. The tongue is attached to the jaw. If the jaw is pushed forward, it pulls the tongue with it. Pushing the jaw from the angles at the back or pulling it by the chin can achieve the same effect. They pull the tongue forward and so pull the epiglottis flap away from the trachea. This is particularly useful where the patient has to be left on their back such as during a cardiac arrest. But it does take hands to hold because as soon as you let go of the jaw, the tongue falls back. And so…
Trick three, the oropharyngeal airway (OPA). Inserted correctly, this device follows the curve of the tongue and mouth with the far end sitting in the back of the throat. If you choose one too small, it will not reach the back of the throat where you need to be. If you choose one too big, it will push into the very soft tissue right at the back of the throat and cause injury. It is important to size it carefully so that the one chosen is just right. It is also important to insert it properly or else you can simply push the tongue backward and defeat the whole purpose. Properly in place though, the OPA will stop the tongue from falling all the way backward and blocking the trachea.
Any or all of these methods can be used to beat the tongue and allow the unconscious patient to stay on their back. Very importantly though, the OPA does not fix any other airway problems. So what else can obstruct the airway and stop it being patent?
The next major obstruction is a foreign body. The mouth is the entry point for food and is connected directly to the stomach. Food or indeed any object placed into the mouth can then become caught in the upper part of the trachea. The object could be part of the mouth if broken during trauma.
Most commonly this can happen during eating causing people to choke. If it doesn’t come out with a cough, it may remain stuck and block the airway. If the patient is conscious but cannot cough you can alternate sharp but not harmful blows in the middle of the upper back with wrapping arms around the patient and squeezing firmly inward on the chest bone. If these do not work or the patient collapses to the floor then you can perform chest compressions to make the air in the lungs push it back out. This is another good reason why starting compressions during cardiac arrest should happen before you muck around with the airway – you already are doing something for the airway.
Foreign bodies can also be removed placing the patient with their head down or on the side allowing the object to fall forward. Fingers can be used to pull it out but nobody should stick fingers into a patient’s mouth. Suction can be used if it is available as it usually is for first responders. There are large blunt tweezers called Magill’s forceps that can be used to literally reach into the mouth and grasp solid objects but they can cause injury. You must know what you are doing with them first.
Not all foreign bodies are trying to go downward. In some cases foreign bodies may come back up from the stomach. Conscious patients vomit and you can see this. Unconscious patients don’t vomit. Instead the food passively flows back up the oesophagus as the muscles that normally hold it closed stop working. The chances of this will be increased if you are pushing air into the lungs during ventilation. That does not mean you are doing something wrong. You can’t push air into the lungs without some making its way down to the stomach. Once the stomach fills with air the pressure can push lunch back out.
It is for this reason that more advanced airway procedures are resorted to by paramedics and medical staff. These devices typically aim to block off either the oesophagus or the trachea to ensure that stomach content cannot flow into the lungs. They become more complex to insert and look after so typically are not part of the first responder bag of tricks.
These are most of the airway problems that can be encountered. Perhaps one other less common problem is swelling in the airway. Allergy/anaphylaxis can cause this as can infections such as croup. These can only be fixed medically such as by administering adrenaline to reduce the inflammation. Recognising the medical problem and having a management option is the key here.
It is important to understand what airway problems are being faced and to understand what trick you have available that might help fix them.
Jeff Kenneally www.prehemt.com
Jeff is the author of the 2014 – 2016 Ambulance Victoria First Responder clinical practice protocols and accompanying education program.