First Aid/Airway Management
Airway management is the process of ensuring that:
- there is an open pathway between a patient’s lungs and the outside world, and
- the lungs are safe from aspiration
Head tilt/Chin lift
The simplest way of ensuring an open airway in an unconscious patient is to use a head tilt chin lift technique, thereby lifting the tongue from the back of the throat.
ILCOR no longer advocates use of the jaw thrust, even for spinal-injured victims. Instead, continue use of the head-tilt chin-lift. If there is no risk of spinal injury, it is preferable to use the head-tilt chin-lift procedure which is easier to perform and maintain.
There are a variety of artificial airways which can be used to keep a pathway between the lungs and mouth/nose.
An oropharyngeal airway can be used to prevent the tongue from blocking the airway. When these airways are inserted properly, the rescuer does not need to manually open the airway. Aspiration of blood, vomitus, and other fluids can still occur.
It is only possible to insert an oral airway when the patient is completely unconscious or does not have a gag reflex. If the patient begins to gag after inserting the oral airway, remove it immediately.
Use and contraindications
The correct size is chosen by measuring against the patient's head (from the earlobe to the corner of the lips). The airway is then inserted into the patient's mouth upside down. Once contact is made with the back of the throat, the airway is rotated 180 degrees, allowing for easy insertion, and assuring that the tongue is secured. Measuring is very important, as the flared ends of the airway must rest securely against the lips to remain secure.
To remove the device, it is pulled out following the curvature of the tongue; no rotation is necessary.
The airway does not remove the need for the recovery position: it does not prevent suffocation by liquids (blood, saliva, food, cerebrospinal fluid) or the closing of the glottis.
The mains risks of its use are:
- if the patient has a gag-reflex they may vomit
- when it is too large, it can close the glottis and thus close the airway
- improper sizing can cause bleeding in the airway
Correction: Airway is measured from the centre of the lips to the angle of the jaw. This is the international method as used by ambulance services.
Nasopharyngeal Airways (NPA)
In the case of an unconscious person who still possesses a gag reflex, the nasopharyngeal airway may be used to maintain an open airway. The airway can come and many different sizes and, since every person is unique, a different size will be used for each individual case.
The correct size is measured against the patient's head (from nostril to earlobe). The airway is inserted with the bevelled side towards the nostrils until the entire airway is inside the patient's nasal cavity. The airway should be well lubricated using a water-based lubricant prior to insertion. This will prevent any excessive damage of the nasal airway during insertion. Some minor bleeding may occur due to the breaking of nasal capillaries, however, as a result of the insertion of the airway, it is not life-threatening.
- Severe spinal/head injuries (risk of pressurizing leaking cerebrospinal fluid or CSF)
A bag valve mask (also known as a BVM or Ambu bag, which is a brand name) is a hand-held device used to provide ventilation to a victim who is not breathing. The device is self fills with air, although it may be connected to an oxygen system.
Use of the BVM to ventilate a victim is frequently called "bagging." Bagging is regularly necessary when the victim's breathing is insufficient or has ceased completely. The BVM is used in order to manually provide mechanical ventilation in preference to mouth-to-mouth resuscitation (either direct or through an adjunct such as a pocket mask).
The BVM consists of a flexible air chamber, about the size of an American football, attached to a face mask via a shutter valve. When the air chamber or "bag" is squeezed, the device forces air into the victim's lungs; when the bag is released, it self-inflates, drawing in ambient air or oxygen supplied from a tank. A bag valve mask can be used without being attached to an oxygen tank to provide air to the victim, but supplemental oxygen is recommended since it increases the amount of oxygen reaching the victim. Some devices also have a reservoir which can fill with oxygen while the patient is exhaling (a process which happens passively), in order to increase the amount of oxygen that can be delivered to the victim by about twofold. A BVM should have a valve which prevents the victim from rebreathing exhaled air and which can connect to tubing to allow oxygen to be provided through the mask.
Bag valve masks come in different sizes to fit infants, children, and adults. Some types of the device are disposable, while others are designed to be cleaned, disinfected, and reused.
The BVM directs the gas inside it via a one-way valve when compressed by a rescuer; the gas is then delivered through a mask and into the victim's airway and into the lungs. In order to be effective, a BVM must deliver between 700 and 1000 milliliters of air to the victim's lungs, but if oxygen is provided through the tubing and if the victim's chest rises with each inhalation (indicating that adequate amounts of air are reaching the lungs), 400 to 600 ml may still be adequate. Squeezing the bag once every 5 seconds for an adult or once every 3 seconds for an infant or child provides an adequate respiratory rate (12 respirations per minute in an adult and 20 per minute in a child or infant).
Professional rescuers are taught to ensure that the mask portion of the BVM is properly sealed around the patient's face (that is, to ensure proper "mask seal"); otherwise, air escapes from the mask and is not pushed into the lungs. In order to maintain this seal, some protocols use a method of ventilation involving two rescuers: one rescuer to hold the mask to the patient's face with both hands and ensure a mask seal, while the other squeezes the bag. However, to make better use of available rescuers, the BVM can be operated by a single rescuer who holds the mask to the victim's face with one hand (using a C-grip), and squeezes the bag with the other.
When using a BVM, as with other methods of ventilation, there is a risk of overinflating the lungs. This can lead to pressure damage to the lungs themselves, and can also cause air to enter the stomach, causing gastric distention which can make it more difficult to inflate the lungs and which can cause the victim to vomit. This can be avoided by care on behalf of the rescuer. Alternatively, some models of BVM are fitted with a valve which prevents overinflation, by blocking the outlet pipe when a certain pressure is reached, though they should all be able to be bypassed in a situation where more pressure is needed, such as in anaphylaxis.
In the case of a victim who vomits or has other secretions in the airway, these techniques will not be enough. Suitably trained first aiders may use suction to clean out the airway, although this may not always be possible. A unconscious victim who is vomiting or has copious secretions in the mouth should be turned into the semi-prone position when there is no suction equipment available, as this allows (to a certain extent) the drainage of fluids out of the mouth instead of down the trachea.