Airway Management:
Airway management is an area of pre-hospital care that often gets overlooked, particularly at the BLS level, yet it is a critical skill to master in order to successfully resuscitate critical patients. A thorough understanding of how to identify difficult airways, and troubleshoot problems is essential in maintaining adequate ventilatory status. In this quick review, I want to cover basic airway management, the types of airways, and advanced airways, as well as go over how to troubleshoot airway problems as they arise.
Basic airway management:
When assessing the patient's airway, we want to do 3 primary things:
Open the airway
Clear the airway
Keep the airway open
Opening the airway itself is initially acheived through manual maneuvers. For patients who are unresponsive without a traumatic mechanism of injury, a head-tilt chin-lift is appropriate. For those with suspected/potential spinal injury, a modified jaw-thrust is preferred. Both methods work by aligning the airway in a straight line, and displacing the tongue from obstructing the trachea.
Once the airway is opened, it needs to be cleared of debris or secretions. We can use a finger sweep, or portable suction device to acheive this goal.
Now that the airway is open and cleared, we have to keep it that way. This is where our airway adjuncts come into play. The BLS airways include oropharyngeal and nasopharyngeal varieties. The OPA is preferred in patients without an intact gag reflex, and works by displacing the tongue forward. The NPA is used in patients with an intact gag reflex, who do not have any evidence of head trauma. It travels the nasopharynx to the back of the throat and does not trigger vomiting. Both airways require monitoring for any further need to suction.
Advanced airways include supraglottic airways and endotracheal tubes. Supraglottic airways such as the King Lt and the Igel sit atop the trachea, and occlude the esophagus. They are not a definitive airway solution because they do not directly enter the trachea, and can still becomd dislodged or obstructed by oral and gastric secretions. Endotracheal tubes are placed through the vocal cords into the trachea itself, and above the carina. These tubes ARE a definitive airway. ETT can still become dislodged or misplaced (usually into the right mainstem), and there is a greater delay in inserting them, which can be detrimental in already hypoxic patients. As I do not have a background in RSI or DSI, I will not be covering these methods of intubation, however there are several good resources available.
Identifying a difficult airway:
Identifying airways that will be difficult to manage is important, because it factors in to our transport decision making, and allows us to prepare secondary plans for when things go wrong. When we intend to place a supraglottic airway, we use the mnemonic RODS to evaluate for difficulty.
R- Restricted mouth opening
O- Obesity
D- Displaced airway
S- Stiff airways
Restricted mouth opening presents a problem, because we can't exactly blindly shove a tube into someone's throat. We still need to be able to provide basic positioning and align the airway for ease of insertion. Patient's with trismus, jaw problems, or anatomical abnormalities make this process problematic. Obesity is an issue that affects our ability to keep a SGA from dislodging. Obese patients have significantly more weight on the chest than do smaller patients. This means that higher ventilatory pressures are required to acheive chest wall expansion. At higher pressures, there is greater risk that the tube may shift, or that air may end up going into the esophagus. A displaced airway refers to traumatic injury to the airway, that affects alignment and landmarking. Stiff airways refers to patients with COPD, Asthma, or other obstructive lung diseases. Again this obstruction increases ventilatory pressures, which is an issue.
We want to factor these difficulties into our decision about whether or not we will use an SGA, or rely upon a BLS airway instead.
ETT intubation uses the mneumonic LEMON for similar discernment of airway difficulty.
L- Look externally: Any facial trauma, jaw or dental abnormalities, facial hair, or a large tongue.
E- Evaluate (332 rule): Distance between incisors 3 fingers, Hyoid to chin distance 3 fingers, Thyroid to mouth distance 2 fingers.
M- Malampati score < 3: Beyond discussing here.
O- Obstruction
N- Neck mobility is limited
All of these factors affect our ability to intubate successfully and should be risk stratified before attempting.
Troubleshooting an airway when ventilation becomes difficult:
When it becomes hard to squeeze the bag, the instinct is to apply more pressure. It is advisable to evaluate using the DOPE mnemonic first.
D- Dislodged tube
O- Obstruction
P- Pneumothorax
E- Equipment failure
These are the basics of airway management in a brief review. Please feel free to contact me for any additional information.
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