Approach to bad airways

Let’s be honest, airway management is a confronting situation, especially when the patient is in a critical state. There is a very good reason why there is further specialised training to deal with the worse of airways we can be faced with… because if we fail in that department, the patient dies.

For every patient presenting with respiratory problems, whether a complaint of shortness of breath or appears having breathing difficulties, you need to immediately ascertain two things:

1. Is this an oxygenation or ventilation issue? Or am I facing a combination of the two?

2. Is this type 1 or type 2 respiratory failure?

Lets review point 1.

Recall the airway has two parts… the upper and lower airway. I try to break it down as this:

Think Upper airway as the tunnel that connects the external world to the internal world of the lungs

Think Lower airway as the conveyer belt where oxygen and carbon dioxide is regularly moved in and out of the body through a process of gas diffusion in the alveoli.

If we think it’s a ventilation issue, we are considering conditions that physically obstruct the upper airway (anaphylaxis, asthma, airway burns leading to upper airway oedema, foreign body obstruction) or conditions that hinder or completely stop the physiological process of inspiration/expiration (Opioid overdoses, GCS3 as a result of head trauma and no chest movement etc…)

If we think it’s an oxygenation issue, we are considering conditions that actively hinder gas diffusion and oxygen/carbon dioxide exchange in the alveoli (cardiogenic pulmonary oedema, pneumonia, ARDS, COPD).

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To summarise this: issues with ventilation is stopping the trucks from entering and leaving the tunnel whilst issues with oxygenation is stopping the trucks from unpacking and packing their goods (oxygen, carbon dioxide) at the alveoli loading docks.

We can also have situations where a bad airway is a combination of ventilation and oxygenation issues. An example is a patient with asthma and COPD where both are acting at the same time (There is active bronchospasm/bronchoconstriction and exacerbation of emphysema due to acute infection).

From here we should then consider if this breathing issue can be classified as a type 1 or type 2 respiratory failure. Let’ review point 2.
Type 1 – Hypoxemia as a result of the respiratory system unable to meet the demands of the bodies tissues
Type 2 – Hypercapnia as a result of the respiratory system unable to adequately remove sufficient carbon dioxide from the body
Quickly identifying the likely answers to these initial questions will aid significantly in guiding clinical judgement and management pathways. The big takeaway from this post is to start immediately thinking potential causes to an airway problem, this can begin whilst en-route to the job or be ever evolving as you get more information, more vital signs or additional patient assessment information. This is aimed to help minimise analysis paralysis by providing a tangible and step wise process of thinking. In the pre-hospital setting, identification of the main provisional problem is half the challenge, once we have a good idea of what is going on, we can start enacting a management and treatment pathway for these patients.