Aeromedical Retrieval Decision Making


An email request from a listener in remote Canada:


From: Grant Laxdal

Sent: Tuesday, October 09, 2012 1:27 AM

To: Le Cong, Minh

Subject: Feedback from


Name: Grant Laxdal


Comment: Hi Minh,

Wondering if you could provid me direction here:


– I have been tasked to develop a head injury decision tool for rural communities on Vancouver Island, Canada to aid in the decision to transport for CT head

-the application of validated instruments (PECARN and Canadian CT Head Rules for example) does not account for the implicit risks of transport and loss EMS/health care provider capabilities in the sending community. I am not sure how to rationally balance the good of the many with the good of the patient.

-I’d love your 2 cents here.

Thanks. Love the podcasts.



Grant, great retrieval question!

When you have to transport and retrieve a sick patient many miles, often by air, it is not a light decision. There are several key factors to consider. How urgent is the medical need? How risky is the transport both in terms of accident risk but also the physiologic stress of transport on the patient? Are there other ways to manage the acute medical situation? Does the patient have to go to definitive care or can definitive care be brought to the patient?

If a transported patient needs paramedic, nurse or doctor escort during the flight/transport, does this leave the remote community without urgent medical service for that window period of perhaps many hours?

Now your question is about transporting for CT head scan and rationalising the decision process.

What you need to consider and develop is what we call in the retrieval industry a :


Essentially this is a decision making tool that facilitates an objective process of risk vs benefit calculation. My service of RFDS Queensland has been using one for 4 years now but several other emergency organisations utilise similar tools.

Here is one from the US Coast Guard that illustrates the risk matrix tool very well

USCG AUXAIR Aviation Risk assessment

Clinical decision tools like PECARN and Canadian CT head rules help you decide as a clinician if a CT head scan is warranted. If the decision is yes it is warranted then you still need to apply an aviation/transport risk process to decide on the timing of the transport/retrieval/evacuation for CT head.

Often to be honest its pretty obvious if an acute head injured patient needs an urgent CT head scan and you would be activating an urgent aeromedical retrieval regardless.

its in the middle risk group who would benefit from a CT head scan to rule out serious injuries but are not clinically all that unwell so its not urgent. In that moderate risk group, the PECARN and CT head rules will help triage those who dont need a CT and can be observed , versus those who would benefit from a CT head or prolonged observation. In that group the transport risk matrix will help decide when to perform the transport for the CT head.

It may well mean that if its a high transport risk i.e at night, bad weather etc., the patient looks stable for now but the decision rule has not excluded them from needing CT head, then prolonged observation is the best compromise till transport risk is much less. If you observe long enough you might safely be able to discharge patients who otherwise would have been CT head scanned.

But you need to apply the validated rules and look for obvious caveats like the patient on anticoagulants. even those who look stable, I would still send them for CT head with a good history of a head injury, even if it meant waiting till next day for bad weather to clear.

Here is a good paper on clinical risk assessment in anaesthesia which highlights some of these principles of risk assessment



Hope that helps Grant!



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: