Head Trauma

Take home messages

• You're trying to prevent secondary brain injury
• Don't forget about the other problems
• Hypoxia doubles mortality, as does hypotension

The damage is done

When head trauma happens it's usually fairly brisk - something large, heavy or speedy interacts enthusiastically with the skull in a short space of time.

The primary injury has already happened, and there's little you as the tube-wielding anaesthetic registrar in the hospital down the road can do to prevent this.

What you, the paramedics, HEMS, ED and the neurosurgeons are all trying to do is reduce the severity of secondary injury.

Blunt vs penetrating

As a general rule, trauma can be blunt, penetrating or psychological.

All are important, but here we'll focus on the first two.

If you have a patient with penetrating head trauma, they need to be in front of a neurosurgeon as soon as possible, and often this process is expedited by the prehospital team, meaning you don't see them at all if you're running CEPOD overnight in a sleepy DGH.

But hey - there are always surprises.

A Scan is not a Plan

The point here is that the surgery is the important bit for any traumatic intracranial haemorrhage, and any unnecessary delay is going to increase mortality and morbidity

Realistically speaking, your trauma patient is getting a scan before the neurosurgeons are going to be interested, especially if a prescription of diesel or kerosene is required to get them there.

The key is not to delay unnecessarily - the surgeon will fix things, the scan won't.

Resuscitate what you can treat, then get in the van.

Monro Kellie

There is a 1.5kg blob of impossibly intricate neural wetwork inside a closed box, with a litre of fluid being pumped in and drained out every minute.

And it's just been assaulted by something large, heavy or speedy, so it swells.

It's already angry, it might be bleeding as well, and it needs careful TLC to stop the existing injury from spreading.

Maintaining perfusion pressure

Just as electrons need a potential difference to flow, fluid needs a pressure gradient to drive forward movement.

• Flow = pressure gradient/resistance

Now, your pressure gradient is also called your cerebral perfusion pressure and is determined by:

• CPP = Mean arterial pressure - (ICP + CVP)

Your cerebral perfusion pressure needs to be at least 60 mmHg, so if your ICP is 10, and your JVP is 10, then you're looking at a MAP of 80 mmHg to achieve this.

Intracranial pressure

Here's our more in depth post on intracranial blood pressure

Cerebral Blood Flow and Intracranial Pressure

What goes in must come out

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How bad is it?

Determining the severity of traumatic head injury is the only time we're actually supposed to use GCS.

In 1974, two surgeons in Glasgow, Graham Teasdale and Bryan Jennett, decided we needed a standardised way of assessing how bad a patient's head injury is.

Because 'stuporous' and 'obtunded' are somewhat ambiguous.

Apparently the score is so good, we use it (completely inappropriately) every time anyone is even remotely sleepy.

• GCS >14 = mild
• 9 - 13 = moderate
• <8 = severe

It's fairly reliably predictive of how bad the badness inside the skull is:

• GCS 15 - 10% will have something to see on CT, and 0.5% will need surgery
• GCS 13 - those numbers increase to 25% on CT and 1.3% will need surgery

Subdural haemorrhage in a young healthy trauma patient is bad news - a lot of force has been imparted to the head and there is likely significant diffuse axonal injury as well.

The sudden drop

Not infrequently one may be called back to resus to re-review the patient that was an uneventful trauma call earlier in the shift.

A young, otherwise well patient had an unfortunate interaction with a car, pavement or weapon and was brought in by the paramedics with a GCS that warranted a scan but no immediate anaesthetic input.

However since then his GCS has plunged and he now requires airway protection and ventilatory support.

What you can do to help

As is often the case in our line of work, the definitive management is going to be done by somebody else, but we can at least do a fair bit to assist.

Here is the comprehensive list of all the things you can help with

• Swelling and raised intracranial pressure.
• Loss of cerebral autoregulation
• Hypoxia
• Hypercapnoea and spontaneous hyperventilation
• Seizures
• Fever
• Vasospasm

How to help

• Really thorough, structured resuscitation as per usual
• Prevent secondary injury - avoiding hypotension, hypothermia, hypoxia, hypercarbia
• Especially during intubation
• Don't intubate through the nose
• Reduce cerebral oxygen demand by preventing and treating seizures and anaesthetising the patient
• Reverse warfarin and deal with coagulopathy as required
• Tranexamic acid within 3 hours - à la Crash 2
• Effective and efficient communication with the relevant teams - ICU, neurosurgery, major trauma centre - depending on your institution's set up

Here's why you don't use albumin.

In the ambulance

As the CT1 newly indoctrinated onto the on-call rota, one of your staple jobs is hopping into the back of the truck and accompanying your patient up to wherever the nearest neurosurgeon can be found.

Things to consider

You will not be able to intubate, cannulate or do anything useful sideways at 70 mph.

• Ensure your tube is taped and taped again
• Have enough access, with enough extensions, and enough flushes, so you can give drugs from your seat
• Have 3% hypertonic saline connected and ready to go, in case Cushing pays a visit on the motorway

A normal hospital bed isn't hopping over speedbumps, or flinging around roundabouts at questionably efficient speeds.

• Ambulances have terrible acceleration but fabulous brakes
• A sudden deceleration will send an enormous rush of blood into your patient's delicate head
• Ask the driver to prioritise being smooth over speedy and avoid heavy braking where possible

Remember the ultimate aim here - get to the neurosurgeon - when considering whether an unexpected emergency warrants pulling over or diverting to the nearest emergency deparment.

• If the patient's tube falls out 5 minutes from the destination, shove an IGEL in and crack on
• If they blow a tension pneumothorax an hour away, pull over and decompress with an orange cannula - if it improves, crack on, if not, head to the nearest ED

Keep your consultant's number handy for advice and remember:

"You are not responsible for the outcome, you are only responsible for your actions."

My favourite picture

What you can control.

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Useful Tweets and Resources

Traumatic Brain Injury (TBI)

CONTENTS Rapid Reference 🚀 Epidemiology Primary vs. secondary injury Glasgow Coma Scale (GCS) Initial evaluation Specific types of injury Diffuse axonal injury (DAI) Contusions & intraparenchymal hematomas Epidural hematoma Subdural hematoma Subarachnoid hemorrhage Intraventricular hemorrhage Cerebral venous sinus thrombosis Fat embolism Management Coagulation management Hemodynamic management ICP management Ventilator management Seizure prophylaxis & management DVT […]

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References and Further Reading

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