Emergency Medicine

Explanation

Answer: Airway with Cervical Spine control> Breathing> Circulation with haemorrhage control> Disability or neurological status> Exposure

In trauma, like resuscitation, an ABC approach is adopted for patient assessment and management (Airway, Breathing, Circulation, Disability, Exposure). In the case of trauma however, the mnemonic is modified to:

• Airway with cervical spine protection
• Breathing
• Circulation with haemorrhage control
• Disability and neurological status
• Exposure/Environment

While in reality, assessment of these areas will run in parallel with a large team, rather than in series with one person, it is important to remember this sequence so as to identify the greatest threats to life first

Explanation

The AVPU scale is a popular tool for rapid neurological assessment of children:

Eventually, the child may be given a more formal score.

The Glasgow Coma Scale (GCS) is the mainstay of defining a patient’s conscious level and communicating it to other professionals. It is derived from best motor, verbal and eye-opening responses, resulting in a score from 3 to 15.

A modified GCS can be used for non-verbal children. When calculating GCS, the best response is taken in each parameter, even if that is not the most consistent.

The Glasgow Coma Scale is as follows:

Explanation

A useful clinical approach for rapid assessment is simply to ask your patient “are you alright?” This sounds obvious, but the patient who responds is telling you:

• their airway is patent
• they are breathing sufficient to answer you
• they are circulating sufficient to perfuse their brain, which is functioning sufficient to process your communication and respond.

A GCS or AVPU score can be calculated thereafter based on the patient’s response to simple questions. The patient who does not respond appropriately (or at all) can then be evaluated with increasing levels of stimulus, ie voice, touch, pain.

Explanation

• Eyes opening to pain = 2
• Moaning incomprehensibly = 2
• Withdraws to pain = 4

Total = 8

It would also be reasonable to say that Jonny is a P on the AVPU scale. (A GCS of 8 is felt to correlate roughly with P on the AVPU scale).

A GCS of 8 is of particular importance as it thought that a patient’s protective airway reflexes become impaired at around this level of decreased consciousness

Explanation

• Eyes opening to voice = 3
• Unintellligible speech = 3
• Localising pain = 5

Total = 11

This is useful information, as there is evidence that initial GCS at scene, particularly the motor component, correlates with ultimate/long-term prognosis. The neurosurgical team will want to know this.

Explanation

In the context of head injury, unequal or unreactive pupils are a major red-flag sign of raised ICP and can progress rapidly to coning and death. To understand the mechanism of this, think of the skull as a closed box:

Inside the box sits the brain, bathed in cerebral spinal fluid (CSF) and perfused by blood in arteries and veins.

In closed head injury, bleeding occurs, which occupies space in the closed box and squashes the other components in the box because the box can’t expand.

The body can cope with this to an extent via the ventricular system but eventually will reach a point where either circulation to the brain is compromised or the brain itself is squeezed irrevocably. This is manifest clinically with a decrease in conscious level and pupillary abnormalities. Ultimately pressure can force the brain to herniate at the tentorium or the brainstem (coning), leading to loss of vital functions and death.

The so-called Cushing’s Triad of bradycardia, hypertension and abnormal breathing, a manifestation of this brainstem pressure, is a very late and grave sign in children. Children are also peculiarly more prone to cerebral oedema in head injury than adults.

Explanation

A, B, C - Intubation and Osmotic Diuretics

In this context of head injury with deteriorating conscious level, one needs to consider the safety of the patient’s airway (due to loss of protective reflexes and risk of aspiration rather than direct injury) and breathing (hypoventilation secondary to coma). Therefore it is common to pre-emptively secure the patient’s airway by Rapid Sequence Intubation.

However, care must be taken when choosing induction agents as some can directly raise ICP (Ketamine) and others are particularly vasoactive in cardiovascular instability (Propofol). Additionally, care must be taken when performing laryngoscopy and tracheal intubation as both can stimulate a rise in ICP.

20% Mannitol, and more recently, hypertonic saline (3%), are given in the setting of acutely rising ICP. Both act by osmotic diuresis to transiently assist decompression, buying time for preparation of definitive management.

Our plan at this stage is to:

• Optimise the patient
• Prevent secondary injury
• Transfer the patient safely for neuro-imaging, and onward to definitive care.

Urgent neuro-imaging (most often CT) will assist the neurosurgical team in planning how to proceed by identifying the site, nature and extent of the injury. In trauma, and particularly head trauma, the concept of optimisation and prevention of secondary injury features alongside resuscitation. The mortality and morbidity associated with major trauma is often thought of as trimodal, with death and disability occurring:

• immediately/rapidly after the injury (i.e. at the scene) - there is often little that can be done here other than primary prevention.
• in the first few hours after injury (the so-called Golden Hour) - this is where our ABC approach to assessment, identification of life-threatening injuries and resuscitation can make a difference.
• in the subsequent hours, days, weeks - the consequences of injury, the body’s natural response to injury and the consequences of our interventions can cause secondary injury. Early attention to the prevention of secondary injury can dramatically reduce morbidity and late mortality.

Explanation

All of the above.

These are so-called Neuroprotective measures.

Blood Glucose:

Neurones are metabolically very active and dependent on glucose for fuel, with no alternate fuel source. Therefore, sustained hypoglycaemia is poorly tolerated generally, let alone in the setting of an injured brain. Sustained hypoglycaemia leads to global brain injury. Equally, sustained hyperglycaemia in critical care patients is associated with adverse outcome.

Blood pressure:

Maintaining a good blood pressure in head trauma is critical to maintaining cerebral perfusion pressure (CPP). CPP is the pressure difference between ICP and Mean Arterial Blood Pressure. It is this pressure difference that supplies the brain with oxygenated blood. As ICP rises or BP falls in head injury, CPP drops proportionally, ultimately compromising cerebral blood flow.

Head Position:

Positioning the patient with a 10-15 degree head-up tilt helps to encourage cerebral venous drainage.

Temperature:

A lot of research is looking into the role of active cooling in various contexts of cerebral insult to decrease cerebral oxygen demand, metabolic rate and inhibit damaging inflammatory responses. While in the context of head trauma the role of active cooling is not fully established, it is accepted that hyperthermia is best avoided as it causes the reverse of the noted cooling effects.

CO2:

Hypercapnia causes cerebral vascular dilatation, which can worsen bleeding and increase ICP. Conversely, hypocapnia causes cerebral vasoconstriction, impairing cerebral blood flow. Neither situation is ideal, therefore ventilation strategies aim to maintain CO2 in the normal range with careful monitoring.

Sodium:

Maintaining electrolyte homeostasis, particularly sodium, is of importance in preventing fluid shift, cerebral oedema and cell death. Hypertonic saline is often employed in the emergency setting of raised ICP, but maintaining sodium in the normal range to avoid subtle fluid shift is also important.

Oxygen:

The brain is metabolically active and dependant on aerobic respiration. The injured brain even more so. Therefore, good oxygenation is essential to prevent secondary brain injury.

Explanation

A left extradural haematoma is shown, with its classical “lenticular” appearance. The haematoma is causing some midline shift, with deformation of the ventricles, giving them an unequal appearance. The dark swirls in the haematoma represent rapid arterial bleeding.

Explanation

Wearing a cycling helmet is the only preventive intervention to have been shown to reduce the incidence and severity of traumatic brain injury in bike accidents.