Last updated 11/11/23
Primary Survey - Disability
Once all immediately life-threatening circulation conditions have been identified and where possible treated, the assessment of the casualty can move on to D - disability.
Whilst it’s known as Disability, D in the Primary Survey includes any cause of reduced level of consciousness, from slight drowsiness to complete unconsciousness. It includes pupil assessment, non-traumatic causes of reduced conscious level such as hypoglycaemia, hypothermia and drug overdose, and any overt indication that spinal cord injury has occurred.
Causes of Reduced Conscious Level
There are many causes of reduced conscious level and the commonest are listed below. Have these in mind as you go through ‘D’. If any of them leap out as the obvious cause, you may need to administer immediate treatment or modify how you manage the casualty. The circumstances of the rescue should help guide you as to your priority. Does the mechanism suggest head injury is likely? Are there obvious signs of head injury such as scalp lacerations or bruising? If so assess for head injury first, then look for other non-traumatic causes. If a casualty is unconscious or showing signs of reduced consciousness but there are no signs of trauma, consider non-traumatic causes first.
Remember - there may be more than one thing going on. Regardless of whether or not there is a head injury, always check for other causes of impaired consciousness since they may have precipitated the head injury e.g. a stroke or seizure causing a fall, etc. In fact this is precisely what happened to a woman we were called to on Stickle Ghyll. Although the alert said ‘female, fallen, face injuries’, witnesses said that it was a seizure that made her fall.
The following can all be causes of reduced level of consciousness and unconsciousness:
Head injury
Stroke or TIA
Hypoglycaemia
Hyperglycaemia
Hypothermia
Heat stroke
Drugs including alcohol
Lightning strike
Post-seizure
Abnormal cardiac rhythm
Simple faint (syncope)
Low blood sodium due to drinking excess clear fluids e.g. during a marathon
Drowning
Other causes that should be picked up earlier in the survey are:
Hypoxia
Cardiac arrest
Severe life-threatening asthma
Severe shock
Death!
Assess the Level of Consciousness
Do this using the ACVPU scale as it’s very quick and easy to do.
A new addition to AVPU is the presence of new agitation and Confusion, so it now becomes ACVPU. Following trauma, this should be noted as a serious indication of traumatic brain injury, or a sign of any of the causes of reduced consciousness above.
Head Injury
Head injury is the most common cause of altered conscious level. Whilst traumatic brain injury (TBI) is the real concern, it can be difficult to diagnose on the hill. For our purposes any significant blow to the head, with or without loss of consciousness, should raise concern that TBI is present and steps should be taken immediately to prevent secondary brain injury. This is discussed further in the section on head injury.
Immediate assessment and management in the Primary Survey
Remember – rapid deceleration of the head can cause a brain injury without any external evidence of head trauma. If a helmet was worn at the time of the incident, check it for signs of damage and ensure it goes with the casualty to hospital.
Oxygen
As with myocardial infarction and stroke, concerns have been expressed about the safety of oxygen in brain injury, but there is no clear evidence for this. Therefore, in MR, if it is not clear whether Traumatic Brain Injury is present or not, administer high flow oxygen regardless of the pulse oximetry reading. This is because the oximeter measures saturation in the finger which has a normal circulation, whereas parts of the injured brain do not. This might explain why hard evidence is lacking for too much oxygen being dangerous.
Other immediate actions
Head raised about 30° to stop blood damming back in the brain
IV fluids if low BP (if someone is available to cannulate the casualty). A head injury by itself does not cause a low blood pressure, so if the BP is low, look for bleeding elsewhere.
Remember – head injury is associated with an increased risk of cervical spine injury. See the head injury section for further details.
F.A.S.T.
Are there reasons to suspect a stroke? If so, quickly assess using the F.A.S.T. test. Remember this is a pass fail test. If they have any one symptom they need urgent evacuation for treatment.
F – Face, fallen to one side, can they smile?
A – Raise their arms. Do they stay there?
S – Slurred speech?
T – Record the time of the stroke as clot busting drugs may only be effective in the first 3 hours.
See Stroke & TIA for further details. Note: this is a UK video, but the emergency phone number at the end is Australian. In the UK, phone 999.
Assess the Pupils
The coloured part is called the iris. The pupil is the black bit in the centre of the iris. It is actually transparent to allow light to pass through, but looks black. The function of the pupil is to control the amount of light striking the retina at the back of the eye. The pupil is like setting the aperture in a camera.
Firstly look at both eyes. In a normal person, the pupils should be the same shape and size.
Measure and record the size of both pupils under ambient light using the scale (in mm) on the pen torch. Do not use descriptive terms such as ‘small’ or ‘large’ as these are subjective and do not convey any useful information.
Differences in size and shape following a head injury could be due to increased pressure within the skull and therefore a serious sign. A single large or ‘blown’ pupil is an especially serious indication of traumatic brain injury.
Small or ‘pinpoint’ pupils can be a sign of opiate overdose or a bleed in the brain stem (the part that connects the brain to the spinal cord). If they are observed, look for signs of drug use.
Using the pen torch, check the pupil reaction to light using the mnemonic P.E.A.R.L.:
|
P |
E |
A |
R |
L |
|
Pupils |
Equal |
And |
Reactive |
to Light |
Check each pupil reacts when light is shone into that eye obliquely (from the side), and then when it’s shone into the other eye i.e. shine it into the left eye twice, first to see if the left eye reacts, then to see if the right eye reacts. Then repeat with the right eye.
The normal reaction is that the pupil constricts briskly when light is shone into the eye. Do not place the torch directly in front of the eyes as this will give a false measurement. Like differences in pupil size, unequal pupil reactions or the failure of one or both to react can indicate increased pressure within the skull and should be considered a serious sign.
Remember – move the pen torch in from the side of the eye as shown on the right.
Repeat the assessments periodically and document the findings. Trends in changes to size and reaction of the pupils are a useful clinical feature for the receiving hospital.
Examples of abnormal pupils
Take a Blood Glucose (BM) Reading
Use the blood sugar tester to measure blood glucose.
How To Take a Blood Glucose (BM) Reading
Open a testing strip. All strips should have been pre-calibrated for use with our tester, so you don’t have to worry about calibrating them. Be careful not to contaminate the strip by touching the sampling end when removing it from the packaging.
Insert the end of the strip with the small microchip strip into the BM tester.
The device should automatically turn on if the strip has been inserted correctly.
A picture of a drop of blood being placed onto the testing strip should flash on the screen.
Swab the skin from where the blood sample will be obtained with an cleaning wipe. One of the least painful sites to take a sample is said to be the outside of the little finger.
Take a lancet and carefully twist the tab until it comes out. NOTE: Just keep twisting until it comes loose. Don’t pull on the tab or you will fire the lancet and not be able to use it to draw blood.
Place the end from which the tab has been removed against the casualty’s skin and press the trigger on the side of the lancet.
You should hear a click when it fires. The needle will then retract back into the housing to prevent inadvertent injury to you.
Dispose of the lancet in a sharps box
Gently squeeze the area around where you have just pricked them to bring out a drop of blood. Wipe away the first drop of blood.
Take the BM tester and hold the end of the testing strip against the second drop of blood while it takes up a sample.
After a few seconds a reading should appear on the screen. Make a note of this on the cas card as the tester will automatically shut off after a minute.
Cover the skin from where you took the sample with a swab,as it will continue to ooze for a minute or so.
Extremely high and low blood sugars can both cause unconsciousness. However, at this stage in the Primary Survey, our main concern is hypoglycaemia as it is something we can treat immediately.
The normal level of blood glucose (BM) is about 5 mmol/l. A reading below 4 indicates hypoglycaemia and must be treated immediately. If the blood glucose level stays low, permanent brain damage will occur.
People who are not diabetic can occasionally get a low blood sugar if they have been exercising vigorously for long periods without taking in any food. Although they might feel light headed, the level never goes low enough for long enough to cause brain damage. The body has a number of compensatory mechanisms to prevent this. Brain damage only occurs if the patient takes a drug, such as insulin, which drives the sugar levels down and keeps them low. See the section on diabetes for further details.
Treat low Blood Glucose Readings IMMEDIATELY
In mild hypoglycaemia (BM 3-4 mmol/l), it is usually sufficient just to give foods that release sugar quickly. Dextrose tablets, sugar or chocolate are good for those who can take food orally. Give as much as is needed to improve conscious level.
If the casualty is unable to eat, then use a fast acting sugar solution such as Glucogel, which is in the Drugs Box This is absorbed rapidly through the lining of the mouth.
In severe hypoglycaemia (<3 mmol/l), give glucagon as well to mobilise glucose stored in the liver (see below for more information about glucagon). If the casualty is unconscious, place them into the recovery position and then use a gloved finger to rub Glucogel into the gums.
Beware – Glucogel can pool and block the airway in unconscious and semi-conscious casualties. Do not give excessive amounts at a time and monitor for airway problems.
Glucogel and glucagon must always be followed up by the administration of slower release sugar in the form of food. This is because the fast acting forms wear off quickly so that some time later, the blood glucose levels will drop back again. Use slow release foods such as bread (sandwiches), cereals, biscuits etc.
Remember – shivering uses lots of energy, try to keep the casualty warm to help them conserve energy.
If hypoglycaemic seizures occur –
GIVE SUGAR FIRST
Then treat with midazolam (if necesssary) AFTER you have started to treat the hypo.
THE SEIZURES WILL STOP ON THEIR OWN ONCE THE BLOOD SUGAR RETURNS TOWARDS NORMAL.
NEVER GIVE MIDAZOLAM ALONE TO A HYPOGLYCAEMIC PATIENT WITH SEIZURES
Glucagon
Glucagon is a hormone produced naturally in the body by the pancreas. In fact it is produced alongside insulin. It is available for us in the Medical Sack in an orange container.
The normal doses of glucagon are 1 mg (the whole vial) IM if >12 years old and 0.5 mg (half the vial) IM for children under 12. It will also work if given just under the skin (subcutaneously). Glucagon takes about 15 minutes to work so it isn’t quick.
After treatment with glucagon, the casualty should recover in around 10-15 minutes.
Whilst they are unconscious, turn them into the recovery position.
How to prepare and administer Glucagon
Glucagon is supplied as a powder which has to be mixed with the contents of the syringe (see below).
Give food on awakening. The effects of glucagon will wear off after about 90 minutes.
Glucagon can cause nausea and vomiting, but this will settle fairly quickly. However, while it is present, it will interfere with providing food or liquid. It can also cause a rapid heart rate.
If glucagon has not worked after 15 minutes
You cannot give a second dose, I.V Glucose will need to be given by team healthcare professionals.
Make sure you have the right diagnosis. Re-check the BM in case there was an error when you did the reading the first time and something else is causing the unconsciousness. When re-checking BM in this situation, prick a different site on the body to get the blood sample.
Beware – Glucagon is much less effective in some situations:
A hypothermic or severely exhausted casualty (because their sugar reserves are used up).
Prolonged fasting (for the same reason)
Excess alcohol consumption
If the casualty has inadvertently taken an overdose of insulin
Signs of Improvement
Look for:
Recovered consciousness – this is the most important
Increased BM reading
Heart rate returning to normal
It is important to continue to monitor casualties with hypoglycaemia even after they have recovered and get them to eat and drink regularly to avoid another blood gluose level fall.
Finally, remember that that all severely hypoglycaemic people are hypothermic. This is because the body’s metabolic rate falls in an attempt to conserve as much glucose as possible for the brain. Therefore, check for hypothermia and expect to need to use heat pads.
Temperature
Hypothermia and heat illness can be the cause of or contribute to either unconsciousness or reduced consciousness. If this is a possibility, take a temperature reading and treat as appropriate. See hypothermia and heat illness for further details.
How to take an Ear Temperature
Put the thermometer in a pocket immediately before use to keep it warm. If the sensor gets cold, it will under-read, if it reads at all (it may just say ‘Lo’). Our thermometers read down to 20 degrees.
If the casualty’s head has been exposed to cold air, ideally cover the ear with a hat for 10 minutes. Similarly, if there is cold water or even snow in the ear canal, carefully attempt to dry at least the outer area before measuring (but NEVER poke anything into the ear canal). Again, cover the casualty’s head. Cold air or water in an ear will make the thermometer under-read. .
Place a new disposable sheath over the probe of the thermometer.
Gently insert the ear probe into the ear canal. If the casualty is conscious, explain to them what you are going to do beforehand as it can be uncomfortable.
The direction of the ear canal is slightly towards the forehead, so angle the probe forwards when you insert it. Push it in until it stops. The idea is to get the tip of the probe as close to the ear drum as possible.
Leave the probe in position for about 15 seconds so that it has time to equilibrate with the temperature inside the ear canal and then do a reading.
After a few seconds, the thermometer will beep to indicate the measurement has been taken. A single reading can be inaccurate so do further readings until you get consistency. If the probe tip has fully warmed up to the body temperature, the readings will be almost identical. If later readings differ from the earlier ones by >0.5 deg C, keep on checking or try the other ear.
A temperature below 35ºC indicates the casualty is suffering from hypothermia (see hypothermia for further details).
A temperature above 37.5ºC indicates the casualty is hyperthermic (see hyperthermia for further details).
Reduced levels of consciousness warrant urgent evacuation.
Once disability has been assessed move on to consider the environment.