Care of the unconscious Patient

Question 1

Causes of Unconsciousness

Answer 1

Primary cerebral (Intracranial) or secondary to a systemic disorder (Extracranial)
Can be due to global cerebral depression or focal lesion
Often multifactorial

Question 2

Intracranial Causes of unconsciousness (6)

Answer 2

Vascular (Haemorrhage or infarction)
Tumours
Infection
Post grand mal fit
Head injury

Question 3

Extracranial Causes of unconsciousness

Answer 3

Cardiovascular (Thromoembolism or syncope)
Infection
Metabolic
Drugs
Physical injury

Question 4

Management of unconsciousness

Answer 4

Primary objective of care is to prevent secondary damage

Primary survey and stablisation with subsequent secondary surveys –> ABCDE

Question 5

Assessment of breathing in the unconscious patient

Answer 5

Observe the work and pattern of breathing –> RS & CVS effort
Signs of CNS injury or depression –> responsive to pain?
Is the patient effectively ventilating and oxygenating
Is breathing problem a cause or consequence of decreased consciousness?

Question 6

Assessment of circulation in the unconscious patient

Answer 6

Assess considering risk of end organ damage from hypotension –> correct with haemorrhagic control, fluid/blood resuscitation, Ix +- invasive monitoring

Question 7

Cerebral perfusion Pressure (CPP)

Answer 7

CPP=MAP - ICP (-CVP) so if ICP increases CPP decreases, below 50mmHg risk of cerebral ischemia (aim >70mmHg)
The cranium is a fixed box and the CSF and Blood volume can compensate for 50-100mls of swelling but further than that ICP will increase

Question 8

Cerebral blood flow (CBF)

Answer 8

CBF=50ml/100gs of tissue, <20mls/100g ischemia occurs
When MAP is 60-140mmHg CBF autoregulates dependent on O2, CO2, temp, drugs, Haematocrit, HTN
Areas around tumors etc may lose auto-regulation

Question 9

Glasgow Coma Score (GCS)

Answer 9

Eyes open –> spontaneously (4), speech (3), pain (2), none (1)
Verbal response –> orientated (5), confused (4), words (3), sounds (2), none (1)
Motor response –> obeys commands (6), localise to pain (5), withdrawals from pain (4), Flexes to pain (3), Extensor response (2), None (1)

Question 10

Limitations of the GCS

Answer 10

Prognostic value depends on aetiology and chronicity
Practical considerations may limit scoring
Should be done in primary survey if possible otherwise in 2ndary

Question 11

Cheyne-stokes breathing

Answer 11

An abnormal pattern of breathing where deeper and faster breaths occur then gradually slow to a period of apnea in a cycle between 30seconds to 2mins
Occurs after damage to respiratory centres, chronic heart failure and at altitude.

Question 12

Monitoring of an unconscious patient

Answer 12

Gases - Sats, ABG, RR
CVS - HR, BP, ECG, Temp, FBC, INR, LFTs
NG or OG tube
Urine output and analysis, U+Es
Imaging - X ray, CT, MRI

Question 13

Long term care of the unconscious patient

Answer 13

Eye, mouth and skin care
Gases, lung compliance and bronchial toilet
Pressure areas, nerve damage and sores
DVTs
Enteral nutrition to maintain mucosal integrity
Temp control

Question 14

Indications for ICP monitoring

Answer 14

Severe closed head injuries - with GCS 3-8 and CT abnormalities OR with normal CT but 2 of:age>40, motor signs, systolic BP <90mmHg, OR
SAH, Reye syndrome, brain tumors, brain swelling or hydrocephalus, meningitis/encephalitis etc

Question 15

Reye syndrome

Answer 15

A syndrome usually seen in children post influenza or varicella infection characterised by vomiting, rash, lethargy, mood changes, hypoglycaemia and drowiness leading to coma and can cause significant liver or brain damage
May be related to aspirin use
Stages 1 to V

Question 16

Hypotension post spinal injury

Answer 16

High spinal cord injuries can cause sympathetic deinnervation leading to hypotension

Question 17

Treatment of raised ICP

Answer 17

If ICP >20mmHg then check positoning and neck veins to maximise venous outflow, consider muscle relaxants and sedatives, treat seizures
Diuretics –> frusemide or mannitol, Consider hypertonic saline 3%
Surgery –> evacuation haemotoma or decompression craniectomy

Question 18

Investigations of Raised ICP

Answer 18

Flow –>Transcranial USS or laser doppler flowmetry
O2 monitoring –> transcranial cerebral/jugular venous bulb or brain tissue tension oximetry
Cerebral metabolism can be measured by intracerebral microdialysis

Question 19

Brain stem death

Answer 19

Effects of sedatives, drugs, metabolic or endocrine disorders and hypothermia must be excluded
Brainstem reflexes absent when tested by two doctors:
pupillary response to light, corneal reflex, oculovestibular reflex, motor response to pain, cough and gag reflex, lack of respiratory effort with adequate CO2 and stimulation

Question 20

Laryngeal mask airway

Answer 20

Pros – allows hands-free maintenance of anaesthesia, easy to put in, can be used in difficult tracheal intubatio
Cons – Wont protect from aspiration, can become disloddged, Wont allow ventilation at high airway pressures.