Head Injuries

Question 1

Define Traumatic Brain Injury (TBI)

Answer 1

is an insult to the brain created from an external mechanical force. Significant insult can lead to an altered level of consciousness and temporary or sometimes permanent impairment of cognitive, physical and psychosocial.

Question 2

Causes of Traumatic Brain injuries

Answer 2

Blunt or penetrating;
•	Falls (most common)
•	Motor Vehicle Crash (Most common cause of TBI deaths)
•	Industrial accidents
•	Sporting injuries

Question 3

Define Head Injury

Answer 3

A severe head injury is defined as a GCS less than nine (9) post traumatic insult.

Question 4

Traumatic force to the head causes a tearing of blood vessels, nerves and or meninges. This result in…

Answer 4

haemorrhage, oedema and ischemia to the cerebral parenchyma. Forces can be either direct or indirect being acceleration and or deceleration.

Question 5

Define Primary injury

Answer 5

occurs at the time of incident, is reversible and typically determines the outcome.

Question 6

A primary injury causes brain tissue deformation through:

Answer 6

• Compression
• Tension (stretch)
• Shearing

Question 7

Primary injury forces lead to four types of cellular and tissue injury:

Answer 7

• Cell membrane disruption and ion channel dysfunction
• Blood-brain barrier and vascular disruption
• Altered auto-regulation
• Local inflammation

Question 8

Secondary Injury

Answer 8

Encompasses the changes occurring after the initial insult.

Onset within minutes up to days after the primary brain injury.

Question 9

Secondary injury includes the cascade of what? What does this contribute to?

Answer 9

cellular, chemical, tissue, and or blood vessel changes occurring in the brain contributing to further destruction.

Question 10

What five states can result in a secondary injury?

Answer 10

• Hypoxia (<90%)
• Hypotension (<90mmHg)
• Hypocapnoea(<30mmHg)
• Hyperthermia (>39C)
• Hyperglycaemia

Question 11

What are the 10 priorities to implement to minimise secondary brain injury?

Answer 11

1. Protect the spine - ensure Cx immobilisation (collar) does not impede jugular venous drainage
2. Cluster cares - minimise stimulus to minimise increasing Intracranial Pressure
3. Advanced airway management - Rapid Sequence Induction
4. Prevent hypoxia and hypocapnoea - appropriate ventilation with oxygen and ETCO2 monitoring
5. Prevent hypotension - appropriate posture (head elevation 30degree postural drainage) and adequate fluid resuscitation.
6. Pharmacology - analgesia, anti-emetics, anticonvulsant and anti-hypoglycaemic
7. Short prehospital times
8. Manage other injuries
9. Delivered to the appropriate, notified hospital
10. Maintaining an awareness that any hypoxic or hypotensive episode

Question 12

mean arterial pressure

Answer 12

the average pressure in a person’s arteries occurring during one cardiac cycle.

MAP is considered as the most appropriate measure of perfusion to vital organs.

Question 13

Calculating a patients MAP:

Answer 13

(Systolic – Diastolic /3) + Diastolic

Question 14

Cerebral Perfusion Pressure (CPP)

Answer 14

Cerebral perfusion pressure calculates blood flow to the brain. Used to describe the pressure gradient relating to cerebral blood flow in to the brain or brain perfusion.

Question 15

CPP is calculated by

Answer 15

CPP = MAP – ICP (5-10mmHg)
(MAP) 93.3 – 10
CPP = 83mmHg