LO5 Head and Facial Injuries (Chapter 12) Flashcards
meninges
Fibrous coverings of the brain
Dura mater, arachnoid mater and pia mater
The intercranial volume is composed of
the brain,
the CSF
blood in the blood vessels which completely fill the cranial cavity
Any increase in one of the components is at the expense of the other two
Monro-kellie doctrine
because of the fix space within the rigid skull as a brain tissue swells it takes up more volume
initially with brain swelling, blood and CSF volumes inside the skull decrease and compensate for the rise and pressure
as brain swelling continues compensation fails and intercranial pressure begins to rise
As the ICP increases the amount of blood they can enter the skull and perfused brain decreases leading to further brain injury
what happens when something obstructing the outflow a spinal fluid
Trumatic blood in the vesicles or subarachnoid space will cause an accumulation of spinal fluid within the brain and an increase in ICP
Primary brain injury
is the immediate damage to the brain tissue that is direct result of the mechanical force and is essentially fixed at the time of injury
Most primary brain injuries occur either as a result of external force is applied against the skull or from movement of the brain inside the skull
deceleration head injuries
the head usually strikes in object which causes a sudden discolouration of the skull
the brain continues to move forward impacting first against the skull in the original direction of the motion third collision and then rebounding to hit the opposite side of the inner surface of the skull a fourth collision
Coup
contracoup
Coup: injuries that occur to the brain in the area of the original impact
Contracoup: injuries that occur to the brain on the opposite side
Secondary brain injury
is the result of hypoxia and or decreased perfusion of the brain tissue
In response to the primary insult swelling can cause a decrease in perfusion
result in Vasodilation with increased blood flow to the injured area
No extra space inside the skull swelling of the injured area or newly formed intracerebral haematoma increases intracerebral pressure leading to a decrease cerebral blood flow that causes secondary brain injury
hypoventilation vs hyperventilation
An increase in the level of CO2 hypoventilation promotes vasodilation of vessel supplying the brain whereas lowering the level of CO2 hyperventilation causes vasoconstriction and decreases blood flow to the brain
Intracranial pressure
The pressure within the
skull
increased ICP
Blood supply will be decreased by the increased ICP and because the brain requires a constant supply of blood to survive brain swelling can be rapidly catastrophic
ICP is considered dangerous when it rises above 15 mmHg cerebral herniation may occur at pressures above 25 mmHg
Cerebral perfusion pressure (CPP):
The net pressure gradient causing blood flow through the brain
It’s value is obtained by subtracting the ICP from the MAP
what happens when ICP increases
the system blood pressure increases to try to preserve blood flow to the brain
the body senses the rising systemic blood pressure and this triggers a drop in pulse rate
why does heart rate drop when ICP increases
the body tries to lower the systemic blood pressure by lowering cardiac output
Cerebral perfusion
Pressure required to perfuse brain
You must maintain a CPP of 60 to 70 mmHg which requires maintaining a map of greater than 70 mmHg in the patient with severe TBI
CPP= MAP-ICP
Map constant + ICP increase = CPP Decrease
Map increases + ICP constant = CPP Increase
MAP decrease + ICP increase =CPP critical
map in normal brain vs ICP brain
Map- normal brain 65+= 90/p
Map- increase ICP = 85 110/p
Cerebral Herniation Syndrome
When the brain swelling or intercranial haemorrhage occurs particularly after a blow to the head a sudden rise in ICP may occur and force portions of the brain downward through the tentorium cerebelli
This leads to obstruction of the flow of CSF in the herniated brain apply significant pressure to the brain stem resulting in cerebral herniation syndrome
Cerebral Herniation Syndrome signs and symptoms
a decreasing LOC that rapidly progresses to coma
dilation of the pupils in an outward downward deviation of the eye on the side of injury
paralysis of the arm and leg on the side opposite the injury or dcerebrate positioning,
vital signs revealed increased blood pressure and bradycardia
signs of Increasing ICP
Respirations- increase, decrease, irregular
Pulse- decrease
Blood pressure- increase, widening pulse
Cushings reflex
increase BP
decrease heart rate
irregular resp: Heyne stroke
Hyperventilation
Hyperventilation will decrease the size of the blood vessels in the brain and briefly decrease ICP
Cerebral herniation syndrome is the only situation in which hyperventilation is still indicated
you must ventilate every three seconds and attempt to keep ET CO2 at 30 to 35 mmHg
When to hyperventilate:
after fixing hypoxia and hypotension
- TBI patient with a GCS score less than 9 with extensor posturing (decerebrate)
- TBI patient with a GCS score less than 9 with asymmetric, dilated, or non-reactive pupils
- -Remember hypoxemia, orbital trauma, substances, lightning strike, and hypothermia also affect people every reaction - TBI patient with an initial GCS score less than 9 that then drops his or her GCS by more than two points
treatment of facial injuries
gentle irrigation with normal Celine if needed an application of Eyeshield
Elevate the head of a stretcher if possible
open skull fracture treatment
Open skull fracture should have the wound dressed but avoid excess pressure when controlling bleeding penetrating objects in the skull should be secured patient transported immediately
Concussion
There is a history of trauma to the head with a variable period of unconsciousness or confusion and then a return to normal consciousness
There may be amnesia following the injury which usually extends to some point before the injury rendering the patient unable to remember events leading up
Patient may report dizxiness, heacdache, ringing in the ears, or nausea
Cerebral contusion
A patient with a cerebral contusion bruised brain tissue will usually have a history of prolonged and consciousness or serious alteration in LOC
The patient may have focal neurologic signs and appear to have suffered a cerebrovascular accident
May have personality changes
Diffuse axonal injury
Result of severe blunt head trauma
Generalized edema
The patient presents unconscious, due to disruption of nerve fibers between the cortex and brain stem with no focal motor deficits
Anoxic brain injury
Perfusion of the cortex is interrupted due to spasm that develops in the small cerebral arteries after 4 to 6 minutes of anoxia
restoring oxygenation and blood pressure will not restore perfusion of the cortex and they will be irreversible damage
Hypothermia seems to protect against this phenomenon
Intracranial hemorrhage
hemmorhage can occur between:
the skull in the Dura,
between the Dura and the arachnoid,
beneath the subarachnoid
or directly in the brain tissue
Acute epidural haematoma
bleeding between dura mater and skull
Because the bleeding is usually arterial bleeding and rise in ICP can occur rapidly and death may occur quickly
symptoms of Acute epidural haematoma
a history of head trauma with initial LOC, often followed by a lucid period
A few minutes to several hours the patient will develop signs of increasing ICP
Lapse into unconsciousness, and develop body paralysis on the side opposite the head injury
pupils Often dilated and fixed people on the side of the head injury
Acute subdural hematoma
bleeding between dura and arachnoid layers
ICP increases slowly and the diagnosis is often not apparent until hours or days after injury
Use of anticoagulants increases the risk of subdural bleeding
Those with alcoholism and older adults are at high risk for this injury after a deceleration injury
Acute subdural hematoma signs and symptoms
headache, fluctuations in LOC, focal neurological signs
Subarachnoid hemorrhage
bleeding between brain and subarachnoid layer
Rarely occurs alone most commonly associated with subdural haematoma or cerebral contusion
The massive amount of subarachnoid blood causes irritation that result in intravascular fluid leaking into the brain causing more Edema
signs and symptoms of subarachnoid hemorrhage
headache, coma, and vomiting
intracranial pressure
Is bleeding within the brain tissue that may result from blunt or penetrating injury so the head
signs and symptoms of intracranial pressure
depend on the regions involved in the degree of the injury
They occur in anatomical pattern similar to those from a stroke in the same area of the brain alteration in LOC is commonly seen
Awake patient complains of headache and vomiting
A basilar skull facture may indicate any of the following
bleeding from the ear or nose, clear fluid from nose or ear, battle signs and raccoon eyes
pupils
are controlled by the third cranial nerve which is affected by the increasing ICP
if both pupils are dilated and do not react to light the patient probably has a brainstem injury
if pupils are dilated but still reactive to light the injury is often reversible
a uni laterally dilated pupil remains reactive to light may be the earliest sign of cerebral herniation
the development of a unilaterally dilated nonreactive pupil (blown pupil) is an extreme emergency and requires hyperventilation
Management of patient with a TBI
- ) Provide good oxygenation
- 1) Maintain goo ventilation
- 2)Endotracheal tubes recommened
- Apply SMR based on MOI/status of spine
- 1) When possible elevate head of stretcher 30degrees to decrease ICP
- Agitated and combative patients fighting against restraints or ventikation will increase ICP
- Record vital signs every 5 mins
- Finger stick glucose
- 2 large bore IV
- Hyperventilation is recommended for cerebral herniation after correcting hypoxia and hypotension
- If the a patient develops hypotension, assume it is due to hemorrhage or rarely spinal cord
Conjunctivas
almost immediately and the eyes begin to predict tears in an attempt to flush out the object
Irritation of the cornea or conjunctiva cause intense pain
Prehospital care involves stabilizing the object and preparing the patient for transport
The greater the length of the foreign object sticking out of the eye the more important stabilization becomes
Hyphemia
is bleeding into the anterior chamber of the eye that scares vision partially or completely
blowout fracture
is the fragments of a fractured bone can entrap some of the muscles that control movement causing double vision especially with upward gaze
Any patient who reports pain, double vision or decreased vision following a blunt injury about the eye should be assumed to have a blowout fracture
Retinal detachment
separation of the inner layers of the retina from the underlined membrane it is often seen in sports injuries
Painless condition produces flashing lights, specs or floaters in the field of vision and a cloud or shade over the patient’s vision
Visual loss that does not improve on the patient blinks
is the most important symptom of an eye injury it may indicate damage to the globe or to the optic nerve
Double vision
usually points to trauma involving the extraocular muscles such as a fracture of the orbit
Foreign body sensation
usually indicates superficial injury to the cornea or the presence of a foreign object trapped behind the eyelids
Injuries to eyelids Dash lacerations, abrasions and contusions
require a little in the way of prehospital care other than bleeding control and gentle patching
Anisocoria
condition in which the pupils are not of equal size
Follow these three important guidelines in treating penetrating injuries of the eye:
Never exert pressure on or manipulate the injured globe in anyway
If part of the globe is exposed gently apply a moist sterile dressing to prevent drying
Cover the injured eye with a protective rigid a shield cup or sterile dressing apply soft dressings to both eyes
If rupture of the globe is suspected
take spinal motion restriction precautions
Elevate the head of the stretcher approximately 30° to 40° and ensure the cervical collar is not too tight
globe may be displaced out of its socket
do not attempt to manipulate it or reposition it
Cover the protruding I with a moist sterile dressing and stabilize it along with uninjured eye to prevent further injury due to sympathetic eye movement
Place the patient in supine to prevent further loss of fluid from the eye
Burns the eye that are caused by ultraviolet light
covering the eye with a sterile moist pad and an eye shield.
Place the patient in a supine position during transport and protect the patient from further exposure to bright light
Chemical burns to the eye
immediate irrigation with sterile water or saline solution
If only one is affected take care to avoid contaminated water is getting into the other eye
Irrigate the eye for at least five minutes if the burn was caused by an alkali or strong acid irrigate continuously for 20 minutes
Always flush from the nose side of the eye towards the outside to avoid flashing material into the other eye
Ruptured ear drum
Perforation of the tympanic membrane can result from foreign bodies in the ear or from pressure related injuries such as blast injuries or diving related injuries
Signs and symptoms of perforated tympanic membrane include loss of hearing and blood drainage from ear
pinna avulsed
carefully realign the ear into position and gently bandage
If it has been completely avulsed attempt to retrieve the part for reimplantation
If detached part is retrieved a treat as an amputation
If blood or CSF drainage is noted apply loose dressing over the ear without stopping the flow and assess the patient for other signs of basillar skull fracture
anterior part of the neck injury zone 1 2 and 3
zone I: can extend into the chest and may not be easily recognized on physical examination
Injuries in this area are associated with the highest mortality rate
Zone II: most common are usually the most obvious and have a lower mortality rate than zone one injuries
Zone III: often are difficult for surgeon to access and repair because many of the structures enter the base of the skull
