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3. Cat & Dog 3 > Traumatic Brain Injury > Flashcards

Traumatic Brain Injury Flashcards

1
Q

Traumatic Brain Injury
— Primary and secondary insults
> what they lead to?

A

Primary insult
— Hemorrhage
— Damaged parenchyma
— Neuroaxonal injury
<><>
Secondary Insult
— Ischemia
— Edema > Maximal effects at 24-48 hrs
<><><><>
This leads to increased ICP

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2
Q

Initial Goals for head trauma

A

— Determine extent of injuries
— Assess brain function
— Broadly localize neurological lesion
> cortical is ‘good’, brainstem is ‘bad’

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3
Q

Patient Assessment for head trauma case

A

— Level of consciousness
— Respiratory pattern / Systemic signs
— Cranial nerve examination
— Head
> Palpate for fractures
> Bleeding / Leakage of CSF – ears, nose, wounds
— Pain perception to limbs
— Motor function / Postural reactions
<><><><>
GPE with MINIMAL manipulation of the head/neck

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4
Q

decreased level of mentation comes from one of these places:

A
  1. Cerebrum (bilateral & severe)
  2. Brain stem – ascending reticular activating system (ARAS)
    <><><><>
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5
Q

Deficits in the cranial nerves indicate:

A

brain stem involvement

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6
Q

Respiratory Pattern for new head trauma patient
— Markedly abnormal respiratory patterns mean what?

A

— Respiratory centers are located centrally
— Markedly abnormal respiratory patterns
> Suggest brainstem lesion
> Carry a poor prognosis

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7
Q

Systemic Signs of head trauma

A

Cushing’s Reflex
— Hypertension
+
— Bradycardia

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8
Q

Cushing’s Reflex - what is it? what does it mean?

A

CPP=MAP–ICP
> if our ICP goes up very high, then our MAP must rise to maintain cerebral perfusion
<><>
To maintain cerebral perfusion pressure (CPP):
— If ICP rises, then MAP must also rise
— This increased MAP triggers a baroreceptor mediated BRADYCARDIA
<><>
Cushing’s Reflex = Systemic Hypertension + Bradycardia
> Imminent brain herniation

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9
Q

Pupillary Light Reflex - what it tells us?

A

— Assesses
— CNII & CNIII
> Constriction suggests CN III is intact
— Note even fine changes
<><>
> CN 3 is at a very important segment of the brainstem

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10
Q

PLR - what does this tell us?

A
  • even a small change in pupil width tells us PLR and thus CN3 is intact
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11
Q

Brainstem Lesion - what will this look like in the eyes? what does this mean for lesion localization and prognosis?

A

Pupils
— Dilated
— Central
— Unresponsive
<><>
— Lack of CNIII input
— Midbrain / Pons
— Grave prognosis
<><><><><>
<><><><><>
Pupils
— Asymmetry
— Ocular vs brain trauma
<><>
— Unilateral rapid changes
— ICP

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12
Q

Physiologic Nystagmus - tells us what?

A

Evaluates
— CN III, IV, VI, VIII
— Medial Longitudinal Fasciculus
<><>
— Global assessment > means we have a breadth of our brainstem that is doing well

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13
Q

Decerebrate Rigidity - tells us what? what does it look like? prognosis?

A

Cortical injury
— Disconnection of the higher centres of the brain &
brainstem
— Patients are comatose, lack PLR, dilated or pinpoint pupils
— Rigidity - extension of all 4 limbs & tail, opisthotonus
— GRAVE prognosis

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14
Q

Decerebellate Rigidity - tells us what? what does it look like? prognosis?

A

Cerebellar injury
— Patients are ALERT & aware
— Neck & forelimbs are in extension
— Hindlimbs are normal (or hyperflexed)
— FAVOURABLE prognosis

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15
Q

Modified Glasgow Coma Score - what does it assess? what is the scale? what is its use?

A
  • Motor activity, brainstem reflexes, level of consciousness
  • scale goes from 6 (best) to 1 (worst) for each category, then add them up
  • It is a good prognostic indicator; higher scores mean better prognosis
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16
Q

Imaging for head trauma - when to do skull ultrasound

A

— puppies, tiny dogs, open skull fractures

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17
Q

Imaging for head trauma - use of CT and MRI?

A

— CT preferred:
> Acute hemorrhage & bone are better visualized
<><>
— MRI
> ID more subtle lesions
> Findings ass’d with prognosis

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18
Q

skull fractures - incidence with brain trauma? associated with what conditions?

A
  • 46-72% incidence
  • associated with Development of seizures, post traumatic epilepsy
    > Worse outcome at 3, 6, 12 months
19
Q

Factors Affecting ICP

A

Intracranial mass lesion – hemorrhage, depressed skull fracture
<><>
Cerebral edema (aggravated by ischemia / poor brain perfusion)
<><>
Vasodilation:
— Venous return
> Head position
> Intrathoracic / intraabdominal pressure
— Cerebral vasodilation - increased PaCO2 ; decreased PaO2
— Fluid overload
— Hyperthermia
— Venous sinus thombosis or other obstruction
— Seizures

20
Q

Emergency Management for head trauma

A
  1. Airway/Breathing/Circulation
    - IV access
    - O2 Supplementation
  2. Stabilize the patient
    - ie. pneumothorax, fatal arrhythmias, etc
21
Q

Treatment for head trauma

A

“make all vitals perfect”
<><><><>
- Maintain normal BP
> MAP 90-100 +mmHg
<><>
- Resuscitate to NORMOVOLEMIA
> Maximize O2 delivery
> Minimize fluid overload
<><>
- O2 Supplementation
<><>
- Fluid Resuscitation
<><>
- Pain Management
<><>
etc…

22
Q

Fluid Resuscitation for brain trauma cases - what are our principles? primary considerations??

A

Low volume resuscitation
— Crystalloids
— Hypertonic Saline
— Colloids
— Blood
<><>
Risks of HYPOTENSION/ HYPOVOLEMIA far outweigh risks of overhydration

23
Q

indication for crystalloids for fluid resuscitation in head trauma case? rate?
what if hypotension persists?

A

Indication
— Mild hypotension
— MAP 60-80 mmHg
<><>
Rate
— Dog – 40 ml/kg (up to max 70 ml/kg)
— Cat – 20 ml/kg (up to max 40 ml/kg)
<><><><>
If hypotension persists
— Add hypertonic saline / colloid

24
Q

O2 Supplementation for head trauma patient
- goal?
- what to avoid? why?
- hypoxemic vs hyperoxemic states and outcomes

A

— Goal – normoxia
> Pulse oximeter 95-98%
> PaO2 3 80mmHg – 105 mmHg
<><>
— Avoid nasal prongs / cannulas > we dont want sneezing
<><>
— Hypoxemia – leads to vasodilation, increased ICP & decreased cerebral blood flow
— Hyperoxemia – also associated with worse outcomes related to ROS!

25
Q

Pain Management for brain trauma case
- what to use and how?

A

Use opioids - TITRATE
- Fentanyl > Short acting, easy to adjust
- Methadone
- Hydromorphone
> TITRATE – avoid vomiting!!!!!!!!!!!!!!!!
<><>
- Opt for NSAIDs once animal stable

26
Q

what signs are we looking for in a head trauma case to start treatment to avoid brain herniation?

A
  1. decreased Level of consciousness
  2. Cushing’s reflex
    — Bradycardia
    — Hypertension
  3. Loss of PLR / Rapid change in pupil size / Loss of physiologic nystagmus
    <><>
    ≥ 2 signs ….. TREAT!!!
27
Q

Elevated ICP - how to treat?

A

Hyperosmolar therapy
— Mannitol
— Hypertonic saline

28
Q

what is mannitol? what does it do?
contraindications?

A

— Osmotic diuretic, useful for treating elevated ICP
— Decreases blood viscosity
— Free-radical scavenger
<><>
Contraindications:
— Hypovolemia, CHF
— Ongoing intracranial hemorrh (empirical)
— IV continuous infusion not recommended

29
Q

Hypertonic Saline - use for treatment of elevated ICP? caution?

A

Hyperosmolar solution
— ‘Draws’ out brain edema
— Also: Improves CBF & O2 delivery
<><>
— Caution – maintain Na+ < 160 mmol/L

30
Q

Hyperosmolar Therapy for increased ICP - treatment plan overall, monitoring?

A

mannitol or Hypertonic Saline
— Try one, if little effect, try the other!
— May need to repeat
<><>
Monitoring q8 hr or more often
— Hydration
— Electrolytes

31
Q

Corticosteroids for increased ICP? what do they do?

A

— Not Recommended
— No beneficial effect to reduce cerebral edema
— May perpetuate:
> Neuronal damage if ischemia present
> Hyperglycemia
— Standard dosing of prednisone & dexamethasone particularly unlikely to benefit

32
Q

CO2 Management for brain trauma patient? values?

A
  1. Hyperventilation
    > decreased PaCO2 > Cerebral Vasoconstriction > Short-term only
    <><>
    — PaCO2 – 30 mmHg (No less)
    — ETCO2 – 35 mmHgw
    <><>
  2. Endotracheal Intubation
    — Topical laryngeal lidocaine spray
    — Pretreat w IV lidocaine 0.75mg/kg IV prior to intubation
    — Induce with propofol
33
Q

Anesthetic Considerations for brain trauma - which do we prefer? why?

A

Propofol preferred ; Barbiturate alternative
- Reduces cerebral metabolic rate for O2
<><>
Sedation
— Benzodiazepines
— Alpha 2 agonists -
> Ultra low doses only
> Dexmedetomidine 1-2 mcg/kg/hr

34
Q

positioning for brain trauma patient

A

Improve Venous Drainage
— Head elevated 30°
— Avoid occlusion of the jugular veins
— Maintain normal intrathoracic/abdominal pressures
— Prevent coughing/sneezing/vomiting

35
Q

how to Prevent Hyperthermia in the brain trauma patient - how should we regulate temp?

A

— Maintain temp at low end of normal
— Allow patient to rewarm passively if the patient is hypothermic on presentation
— Avoid shivering > shivering using oxygen
> Temp > 36.5°C (98°F)

36
Q

issues with hyperglycemia and hypoglycemia in the brain trauma patient

A

hyperglycemia:
— Associated with increased cerebral lactate / acidosis & cell death
— Worsening neurological outcome
<><>
hypoglycemia:
— Worse cerebral metabolic effects
<><><><><><><><>
Normoglycemia is the goal

37
Q

Seizure Management for the head trauma patient
- incidence?
- treatment
- management

A

Seizure incidence
— ~ 14+% within 24 hours of injury, or within 1 week of injury
— Increased incidence with skull fractures & herniation
<><>
Treatment
— Diazepam
— Levetiracetam
<><>
Management
— Levetiracetam PO TID
— Diazepam infusion
— Phenobarbitol

38
Q

antiemetics for head trauma patient? what about hemorrhage control?

A
  • yes we can try to do both
    <><>
    Antiemetic
    — Maropitant
    — Metoclopramide
    — Dimenhydrinate
    <><>
    Tranexamic Acid
    — Anti-fibrinolytic (maintain clot)
    — Control hemorrhage
39
Q

General Management for head trauma patient

A

— Early enteral feed
— Eye care / oral care
— Avoid bladder distension —- increase ICP
> Continuous drainage
— Nursing care (turning patient, physio)

40
Q

Recovery for head trauma patient

A

— Time!
<><>
— Expectations:
— Ataxia
— Circling
— Signs of cerebellar disease
** Markers of improvement in previously recumbent patient **
> most of the time recover well if they survive first 24 hours

41
Q

Critical Periods for head trauma patient

A

— 1st 24 hours for survival
— 1st 72 hours for change in neuro status > if they make it this far, in good shape!
— Thereafter recovery period

42
Q

Prognosis for brain trauma patient

A

— Non-survival (mortality ~15%) predicted by:
- Modified Glasgow Coma Score
- ≦ 8 associated with ~ 50% non-survival
- Concurrent injuries with evidence of decreased perfusion / oxygenation (ie. Increased lactate, decreased pH, SpO2)
- Need for endotracheal intubation or HTS administration
<><><><>
Poor outcome ass’d with:
— Brain herniation
— Skull fractures
— Increased size of intra-parenchymal lesions

43
Q

Sequelae to brain trauma

A

— Impossible to predict at initial exam
<><>
Thalamocortical injury
— Personality changes
— Visual deficits
— Circling
— Weakness in 1+ limb
— Late onset epilepsy - seizures within 1 year of injury
<><>
— Generally excellent prognosis

44
Q

brain trauma summary
- things to focus on for assessment
- keep in mind, what to regulate, what to watch for
- overall prognosis

A

Important points
— Good neurological assessment
— Appropriate lesion localization
<><>
— Rapidity of changing neuro status
— Regulation of blood pressure, O2, CO2
— Recognition of signs of imminent brain herniation
<><>
Excellent prognosis in many patients

3. Cat & Dog 3 (26 decks)

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