SACCM 128: Traumatic Brain Injury

Question 1

What are concussions

Answer 1

transient paralysis of the brain characterized by a brief loss of consciousness

not associated with an underlying histopathology of the brain

Question 2

What are brain contusions?

Answer 2

hematoma or edema of the brain parenchyma

Question 3

What are the two types of brain contusions in regards to location?

Answer 3

Coup lesion - directly under the site of impact
countercoup lesion - in the opposite hemisphere

Question 4

What is the prevelance of extra-axial brain hemorrhage in small animals sustaining TBI?

Answer 4

• in up to 10% of mild cases
• in > 80% of severe cases

Question 5

List 8 factors leading to secondary brain injury

Answer 5

• ischemia
• ATP depletion
• cerebral lactic acidosis
• accumulation of IC Na+ and Ca++
• excitotoxicity
• NO accumulation
• production of ROS
• inflammation

Question 6

List systemic insults in TBI patients that may contribute to secondary brain injury

Answer 6

• hypotension
• inflammation
• hypoxemia
• hypercapnia/hypocapnia
• hyperglycemia/hypoglycemia
• hyperthermia
• electrolyte imbalances
• acid-base disturbances

Question 7

List intracranial insults that may contribute to secondary brain injury in TBI patients

Answer 7

• increased ICP
• compromised BBB
• mass lesions
• cerebral edema
• infection
• vasospasm
• seizures

Question 8

name the equation for the monroe kellie doctrine

Answer 8

V(intracranial) = V(brain) + V(CSF) + V(blood) + V(mass lesion)

Question 9

What are the goals for oxygenation parameters in TBI patients?

Answer 9

SpO2 >94%
PaO2 > 80 mm Hg

if not able to monitor these —> recommend to supplement O2

Question 10

What are the target arterial and venous pCO2 values for TBI patients?

Answer 10

PvCO2 40-45 mm Hg
PaCO2 35-40 mm Hg

Question 11

Explain the different beneficial properties of mannitol in TBI and their timing of effect

Answer 11

• rheologic effects - decreasing blood viscosity –> increasing CBF and cerebral DO2 –> benefits seen clinically within minutes
• osmotic effects - drawing water out of brain parenchyma into intravascular space –> within 15-30 min, effects last 1.5-6 hours

also has free radical scavenging properties

Question 12

why should mannitol be given as intermittetn boluses to TBI patients and not as CRI?

Answer 12

can cause increased BBB permeability –> allowing mannitol to leak out of IV space –> worsens brain edema

these effects are pronounced if mannitol remains in the circulation for longer periods

Question 13

What are additional beneficial effects of HTS in TBI patients (beyond rheologic and osmotic effects)?

Answer 13

• vasoregulatory
• immunoregulatory

Question 14

What is the reported prevalence of post-TBI seizures in dogs and cats?

Answer 14

dogs 6.8% (but very wide 95% CI) and 0% in cats