PCTH - Head Injuries Flashcards
What % of multi-system trauma patients will presetn with some form of TBI? How does this increase the mortality rate?
40%; increases mortality rate by 2x
List the structures that are considered as part of the head.
1) scalp
2) skull
3) meninges
4) brain tissue
5) CSF
6) vascular components
7) facial structures
What does CSF look like?
straw coloured fluid (typically mixed with blood)
Brain adjusts its own blood flow in response to _____________. Autoregulation is controlled by the level of what?
metabolic needs
CO2
Hypoventilation would cause an (increase/decrease) of CO2 in the brain, leading to (vasodilation/vasoconstriction).
Hyperventilation would cause an (increase/decrease) of CO2 in the brain, leading to (vasodilation/vasoconstriction).
Hypoventilation: increase CO2; vasodilation
Hyperventilation: decrease in CO2; vasoconstriction
Primary brain injuries occur when…..?
when there is immediate damage to the brain (i.e. baseball bat hitting the skull) - results from mechanical injury at the time of the trauma
Secondary brain injuries
- as a result of the initial impact (ex. brain being injured as a result of hitting the inside of the skull, of a bat hitting the skull which is your primary injury)
- can lead to swelling which can cause a decrease in perfusion
- results in hypoxia
- presence of edema increases intracranial pressure and exacerbates reduction in blood flow
Coup-Contre Coup Injury
A coup injury occurs on the brain directly under the point of impact (primary impact)
A contrecoup injury occurs on the opposite side of the brain from where the impact occurred (secondary impact)
Primary brain injuries are best managed by:
prevention (occupant restraint systems, sports equipment, helmets, etc.
Cerebral Herniation
- sudden increase in ICP
- portions of the brain get pushed down into foramen magnum
- increase pressure on brain stem = cerebral herniation
What is a concern regarding hyperventilating all patients with TBIs?
you are delivering significant amount of oxygen to the patient which causes vasoconstriction and reduced oxygen flow to brain causing cerebral ischemia
oxygen is a vasodilator. true or false?
false. it vasoconstricts
S/S of Cerebral Herniation
- rapidly decreasing LOC
- dilated pupil and downward outward deviation of the eye on the side of the injury
- paralysis of the arm and leg on the side of the injury OR decorticate/decerebrate posturing
- Cushing’s Triad/Reflex
- Rapid decline in sx to cardiac arrest
Cushings Triad/ Reflex
↑ BP (usually 170-180 SBP)
↓ HR (bradycardia)
irregular RR
The purpose of hyperventilating a patient with cerebral herniation is because….?
you want to induce vasoconstriction to reduce swelling pushing into brainstem where respiratory center is