4. Brain Resus Flashcards
How much of CO and oxygen percent of total body does brain get?
CO - 15%
O2 percent 20%
Elevated ICP causing cerebral edema - how does this occur?
Elevated intracranial pressure can result in ischemia
This ischemia leads to failure of oxidative phosphorylation and leads to inability to maintain ATP, thus osmotic gradient failure
Increased intracellular osmolarity means influx of water and Cytotoxic edema then leads to brain secondary injury
Monro Kellie doctrine
Increasing cerebral edema volume means that in a finite space, other components of brain volume must decrease (3 components: brain, blood, csf)
How does Monroe Kellie doctrine actually play out?
Shift IC to subarachnoid
Reduction of fluid in cerebral veins and dural sinuses
In final stages, how does ICP progress?
Herniation cerebellar tonsil through formed magnum and compresses medulla
CPP= ? - ?
MAP - ICP
CPP = MAP - ICP how does an incr in ICP compensate… and then become a viscous cycle?
Cerebral arteriolar vasodilation for decr MAP
When then can actually just increase further blood volume and increase ICP
How long do studies recommend before using neuro exam for prognostication?
72 hours
Elevated ICP: how to manage initial pain, fever, normothermia?
Fentanyl 25-50 mcg q5h PRN
Avoid coughing so procedurally sedate with propofol
Ongoing ICP despite these? Pentobarbital
If spikes in ICP and active herniation consider mannitol if fluid overload (0.25-1g/kg) q6h for serum osmol of 320 goal or need resus fluid 3% hypertonic saline 30-60ml q6h to aim for sodium of max 160
If seizure with ICP increase, how to manage
Regular - lorazepam 0.1mg/kg up to 4mg
Continues; second line agent of Keppra, VPA, fospheny
Not really clear in tbi prophylaxis: if used, what and what dose?
Keppra 500mg po tid
ICH seizure prophylaxis yes or no?
No
In the event of cardiac arrest, what is the first priority of cerebral resus?
rosc
depndent on complete and relative ischemia to brain
What is cerebral autoregulation?
change in SBP causes change to cerebrovasulcar resistance to keep cerebral blood flow at certain level over wide range of arterial BP
MAP and SBP goal for ICP pt
Map >65
sbp >90 cardiac arrest
ICH - goal BP?
<140 but <160 if controlled chronic HTN who are severe HTN on presentation
How does hyperventilation quickly lower ICP?
CO is potent vasoactive agent that lowers CO arterial partial pressure to reduce cerebral blood flow 2% q1mmHg decrease in paco2
Paco2 goal in hyperventilation to maintain ICP?
35-40
Goal O2 in ICP
pao2 80-120mmhg with o2 sat high 90s on lowest fio2 possible
CT findings of intracranial HTN?
compressed basal cistern
disffuse sulcal effacement
diffuse loss of differentiation grey and white matter
Suggestive clinical features ICP
papilledema
bilateral sixth nerve palsy
new third n palsy if comatose
Which level of ICP has been associated with worse neuro outcomes and should trigger treatment?
> 22
Best management steps for general ICP: 5
- Position pt head up to 30 deg
- Neutral head and neck to avoid JV compression
- Tx fever with antipyretic for temp </=37
- Minimize triggers of ICP increase (like suction, freq turning) - meds for sedation
- Osmolar therapy if required
If ICP pt has a ventriculostomy how to manage?
clamp to get cont ICP measure but if elevated unclamp to decrease ICP
Tx cases of refractory ICP with what 2 options?
- Cont pentobarbital infusion
- Mild induced hypothermia (32-36). Avoid rapid rewarm
Surgical tx of ICP
if refracotry in TBI - decompressive craniectomy
If temp in a an incr ICP pt goes up above 38, how to tx?
acetaminophen
surface cooling
What clinical finding indicates poor outcome with low FP rate and narrow confidence interval at 72 h after ICP?
bilateral absent pupillary light reflex
Additional features (than bilat absent pupillary light reflex) of poor px in pt with Inc ICP?
absent corneal reflex
absent reactivity or burst suppression pattern on eeg
myoclonic status epi
diffuse anoxic injury on ct/mri
nresponsive survivors of out-of-hospital cardiac arrest should have rapid initiation of targeted temperature management (TTM) in the emergency department and be maintained at a constant target of __ to __ C in an ICU setting for 24 h after resuscitation.
33-36
