Trauma / Critical care Flashcards
ICP waveforms P1, P2, P3: what do they represent
P1: percussion wave: arterial pulsation
P2: tidal wave, represents compliance (decreased leads to high wave)
P3: dicrotic: ao valve closure
duret hemorrhages occur in what herniation
central
goal cerebral perfusion pressure
> 60
Dose of osmotic treatment for ICP (2 choiceS)
- Mannitol 0.25-1g/kg bolus, can repeat q8
2. 23% NaCl 30 mL bolus
what causes duret hemorrhages
shearing of basilar perforators
type of herniation that causes midbrain findings and CN 3 pupil dilation
tentorial / uncal herniation
what is kernohan’s notch phenomenon
compression of contralateral cerebral peduncle against tentorium with uncal herniation
stroke scale scores that may be suggestive of increased risk of herniation with malignant ischemic stroke
left hem >20
rt hem >15
Mild TBI / concussion, define three grade?
- transient confusion < 15m, NO LOC
- longer transient confusion > 15m, NO LOC
- any LOC
dose of steroids that can possibly used in traumatic spinal cord injury (not clearly beneficial)
< 3 hrs, 30mg/kg methylpred, then 5.4mg/kg/hour for 23h (longer if presenting from 3-8 hrs : 2 d)
steroid dosing for cord compression
10-100mg dexamethasone, then 4mg q4H 3-5 d
patient arouses but no awareness, eyes open and may track. There are diurnal/nocturnal cycles
persistent vegetative state
mild to moderate reduced alertness, slow psychologic response to stimulation
obtundation
arousal only with vigorous continuous stimulation
stupor
no arousal
coma
in persistent vegetative disease, what happens with day/night
preservation of cycles
in cold calorics, what drives eyes toward cold stimulus vs nystagmus away
toward cold: brainstem only
saccadic component of nystagmus away (COWS: Cortical)
if you get tonic deviation of eyes to cold water in cold calorics what is the issue
cortical lesion (you get brainstem drive only)
cold calorics with no response indicates what
no cortical or brainstem response
right way eyes look where
What happens with oculocephalics
frontal cortical lesions toward the lesion (not the weakness)
oculocephalics will overcome
wrong way eyes look where and what lesion and what happens with oculocephalics
look toward weakness not lesion, as in with pontine lesions and this is due to a CN VI palsy and will not be overcome by oculocephalics
what causes skew deviation of eyes
midbrain lesion
what location of lesion causes ocular bobbing
pons lesion
respiration pattern:
what causes cheyne strokes (2 types of lesions and expected motor responses)
bihemispheric or diencephalic lesions, can tell which based on whether hemiplegic or whether decorticate
hyperventilation occurs in what type of lesion and what do you see for motor?
midbrain lesion causes decorticate posture
what is decorticate posturing and where is lesion
arms flexed pointing to head due to involvement of red nucleus
decerebrate posturing indicates a lesion where, what posture
arms down, not involving red nucleus, lesions below
apneustic or cluster breathing and decerebrate posturing indicates lesion where
pontine
where is lesion causing ataxic or frank apnea and no motor response
medulla
cells very susceptible to hypoxic injury (5)
CA1 pyramidal cells in hippocampus
cortical layers III and V
purkinje cells/dentate
GP
man in barrel syndrome
what else may be present sx
transcortical motor aphasia
watershed infarct in ACA/MCA borderzone
typical presentation of mca/pca watershed infarct
balint’s syndrome and transcortical sensory aphasia
what NSE level when may predict poor prognosis in coma
neuronal specific enolase
Day 1-3, NSE >33
when is absent N20 response most predictive of bad prognosis in coma
day 1-3
define parameters for brain death apnea test
if there is no resp drive with PaCO2 of 60 or 20mmHg above baseline
what temp do you need for brain death exam
<36.5
