Neuro Flashcards
What supplies the majority of blood to the brain
80% - Internal carotid arteries- the majority
—20% - Vertebral arteries
What affect CBF
Cerebral metabolic rate- how much does the brain need coming into it
Cerebral perfusion pressure
Intracranial pressure
Arterial PaCO2
Arterial PaO2
Cerebral metabolic rate / CMRO2 normal
Average – 50ml/min (3-3.8 ml/100g/min)
Measured as O2 consumption- how much oxygen does the brain need
things that Decrease CMR
-Hypothermia-7% decrease for every 1 Degree C in temp, achieve EEG suppression at 18-20 degrees C
-Anesthetic agents-VAA’s, propofol, etomidate and barbiturates. – put them into a sedation induced coma to decrease cmr.
Things that increase cmr
-Hyperthermia, seizures (give prophylaxis), ketamine (causes systemic surge), nitrous oxide (increase ICP w/ vasodilation), pneumocephalis
Causes; Shivering = increase cmr (keep sedated and paralyzed), warming blanket, hot IV fluid, infections process, head trauma.
Hyperthermia >42 causes what
denatures proteins and destroys neurons, CBF decreases
2 things that kill neuro patients
hypoxia
hypotension
Bad temperatures
low; 36
high; 42
Cerebral perfusion pressure equation
CPP=MAP-ICP
MAP equation
(2DBP + SBP)/ 3
normal CPP and map
CPP 80-100 mmHg or MAP of 60-160
not in range; Otherwise, pressure-dependent
Cerebral Autoregulation
↑ MAP Cerebral vasoconstriction
↓ MAP Cerebral vasodilatation
Constant CBF is maintained
CPP above 150mmHg causes….
Disruption BBB
Cerebral edema
Hemorrhage
medication that can creat shift the L
Volatile anesthetic agents
Ketamine
MONRO-KELLIE DOCTRINE
The cranial vault is a rigid structure with fixed volume
Brain 80%; diuresis
Blood 12%; crani
CSF 8%; vp shunt
things that cause increases in Intracranial Pressure
Tumor
Hematoma
Blood in CSF- LP, SAH
Infection- meningitis,
Aquaductal stenosis-
ICP > 30mmHg causes
compromise CPP
More dependent on MAP
CPP autoregulation range
50-150 mmhg
or MAP of 60-160mmhg
most common type of hydrocephalus
obstructive hydrocephalus
decrease PaO2 causes
immediate vasodilation (to encourage bf)
Pao2 <50-60 causes vasodilation and increases CBF- to encourage blood flow
Arterial PaCO2
Excess CO2 combines with water…carbonic acid… H- ion
Vasodilation of cerebral vessels
CBF constant PaCO2 between 20 – 80 mmHg
Vasodilation and vasoconstriction for Paco2
Max vasodilation occurs at PACO2 80-100
Max constriction occurs at PACO2 ~25
Intracranial pressure normal
Normal 5-15 mmHg
tearing back pain
AAA
worst ha of my life
SAH
cushings triad
Hypertension
Bradycardia
Respiratory Abnormalities- Cheyne stokes. Apnea, hyperventilation.
Most common site of transtentorial herniation
temporal uncus (Uncal herniation)
How to Decrease ICP
hob > 30
hyperventilation
csf drainage
hyperosmotic drugs (mannitol)
diuretics
corticosteroids
surgical decompression
mannitol dose
1gm/kg…0.5gm/kg (give quickly)
decrease in hct lead to______
-decrease viscosity and increased CBF
-Decreased O2 carrying capacity
Increased hematocrit leads to increased viscosity and decreased CBF
Optimal hematocrit – 30% to 34%
Luxury Perfusion
The combination of a decrease in CMRO2 and increase in CBF has been termed luxury perfusion.
Intracerebral Steal
vasodilatation in a normal area would shunt blood away from the diseased area.
Reverse steal/ robin hood phenomenon
Using hyperventilation to constrict cerebral vessels that supply healthy brain tissue. Flow is then redistributed to ischemia regions.
CN 1
olfactory
ID of odors
CN 2
optic nerve
snellen chart
CN3
oculomotor
Accommodation-convergence; reaction to light
CN 4
trochlear
Accommodation-convergence; reaction to light
CN 5
Trigeminal
Facial sensation; palpation of masseter/temporalis muscles
CN 6
Abducens
Accommodation-convergence; reaction to light
CN 7
Facial
Facial symmetry; smile; tastes anterior 2/3
Cn 8
Acoustic
Normal conversation; tuning fork
CN 9
Glossopharyngeal
Gag reflex; taste posterior 1/3
CN 10
Vagus
Swallowing; “ah”
CN 11
spinal accessory
Shrugging shoulders; chin flexion against resistance
CN 12
Hypoglossal
Tongue protrusion
Eye movement controlled by CN
CN 3,4 &6
Bell’s Palsy result from injury to
CN 7.
GCS eye
1; does not open
2; open to painful stimuli
3; open in response to eyes
4; spontaneously opens
GCS verbal
5; oriented
4; confused
3; utters incoherent words
2; incomprehensible sounds
1; makes no sounds
GCS motor
1; no movement
2; extension to painful stimuli ( decerebrate)
3; flexion to painful stimuli (decorticate)
4; flexion / w/d to painful stimuli
5; localized painful stimuli
6; obeys commands
paraplegia associated injury
T2-T12
quadriplegia associated injury
C5-T1
diaphragmatic paralysis associated injury
> C5
lesion T1-T4 may result in….
bradycardia
how early do we avoid succ
Avoid succinylcholine after 48 hours if not sooner- risk of hyperkalemia.
Lesion T7 or higher may lose ability to …..
sweat and develop hyperthermia- may need to be cooled
Anterior Cord Syndrome
Anterior Spinal Artery Syndrome
Ischemic insult
Loss of pain and temperature sensation
Maintain vibration and proprioception
Central Cord Syndrome
Most common incomplete SCI
Motor deficit more pronounced in upper extremities
Pain and Temperature sensation decreased in lower extremities
Brown-Sequard Syndrome
Usually occurs due to lateral SCI in the cervical or thoracic region
Present with lateral hemiplegia
Loss of proprioception and vibration on the side of the injury
Loss of pain and temperature sensation on the contralateral side
C8 dermatomes
little finger
T4 dermatomes
nipple
T6 dermatome
Xyphoid process
T10 dermatome
Umbilicus
Stroke pneumonic
face
arm
speech
time
5th leading cause of death
stroke
primary ischemic- 80%
hemorrhage - 20%
Large Vessel Occlusions (LVO)
Large vessel occlusions(LVOs) are ischemic strokes that result from a blockage in one of the major arteries of the brain.
Occurrence 17-20%
Risk factors in acute ischemic stroke
Systemic hypertension
Cigarette smoking
Hyperlipidemia
Diabetes
Excessive alcohol consumption
Management: ischemic stroke
ASA
Thrombolytic therapy
Management of airway/oxygenation/ventilation
Control of blood pressure
Acute Hemorrhagic Stroke deterioration
May deteriorate for 1st 24-48 hours
Cerebral edema
Acute Hemorrhagic Stroke Risk factors
Hypertension
Cigarette smoking
Cocaine abuse
Female
Management: hemorrhagic stroke
PCC
FFP
Plat
Ventricular drainage of blood
Blood pressure control; Maintenance of CPP
Aneurysm control
nimodipine
Lucid interval present in….
epidural hematoma
Alzheimer’s Disease findings
Diffuse amyloid-rich plaques
Changes in synapses
Decreased neurotransmitters (Ach most common)
Progressive cognitive changes
Anesthesia is transiently blamed for increasing the rate of Alzheimer’s disease
Treatment for alzheimers
Cholinesterase inhibitors
Aricept, Razadyne, Cognex
palliative
Parkinson’s Disease
Neurodegenerative, unknown cause
Risk increases with age and environmental exposure (welding, herbicides, pesticides and possible genetics
Loss of dopaminergic fibers in basal ganglia
Unopposed stimulation of extrapyramidal motor neurons
Parkinson’s Disease Primary Symptoms
Skeletal muscle rigidity
Resting Tremor (Pill Rolling)
Bradykinesia (slow movement and reflexes)
Postural Instability
Parkinson’s Disease tx
Dopamine precursor
Levodopa
Decarboxylase inhibitor
Peripheral conversion
Side effects
Deep brain stimulator
For DBS Preoperative
IV challenges
Minimal sedation
GABA drugs vs opioids and dex
Hold levodopa so they can locate problem areas
What can exacerbate symptoms in MS patients?
1 degree Celsius can exacerbate symptoms; maintain warmth!
Classification of sz
LOC: simple/complex
Focus: Partial/generalized
2 or more sz for a certain amount of time
Status Epilepticus
Goal of status epilepticus
Airway, ventilation
IV access
r/o hypoglycemia
ABG monitoring…acidosis
AION-
Anterior Ischemic Optic Neuropathy
Sudden, painless
Asymmetric optic disk swelling
PION
Posterior Ischemic Optic Neuropathy
More common postop
No initial ophthalmoscopic findings
Ischemic Optic Neuropathy
Visual loss during 1st week after surgery
Central &/or peripheral vision….slight decrease to blindness
Minimal recovery
ION risk factors
Positioning-
anemia
hypotension
Excessive fluid administration- papillary edema
Excessive vasopressor use