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148 Cards in this Set
- Front
- Back
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HOw much does the brain weigh?
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1500 Gms
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What percent of total body oxygen consumptions goes to brain?
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20%
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What is total cerebral blood flow?
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50 ml/100 Gm of brain tissue/minute
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What is the cerebral Metabolic Rate for O2?
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40 ml/100 Gm of brain tissue/minute
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What are the 2 substrates that the brain is dependent on?
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glucose and Oxygen
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When O2 is sufficient in the brain what is glucose metabolized to ?
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Pyruvate and 38 molecules of ATP
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What it metabolism in the brain coupled to?
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FLOW
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What happens to CBF when hyperventilation occurs?
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CBF is decreased
The PaCO2 goes down and the pH goes up (alkolotic) and this causes cerebral vasoconstricion. This will only last for 6-8 hours b/c brain will begin to compensate and normalize pH by excreting Bicarbonate. |
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What is Intracerebral Steal Syndrome
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When the CO2 is high, the brain is unable to re-direct flow b/c everything is dilated (b/c H+ ions cause vasodilation)
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For every increase in Pa CO2 by 1, how much does CBF increase?
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1-2 ml/100 Gm/ min
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What is Intracaranial HTN pressure?
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20 mm Hg
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What is the Robin Hood Phenomena
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During focal ischemic events, pt can e hyperventilated, so the overall CBF is decreased, but vessels in the ischemic area will dilate due to metabolites and low pH, so flow would be maximized in this area.
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Hiow is the CBF autoregulation curve shifted in HTN?
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Shifted to the right, so that CBF does not change with MAP in range of 70 - 170 vs normal 50 -150 range.
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What happens to CBF, when pt's MAP goes above 150?
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CBF goes up
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What happens to CBF when pt's MAP goes below 50?
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CBF goes down
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What two solutions can be used to treat increased ICP (if pt has intact BBB)?
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Mannitol
3% NS both have molecules that won;t cross the BBB, so pull water out of the brain by osmosis |
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What is the Blood-CSf barrier made up of?
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Epithelial cells of the choroid plexus
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What is the total amount of CSF in the brain?
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120 ml
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how often is CSF replaced in a day
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3-4 x
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What is allowed to pass BBB?
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water, lipid-soluble molecules, gases
no ions or large molecules |
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What is the Glascow coma scale for minor injury?
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13-15
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What is Glascow coma scale for moderate injury
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9-12
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What is the Glascow coma scale for severe injury
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<9
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what is the critical value of CPP?
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70
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What artery in the brain do the left and right vetebral arteries join to form?
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Basilar artery
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What are the symptoms of vetebrobasilar brain disease
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MOre Global:
Bilateral vision impairments ataxia Bil weakness Amnesia |
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What are the symptoms of carotid artery disease?
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Unilateral vision impairment or weakness
Aphasia |
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What does CVA result in for 4-6 weeks?
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alterations in CO2 responsiveness and alterations in the BBB
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HJow long should elective surgery be delayed for after a CVA?
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6 weeks
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When a person has a CVA, what does muscle atrophy result in?
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Mild to marked Up regulation of Ach receptors
usually occurs 4-7 days following a stroke degree of up-regulation may be r/t the severity of the stroke |
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What is most common cause of elevated ICP?
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Obstruction of the CSF pathway
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When patietn has Up-Regulation, are they sensitive or resistant to nondepolarizers?
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Resistant
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If patietn has a weak or paralytic side, where do you put the nerve stimulator?
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On the normal side, b.c the paralytic side muscle will be resistant to nondepolarizer and will always have 4 twitches (can cause you to overdose the nondepolarizer)
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Wehre is the CSF absorbed in the brain
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villi of the arachnoid membrane
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Where is CSF formed, what is its pathway?
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Formed in the choroid plexus -- thru the Foramen of Monro into the third ventricle -- thru the aquaduct of silvius to fourth ventricle -- thru 2 lateral foramena of Luschka or foramena magendie into the sisterna magna (pool of CSF at the base of the brain that connects to the subarachoid space)
reabsorbed in the arachnoid villi and enters the venous blood |
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What causes non-obstructive hydrocephalus?
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overproductive CSF or inadequate absorption of CSF
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what type of seizure will always have impaired consciousness
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Generalized
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What anesthetic drugs do you avoid in pt with sz disorder?
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ketamine, methohexital/Brevital: all lower the sz threshold
Etomidate: can cause myoclonus |
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what anesthetic drugs increase the sz threshold and are good to use in pt with sz disorder?
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Benzos, barbiturates, propofol
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how does dilantin effect certain anesthetic management?
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Dilantin induce CYP450 system, so drugs are metabolized faster.
may need more frequent redosing of nondepolarizers |
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What happens to metabolism and cerebral O2 demand during a sz?
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250% increase in ATP usage
60% increase in cerebral O2 demand -a defecit of ATP and glucose can occur and lactate can accumulate |
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when pt has high ICP, what is concern during intubation?
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want to avoid SNS response to intubation-- intubate deep, use narcotic, and lidocaine (1-1.5 mg/kg)
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If pt has sz disorder and IDDM and has a sx during surgery what is the cause?
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low BS or possibly local anesthetic overdose
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Anything with the word thalamus in the brain is part of what section?
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diencephalon
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Where do nerves synapse in the brain?
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Gray matter/ cerbral cortex
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Where is the site of intelligience in the brain?
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cerebral cortex
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What are the four lobes in the cerebrum?
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parietal, occipital, frontal, temporal
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What are the 5 parts of the brain stem?
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midbrain, pons, medulla
reticular formation and the vestibular formation |
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What does the vestibular system in the brain stem do?
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maintain the tone of muscle and coordinates movements (balance)
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what does the reticuliar formation in the brain stem do?
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it is the relay station for motor control (descending), except for that going down the pyramidal tract
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What does the brain stem do?
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responsible for intrinsic life processes (BP and Resp.)
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What are the 5 parts of the basal ganglia?
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substantia Nigra
Subthalamic nucleus Globus Pallidus Putamen caudate Nucleus |
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What does the thalamus do?
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sensory integrative center of the brain
Ex: tumor of the thalamus: vague sense of pain and inability to localize pain |
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what does the cerebellum do?
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located near the brainstem and controls posture, movement, and tone on the ipsilateral side
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What nerves are easiest to block and why
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Type C nerves (sympathetic nerves)
b/c they are smallest in diameter (0.5-2 micrometers) |
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what sensation does the A delta nerve carry?
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Pricking pain sensation (sensory)
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What type of nerves are the hardest to block?
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motor nerves (they are biggest)
ex: skeletal muscle |
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What it another name for Ascending nerves?
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Sensory/Dorsal
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What are the 2 pathways that sensory info coming form the periphery can go up to brain through
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anteriolatera/spinothalamic
dorsal/posterior |
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What is the main motor tract that motor nerves travel on form the brain?
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corticospinal tract
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what 2 things make up the dorsal column (sensory pathway to the brain)
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Fasciculus Gracilus
Fasciculus Cuneatus |
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where do motor nerves synapse when coming form the brain?
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anterior/ventral horn
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What is another name for anterior?
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ventral
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What tract does pain impulse travel on?
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Pain travesl in the spinothalamic tract via Lissauer's tract
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what do SSEPs assess?
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function of the dorsal column
not looking at anterior (motor) function |
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What are the 4 sensory pathways?
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Spinothalamic tract (major)
2 Posterior Columns Spinocerebellar tract |
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Where are pain impulses carried?
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spinothalamic tract via the tract of Lissaur to the thalamus where it synapses and then the 3rd order neuron projects into the somatoseneory cortex
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What tract transmits vibration and touch?
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dorsal Column
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What are the 4 motor pathways?
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Coroticospinal/Pyramidal
Rubrospinal Lateral Vestibulospinal reticulospinal |
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what are the signs/symptoms of upper motor neuron lesions?
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Hyperreflexia and spastic Paralysis
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What are the signs and symptosm of lower motor nueron lesions
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They effect the muscle the nerve innervates; flaccid paralysis
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What part of the spinal cord does the sympathetic outflow come from?
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Thoracolumbar region
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What part of the sc does the parasympathetic outflow coem from
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Craniosacral (vagal nerve)
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What is a Mass Reflex?
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Denervation Hypersensitivity/Autonomic Hyperreflexia
simultaneous excitation of all sc reflexes occurs when there is stimulus below the level of the transection or distention of the bladder |
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What pts with sc injury are more likely to develop autonomic hyperreflexia?
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when injury is at T5 or above
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What are the signs and symptoms of Autonomic hyperreflexia?
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systemic HTN d/t vasoconstriction and Bradycardia b/c the carotid sinus receptors respond t vasoconstriction with bradycardia
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How do you treat Autonomic hyperreflexia?
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Titratable vasodilator -- Nitro or Nipride
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What type of surgery is EEg used for?
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carotid surgery
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What are the 3 main waveforms of EEGs?
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Alpha: relaxed with eyesclosed
Beta: concentrating Delta: normal sleep |
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what do anesthetics do to EEGs
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depress the EEG in dose dependent way; if slow EEG enough, there is burst suppression and eventually get electrocortical silence
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When give high dose of anesthetics what is it similiar to on EEG
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will look exactly same as ischemia
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when EEG changes: has dampening/slowing/burst suppression, what does that mean?
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Could be ischmia or anesthesia (propofol bolus)
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What is the treatment for EEG changes?
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decrease anesthetic
maximize BP increase FiO2 to 100% |
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What anesthetics depress the SSEPs?
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volatiles, nitrous, and Benzos
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How do we montior the anterior spinal cord function?
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Motor evoked potential monitoring
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Name 2 things that affect the BIS score?
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hypothermia and beta blockers
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What does the BIS do?
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analyzes the EEG and inferes state of conscioussness
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What are people most likely to remember when under anesthesia?
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threatening things
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What does BIS score of
100 mean 80 mean |
100 = awake
80 = sedated 45-60 = GA 20 -40 = Deep anesthesia 0-20 = Isoelectric EEG |
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what percent of pts have high incidence of awareness?
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pt that have had muscle relaxants
0.15 incidence overall 0.18 if muscle relaxants given 0.10 if no muscle relaxants |
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Hypotonia
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decreased muscle tone; flaccidity
thought to be caused by decreased muscle spindle activity due to decreased excitability of neurons |
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Hypertonia
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Spaicity results for hyperexcitability of stretch reflexes and overactivation of motor nuerons
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hyperkinesia
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Abnormally excessive movement
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Hypokinesia
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loss of voluntary movement despite preserved consciousness
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What is another name for the Myonueral Junction?
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Neuromuscular junction
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Where do Upper motor neuron lesions occur
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occur form interruption in the spinocortical tract b/t the brain and the anterior horn of the spinal cord
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What nerves are injured with bulbar paslies?
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LMN injury to CN 9, 10, or 12
injury to part of the brain called Myencephalon |
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What becomes paralyzed with bulbar palsy injury
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paralysis of face, jaw, pharynx, and tongue (difficulty swallowing)
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what are extrapyramidal syndromes?
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Problems in cerebellar or basal ganglia
-cause either excess movement or abnormally decreased movemnet |
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What happens in problems with the basal ganglia?
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there is an imbalance of dopaminergic and cholinergic activity
increased Ach = akinesia (inability to form a movement) increased dopamine = hyperkinesia |
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What is major concern when caring for pts with neuromuscular disease?
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Respiratory insufficinecy
Unable to deep breathe and generate effective cough Expiratory weakness, so have difficulty clearing secretions -- atelectasis and pna |
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what is major cause of death of pt with neurosmuscular disorders?
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Respiratory insufficiency (pna)
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what are the 4 types of Respiratory Insufficiency
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Progressive: ALS
Reversible: Guillian Barre Reversible with therapy: Myasthenia Gravis Relapsing: Muscular sclerosis |
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What 2 things (besides resp. insufficiency) are neuromuscular diseases often ass. with?
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Cardiac dysfunction and autonomic dysfunction
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What are s/s of autonomic dysfunction?
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resting tachycardia
Orthostatic hypotention venous pooling hypovolemia decreased contractility |
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What pressor is best to treat hypotension in pt with autonomic dysfunction?
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Phenylephrine
(may have erattic response to indirect acting pressor (Ephedrine) b/c they have altered amts of presynpatic catecholamines |
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name a Neurosmuscular dis. often ass with autonomic dyfunction?
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Guillian Barre syndrome
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What type of movement disorder do parkinson's have
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akinesia (too much Ach -
Basal ganglia) |
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What drug is contraindicated in pt with Parkinson's dis.
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Reglan: antidopinergic
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What is a good choice of antiemetic for parkinson's pts?
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Benadryl (diphenhydramine): anticholinergic
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What is the drug that has been shown to help abolish parkinsonian tremors?
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Propofol
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What disorder of the basal ganglia is opposite of Parkinson's
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Huntington's Chorea
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In pt with Halloverdan Spatz Dz what is imp. for anesthesia?
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can be bony changes in C spine and TMJ, making intubation difficult
progressive respiratory insufficiency |
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What is most likely cause of exacerbation in muscular sclerosis pt perioperatively?
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Hyperthermia
1 degree celsius increase predisposes to breakdown of neuromuscular junction |
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is the toxic dose of local anesthetics lower or higher in pts with muscular sclerosis?
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Lower .
-bc the BBB may be more permeable to local anesthtics due to demyelination |
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What is Chancot Mare Tooth Disease
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Demyelinating disease with both motor and sensory demyelinating polyneuropathy
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What are the 5 Motor Neuron Diseases?
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Spinal muscular Atrophy (lower motor neurons)
Fredrich's Ataxia (both upper and lower) ALS (both upper and lower) Syeringomyela (LMN) Syeringobulbi (LMN) |
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Anesthesia concerns with ALS (and other motor neuron diseases)
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Succs in contraindicated (muscle atrophy)
senstitive to nondepolarizers due to upregulation at risk of resp. insufficincy in post op period |
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Which motor neurons are involved with Guillian Barre upper or lower?
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Lower - paralysis is flaccid
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Why should succinyl be avoided in pt with Myasthenia gravis?
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b/c their Ach receptors are destroyed, so they don't have a lot of anticholinesterase (b.c they don't need it), so won't be able to metabolize the succs.
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what is the patho with myasthenia gravis?
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autoimmunie disease where the Ach receptors are destroyed
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Waht antibiotic can aggravate skeletal muscle weakness?
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aminoglycosides (gentamycin)
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What anesthetic drugs should be avoided in Myasthenia Gravis
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Muscle relaxants; if have to give, use nondepolarizers
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will you have hyperkalemia when you give succinyl to pt with myasthenia gravis
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no b/c pt does not have muscle atrophy, but will not be able to breakdown succs b.c does not have enough anticholinesterases
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how is the heart effected in Duchenne's muscular dystrophy?
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degeneration of cardiac muscle -- decreased EF
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what is the main complications with muscular dystrophy?
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cardiac arrest with succinylcholine and potent inhalation agents
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what is the patho of muscular dystrophy?
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painless degeneration and atrophy of skeletal muscle (progressive mus weakness with intact sensation)
muscles become abnormally permeable to Ca and the neuronal cells necrose |
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What is Steinert's Disease?
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Myotonic Dystrophy (type of muscular dystrophy)
persistent contracture of skeletal muscle after the voluntary contraction ceases. |
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in pts with steniert's what things can precipitate myotonia?
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Anticholinesterase drugs
cold temps surgical manipulation electrocautery |
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What is Central Core Disease?
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nonprogressive or slowly progressiive congenital myopathy
Main concern is MH NO succs/volatile agents |
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Name the Demyelinating diseases
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Muscular sclerosis and Chancot Mare Tooth Disease
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Name the Extra-Pyramidal motor syndromes
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parkinson's
Huntington's Chorea Holloverdan Spatz disease |
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Name 4 Main concerns in dealing with pts with Neuromuscular disease
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1. Respiratory Insufficiency
2. Muscle atrophy 3. Autonomic dysfunction 4. Cardiac Dysfunction |
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What does hypoxia (PaO2 < 50) do to CBF
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increases CBF
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If the Venous blood flow in the intracranial compartment is high, what can be done?
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improve cerebral venous drainage by increasing the HOB and avoid coughing
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What is Cushing's Triad
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HTN, Low HR, Irregular RR: a sign of high ICP > 20
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What does Succinylcholine do to ICP?
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slightly increases it, but if give defaciculating dose will have less increase in ICP
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What kind of hematoma has progressive loss of consciousness?
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subdural
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If pt has increased ICP and being hyperventilated to decrease CBF, how long is this effective?
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6-8 hours
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What sensory tract carries vibration and touch to the brain
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Dorsal/Posterior column
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What does the cerebellum control?
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Posture, movement and tone on the ipsilateral side
Ataxia (problems with gait) are frequently from cerebellar disorders |
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What does increased Ach in the basal ganglia cause?
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Akinesia = inability to perform a movement
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What does increased dopamine in the basal ganlgia cause?
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Hyperkinesia = abnormally excessive movement
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What are signs/symptoms of cerebellar symptoms?
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loss of muscle tone, muscle weakness on ipsilateral (same) side, and difficulty coordinating movement
Ataxia (problems with gait) |
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What neuromuscular diseases are associated with autonomic dysfunction?
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Parkinson's
Multiple sclerosis Chancot Mare tooth disease Guillian Barre Syndrome |
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Is paralysis flaccid or spastic in Guillian Barre syndrome?
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flaccid
Involves lower motor neurons -- polyneurites, denervation and axonal degeneration |
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Which disease can have bulbar involvement, making the patient a "full stomach"?
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Guillian Barre syndrome
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What is another name for spinothalamic tract?
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anterolateral/sensory
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