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162 Cards in this Set
- Front
- Back
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PH of the brain and csf returns to normal after
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8 to 12 hrs
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increased JVD caused ..as evidenced by the vent
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increased airway pressures
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..PACO2 caused increased JVD
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increased
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...PACO2 increases blood volume
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increased
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four components of intracranial volume
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CSF/tumors/fluid or edema/blood volume
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increased ICP causes herniation and...perfusion pressure
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decreased
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potential vasodilators are
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n20, volitiles, calcium chanel blockers, nitro
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methods at pre induction to reduce ICP
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avoid head flexion, avoid JVD compression, head straight, hyperventilate on demand
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osmotic diuretics to decreased ICP
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mannitol and hypertonic saline
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ventilation for lower ICP
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PA02 at 100 mmg h, Pac02 35 and minimal intrathoraci pressures
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improve cerebral venous drainage (3)
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head up, no peep, reduce inspiratory time
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intraop mannitol dosing for dieuresis to ensure low ICP
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.5-.75 mg/kg
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fluids used to ensure lower ICP
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.9NS Hes 6% not LR
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considerations related to posterior fossa surgery
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VAE, hemodynamic effects r/t sitting position, pardoxic air embolism, hemondynamics effects of brain stem and cranial nerve manipulation, quadrapalegia, microglossia, pneumocephalus
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most sensative method to indicated vae
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transesophageal echo
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least sens. method to detect VAE
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increased end tidal n20
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indicators of VAE
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Most to least sent., trans. echo, precordial doppler, increased pulmonary artery pressure, decreased etco2, increased n20.
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during VAE prevent further air entry by
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flooding field
avoid JVD compression lower patients head |
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treat intravascular air during VAE by
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aspirate right catheter
discontinue n20 increase fio2 to 1.0 pressor intotropes chest compression |
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pituitary tumors are two types
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non functioning and hypersecreting
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symptoms of non functioning pituitary tumors
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Symptoms include headache, impaired vision, cranial nerve palsies, increased ICP and hypopituitarism
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...of ADH results from pressure placed by a tumor on the pituitary
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hyposecretion
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pituitary apoplexy is
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Pituitary Apoplexy is a term used to describe sudden enlargement of the pituitary caused by hemorrhage or infarction of the piituitary caused by the tumor
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treatment for pituitary apoplexy
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Treatment includes corticosteroids and surgical decompression
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most commons hormone secreted with hypersecreting pituitary tumor
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The most common hormone hypersecreted is Prolactin, followed by Growth Hormone followed by ACTH (Adrenocorticotropin).
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hypersecreting pituitary hormones cause hypersecretion of
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Commonly, tumors cause hypersecretion of both Prolactin and Growth Hormone
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cushings is caused by
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hypersecreting pituitary tumors
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unruptured anyrusum is grade
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o
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Grade I anurysum is marked by
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slight nuchal rigidity w/without asymptomatic headache
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Grade II aneurysm
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moderate to sever ha, w/ nuchal rigidity, no neurological defecit other than cranial palsy
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Grade III aneurysm
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drowsiness, confusion, mild focal defecit
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Grade IV aneurysm
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stumor, mild to moderate hemipharesis, early decerbation, mild vegetative distirbance
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Grade V aneurysm
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deep coma, decerberate regidity, moribound
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craniotomy for aneurysms requires intraoperative blood regulation of
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mild hypotension
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during anurysmal dissection blood pressure regulation requires
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decrease blood pressure to lower limits of autoregulation w iso or sodium nitro
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after aneurysmal clipping blood pressure regulation requires
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elevation slightly above normal
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intravascular volume replacement during aneurysm surgery should be
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colloid, blood, isotonic crystalloid
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during rupture of cerebral aneurysm, reduction of blood flow is accomplished with
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ipsilateral carotoid artery compression, sodium nitro
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during rupture of cerebral aneurysm (3)
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fio2 100
reduce blood flow give blood |
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after controlling hemmorghage after cerebral aneurysm rupture..
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cerebral preservation (elevate blood pressure, barbituates/isoflourane)
reduce edema (mannitol csf/drainage) post op (controlled ventilation/monitor ICP) |
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..given to for cerebral preservation
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barbituates/iso
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relative contraindications for induced hypotension
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ischemic cerebrovascular disease
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increased ICP causes herniation and...perfusion pressure
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decreased
|
|
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potential vasodilators are
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n20, volitiles, calcium chanel blockers, nitro
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|
|
methods at pre induction to reduce ICP
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avoid head flexion, avoid JVD compression, head straight, hyperventilate on demand
|
|
|
osmotic diuretics to decreased ICP
|
mannitol and hypertonic saline
|
|
|
ventilation for lower ICP
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PA02 at 100 mmg h, Pac02 35 and minimal intrathoraci pressures
|
|
|
improve cerebral venous drainage (3)
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head up, no peep, reduce inspiratory time
|
|
|
intraop mannitol dosing for dieuresis to ensure low ICP
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.5-.75 mg/kg
|
|
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fluids used to ensure lower ICP
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.9NS Hes 6% not LR
|
|
|
considerations related to posterior fossa surgery
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VAE, hemodynamic effects r/t sitting position, pardoxic air embolism, hemondynamics effects of brain stem and cranial nerve manipulation, quadrapalegia, microglossia, pneumocephalus
|
|
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most sensative method to indicated vae
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transesophageal echo
|
|
|
least sens. method to detect VAE
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increased end tidal n20
|
|
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indicators of VAE
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Most to least sent., trans. echo, precordial doppler, increased pulmonary artery pressure, decreased etco2, increased n20.
|
|
|
during VAE prevent further air entry by
|
flooding field
avoid JVD compression lower patients head |
|
|
treat intravascular air during VAE by
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aspirate right catheter
discontinue n20 increase fio2 to 1.0 pressor intotropes chest compression |
|
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pituitary tumors are two types
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non functioning and hypersecreting
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symptoms of non functioning pituitary tumors
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Symptoms include headache, impaired vision, cranial nerve palsies, increased ICP and hypopituitarism
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|
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...of ADH results from pressure placed by a tumor on the pituitary
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hyposecretion
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pituitary apoplexy is
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Pituitary Apoplexy is a term used to describe sudden enlargement of the pituitary caused by hemorrhage or infarction of the piituitary caused by the tumor
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|
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treatment for pituitary apoplexy
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Treatment includes corticosteroids and surgical decompression
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most commons hormone secreted with hypersecreting pituitary tumor
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The most common hormone hypersecreted is Prolactin, followed by Growth Hormone followed by ACTH (Adrenocorticotropin).
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dosing sodium nitpro
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.5-10 ug/kg/min
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adv of sodium nitro
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rapid onset offset and titration
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dis of sodium nitro
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cyanide tox, increased ICP, rebound hypertension, increased pulmonary shunting, coagulation abnormalities
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dosing of nitro
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1-10 ug/kg/min
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adv. of nitro
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rapid onset, offset, titration
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disadv. of nitro
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ncreased ICP, rebound hypertension, increased pulmonary shunting, coagulation abnormalities
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dosing trimethephan
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1-5 mg/min
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adv. trimethephan
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rapid onset offset
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mode of action of trimethephan
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ganglionic blockade
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disadv. of trimethephan
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histamine release, cerebral compromise w/map below 55, decreased pseudocholinesterase
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dosing emolol
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.2-.5 mg/kg/min loading dose
50-200 mcg /kg/min |
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adv of esmolol
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rapid onset offset
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mode of action esmolol
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a adrenergic blockade
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labetolol dosing
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20 mg test dose. .5-2.0 mg/min total 300 mg
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labetalol mode of action
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a/b adrenergic blockade
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adv. labetelol
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reducing probability of adverse effects
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disadv. of labetelol
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limited efficacy bronchospasm
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disadv. of emsolol
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limited efficacy, bronchospasm, cardiac depression
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prostoglandin E dosing
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.1-.65 ug/kg/min
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prostoglandin E adv
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rapid onset, decreased reflex tachycardia, stable CBF
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prostoglandin E disadv
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slow offset, bradycardia, hyperthermia
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nicardipine dosing
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begin 5 mg/hr infusion, total 15
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mode of action nicardipine
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coranary and peripheral vasodilation
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adv. of nicardipine
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rapid onset, decreased reflex tachycardia
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disadv. of nicardipine
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resists antihypertensive therapy, slow offset, increased pulmonary shunting,
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complications of induced hypotension
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cerebral ischemia, coronary artery thrombosis, renal insufficiency, hepatic failure, postop pulmonary dysfunction, rebound hypertension, increased bleeding at operative site
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rebound hypertension is common after
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sodium nitroprusside use
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glasgow coma scale best eye opening
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4
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glasgow coma scale best motor response
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6-to verbal command
5- to pain localized 4 to pain withdraws |
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glasgow coma scale best verbal response
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5 oriented
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anterior cerebral circulation originates from the
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carotoid artery
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posterior circulation results from the
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vertebral arteries
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cerebral blood flow is directyly prop to pac02 between
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20 and 80
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blood flow changes approx ...ml per mmhg change in paco2
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1-2 ml/100g
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movement of a given substance across the bb b is governed by
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size, charge , lipid sollubility, degree of protein binding
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bbb may be disrupted by
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severe HTN, tumors, trauma, strokes, infection, marked hypercapnia, hypoxia, sustained seizures
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cranial vault is composed of...,...,... by %
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CSF 8
brain 80 blood 12 |
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with the exception of...all iv agents have little effect on or reduce CRMO2 and CBF
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ketamine
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with normal autoreg and an intact bbb, vasopressors increase CBF only when MAP is below or abvoe
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below 50 /60 or above 150-160
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brain consume...% of o2
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20
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cmro2 averages
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3.0-3.8 ml/100 g (50 ml/min)
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crmo2 is greatest in
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gray matter of the cerebral cortex
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cmro2 generally parallels
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cortical electrical activity
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...and...are most sensitive to hypoxic injury
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cerebellum and hippocampus
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brain glucose consumption is
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5/mg/100 g/min of which 90% is metabolized aerobically
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total cbf in adults averages
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750 ml/min of 15-20% cardiac output
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blow rates below..are associated with cerebral impairment and are indicated as isolelectric values on eeg
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20-25 ml/100g
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MAP - ..or..= CPP
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ICP/CVP which ever is greater
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CPP is between
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80-100
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sustain perfusion pressures less than..result in irreversible brain damage
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25
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decreases is CPP result in cerebral ...whereas ...result in....
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decreases in cpp results in cerebral vasodilation where as increases results in vasoconstriction
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in HTN, cfb becomes more pressure dependent at ...in return for cerebral protection at....
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in HTN, flow becomes more pressure dependent at low normal arterial pressures in return for cerebral protection at higher arterial pressures.
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metabolites involved in the myogenic resopnse are
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nitric oxide, adenosine, prostoglandins, ionic concentraction gradients.
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the most important extrinsic influences on cbf are
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respiratory gas tension
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effect of pac02 on cbf is almost immediate and is thought to be secondary to
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changes in pH of CSF and cerebral tissue
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cbf changes ...per 1 degree C
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5-7%
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between 17C and 37 C, for every 10 increase in temp the
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CMR doubles
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at....C the EEG is isoelectric
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20 C
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some studies suggest that optimal cerebral oxygen delivery ma occur at hematocrits of
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30
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rapid changes in plasma electrolyte concentrations and secondarily osmolality produce a
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transient osmotic gradient betwen plasma and the brain
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acute hypertonicity of plasma results in
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net movement of water out of the brain
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acute hypotonicity of plasma results in
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net movement of water into the brain
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marked abnormalities in serum sodium or glucose should be corrected
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slowly
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when the bbb is disrupted, fluid movement becomes more dependent on..than on..
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hydrostatic than osmotic gradients
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major function of csf is to
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protect the CNS from trauma
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in adults normal csf production is
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21 mll/hr
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total csf volume is
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150 ml
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csf formation involves the active secretion of
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sodium into the choroid plexus
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......decrease csf production
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carbonic anyhydrase inhibitors, lasix, iso, vasconstrictors, steroid, spironolactone
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csf absorption is directly proportional to..and inv. prop to
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diretly to ICP and inv to to Cerbral venous pressure
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increases in blood pressure can ...cererbral blood volume because autoregulation induces...
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increases in blood pressure can reduce cerebral blood volume because autoregulation can induce vasoconstriction in order to main CBF
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hypotension can ...cerebral blood volume as cerebral blood vessels..to maintain blood flo
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hypotension can increase cerebral blood volume as cerebral vesels dilate to maintain blood flow
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..produces the greates depression in CMR and ..has the lest
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iso the most, hal the least
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iso reduces metabolic rate mainly in the
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neocortex
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volitile anes. dilate cerebral vessels and impair ...in a dose dependent manner
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autoregulaton
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..has the greatest effect of vol. anes. on cerebral blood flow
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halothane
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luxury perfusion
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increase CBF, with decrease in metabolic deman
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circulatory steal syndrome
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vol anes can increase blood flow in normal areas of the brain not in ischemic areas. redistribution of blood away from ischemic to normal areas
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volitile anes. alter both the..and ..of csf
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formation and absorption
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..is the only agent with fav. effects on csf dynamics
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iso
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the net effect of vol anes on icp is the result of
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immediate changes in cbv, delayed alt in csf dynamics and arterial co2 tension
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nitorus oxide has ...effects on icp/cbf
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minimal
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barb have four major actions on the cns
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hypnosis, depression of CMR, reduction of CBF due to increased Cerebral vascular resistance, 4) anticonvulsant activity
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opiod...is generally not used in neuro surg because of
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morphine,,poor lipid sol
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during ischemia, intracell ..increases and intracel...decreases
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k dec, na inc
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intracellur Ca ..during ischemia
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increases because of failure of atp dependent pumps to either extrude the ion extracellularly or into intracellular cisterns, increases intracellular na conc and release of excitatory neurotransmitter glutamate
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focal ischemia includes
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embolic, hemorrahic and atherosclerotic storkes as well as trauma
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hypercarbia may induce a..phenomena in the face of focal ischemia
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steal
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deep anes results in eeg changes that are
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high voltage and low freq
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most anes produce a..pattern on the eeg consisting of
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most anes produce a biphasic pattern on the eeg consisting of initial activation followed by a dose dependent depression
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iso is the only vol anes that can produce..eeg at high clinical doses
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isoelectric
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des and sevo produce a burst suppresion pattern at
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high doses
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....potentials are used for surgery to the
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posterior fossa
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visual evoke potent are used for
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optic nerve , upper brain stem, large pituitary tumors
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evoked pot are decribed as
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short, interm, long
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short latency pot are mostly effected by
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vol anes
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..pot are mos effected by anes
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visual evoked
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..least effected by anes
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brain stem auditory
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..vol anes cause..decreases in ..and icnreases in ..on evoked pot
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decreases in amp, increases in lat
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limiting iso to ..mac and halothane to..mac decreased anes induced changes to evoked pot
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iso .5 mac...hal to 1 mac
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