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34 Cards in this Set
- Front
- Back
What three factors determine intracranial pressure?
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cerebral blood flow
cerebral spinal fluid brain matter |
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How is intracranial hypertension defined? (what value?)
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ICP >15mmHg sustained
increase can be in tissue or fluid (blood or CSF) |
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Name 5 s/s of Increased ICP
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H/A
N/V papilledema altered LOC focal neurologic deficits |
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Describe the circular pattern of intracranial hypertension
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ICP>30mmHg -> decreased cerebral blood flow -> cerebral ischemia -> brain edema -> further increase in ICP -> .....
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What is the end result of the circular pattern of increased ICP if untreated?
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Herniation of brain stem
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A pre-op neuro eval will include....?
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1)Assessment for neuro DEFICITS
2)Check for neurological MONITORS 3) Identify specific MEDICATIONS for increased ICP 4)assess for MIDLINE SHIFT on CT or MRI |
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When assessing a ventriculostomy, what should be noted?
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LEVEL of drainage
AMOUNT of drainage CHARACTERISTICS of drainage |
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Is a Camino Monitor or Bolt a direct measure of ICP?
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Yes
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In assessing medications pre-op, what therapies should you be alert to?
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-Anticonvulsants
-Diuretics-osmotic (Mannitol) and loop (Lasix) -Corticosteroids |
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The patient is on dilantin. What is important to remember?
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Dilantin increases the metabolism of most drugs and has many interactions
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When assessing CT or MRI pre-op, what are you looking for?
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1)Midline shift > 0.5 cm (compression of one of the ventricles on one side vs. the opposite side)
2) ventricular size 3) signs of brain edema |
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Should patients with increased ICP be premedicated? Explain why or why not.
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AVOID! Premedication can drop RR, causing increase in CO2 and increased cerebral blood flow, increasing ICP
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What is the overall goal during induction of patient with increased ICP?
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keep the ICP the same or lower oif possible
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Where do you want the BP of a patient with increased ICP?
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As close to normal as possible to provide appropriate cerebral perfusion pressure.
(MAP of 60 if not higher) |
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How is CPP calculated?
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CPP=MAP-ICP or
CPP=MAP-CVP if ICP is not available |
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Can central lines be placed in patients with increased ICP?
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Yes, but avoid IJ-can obstruct venous drainage from brain
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How should BP be monitored in pt with increased ICP?
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A -line is best to closely monitor thru induction and intubation
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What special consideration should be taken when placing a line in apatient with increased ICP?
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Use local to prevent pain related hypertension
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Which induction agent should be avoided in patients with increased ICP? Why?
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Ketamine-will increase ICP
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Is Etomidate an appropriate induction agent for use in patients with increased ICP?
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Yes if used with sufficient amounts of fentanyl
(5mcg/kg) |
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What is the dose of fentanyl that should be given with Etomidate if used for induction?
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5mcg/kg
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what are the best choices for induction of a pt with increased ICP? Why?
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Propofol and Thiopental
-Provide decrease in CMRO2 -Provide quick, deep induction (neuroprotective effects) |
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Is it better to give a low, medium or high dose of induction agent to a patient with increased ICP? why?
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Better to start low-you can always give more. The goal is to provide induction but maintain appropriate CPP
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What effects do VA have on ICP? What actions are appropriate by the anesthetist when turning on VA?
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Halogenated agents will cause vasodilation of the cerebral vasculature but Small amount of agent is used to deepen anesthetic prior to intubation, so hyperventilate(RR 20-30) pt to lower CO2 and decrease cerebral blood flow
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What is the physiologic response to direct laryngoscopy?
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DL is very stimulating -> increased HR and BP will increase ICP
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What adjuncts are used to provide blunting of airway reflexes prior to intubation of pt with increased ICP?
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Fentanyl 5-10 mcg/kg
Lidocaine 0.5-1.0 mcg/kg (avoid if seizure risk) |
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Which muscle relaxant should be avoided in a patient with increased ICP?
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Succinylcholine-it causes a transient increase in ICP-avoid if possible
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Which muscle relaxant is the best choice for a pt with increased ICP?
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Choose any non-depolarizing muscle relaxant according to pt hx
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If you attempt to intubate prior to full effect of the muscle relaxant in a pt with increased ICP, what do you risk?
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Coughing, which will sharply increase ICP
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What is the overall goal while intubating a patient with increased ICP?
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Minimal change in VS!
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How can the anesthetist ensure airway reflexes are blunted prior to intubation in a pt with increased ICP?
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1) DEEP level of anesthesia
2) Appropriate MUSCLE BLOCKADE 3) Attenuation of AIRWAY REFLEXES |
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How can the anesthetist control BP and HR during intubation?
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Recognize that DL is stimulating only briefly - Use short acting agents-stay off the roller coaster- Esmolol,and small doses of induction agents (propofol and thiopental) will lower heart rate and BP for short periods of time
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What positioning issues are associated with surgery on pt with increased ICP?
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Position appropriately to promote venous drainage and drainage of CSF
-head in neutral position so as to not compress jugular veins -HOB increased to promote drainage |
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Where will the OR table be in relation to the anesthetist for surgery on pt with increased ICP Why is this of special concern?
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bed will be 90-180 degrees from anesthetist. A loss of airway or disconnect will cause increased CO2, resulting in increased ICP.
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