Neuroaneesthesia Flashcards by Alyssa Rivera

What 6 things are used to lower ICP?

Mannitol 
Hypertonic saline (3%)
Furosemide 
Corticosteroids 
Barbiturates 
Propofol

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How do IV hyperosmotic drugs work?

Produce transient increase in osmolality of plasma; draws water from tissues into plasma and eliminated renally

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What are the 2 secondary effects of IV hyperosmotic drugs?

Diuretics and reduction

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3 adverse effects of mannitol?

Hyper osmolality, hyponatremia, hypokalemia

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How fast does mannitol work?

Rapidly

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Dose of mannitol?

.25g-.5g/kg

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Goal serum osmolality for mannitol?

300-315 mOsm/L

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What serium should you stop mannitol?

320

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When can you get a rebound increase in ICP with mannitol?

Larger initial dose

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What 3 cautions are taken with mannitol?

Intact BBB
LV dysfunction/poor cardiac reserve/HF
Aneurysms/arteriovenous malformations/intracranial hemorrhage

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How should hypertonic saline be administered?

Central venous catheter

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Target serum Na and serum osmolarity?

Na: 145-155
Osm: <320

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Is hypertonic saline a higher risk than mannitol?

YES

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How is the efficacy of furosemide compared to mannitol and hypertonic saline?

Significantly less

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When is furosemide useful?

Increased IV volume; pulmonary edema

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Is furosemide used to aid tolerance of mannitol or hypertonic solution?

YES

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When are corticosteroids effective?

Lowering ICP caused by localized vasogenic edema (brain tumor or craniotomy)

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When using corticosteroids, what should be monitored and why?

Blood glucose because may cause hyperglycemia needing insulin

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Barbiturates in what kind of doses an lower ICP after acute head injury?

High doses

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When should propofol be taken in caution?

Peds

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When should propofol be avoided?

High anion-gap metabolic acidosis

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Should you continue therapies for cerebral edema or increased ICP for preop management?

YES

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Why should you use sedative and opioids sparingly?

Can leads to not breathing=hypoventilation=hypercarbia=increase ICP

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2 things needed for induction of anesthesia for brain tumor?

Propofol (or barbiturate)

Non depolarizing muscle relaxant

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You should use NMB to prevent straining, bucking, movement except when?

Neuro physiological monitoring needed

What kind of solution should be avoided for cranial tumor surgery?

Dextrose

What 4 things can be given to attenuate skull pinning?

Opioid (fent or remi) Propofol Esmolol Lidocaine

When should you give opioid and esmolol before pinning?

1 min

Does brain tissue have pain receptors?

Which drug activates seizure foci for induction?

Methohexital

What 2 drugs do you want to avoid for induction?

Etomidate and ketamine

3 NMB, non-histamine release agents used for induction for craniotomy

Roc, vec, cisatracurium

If ICP is a concern for craniotomy, what should be added when using sux for rapid sequence induction?

Defasciculating dose of non depolarizing agents

Which maintenance is preferred if ICP is elevated for craniotomy?

IV technique (propofol, opioids, dexmedetomidine)

Which opioid should be avoided due to histamine release?

Morphine

Should you keep pt paralyzed while skull pins are in place?

Yes

TOF peripheral nerve stimulator to guide depth, deep for skull pins?

1-2 twitches

CPP equation?

MAP - ICP (CVP)

Goal CPP?

65-80 mmHg

Normal ICP?

5-10 mmHg

Normal MAP?

75-90 mmHg

For craniotomy, if hypovolemia and hypotensive what kind of colloid should be used and should be avoided?

Used: albumin Avoid: starch

BG target range for craniotomy?

110-150, and treat >180

When should you gibe antiemetic for craniotomy?

1 hr prior to emergence (zofran)

Should you give long acting opioids for emergence of craniotomy, like hydromorphone?

BP control for emergence of craniotomy?

SBP <160 but avoid hypotension

Emergence BP meds for craniotomy (3)?

Labetalol Esmolol Nicardipine

Does esmolol need continuous infusion otherwise rebound HTN?

YES

Hypotensive management due to neurogenic shock for organ retrieval (3):

1. Fluid resuscitation without causing hypervolemia 2. Avoid vasoconstrictors 3. Inotrope preferred (dobutamine, dopamine, then epi at low dose)

Organ retrieval DM leads to hypovolemia, how to do you treat? (2)

Hypotonic solution | Inotropic support with vasopressin

For acute ischemic stroke, antiHTN only necessary when?

BP > 220/120 (labetalol or infusion of esmolol and clevidipine)

Transient alteration of behavior due to disordered, synchronous, and rhythmic firing of populations of brain neurons (provoked or unprovoked)

Seizure

Disorder of brain function with periodic and unpredictable occurrence of seizures

Epilepsy

3 drugs for seizures:

Antiepileptic drugs (AEDs) Anti seizure drugs Anticonvulsants

One area of brain seizure:

Focal seizure

Both hemispheres seizure of brain:

Generalized seizure

Antiseizure general mechanisms of ions:

Modulation of Na, K, Ca channels - prolonged of inactivated state of voltage gated Na channels - positive modulation of K channels - inhibition of Ca channels

Anti seizure general mechanism of GABA:

Enhancement of GABA transmission through actions on GABA receptors, modulation of GABA metabolism, inhibition of GABA reuptake

How do most antiseizure drugs metabolize?

Hepatic metabolism before undergoing renal elimination

Which drugs are exception of live metabolism and rely only on renal elimination?

Gabapentin | Levetiracetam

Do gabapentin and levetiracetam have other drug interactions?

CYP enzyme induction agents for antiseizure?

Phenytoin, carbamazepine, phenobarbital

Do phenytoin, carbamazepine, and phenobarbital alter rate of metabolism of other drugs?

YES

Pts receiving chronic treatment with certain anticonvulsants are relatively resistant to what due to accelerated clearance of these drugs?

Non depolarizing NMBs

Which 2 drugs shorten duration of action of NMB?

Carbamazepine and phenytoin

Do you continue antiseizure meds periop?

YES

What are 3 parenteral agents of antiseizure meds?

Levetiracetam, phenytoin and fosphenytoin

If new seizure, need to determine cause and not assume anesthetic adverse effect; what could be the cause?

What can have both proconvulsant and anticonvulsant effects?

Methohexital and etomidate can activate epileptic foci

What can cause epileptiform EEG activity in pts without epilepsy, but can also suppress such activity (5)

``` Alfentanil Ketamine Enflurane Iso Sevo ```

This of large doses or pts with renal insufficiency an cause seizures?

Meperidine

Proconvulsant metabolite of atracurium and cisatracurium:

Laudanosine

This metabolite derangements can cause periop seizures?

Hyponatremia, hypocalcemia, sepsis, hypoglycemia

4 commonly used drugs for acute seizure management:

Fosphenytoin Levetiracetam Valproate acid Propofol

What acute seizure drug is a parent drug and rarely used due to hypotension, asystole, widened QRS and prolonged QT, arrhythmia, and CANNOT be given IM

Phenytoin

Acute seizure management drug that is water soluble prodrug for IV or IM and doses expressed as phenytoin equivalents?

Fosphenytoin

After how long is it less likely to spontaneously terminate?

5min

What is more likely to cause neuronal damage and is continuous or intermittent for more than 5 min without recovery or consciousness?

Status epilepticus

What should be considered for status epilepticus?

Intubation

1 and 2 drugs for managing status epilepticus:

1: benzodiazepine 2: antiseizure drug

First and second choice of benzodiazepines?

1: diazepam 2: lorazepam

Which is short lived anti seizure action but need to add anticonvulsant?

Benzodiazepines

Which benzodiazepines is longer antiseizure duration of action?

Lorazepam

Which sedation is used to avoid epileptiform activity?m (3)

1. Thiopental 2. Opioids 3. Benzodiazepines

Which anesthesia maintenance is used to avoid epileptiform activity? (4)

ISO, des, sevo, propofol

For pts under GA and muscle relaxation, how do you know one manifests and what do you do?

- abrupt changes in HR and BP | - add or increase doses of propofol, barbiturate, benzodiazepines

Agents that suppress epileptic activity (4)

Benzodiazepines Volatile agents Barbiturates Propofol

Agents to use during electrocorticography to isolate epileptic foci (5)

``` Opioids Nitrous oxide Droperidol Diphenhydramine Dexmedetomidine ```

Agents to enhance epileptiform activity (3)

High dose short acting opioids Methohexital Etomidate

4 complications of seizures:

Musculoskeletal injury Hypoventilation Hypoxemia Aspiration

Drugs that may be epileptogenic (3)

1. Ketamine, enflurane, etomidate 2. Methohexital (paradoxical small doses) 3. Metabolites - meperidine, atracurium