IV Sedatives and Hypnotics Flashcards

1
Q

What does GABA stand for?

A

Gamma Aminobutyric Acid

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2
Q

There are three phases that occur after a bolus injection of propofol:

A
  1. Rapid distribution (moves into tissues until they equilibrate with plasma)
  2. Slow distribution phase (return of drug to the plasma)
  3. Terminal Phase (removed from the body)
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3
Q

What is context sensitive half time?

A

Time required to acheive a 50% reduction in concentration after stopping a continuous infusion in drugs that are not limited to the blood (i.e. all IV anesthetics)

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4
Q

Where is propofol metabolized?

A

The liver

Excreted by the kidneys

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5
Q

How does reduced liver function effect propofol metabolism?

A

Interestingly, it doesn’t

This suggests there must be other forms of metabolism at work, but we’re not sure what they are

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6
Q

Propofol Classification

A

GABA Agonist

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7
Q

How does propofol effect ICP?

A

It lowers ICP by lowering CBF

Generally considered neuroprotective

It’s also a free radical scavenger

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8
Q

What are the characteristic hemodynamic effects of a propofol bolus?

A

Drop in SBP and DBP WITHOUT the expected increase in HR

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9
Q

What is the drug dose of propofol in healthy adults?

A

1-2.5 mg/kg

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10
Q

How do elderly patients respond to propofol?

A

Prolonged effects and increased sensitivity

BECAUSE of decreased CO and clearance

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11
Q

How do pediatric patients respond to propofol?

A

larger than average volume of distribution and quicker clearance, resulting in creased propofol requirement per kg

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12
Q

When calculating the appropriate propofol amount for a morbidly obese patient, what weight should be used?

A

LBW, not actual weight

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13
Q

Maintenance of general anesthesia can commonly be acheived with prop infusion of:

A

100-200 mcg/kg/min

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14
Q

What is the recommended maximum propofol dose?

A

4 mg/kg/hr

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15
Q

Why isn’t etomidate used as an infusion?

A

It’s associated with adrenal suppression

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16
Q

Etomidate classification

A

GABA - A receptor agonist

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17
Q

Is etomidate a good choice for neuro patients?

A

It reduces ICP, but it’s often associated with EEF spikes

Used frequently for ECT

proconvulsant and lowers the seizure threshold

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18
Q

Why does etomidate cause adrenal suppression?

A

It inhibits the enzyme that converts cholesterol into cortisol

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19
Q

Ketamine Classification

A

NMDA receptor Antagonist

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20
Q

Why is ketamine analgesic?

A

Believed to be in the prevention of developing hyperalgesia

preventing wind up at NMDA receptors

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21
Q

Which patients should not receive ketamine?

A

CAD patients (if they can’t tolerate the increased BP and HR)

R sided HF patients (increases PVR)

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22
Q

How is ketamine useful in post op pain?

A

It reduced opiate requirements, but it cannot replace opiates altogether

Most useful in patients who will require high does of opiates

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23
Q

Should ketamine be used in patients with increased ICP?

A

Historically, no. But studies are showing that ICPs remain normal with ketamine even though it has an excitatory CNS effect

It may even be neuroprotective

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24
Q

Dexmedetomidine Classification

A

Alpha 2 Adrenergic Agonist

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25
Q

What are the main side effects of ketamine?

A

emergence delirium

hallucinations

nystagmus

increased salivation

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26
Q

What effect does ketamine have on bronchioles?

A

Bronchodilator

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27
Q

Precedex provides analgesia at the ______ level

A

spinal cord

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28
Q

What are the cardiovascular effects of precedex?

A

bradycardia and hypotension

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29
Q

What do alpha 2 receptors do?

A

Peripherally, they are located on presynaptic nerve terminals and regulate transmitter release

Centrally,

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30
Q

Benzodiazepine classification

A

GABA-A receptor agonist

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31
Q

PROPOFOL

CHEMICAL NAME & MOA

A

2,6 - diisopropylphenol

Direct GABA agonist: Increases Cl influx, causing hyperpolarization

32
Q

PROPOFOL

ONSET & DURATION

A

Onset: 30-60 seconds

Duration: 5-10 min

33
Q

PROPOFOL

INDUCTION DOSE & INFUSION DOSE

A

INDUCTION: 1.5-2.5 mg/kg

INFUSION: 25-200 mcg/kg/min

34
Q

What does GABA-A receptor stimulation cause?

A

Increased Cl- influx into the cell, which hyperpolarizes the neuron and prevents firing

35
Q

What are the CV effects of propofol?

A

Decreased BP, SVR, venous tone (hence preload), and myocardial contractility

36
Q

What are the respiratory effects of propofol?

A

Decreased sensitivity to CO2, causing apnea and hypoventilation

inhibits hypoxic respiratory drive

37
Q

What effect dose propofol have on ICP and CBF?

A

Reduces both

38
Q

What organs are primarily responsible for propofol metabolism?

A

Liver and Lungs

39
Q

What causes Propofol Infusion Syndrome?

A

Increased long chain triglyceride load in the blood impairs oxidative phosphorylation and fatty acid metabolism

Cells literally starve from lack of oxygen, usually cardiac and skeletal are effected first

40
Q

What are some risk factors for Propofol Infusion Syndrome?

A

infusions exceeding 4 mg/kg/hr (67 mcg/kg/min)

Infusion greater than 48 hours

Sepsis

Catecholamine infusions

41
Q

What is the clinical presentation of propofol infusion syndrome?

A
42
Q

How long is propofol in a syringe good for?

A

6 hours

43
Q

What are the benefits of fospropofol?

A

Prevents burning

Doesn’t require preservatives

44
Q

What are the downsides of fospropofol?

A

Longer onset and duration

45
Q

Is ketamine better at treating somatic or visceral pain?

A

Somatic

46
Q

What are the cardiovascular effects of ketamine?

A
47
Q

KETAMINE

MOA

A

NMDA receptor Antagonist

Dissociates the thalamus from the limbic system

Also targets opioid, MAO, serotonin, NE, muscarinic and Na channel receptors

48
Q

KETAMINE

ONSET AND DURATION

A

ONSET 30-60 seconds

DURATION 10-20 minutes

49
Q

KETAMINE

INDUCTION, MAINTENANCE, AND LOW DOSE

A

INDUCTION: 1-2 mg/kg

MAINTENANCE: 1-3 mg/min

LOW DOSE: 1-3 mcg/kg/min

50
Q

What are the respiratory effects of ketamine?

A
51
Q

What are the CNS effects of Ketamine?

A
52
Q

What drug prevents hyperalgesia after remifentanil infusion?

A

Ketamine

53
Q

Which IV anesthetic has the lowest protein binding rate?

A
54
Q

ETOMIDATE

MOA

A

GABA-A agonist

55
Q

What is the induction dose of Etomidate?

A

0.2-0.4 mg/kg

56
Q

ETOMIDATE

Onset and Duration

A

Onset: 30-60 seconds

Duration: 5-15 min

57
Q

What are the cardiovascular effects of etomidate?

A

Pretty minimal

Small reduction in SVR

Does not blunt the SNS response to laryngoscopy and noxious stimuli, so an opioid or esmolol will be needed

58
Q

What are the respiratory effects of etomidate?

A

Does cause respiratory depression, but not nearly as much as propofol or barbituates

59
Q

What are the CNS effects of Etomidate?

A
60
Q

Which anesthetic agent increased mortality in patients with Addison’s Disease?

A

Etomidate

61
Q

Which patients should never get etomidate?

A

Patients who are extremely dependent on cortisol (sepsis, acute adrenal failure)

62
Q

What IV induction agent has the highest incidence of PONV?

A

Etomidate

63
Q

Which drugs should be avoided in patients with Acute Intermittent Porphyria?

A
64
Q

Anesthetic management of a patient with porphyria should include:

A
65
Q

Which drug is the gold standard for ECT therapy?

Why?

A

Methohexital

It decreases the seizure threshold

66
Q

DEXMEDETOMIDINE

MOA

A

Alpha 2 agonist

67
Q

DEXMEDETOMIDINE

LOADING DOSE & INFUSION

A

Loading: 1 mcg/kg over 10 min

Maintenance: 0.4-0.7 mcg/kg/hr

68
Q

DEXMEDETOMIDINE

ONSET AND DURATION

A

Onset (with bolus): 10-20 min

Duration: 10-30 min after infusion stopped

69
Q

Who does precedex impact shivering?

A

It impairs the shivering mechanism

70
Q

Why does precedex produce analgesia?

A

Alpha 2 stimulation in the spinal cord results in reduced glutamate and Substance P release

71
Q

What is the MOA for benzodiazepines?

A

GABA-A agonist by increasing the frequency of opening (and therefore Cl influx and hyperpolarization)

72
Q

What is the induction dose of Versed?

A

0.1-0.4 mg/kg

73
Q

What is the sedation dose of Versed?

A

0.01-0.1 mg/kg

74
Q

What is the onset and duration of versed?

A

Onset 30-60 seconds

Duration: 20-60 minutes

75
Q

Which benzodiazepine is most potent? Least potent?

A

Most: Lorazepam

Least: Diazepam

76
Q

What is Flumazenil’s MOA?

A

Competitive antagonist at the GABA-A receptor

77
Q

What is the duration of Flumazenil?

A

Only 30-60 minutes, will probably need redosing before benzo is completely out of their system