IV Sedatives and Hypnotics

Question 1

What does GABA stand for?

Answer 1

Gamma Aminobutyric Acid

Question 2

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

Answer 2

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)

Question 3

What is context sensitive half time?

Answer 3

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)

Question 4

Where is propofol metabolized?

Answer 4

The liver

Excreted by the kidneys

Question 5

How does reduced liver function effect propofol metabolism?

Answer 5

Interestingly, it doesn’t

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

Question 6

Propofol Classification

Answer 6

GABA Agonist

Question 7

How does propofol effect ICP?

Answer 7

It lowers ICP by lowering CBF

Generally considered neuroprotective

It’s also a free radical scavenger

Question 8

What are the characteristic hemodynamic effects of a propofol bolus?

Answer 8

Drop in SBP and DBP WITHOUT the expected increase in HR

Question 9

What is the drug dose of propofol in healthy adults?

Answer 9

1-2.5 mg/kg

Question 10

How do elderly patients respond to propofol?

Answer 10

Prolonged effects and increased sensitivity

BECAUSE of decreased CO and clearance

Question 11

How do pediatric patients respond to propofol?

Answer 11

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

Question 12

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

Answer 12

LBW, not actual weight

Question 13

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

Answer 13

100-200 mcg/kg/min

Question 14

What is the recommended maximum propofol dose?

Answer 14

4 mg/kg/hr

Question 15

Why isn’t etomidate used as an infusion?

Answer 15

It’s associated with adrenal suppression

Question 16

Etomidate classification

Answer 16

GABA - A receptor agonist

Question 17

Is etomidate a good choice for neuro patients?

Answer 17

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

Used frequently for ECT

proconvulsant and lowers the seizure threshold

Question 18

Why does etomidate cause adrenal suppression?

Answer 18

It inhibits the enzyme that converts cholesterol into cortisol

Question 19

Ketamine Classification

Answer 19

NMDA receptor Antagonist

Question 20

Why is ketamine analgesic?

Answer 20

Believed to be in the prevention of developing hyperalgesia

preventing wind up at NMDA receptors

Question 21

Which patients should not receive ketamine?

Answer 21

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

R sided HF patients (increases PVR)

Question 22

How is ketamine useful in post op pain?

Answer 22

It reduced opiate requirements, but it cannot replace opiates altogether

Most useful in patients who will require high does of opiates

Question 23

Should ketamine be used in patients with increased ICP?

Answer 23

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

Question 24

Dexmedetomidine Classification

Answer 24

Alpha 2 Adrenergic Agonist

Question 25

What are the main side effects of ketamine?

Answer 25

emergence delirium hallucinations nystagmus increased salivation

Question 26

What effect does ketamine have on bronchioles?

Answer 26

Bronchodilator

Question 27

Precedex provides analgesia at the ______ level

Answer 27

spinal cord

Question 28

What are the cardiovascular effects of precedex?

Answer 28

bradycardia and hypotension

Question 29

What do alpha 2 receptors do?

Answer 29

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

Question 30

Benzodiazepine classification

Answer 30

GABA-A receptor agonist

Question 31

**PROPOFOL** CHEMICAL NAME & MOA

Answer 31

2,6 - diisopropylphenol Direct GABA agonist: Increases Cl influx, causing hyperpolarization

Question 32

**PROPOFOL** ONSET & DURATION

Answer 32

Onset: 30-60 seconds Duration: 5-10 min

Question 33

**PROPOFOL** INDUCTION DOSE & INFUSION DOSE

Answer 33

INDUCTION: 1.5-2.5 mg/kg INFUSION: 25-200 mcg/kg/min

Question 34

What does GABA-A receptor stimulation cause?

Answer 34

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

Question 35

What are the CV effects of propofol?

Answer 35

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

Question 36

What are the respiratory effects of propofol?

Answer 36

Decreased sensitivity to CO2, causing apnea and hypoventilation inhibits hypoxic respiratory drive

Question 37

What effect dose propofol have on ICP and CBF?

Answer 37

Reduces both

Question 38

What organs are primarily responsible for propofol metabolism?

Answer 38

Liver and Lungs

Question 39

What causes Propofol Infusion Syndrome?

Answer 39

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

Question 40

What are some risk factors for Propofol Infusion Syndrome?

Answer 40

infusions exceeding 4 mg/kg/hr (67 mcg/kg/min) Infusion greater than 48 hours Sepsis Catecholamine infusions

Question 41

What is the clinical presentation of propofol infusion syndrome?

Answer 41

Question 42

How long is propofol in a syringe good for?

Answer 42

6 hours

Question 43

What are the benefits of fospropofol?

Answer 43

Prevents burning Doesn't require preservatives

Question 44

What are the downsides of fospropofol?

Answer 44

Longer onset and duration

Question 45

Is ketamine better at treating somatic or visceral pain?

Answer 45

Somatic

Question 46

What are the cardiovascular effects of ketamine?

Answer 46

Question 47

**KETAMINE** MOA

Answer 47

NMDA receptor Antagonist Dissociates the thalamus from the limbic system Also targets opioid, MAO, serotonin, NE, muscarinic and Na channel receptors

Question 48

**KETAMINE** ONSET AND DURATION

Answer 48

ONSET 30-60 seconds DURATION 10-20 minutes

Question 49

**KETAMINE** INDUCTION, MAINTENANCE, AND LOW DOSE

Answer 49

INDUCTION: 1-2 mg/kg MAINTENANCE: 1-3 mg/min LOW DOSE: 1-3 mcg/kg/min

Question 50

What are the respiratory effects of ketamine?

Answer 50

Question 51

What are the CNS effects of Ketamine?

Answer 51

Question 52

What drug prevents hyperalgesia after remifentanil infusion?

Answer 52

Ketamine

Question 53

Which IV anesthetic has the lowest protein binding rate?

Answer 53

Question 54

**ETOMIDATE** MOA

Answer 54

GABA-A agonist

Question 55

What is the induction dose of Etomidate?

Answer 55

0.2-0.4 mg/kg

Question 56

**ETOMIDATE** Onset and Duration

Answer 56

Onset: 30-60 seconds Duration: 5-15 min

Question 57

What are the cardiovascular effects of etomidate?

Answer 57

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

Question 58

What are the respiratory effects of etomidate?

Answer 58

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

Question 59

What are the CNS effects of Etomidate?

Answer 59

Question 60

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

Answer 60

Etomidate

Question 61

Which patients should never get etomidate?

Answer 61

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

Question 62

What IV induction agent has the highest incidence of PONV?

Answer 62

Etomidate

Question 63

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

Answer 63

Question 64

Anesthetic management of a patient with porphyria should include:

Answer 64

Question 65

Which drug is the gold standard for ECT therapy? Why?

Answer 65

Methohexital It decreases the seizure threshold

Question 66

**DEXMEDETOMIDINE** MOA

Answer 66

Alpha 2 agonist

Question 67

**DEXMEDETOMIDINE** LOADING DOSE & INFUSION

Answer 67

Loading: 1 mcg/kg over 10 min Maintenance: 0.4-0.7 mcg/kg/hr

Question 68

**DEXMEDETOMIDINE** ONSET AND DURATION

Answer 68

Onset (with bolus): 10-20 min Duration: 10-30 min after infusion stopped

Question 69

Who does precedex impact shivering?

Answer 69

It impairs the shivering mechanism

Question 70

Why does precedex produce analgesia?

Answer 70

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

Question 71

What is the MOA for benzodiazepines?

Answer 71

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

Question 72

What is the induction dose of Versed?

Answer 72

0.1-0.4 mg/kg

Question 73

What is the sedation dose of Versed?

Answer 73

0.01-0.1 mg/kg

Question 74

What is the onset and duration of versed?

Answer 74

Onset 30-60 seconds Duration: 20-60 minutes

Question 75

Which benzodiazepine is most potent? Least potent?

Answer 75

Most: Lorazepam Least: Diazepam

Question 76

What is Flumazenil's MOA?

Answer 76

Competitive antagonist at the GABA-A receptor

Question 77

What is the duration of Flumazenil?

Answer 77

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