IV sedatives-hypnotics

Question 1

Advantage of propofol

Answer 1

More rapid return of consciousness with minimal residual effects compared to other induction agents

Question 2

Propofol MOA

Answer 2

Increases GABA affinity for GABAa receptor - prolonged channel opening, increased Cl- influx

Question 3

Effect of increased Cl- influx

Answer 3

Neuronal cell hyperpolarization - inhibition of the cell

Question 4

Propofol metabolism

Answer 4

P450 - water soluble metabolites excreted via kidneys. <0.3% excreted unchanged in urine

Question 5

Propofol induction dose:
MAC dose:
TIVA dose:

Answer 5

I: 1.5-2.5 mg/kg
MAC: 25-100 mcg/kg/min
TIVA: 100-300 mcg/kg/min

Question 6

Propofol PONV dose:

Answer 6

Subhypnotic: 10-15 mg IV

Question 7

Propofol CNS effects:

Answer 7

Decreased - CMRO2, CBF, ICP

DOES NOT EFFECT - cerebral autoregulation

Question 8

Propofol cardiovascular effects:

Answer 8

Decreased - SVR, inotropy
DOES NOT EFFECT - HR
Decreased SVR may be augmented in hypovolemic, elderly, compromised LV function

Question 9

Propofol SNS effect:

Answer 9

Suppression of sympathetic nervous system activity

Question 10

Propofol effects respiratory:

Answer 10

Dose-dependent decrease ventilation

Question 11

Propofol effects intraocular pressure:

Answer 11

Decreased immediately after induction of anesthesia

Question 12

Etomidate MOA:

Answer 12

Increases GABA affinity for GABAa receptor - prolonged channel opening, increased Cl- influx

Question 13

Etomidate metabolism:

Answer 13

Hepatic microsomal enzymes and plasma esterases

Question 14

Etomidate induction dose:

Answer 14

0.2-0.4 mg/kg IV

Question 15

Etomidate cardiovascular effects:

Answer 15

Minimal changes in - HR, SV, CO

Decreases - up to 15% decrease in MAP d/t decrease in SVR

Question 16

5 Benzodiazepine effects:

Answer 16

Anxiolysis, sedation/hypnosis, anticonvulsant, anterograde amnesia, SK muscle relaxation

Question 17

Benzodiazepine MOA:

Answer 17

Increased GABA affinity for GABAa receptor - increased frequency of channel opening, increased Cl- influx

Question 18

Benzodiazepine amnesic effect?

Answer 18

Amnestic effect is greater than sedative effect - patients may be awake, but remain amnestic for events and conversations

Question 19

Midazolam Vd elderly and obese:

Answer 19

Increased Vd resulting from enhanced distribution into peripheral adipose tissue

Question 20

Midazolam metabolism:

Answer 20

Rapidly metabolized by hepatic and small intestine P450 (CYP3A4) - hydroxymidazolam (1/2 potency) is rapidly conjugated and renally excreted

Question 21

Drugs that decrease midazolam metabolism?

Answer 21

cimetidine, erythromycin, calcium channel blockers, antifungal drugs - inhibit P450

Question 22

Midazolam CNS effects:

Answer 22

Decreases CMRO2, CBF. Autoregulation is preserved.

Question 23

Solo midazolam induction:

Answer 23

Increased ICP associated with laryngoscopy is not blunted

Question 24

Midazolam respiratory effects:

Answer 24

Dose-dependent decrease in ventilation by decreasing hypoxic drive

Question 25

Midazolam cardiovascular effects:

Answer 25

Decrease in BP, SVR. Increase in HR.

Question 26

Midazolam doses:

Answer 26

Induction: 0.1-0.2 mg/kg
IV sedation: 1-2.5 mg
Onset 30-60 sec, Peak 5.5 minutes, Duration 15-80 min

Question 27

Flumazenil MOA:

Answer 27

Benzodiazepine antagonist at GABA receptor sites, however lacks agonist activity

Question 28

Flumazenil dose:

Answer 28

0.2 mg, subsequent doses of 0.1 mg q1min

Question 29

Ketamine MOA:

Answer 29

Produces dissociative anesthesia by interrupting signals between the thalamus and cerebral cortex. Patient is amnesic and analgesic

Question 30

Limit as sole anesthetic:

Answer 30

High frequency of emergence delirium

Question 31

Ketamine specific targets:

Answer 31

NMDA: inhibits activation by glutamate and prevents presynaptic release of glutamate
GABAa: only weak actions compared to propofol

Question 32

Ketamine dose:

Answer 32

Intubating: 1-2 mg/kg IV
Analgesia: 0.2-0.5 mg/kg IV

Question 33

Ketamine CNS effects:

Answer 33

Mildly increased ICP, can be maintained with normal ventilation

Question 34

Ketamine cardiovascular effects:

Answer 34

SNS stimulation - increases systemic and arterial blood pressure, HR, CO, myocardial O2 demand

Question 35

Ketamine respiratory effects:

Answer 35

DOES NOT decrease ventilation. Bronchodilates. Increased salivary and pulmonary secretions - glyco

Question 36

Ketamine cardioprotective effects:

Answer 36

R(-) isomer blocks cardiac preconditioning

Question 37

Dexmedetomidine MOA:

Answer 37

Alpha-2 agonist - sedation produced by a reduction in SNS tone

Question 38

Dexmedetomidine ventilation effects:

Answer 38

Dose not reduce ventilation