Monday, 8-22-General Anesthetics-DSA-Kruse

Question 1

__ and ___ in conscious sedation protocols have the advantage of being reversible by the specific receptor antagonist drugs (flumazenil and naloxone, respectively)

Answer 1

Benzodiazepines and opioid analgesics

Question 2

IV agents used in deep sedation protocols mainly include the sedative-hypnotics __ and __, sometimes in combo with potent __, depending on the level of pain associated with the surgery or procedure

Answer 2

Propofol and midazolam

Opioid analgesics or ketamine

Question 3

These channels remain the primary inhibitory ion channels considered legitimate candidates of anesthetic action

Answer 3

Cl channels (GABAa and Glycine receptors) and K channels

Question 4

What are some of the excitatory ion channel targets of general anesthetics?

Answer 4

Those activated by Ach (nAChRs and mAChRs), by EAAs (AMPA), kainite, and NMDA receptors, or by 5-HT receptors

Question 5

Halothane, enflurane, isoflurane, desflurane, and sevoflurane are examples of these anesthetics

Answer 5

Volatile inhaled

Question 6

NO is an example of this type of anesthetic

Answer 6

Gaseous inhaled

Question 7

The driving force for uptake of an inhaled anesthetic is the __

Answer 7

Alveolar concentration

Question 8

Describe the FA/F1 ratio and speed of inhaled anesthesia induction

Answer 8

The faster FA/F1 approaches 1, the faster anesthesia will occur during an inhaled induction

Question 9

Agents with __ blood solubility (NO, desflurane), reach high arterial pressure rapidly, which in turn results in rapid equilibration with the brain and fast onset of action

Answer 9

Low

Question 10

Agents with __ blood solubility (halothane) reach high arterial pressures slowly, which in turn results in slow equilibration with the brain and a slow onset of action

Answer 10

High

Question 11

Describe the onset and recovery with inhaled NO

Answer 11

Rapid onset and recovery; incomplete anesthetic

Question 12

Describe the volatility and recovery from inhaled desflurane

Answer 12

Low volatility; poor induction agent; rapid recovery

Question 13

Describe the onset and recovery from inhaled sevoflurane

Answer 13

Rapid onset and recovery

Question 14

Describe the onset and recovery with inhaled isoflurane, enflurane, and halothane

Answer 14

Medium rate of onset and recovery

Question 15

These tissues are highly perfused and receive over 75% of the resting CO, and as a result have higher immediate concentrations of anesthetic

Answer 15

Brain, heart, liver, kidneys, and splanchnic bed

Question 16

Inhaled anesthetics that are relatively insoluble in the blood and brain are eliminated at __ rates compared to more soluble anesthetics

Answer 16

Faster

Question 17

Clearance of inhaled anesthetics via ___ is the major route of eliminate from the body

Answer 17

The lungs

Question 18

Although recovery may be rapid with more soluble agents following a short period of exposure, recovery is slow after prolonged administration of ___

Answer 18

Halothane or isoflurane

Question 19

In regards to the stages of increasing depth of CNS depression, this stage is described by the pt experiencing analgesia without amnesia. Both analgesia and amnesia are produced at the end of this stage

Answer 19

Stage 1

Question 20

In regards to the stages of increasing depth of CNS depression, this stage is described by the pt appearing delirious. Respiration is irregular in both volume and rate, retching and vomiting may occur if pt is stimulated, and regular breathing is established at the end of this stage

Answer 20

Stage 2

Question 21

In regards to the stages of increasing depth of CNS depression, this stage is described by beginning with regular breathing and extending to complete cessation of spontaneous respiration (apnea)

Answer 21

Stage 3

Question 22

In regards to the stages of increasing depth of CNS depression, this stage is described by including severe depression of the vasomotor center in the medulla as well as the resp center

Answer 22

Stage 4

Question 23

In regards to the effects of inhaled volatile liquid anesthetics on the CV system:

___ can cause bradycardia

___ increase heart rate

Answer 23

Halothane

Desflurane and isoflurane

Question 24

Depression of mucociliary function in the airway due to volatile anesthetics can result in ___

Answer 24

Pooling of mucus and post-op resp infx

Question 25

What are some common side effects of inhaled anesthetics?

Answer 25

Common-nausea and vomiting

Question 26

__ may cause hepatitis with or without previous exposure and develops 2-3 weeks after exposure

Answer 26

Halothane Symptoms --> anorexia, nausea, myalgias, arthalgias, and rash, eosinophilia, hepatomegaly, and jaundice

Question 27

Agents metabolized to products including fluoride ions (enflurance and sevoflurane) may cause ___

Answer 27

Renal toxicity

Question 28

In combo with ___, inhaled volatile anesthetics may cause malignant hyperthermia, which consists of rapid onset tachycardia and HTN, severe muscle rigidity, rhabdomyolysis, hyperthermia, hyperK, and acid-base imbalance with acidosis. What is the antidote to this?

Answer 28

Succinylcholine Dantrolene is the antidote

Question 29

__ are widely used to facilitate rapid induction of anesthesia and have replaced inhalation as the preferred method of anesthesia induction in most settings

Answer 29

Nonopioid IV anesthetics

Question 30

__ anesthetics are highly lipophilic and preferentially partition into highly perfused lipophilic tissues (brain and SC), which accounts for their quick onset of action

Answer 30

IV

Question 31

__ is the most commonly used parenteral anesthetic in the US. Its PK properties allow for continuous infusions and maintenance of anesthesia, sedation in the ICU, conscious sedation and short-duration general anesthesia in locations outside the OR

Answer 31

Propofol

Question 32

What is the MOA of Propofol?

Answer 32

Most likely targets GABAa receptors as an agonist and potentiates the Cl current

Question 33

Describe the pharmacokinetics of propofol:

Answer 33

- Rapidly metabolized in the liver - Low hangover effect (high plasma clearance) - rapid rate of onset, rapid recovery, pts can ambulate quickly after use - time of onset is 15-30 secs

Question 34

Describe some CNS effects with propofol

Answer 34

- no analgesic properties - decreases cerebral blood flow which decreases ICP and intraocular pressure - burst suppression in EEG when administered in large doses --> neuroprotective effect during neurosurg procedures

Question 35

Describe CV effects with propofol:

Answer 35

Pronounced decrease in systemic BP due to profound vasodilation Hypotensive effects augmented by inhibition of normal baroreflex response

Question 36

List respiratory effects of propofol

Answer 36

- potent resp depressant | - greater reduction in upper airway reflexes than thiopental does

Question 37

__ is a water-soluble prodrug of propofol that is rapidly metabolized by alkaline phosphatase. Its onset and recovery are prolonged (compared to propofol) because the prodrug must first be converted into an active form

Answer 37

Fospropofol

Question 38

What are some common adverse effects with administration of Fospropofol?

Answer 38

Common adverse effect is the experience of parasthesias and pruritis are mostly limited to the first 5 minutes of admin and usually described as mild-moderate in intensity (unknown mechanism)

Question 39

__ has hypnotic but no analgesic effects. Its MOA enhances the actions of GABA on GABAa receptors. It causes minimal CV and resp depression and useful in pts with impaired CV and pulm systems. It produces rapid loss of consciousness and less rapid recovery rate compared to propofol. It is extensively metabolized by the liver and in the plasma

Answer 39

Etomidate

Question 40

What are CNS effects of Etomidate?

Answer 40

Potent cerebral vasoconstrictor; decreases cerebral blood flow and ICP

Question 41

What are some CV effects of Etomidate?

Answer 41

CV stability is maintained even after bolus injection; minimal change in HR and CO

Question 42

What are endocrine effects with Etomidate?

Answer 42

- causes adrenocortical suppression by producing a dose dependent inhibition of 11 B-hydroxylase - suppression lasts 4-8 hrs after induction dose - endocrine adverse effects limit use for continuous infusion

Question 43

___ is an NMDA receptor antagonist and produces a dissociative anesthetic state characterized by catatonia, amnesia, and analgesia with or without loss of consciousness (pts eyes remain open with a slow nystagmic gaze). Similar in structure to PCP

Answer 43

Ketamine Lacrimation and salivation are increased upon administration and premedication with an anticholinergic may be indicated

Question 44

What is a CNS contraindication for ketamine?

Answer 44

Not recommended for use in pts with intracranial pathology, especially increased ICP Ketamine increases cerebral blood flow as well as CMRO2

Question 45

___ is an a-2 adrenergic agonist that produces hypnosis presumably from stimulation of a-2 receptors in the locus ceruleus and analgesic effects at the level of the SC. Its sedative effect more completely resembles a physiologic sleep state through activation of endogenous sleep pathways

Answer 45

Dexmedetomidine

Question 46

___ is principally used for short-term sedation of intubated and ventilated pts in an ICU setting or as an adjunct to general anesthesia

Answer 46

Dexmedetomidine

Question 47

What are some common opioid analgesics? What are their MOA?

Answer 47

Fentanyl, sufentanil, remifentanil, and morphine MOA: agonists at opioid receptors

Question 48

List some barbiturate anesthetic adjuncts:

Answer 48

Thiopental (prototype) and Methohexital

Question 49

__ are anesthetic adjuncts that are highly lipophilic and quick plasma:brain equilibrium. It causes dose-dependent CNS depression ranging from sedation to general anesthesia (no analgesia) and causes respiratory depression

Answer 49

Barbiturates

Question 50

What is the MOA of barbiturates?

Answer 50

Acts on the GABAa receptor to increase duration of channel opening (agonist) and enhances inhibitory neurotransmission

Question 51

This barbiturate may be preferred over thiopental for short ambulatory procedures due to is rapid elimination

Answer 51

Methohexital

Question 52

List some common benzodiazepine anesthetic adjuncts

Answer 52

Diazepam, lorazepam, and midazolam

Question 53

This anesthetic adjunct is commonly used in the perioperative period because of their anxiolytic properties and ability to produce anterograde amnesia; actions can be terminated by the antagonist flumazenil

Answer 53

Benzodiazepines

Question 54

This benzodiazepine anesthetic adjunct is frequently administered IV before pts enter the OR because it has a more rapid onset, shorter elimination 1/2 life (2-4 hrs), and steeper dose-response curve than other benzodiazepines

Answer 54

Midazolam

Question 55

This anesthetic adjunct has potent anticonvulsant properties; used in tx of status epilepticus, alcohol withdrawal, and local anesthetic-induced seizures

Answer 55

Benzodiazepines

Question 56

Monitored anesthesia care is performed without general anesthesia. It typically involves the use of __ for premedication (to provide anxiolysis, amnesia, and mild sedation), followed by a __ infusion (to provide moderate to deep levels of sedation). A potent ___ may be added to minimize the discomfort associated with the injection of local anesthesia and surgical manipulations

Answer 56

Midazolam Titrated propofol Opiod analgesic or ketamine