Pharm General Anesthetics

Front 1

Question: A new halogenated gas anesthetic has a blood:gas partition coeffiient of 0.5 and a MAC value of 1%. Which prediction about this agent is most accurate?

Back 1

Speed of onset will be similar to nitrous oxide. Inhaled anesthetics with low blood:gas solubility have a fast onset of action and a short duration of recovery. MAC stands for minimum alveolar anesthetic concentration.

Front 2

Question: Hepatitis after general anesthesia has been linked to?

Back 2

Halothane

Front 3

Question: Mild generalized muscle twitching occurs with?

Back 3

High doses with enflurane

Front 4

Question: Chest muscle rigidity often follows the administration of?

Back 4

fentanyl

Front 5

Question: Intraoperative use of midazolam with inhalation anesthetics may prolong the?

Back 5

postanesthesia recovery period

Front 6

Question: A 23 year old man has a pheochromocytoma, blood pressure of 190/120 mm Hg, and hematocrit of 50%. Pulmonary function and renal function are normal. His catecholamines are elevated, and he has a well-defined abdominal tumor on MRI. He has been scheduled for surgery. Of the following agents, which agent should NOT be included: desflurane, fentanyl, halothane, midazolam, thiopental?

Back 6

Halothane (also lesser extent isoflurane, not listed). It sensitizes the myocardium to catecholamines. Arrhythmias may occur in PTs with cardiac disease with high circulating levels of catacholamines.

Front 7

Question: What is a useful component of anesthesia protocols because it lacks cardiovascular depression?

Back 7

Nitrous oxide. It is the least potent of the inhaled anesthetics and it does not cause anemia.

Front 8

Question: A low MAC means?

Back 8

High potency. Desflurane has the lowest blood:gas partition coefficient of the inhaled anesthetics, followed by nitrous oxide.

Use of opioid analgesics with inhaled anesthetics lowers the MAC value.

Front 9

Question: Total IV anesthesia with fentanyl has been selected for a frail 72 year old woman about to undergo cardiac surgery. What is an accurate statement about the anesthesia protocol? What is a disadvantage?

Back 9

PT awareness may occur during surgery, with recall after recovery--this can be decreased by concomitant use of a benzo.

Intravenous opioids (eg, fentanyl) are widely used in anesthesia for cardiac surgery because they provide full analgesia and cause less cardiac depression than inhalation anesthetic agents. They are not cardiac stimulants, and fentanyl is more likely to cause skeletal muscle rigidity than relaxation.

Disadvantages of this technique are PT recall (decreased by use of a benzodiazepine) and the occurrence of hypertensive responses to surgical stimulation.

Front 10

Question: Which anesthetic has a low blood:gas partition coefficient but is not used for induction of anesthesia because of airway irritation?

Back 10

Desflurane, used rarely for anesthesia due to high incidence of being a pulmonary irritant that produces coughing and sometimes bronchospasm.

Front 11

Question: A 20 year old male PT schedule for hernia surgery was anesthetized with halothane and nitrous oxide; tubocurarine was provided for skeletal muscle relaxation. The PT rapidly developed tachycardia and became hypertensive. Generalized skeletal muscle rigidity was accompanied by marked hyperthermia. Laboratory values revealed hyperkalemia and acidosis.

This unusual complication of anesthesia is most likely caused by?

The PT should be treated immediately with?

Back 11

Excessive release of calcium from the sarcoplasmic reticulum. Malignant hyperthermia may occur with halogenated anesthetics and/or succinylcholine

With malignant hyperthermia, dantrolene should be administered.

Front 12

Question: The inhalation anesthetic with the fastest onset of action is?

Back 12

Desflurane, followed by nitrous oxide (N2O).

Note: Nitric oxide (NO) is a powerful vasodilator. Nitrogen dioxide (NO2) is a pulmonary irritant in fermenting silage, with farmers. Nitrous oxide is the inhalation anesthetic agent.

Front 13

Question: Respiratory depression after use of what agent may be reversed by administration of flumazenil?

Back 13

Midazolan.

Note: Flumazenil is a benzodiazepine receptor antagonist.

Front 14

Question: If ketamine is used as the sole anesthetic in the attempted reduction of a dislocated shoulder joint, its actions will include?

Back 14

Analgesia.

Note: Cardiovascular stimulant (increase HR and BP). Stimulates CNS by inhibition of NOR reuptake at SYMP nerve endings.

Front 15

Question: An intravenous bolus dose of thiopental usually leads to loss of consciousness within 10 - 15 s. If no further drugs are administered, the PT will regain consciousness in just a few minutes. This is because thiopental is?

Back 15

Redistributed from the brain to other body tissues

Note: The high lipophilicity of thiopental ensures rapid entry to the CNS. Once blood levels fall, thiopental exits the brain and is redistributed to other highly perfused tissues.

Front 16

Question: Which agent is associated with a high incidence of disorientation, sensory, and perceptual illusions, and vivid dreams during recovery from anesthesia?

Back 16

Ketamine.

Administration of diazepam before ketamine reduces these incidence.

Front 17

Question: Post operative vomiting is uncommon with this intravenous agent, and PTs are able to ambulate sooner than those who receive other anesthetics.

Back 17

Propofol, which also has antiemetic actions

Front 18

The potency of inhaled anesthetics is roughly proportional to their?

Back 18

Lipid solubility.

Note:
Low blood and lipid solubility = fast induction and low potency (e.g., N2O)

High lipid and blood solubility = high potency and slow induction (e.g., halothane)

Front 19

What drugs activate GABAa receptors?

Back 19

Inhaled anesthetics, barbiturates, benzodiazepine, etomidate, and propofol

Front 20

What is ketamine's MOA?

Back 20

Antagonist of excitatory neurotransmitter glutamic acid on NMDA receptor

Front 21

In addition to inhibiting GABAa receptors, most inhaled anesthetics inhibit?

Back 21

Nicotinic acetylcholine (ACh) receptor at moderate to high concentrations.

Front 22

Inhibition of neurons involved in pain pathways occurs before?

Back 22

Inhibition of neurons in the midbrain reticular formation.

Front 23

Inhalation anesthesia include?

Back 23

Nitrous oxide and halogenated hydrocarbons (halothane, desflurane, enflurane, isoflurane, sevoflurane, and methoxyflurane.

Front 24

What factors affect the speed of inhaled anesthetics for inducing an anesthetic affect?

Back 24

Solubility

Inspired gas partial pressure

Ventilation rate

Pulmonary blood flow

AV concentration gradient

Front 25

How does solubility affect inhaled anesthetics?

Back 25

The less soluble the anesthetic is in blood, the faster the onset

Drugs with low blood:gas partition coefficient (eg., nitrous oxide) equilibrate more rapidly than those with a higher blood solubility (eg., halothane)

The more rapidly a drug equilibrates with the blood, the more quickly the drug passes into the brain.

Front 26

How does the inspired gas partial pressure affect inhaled anesthetics?

Ventilation rate?

Back 26

Higher partial pressure of gas in lungs results in a faster response in the blood.

Greater the ventilation, the more rapid of a response.

Front 27

What is the affect of pulmonary blood for inhaled anesthetics?

AV concentration gradient?

Back 27

High pulmonary blood flow, the gas partial pressure rises at a slower rate; thus, the speed of onset is reduced.

Note: circulatory shock will produce a rapid onset.

Uptake of soluble anesthetics into highly perfused tissues may decrease gas tension in mixed venous blood. Equilibrium is dependent on the difference in anesthetic tension between arterial and venous blood.

Front 28

How are anesthetics eliminated?

Back 28

Through the lung

Front 29

The rate of recovery of anesthesia is dependent on what? When is the rate of recovery faster?

Back 29

Agents with low blood:gas partition coefficients have a faster rate of recovery than anesthetics with high blood solubility.

Thought?: More soluble the anesthetic is in the blood, less likely it is to leave the blood to produce an affect; also, less likely to be eliminated with ventilation.

Front 30

What three drugs have a low blood solubility and is characterized by faster recovery times?

Back 30

Nitrous oxide, desflurane, and sevoflurane.

Front 31

Potency of inhaled anesthetics is characterized by MAC, what is it?

Back 31

Minimum alveolar anesthetic concentration: the alveolar concentration of an anesthetic that is required to prevent a response to a std. painful stimulus in 50% of PTs.

Note: MAC is lower for children and elderly. Several anesthetic agents used simultaneously, their MAC is additive.

Front 32

What are the CNS affects of inhaled anesthetics?

Enflurane and nitrous oxide effect?

Back 32

Decrease brain metabolic rate; reduction of vascular resistance (increase blood flow; possible increase intracranial pressure).

Enflurane: cause spike-and-wave activity and muscle twitching.

Nitrous oxide: low anesthetic potency (high MAC), however, exerts marked analgesic and amnestic actions.

Front 33

What are the cardiovascular affects of inhaled anesthetics?

What two organs have reduced blood flow by most inhaled agents?

Back 33

Most decrease arterial blood pressure

Liver and kidney

Front 34

Inhaled anesthetics:

(2) myocardial depressants with decrease CO. Which one is less likely to?

Peripheral vasodiltation

Less likely to lower BP?

(2) That may sensitize the myocardium to arrhythmogenic effects of catecholamines.

Back 34

Enflurane and halothane. Nitrous oxide is the least likely to do so.

Isoflurane, descflurane, sevoflurane

Nitrous oxide

Halothane and isoflurane (lesser extent)

Front 35

Although respiration may be increased with inhaled anesthetics, but at what cost?

Back 35

Dose-dependent decrease in tidal volume and minute ventilation --> CO2 retention.

Front 36

Inhaled anesthetics:

What has the smallest effect on respiration?

Most are bronchodilators, but what is a pulmonary irritant and can cause bronchospasm?

The pungency of what limits its use in anesthesia induction by "breath-holding"?

Back 36

Nitrous oxide

Desflurane

Enflurane.

Front 37

Inhaled anesthetic SE:

General for all (also, with tissues with succinylcholine):

Halothane:

Methoxyflurane, enflurane, sevoflurane:

Proconvulsant

Nitrous oxide:

Back 37

Myocardial and respiratory depression, increase cerebral blood flow. Malignant hyperthermia with succinylcholine.

Hepatotoxicity, and sensitizes the myocardium to catecholamines

Fluoride released from metabolism with potential of nephrotoxicity.

Enflurane

Decrease methionine synthase --> megaloblastic anemia

Front 38

When the neuromuscular blocker, succinylcholine, is administered with an inhaled anesthetic, was is a SE, and what drug can be used to be counteracted? What's the logic behind this?

Back 38

Malignant hyperthermia: there is uncontrolled release of Ca by sarcoplasmic reticulum of skeletal muscles leading to muscle spasm.

Dantrolene inhibits Ca release.

Front 39

What are the IV general anesthetics?

Back 39

Barbiturates (thiopental, methohexital)

Dissociative (ketamine)

Benzodiazepines (midazolam)

Propofol

Opioids (morphine, fentanyl)

Front 40

What is benzodiazepine used for?

How does the benzo midazolam compare to barbituarates?

What benzo receptor antagonist accelerates OD recovery?

Back 40

Adjunctively with inhaled anesthetics and IV opioids.

Slower CNS onset (even compared to thiopental) and longer duration.

Respiratory depression.

Flumazenil

Front 41

What is ketamine MOA? SE?

Back 41

Blocks NMDA receptors; therefore, decreases neuronal conduction.

Cardiovascular stimulate --> increase in intracranial pressure

Emergence reaction: disorientation and hallucinations from recovery of ketamine anesthesia.

Front 42

What happens to the PT during ketamine anesthesia?

Back 42

Dissociative anesthesia: PT remains conscious, but marked catatonia, analgesia, and amnesia.

AKA phencycline (PCP)

Front 43

What two opioids are used with other CNS depressants (N2O, benzo) for anesthesia?

What two opioid receptor antagonist can be used post-operatively, and for what?

What are their receptors?

Back 43

Morphine and fentanyl. Valuable for high-risk PTs who might not survive full general anesthetic.

Chest wall rigidity --> impair ventilation. Respiratory depression.

Naloxone and naltrexone for respiratory depression

U, k, delta

Front 44

What is neuroleptanesthesia and what causes it?

Back 44

State of analgesia and amnesia produced when fentanyl is used with droperidol and nitrous oxide.

Front 45

What opioid has a faster recovery than other opioids used in anesthesia?

Back 45

Remifentanil

Front 46

What is propofol MOA?

What is it used for?

SE.

Back 46

Potentiates GABAa

For rapid anesthesia induction and short procedures. Can be used for maintenance of anesthesia. Also has an antiemetic action.

Marked hypotension via decreased peripheral resistance.

Front 47

What is etomidate's used for, and what does it not come with?

What minimal effect does it produce, and therefore, what is its primary advantage.

2 SE.

Back 47

Rapid induction, but etomidate does not produce an analgesic effect.

Cardiac functioning and respiratory effect; therefore, is gold in PTs with limited cardiac/respiratory reserve.

Pain, myoclonus on injection. Adrenal suppresion.