Inhalational anesthetics

Question 1

Inhalational anesthetics - MOA

Answer 1

Bind to GABAa receptor-chloride ion channel. Increased Cl influx and K efflux cause hyperpolarization and reduced excitability.
Also reduce Na and Ca influx which prevents nerve firing and release of neurotransmitters.

Question 2

Effects of inhalational anesthetics - 4 stages

Answer 2

1) Spinal cord inhibition: analgesia + conscious sedation.
2) Paradoxical excitation (often not observed).
3) Goal: suppression of reticular-activating system, loss of consciousness, inhibition of spinal reflexes.
4) Avoid: cardiovascular collapse, depression of resp and vasomotor nuclei in brain stem.

Question 3

Which group is often used with opioids, muscle relaxants ect. and why

Answer 3

Halogenated anesthetics. Cause little analgesia and skeletal muscle relaxation.

Question 4

Halogenated anesthetics - adverse effects

Answer 4

Malignant hyperthermia, resp and cardiovascular depression, uterine relaxation.

Question 5

Induction rate is determined by - 3 factors

Answer 5

1) Alveolar partial pressure of the anesthetic in inspired air.
2) Ventilation rate.
3) How the partial pressure of drug in the blood changes with the inhaled anesthetics.

Question 6

Nonhalogenated inhalational anesthetics - 1 drugs

Answer 6

Nitrous oxide (“laughing gass”)

Question 7

Halogenated inhalational anesthetics - 5 drugs

Answer 7

Halothane
Desflurane
Enflurane
Isoflurane
Sevoflurane

Question 8

Nitrous oxide - potency and effects

Answer 8

Least potent inhalational anesthetic, no loss of consciousness. More analgesic effects.

Question 9

Does nitrous oxide cause muscle relaxation, cardiovascular or resp depression

Answer 9

No

Question 10

Nitrous oxide - indications

Answer 10

Minor surgery, dental procedures.

Component of balanced anesthesia.

Question 11

Nitrous oxide - adverse effects

Answer 11

Megaloblastic anemia (chronic exposure) - bec of oxidizing B12, inhibiting methylation of nucleic acids and proteins. 
Mild euphoria.

Question 12

Halothene - effects

Answer 12

Most potent inhalational agent.
More sensitization of heart to catecholamines.
Little skeletal muscle relaxation. 
Airway irritation, bronchodilation. 
Reduced cardiac output.

Question 13

Halothene - contraindications

Answer 13

Should go 6-12 months between each exposure (hypersensitivity & hepatitis)

Question 14

Halothene - adverse effects

Answer 14

Halothane hepatitis.

Cardiac dysrhythmias.

Question 15

Desflurane - adverse effects

Answer 15

Respiratory tract irritation

Question 16

Enflurane - adverse effects

Answer 16

Seizures (high doses).

Respiratory depression

Question 17

Isoflurane - effects

Answer 17

Reduced systemic vascular resistance.
Muscle relaxation.
Airway irritation, respiratory depression and bronchodilation.

Question 18

Ideal inhalational anesthetic

Answer 18

Sevoflurane.