Inhaled Anesthetics

Question 1

Uptake

Answer 1

Level in brain depends on levels in alveoli

Goal= high Fa/Fi ( higher=faster induction)

Question 2

Solubility

Answer 2

Lower solubility=rapid induction and equilibrium

Higher solubility= slower induction and equilibrium

Question 3

CO affect on induction

Answer 3

Higher CO= lower amount of gas in alveoli=slower induction

*same with R to L shunt

Question 4

Things that increase the speed of induction

Answer 4

Low solubility
Low CO
High alveoli ventilation
High [ ] on inspired gas

Question 5

Elimination of gas

Answer 5

Exhalation and small bio transformation

Question 6

Blood Gas coefficient and MAC

Answer 6

N2O = 0.46, 104
Halothane = 2.5, 0.75
Isoflurane = 1.5, 1.2
Desflurane = 0.42, 6.6
Servo foursome = 0.65, 1.8

Question 7

Diffusion hypoxia

Answer 7

High [ ] of gas causes less space for O2 and CO2 which leads to hypoxia and hyper arnica and decreased respiratory drive

Question 8

Minimum Alveolar Concentration

Answer 8

Unit less value of potency
1 = ED50
1.3’= ED 95

Question 9

Factors decreasing MAC

Answer 9

Acidosis
Age
Anemia
Benzos
IV anesthetic a
Hypotension
Hypothermia
Opiates
Press

Question 10

Factors that increase Mac

Answer 10

Chronic alcohol
Toddler
Hyperthermia
MAOI, TCA, cocaine

Question 11

Systemic Effects of Inhaled

Answer 11

CV: decrease SVR which decreases MAP
Resp: increased RR and decreased TV (increased PaCO2), bronchodilators
Neuro: they all increase CBF which increases ICP, decreased responsiveness to hypoxia and hypercarbia
Hepatic: all decrease flow thru portal vein but halothane also constricts hepatic artery
Renal: all decrease flow, GFR, and UO
Muscle/Skin: vasodilate and increase flow

Question 12

MOA

Answer 12

Unknown/unsure

Likely has to do with decreasing glutamate (excitatory NT) by decreasing Na and Ca