Inhaled Anesthetics Flashcards
Function of the Respiratory System
- Gas exchange
- Acid-base balance
- Phonation
- Pulmonary defense
- Metabolism
• Upper Airway Function
Humidification and filtration of inspired air.
Tracheobronchial tree function
conduct gas flow to and from the alveoli
alveoli generations present secondary to dichotomous division
23
How many alveoli are present for gas exchange?
300 million
Gas exchange begins at generations
17-19
Largest alveoli are found where?
Apex
Function of the THIN side of alvoli?
gas exchange
Function of the thick side of alveoli?
Structural support
Supplies circulation to the tracheobronchial tree to the level of the respiratory bronchioles
Bronchial circulation
bronchial circulation arrives from the aorta via which vessels
2 left arteries & 1 right artery
receives output from the right heart and pulmonary arteries
pulmonary circulation
takes part in perfusion tissues taking part in gas exchange
Pulmonary circulation
perfusion of tissues that TAKE PART in pulmonary exchange
Pulmonary circulation
passes through pulmonary capillaries, O2 is taken up, and CO2 eliminated
Deoxygenated
blood returned to the left side of the heart via the pulmonary veins is said to be
oxygenated
Combination of what elements decreased flammability?
Carbon together with fluorine
Halothane produced what negative side effects when introduced in the 1950’s?
Hepatitis and dysthymias
Halothane is a dysrhymogenic worsened by which drug?
Epinephrine
Halothane brand name
Fluothane
Enflurane brand namE
Ethrane
Isoflurane brand name
Forane
Desflurane brand name
Suprane
Sevoflurane brand name
Ultane
all agents are volatile anesthetics except
Nitrous oxide
Most beneficial features of IA
speed of onset, gaseous state, route of administration.
Features of IA contributing to rapid diffusion.
unionization & low molecular weight
How drugs affect the body
pharmacodynamics
how the body affects drugs
pharmacokinetics
Pharmacokinetic features unique to IA
uptake, redistribution, biotransformation, excretion
absorption equates to what for IA
uptake
metabolism equates to what for IA
biotransformation
distribution equates to what for IA
redistribution
elimination equates to what for IA
excretion
propels IA across barriers to action sites in the CNS
partial pressure gradients
tissue group first reach by blood/anesthetic
VRG
VRG includes which organs
brain, kidney, heart, liver
second tissue group reached by anesthetic/blood mixture
muscle, skin
last tissue group reached by anesthetic/blood mixture
fat, connective tissue
VRG AKA tissue of ____ effect
desired
muscle and skin AKA the tissue of ____ effect
undesired
fat and connective tissue is known as the site of ___.
accumulation
At what point does the saturation of fat tissue play a role in emergence?
> 4 hour anesthetic time
VRG % body mass
10%
Muscle % body mass
50%
fat % body mass
20%
VRG % cardiac output
75%
Muscle % cardiac output
19%
Fat % cardiac output
6%
VRG perfusion
55-500 (ml/min/100g)
muscle perfusion
3 (ml/min/100g)
fat perfusion
1 (ml/min/100g)
goal of anesthesia
establish specific concentrations of anesthetics in the CNS.
Partial pressure in the CNS equates to what other compartments?
blood and alveoli
Sevo Vapor pressure
157
Des vapor pressure
669
Iso vapor pressure
238
Enflurane vapor pressure
172
Halothane vapor pressure
243
Sevo B/G coefficient
0.65
Des BG coefficient
0.42
Iso BG coefficient
1.46
Enflurane BG coefficient
1.9
Halothane BG coefficient
2.5
Nitrous oxide BG coefficient
0.46
Nitrous oxide vapor pressure
38,770
Nitrous oxide vapor pressure
38,770
Sevo MAC
1.8%
Des MAC
6.6%
Iso MAC
1.17%
Enflurane MAC
1.63%
Halothane MAC
0.75%
Nitrous oxide MAC
104%
IA that are unstable in MOIST CO2 absorber?
Sevo & Halothane
vapor pressure
pressure exerted by a vapor in a closed container when at equilibrium with its liquid and gas phase.
vapor pressure increases as ____ increases.
temperature
boiling point
temp at which a liquid’s vapor exceeds atmospheric pressure in an open container.
1 atmosphere = _____ mmHg
760
Partial pressure
fractional amount of pressure a single gas exerts within a gas mixture.
Dalton’s law of partial pressures
the total gas pressure in a container is equal to the sum of the partial pressures exerted by each individual gas.
solubility
the tendency of a gas to equilibrate with a solution, determines concentration.
Gases are more soluble in liquid when temperature ____.
decreases
uptake looks at the concentration of
alvolar / inspired
Fi (fraction inspired) represents
concentration of anesthetic leaving the circuit
factors increasing Fi
increased FGF, increased Fd (delivered) from FGO, decrease volume of breathing system (dead space)
factors that decreasing Fi
decreased FGF, increased volume of breathing system (dead space), absorption by anesthesia machine parts, CO2 absorbent decomposition.