E3 Flashcards
Boyles Law
Pressure and volume are inversely proportional
Ficks diffusion law
Diffusion depends on: Partial pressure gas gradient Solubility of gas Membrane thickness Size of molecule
How does molecule size, membrane thickness, gas solubility, and pressure gradient affect gas effusion.
Molecule size
Big= slow
Small = fast
Solubility
High=
Low=
Pressure gradient
High=fast
Low=slow
Membrane thickness
Thick=Slow
Thin=Fast
What is a blood:gas partition coefficient?
What is it dependent on?
Equilibration ratio of pressure of volatile between gas in alveoli and blood
Dependent on:
CO
A-V pressure gradient
What is a blood:brain partition coefficent? What is it dependent on?
Equilibration ratio of pressure of gases between blood and brain.
Dependent on:
CBF
a-v pressure gradient
Influence of age on PK/metabolism of volatile.
<30 yo = INC met by 6% per decade
> 55 yo = DEC by 6% per decade
4 factors that alter volatile PK/metabolism
Age
DEC Lean body mass
INC fat
DEC hepatic fxn
What is the goal of volatile anesthetic
PA = Pa = PBr
End tidal PA = PBr
What does alveolar pressure indicate?
Depth of anesthesia
Recovery of anesthesia
Potency
What occurs to PA & PBr during anesthesia recovery
PA starts to INC
PBr DEC
What is concentration effect?
- Impact of INSPIRED pressure (Pi) on rate of rise of PA
- Higher the Pi FASTER PA = Pi b/c HIGH delta-P
How does Pi r/t end tidal?
Picking up gas:
Pi > end tidal
Balance:
Pi = end tidal
How does Pi affect uptake & PA?
Low Pi = longer uptake and equilibration w/ PA
Higher Pi = more rapid uptake and equilibration w/ PA
8) What are some disadvantages of methoxyflurane
Disadvantage = dose related nephrotoxicity d/t fluroide
9) What are some advantages and disadvantages of enflurane?
Advantage= doesn’t sensitize myocardium to catechols
Not associated w/ hepatotoxicity
Disadvantage = Metabolism could lead to Sz in high concentration
10) What are some advantages and disadvantages of isoflurane?
Advantages= lack of cardiac dysrhythmias
lack of organ toxicity
rapid induction and emergence
Disadvantages = longer than sevo and des
11) What are some advantages and disadvantages of sevoflurane and desflurane?
Advantages = wholly fluorinated, low blood solubility
rapid induction
12) What characterizes the anesthetic state?
Characteristics of the anesthetic state include immobility, amnesia, analgesia and skeletal muscle relaxation
13) Which characteristics of the anesthetic state are achieved by the administration of inhaled volatile anesthetics?
Immobility
amnesia
skeletal muscle relaxation
14) Which characteristics of the anesthetic state are achieved by the administration of nitrous oxide?
Immobility, but not as sole anesthetic
Amnestic effects
No skeletal muscle relaxation
15) What is the mechanism of action of inhaled anesthetics in the central nervous system?
CNS depression by enhancing inhibitory ion channels and block excitatory ion channels
Affect release of NTs
16) Why are vaporizers required for the inhaled administration of volatile anesthetics?
How does this apply to N2O
Volatiles are liquid @ room temp and P_atm
They accurately deliver specified concentration of anesthetic
N2O is a gas at room temp so it doesn’t require vaporizer for delivery
4 purposes of anesthesia circuit
Deliver O2
Deliver inhaled drugs
Maintains temp and humidity
Removes CO2 and exhaled gases
3 Types of gas delivery systems
Rebreathing (Bain)
Non-rebreathing (self-inflating BVM)
Circle system
Set-up of Bain system, what it has and doesn’t have and its use?
Set-up Has APL valve, circuit tubing No scavenger, CO2 absorver or HME Use Rebreathing circuit for transport
7 Component parts of circle system
Fresh gas inlet inspiratory and expiratory limbs resevoir bag CO2 absorbent one-way valves (insp/exp) Y piece Scavenger system
