Prodigy Films F to O Flashcards
What are FA & FI?
FA - fractional concentration of anesthetic in the ALVEOLI
FI - - - - - - INSPIRED GAS
explain FA FI importance
faster FA/FI = 1 faster induction will occur
how to increase FA/FI
increase minute ventilation Decrease FRC & CO Increase FGF > 4 L/min Decrease circuit volume, Decrease agent solubility (helps circuit absorbs less too)
what is most important factor in the rate of rise in the FA/FI
uptake
how does uptake affect FA/FI? how about CO?
decreases FA, so it slows the rate of rise of FA/FI
increased CO increases uptake and decreases FA even more
What factors increase MAC? (need more Gas)
Young age Chronic alcohol abuse CNS stimulants Hyperthermia Hyperthyroidism Hypernatremia Red hair female
What factors decrease MAC?
increased age (6% per decade) Pregnancy Metabolic acidosis lithium acute alcohol ingestion anemia Lidocaine, Opioids, Ketamine, Benzo, Alpha 2 agonists, hypothermia, Hypoxia, Hyponatremia, Hypoosmolarity
What is MAC?
necessary to prevent skeletal muscle movement 50% pt’s to noxious stimuli
Name factors that don’t affect MAC
Duration of anesthetic Gender Hypo/Hypercapnia K imbalances Metabolic alkalosis HTN
what factors affect fetal transfer of drugs
Molecular weight < 500 Daltons (BB, NTG, Nitro)
lipid solubility (fent/ Ketamine)
ionization
concentration gradient
what drugs do not cross placenta
Heparin ,Insulin, Protamine (all large Daltons > 1000)
Glyco / SUX ( water soluble drugs do not)
What drugs do cross placenta
beta blockers
NTG
Nitroprusside
Fentanyl / Ketamine (lipid soluble)
what is Fick’s Law of DIssusion?
What factors affect it (4)?
- rate of diffusion across membrane,
- takes into account
1 molecular weight (inversely proportional),
2 solubility
3 concentration gradient (directly proportional),
4 membrane thickness
(helps explain diffusion hypoxia)
what is first pass metabolism
orally administered drugs are metabolized by the liver prior to entering circulation
flow volume loops
what does point in top left corner represent?
middle right ?
lower left corner?
top left = peak expiraotry flow rate
right most point = residual volume
lower left corner = TLC
flow volume loop X & Y axis?
X = volume 8 to 1 L Y = flow 0 to 7.5 up and 0 to 7.5 down