Oral: IAs Flashcards
Class: ISOFLURANE
Halogenated methyl ethyl ether
Isomer of EN
MOA: ALL IAs
Controversial;
most popular theory is the Meyer Overton theory, which targets proteins (channels/receptors) as the site of action for IA, but has been disproven;
unknown MOA
Alveoli = windows to the brain
ADD to N2O: (in addition to the general MOA for this class) Used for 2nd gas effect with other IAs to ⬆ uptake and ⬇ MAC of other gas.
Pungent: ISOFLURANE and DESFLURANE
Pungent, causes cough/laryngospasm
PK: ISOFLURANE
Pungent, causes cough/laryngospasm Vd L/kg: BG = 1.4, VP = 240 Onset: 2.1 min to VRG Met: < 0.2% hepatic metab Elim: exhalation
good for liver, kidney, CV dz
Minimal cardiac depression + dilates coronary vessels
Elimination: ALL
exhalation
SE: ISOFLURANE and DESFLURANE and SEVOFLURANE
- MH
- potentiates NMBs
- inc CBF, ICP, dec CMRO2
- bronchodilation
- inc RR, dec TV = dec MV
SE: ISOFLURANE
- MH
- potentiates NMBs
- inc CBF, ICP, dec CMRO2
- bronchodilation
- inc RR, dec TV = dec MV
- a/w irritation – cough, buck, laryngospasm
- inc CSF reabsorption
- coronary steal by dec cor art BF
- dec BP and SVR, inc HR – no change in CO
- dec RBF, GFR, UOP
- HBF maintained
CI: ISOFLURANE and DESFLURANE
- peds – d/t smell/cough
2. MH hx
MAC: ISOFLURANE
1.2
Class: DESFLURANE
Fluorinated methyl ethyl ether
PK: DESFLURANE
Pungent, causes cough/laryngospasm Vd L/kg: BG = 0.42, VP = 660 Onset: Fast on/off Met: < 0.1% hepatic metab Elim: exhalation
Ideal for same day surgery
Used for maintenance – NOT induction d/t a/w irritation
SE: DESFLURANE
- MH
- potentiates NMBs
- inc CBF, ICP, dec CMRO2
- bronchodilation
- inc RR, dec TV = dec MV
- a/w irritation – cough, buck, laryngospasm
- CO RISK WITH LOW FLOWS
- dec BP and SVR, inc HR – no change in CO
- dec RBF, GFR, UOP
- “dec HBF”
MAC: DESFLURANE
6
Class: SEVOFLURANE
Fluorinated methyl isopropyl ether
PK: SEVOFLURANE
Sweet smell - No a/w irritation
Vd L/kg: BG = 0.69, VP = 157
Met: 2- 3 % hepatic metab, Compound A
Elim: exhalation
Good for liver, kidney, CV dz
SE: SEVOFLURANE
- MH
- potentiates NMBs
- inc CBF, ICP, dec CMRO2
- bronchodilation
- inc RR, dec TV = dec MV
- compound A – renal tox w/ low flows
- inc HR and dec SVR, BP, “CO”
- dec RBF, GFR, UOP
- HBF maintained
CI: SEVOFLURANE
- severe renal dz
2. MH hx
MAC: SEVOFLURANE
2
CI: ALL but NITROUS OXIDE
MH hx
Class: NITROUS OXIDE
Inorganic gas
PK: NITROUS OXIDE
Vd L/kg: BG = 0.47, VP = 38,770 Onset: Fast on/off d/t low BG – can achieve alveolar/arterial equilibrium quickly 34x more soluble than N2 Met: < 0.01% hepatic metab Elim: exhalation
has analgesia properties
SE: NITROUS OXIDE
- potentiates NMBs
- inc CBF, ICP, CMRO2
- inc PVR, bronchoconstriction
- PONV
- inhibits B12
- diffusional anoxia
- dec RR, TV
- dec RBF, GFR, UOP, HBF
- myocardial depressant
CI: NITROUS OXIDE
- PTX, air embo, pneumocephalus d/t expansion of gas
- lap surgery with CO2 insufflation
- pregnancy
- Pulm HTN
- intestinal obstruction
- Eye or tympanic surgery
min risk of MH
MAC: NITROUS OXIDE
105
2nd gas effect of other IAs – N2O 70% and inc conc/uptake of other gases
