MAC and awareness Flashcards
(23 cards)
Blood:Gas partition coefficient of halothane
2.5
Blood:Gas partition coefficient of enflurane
1.9
Blood:Gas partition coefficient of isoflurane
1.4
Blood:Gas partition coefficient of sevoflurane
0.65
Blood:Gas partition coefficient of N2O
0.47
Blood:Gas partition coefficient of Desflurane
0.45
Oil: Gas partition coeff of halothane
197
Oil: Gas partition coeff of enflurane
98.5
Oil: Gas partition coeff of isoflurane
90.8
Oil: Gas partition coeff of sevoflurane
50
Oil: Gas partition coeff of N2O
1.3
Oil: Gas partition coeff of Desflurane
19
MAC halothane
0.75%
MAC enflurane
1.7%
MAC isoflurane
1.2%
MAC sevoflurane
2.2%
MAC N2O
104%
MAC Desflurane
6.6%
When is MAC highest?
6 months
At what age does MAC decline 6% per decade?
40 years
Factors decreasing MAC
Medications:
- opiates
- benzos
- barbiturates
- Propofol
- ketamine
- alpha2 agonists
- chronic meth use
- verapamil
- IV administered local anesthetic agents
Alcohol- acute ethanol ingestion
Physiologic conditions
- hypothermia
- severe hypotension
- severe hypoxemia
- severe anemia
- acute metabolic acidosis
- sepsis
Pathophysiologic conditions
-Hypothermia, severe hypotension, severe hypoxemia, severe anemia, acute metabolic acidosis, sepsis
Genetic factors- none established
Factors increasing MAC
Genotypes related to red hair
Hyperthermia, hyperthyroidism, increased extracellular Na in CNS (hypernatremia)
First months of life for infants (<6mos of age)
chronic ethanol abuse
inhibition of catecholamine reuptake (amphetamines, ephedrine, L-dopa, TCA)
Risk factors for awareness under general anesthesia
pediatrics
when NMBA used
if chronically using alcohol, opiates, meth, cocaine
if high risk surgery where deep anesthesia is avoided
Usually happens during induction or emergence. Hearing voices is common. Early counseling is needed
