Eger Video #2 Flashcards
2 modern inhaled anesthetics which differ only because they have a flurane substitued for another halogen which is chlorine
Isoflurane and Desflurane
Formula for isoflurane
formula for desflurane
The flurane substitution on desflurane does what to desflurane? (6)
What is the boiling point of Desflurane?
increases vapor pressure
decreases boiling point
less biodegradable, more stable
less toxic
solubility decreases
potency decreases (MAC increases)
boiling point of des is 22.5 C
In a closed circuit anesthesia system, the temperature in the absorbant is?
40-60 C
It is hotter than the OR room due to the exothermic reactions between the absorbant and the carbon dioxide, creating heat
What is more stable in soda lime, des or iso?
desflurane has greater stability than isoflurane –> high absorbant temperatures caused isoflurance to break down more easily than desflurane
degradation of soda lime is caused by what component of the soda lime?
Monovalent bases:
NaOH and KOH
What are the degradation products from the modern inhaled anesthetics (iso/des/sevo)?
carbon monoxide (mainly from des, iso and enflurane)
Comound A from Sevo is NOT TRUE
how much moisture is in soda lime and baralyme?
15% water
important because it can accelerate the reaction with CO2 and protects against the degradation of the inhaled anesthetics
T/F: With moist absorbant, desflurane and isoflurane have no production of CO
true
CO is produced only if the absorbant is dry by > 90%.
Drying of the absorbant is caused by leaving the flow rate on along with removal of the reservoir bag, leads to production of CO.
Issue with compound A?
attack on kidneys
what is compound A?
vinyl ether
highly reactive compound that reactes with proteins in the body.
Disappears in the blood because it binds to the proteins in the blood
what is the evidence of renal injury from compound A?
Albuminuria, enzymuria, glucosuria
Necrosis haven’t been tested in humans but necrosis is evident in rats.
How to prevent drying of the absorbant?
keep low flow rates
How to tell if absorbant is dry?
condensation, which is misleading (carbon dioxide in absorbant produces water)
how to manage dry absorbants
add water or replace it
Which anesthetic can spontaneously degrade? and under what circumstance?
sevoflurane.
2 circumstances: The aluminum of the bottle and the dry condition predisposes sevo to degradation
Now no longer an issue due to adding water to the bottle and producing a plastic liner for the bottle.
Can inhaled anesthetics hurt the environment?
yes, due to the breakdown products such as chlorine.
isoflurance has chlorine
sevo and des don’t have chlorine
Occupational exposures that are concerning in anesthesia
Nitrous oxide can lead to abortions, but that’s negligable due to the low amounts in the OR.
Amounts are low in the OR due to the scavenger system and high room air turn overs.
What are the limits in inhaled anesthetics
2 parts per million for potent inhaled agents
25 parts per million for nitrous oxide
Nitrous Oxide and occupational exposure
Involves the inactivation of thiamine synthase, B12
prolonged use can lead to aplastic anemia and death
however we breath low concentrations in the OR and nitrous oxide isn’t given that long in patients to lead to these risks
What group of people are at high risk for injuries from the use of nitrous oxide?
B 12 deficiency, pernicious anemia
