Lecture # 05_Fall Flashcards
Indicate whether the following is a factor that increases or decreases MAC:
use of premedication
decrease
Indicate whether the following is a factor that increases or decreases MAC:
younger age
increase
Indicate whether the following is a factor that increases or decreases MAC:
older age
decrease
Indicate whether the following is a factor that increases or decreases MAC:
anxiety
increase
Indicate whether the following is a factor that increases or decreases MAC:
Chronic EtOH
increase
Indicate whether the following is a factor that increases or decreases MAC:
Acute EtOH
decrease
Indicate whether the following is a factor that increases or decreases MAC:
hyperthermia
increase
Indicate whether the following is a factor that increases or decreases MAC:
pregnancy
decrease
Indicate whether the following is a factor that increases or decreases MAC:
hypothermia
decrease
Indicate whether the following is a factor that increases or decreases MAC:
acute use of cocaine or other sympathetic stimulant
increase
What does MAC stand for and what is the definition?
Minimal Alveolar Concentration - alveolar concentration of anesthetic gas that prevents movement in 50% of patients in response to surgical stimulus
What is MAC awake?
0.1 x MAC
What is MAC recall?
0.3-0.5 x MAC
What is MAC BAR and what does the BAR stand for?
1.7-2.0 x MAC
Blocked Autonomic Response
MAC of Iso = ____%
1.2% (1.2 kind of looks like Is for Iso)
MAC of Sevo = ____%
2.0 % (2 kind of looks like the S of Sevo)
MAC of Des = ____%
6.0%
MAC of N2O = ____%
105%
MAC of Halothane = ____%
0.75%
The vapor pressure of halothane is closest to the vapor pressure of which other inhalational anesthetic?
Isoflurane 240mmHg compared to halothane at 243mmHg
What is the blood gas partition coefficient for Sevoflurane?
0.65
What is the blood gas partition coefficient for N2O?
0.47
What is the blood gas partition coefficient for Isoflurane?
1.4
What is the blood gas partition coefficient for Desflurane?
0.42
What is the blood gas partition coefficient for Halothane?
2.4
Is induction with halothane fast or slow? Why?
Slow. Because it is so soluble, it has greater uptake and it takes longer for for the CNS to become saturated since it takes longer to reach EQ (Palveoli=Pblood=Pcns).
(from lecture #4)
What does a blood gas partition coefficient of 2.4 for halothane mean?
that there is 2.4 times as much halothane dissolved in the blood than in the air.
blood can dissolve halothane 2.4 x better than air
(from lecture #4)
Which inhalational anesthetic does not trigger MH?
N20
Which inhalational anesthetic is used for inhalational induction for pediatrics? Why?
Sevoflurane b/c it is non-pungent, so it is not irritating to the airway, and it has bronchdilator properties
What does the tem “Halothane Hepatitis” mean?
Halothane is commonly associated with liver toxicity (hepatotoxicity). 1 in 5 adults develop mild hepatotoxicity. This is likely because it causes decreased renal blood flow .
Less commonly, massive hepatic necrosis/death is seen (Halothane Hepatitis).
20% (sevo is only 5%) of halothane is metabolzed in the liver to TFA (trifluoroacetic acid) and the increased fluoride levels are associated with hepatotoxicity
Which 2 inhlational anesthetic gases are non-pungent bronchodilators?
Sevo and Halothane
Halothane has better bronchodilator properties
Which inhlational anesthetic is sensitive to catecholamines?
Halothane
Why do you care about this? In another lecture you will have to remember that Epi when used with Halothane can cause ventricular dysrhythmias - so remember this!
Compound A is associated with which inhlational anesthetic? What is required to prevent formation of this?
Sevoflurane
Keeping your fresh gas flows at least 2L/min/MAC helps to prevent formation of compound A (but no data to support this??)
Just remember - S of sevo looks like a 2 - MAC is 2.0 and you need 2L FGF
Which 2 inhlational anesthetics are good bronchodilators but are irritating the the airway (pungent) and lead to salivation, coughing, breath holding and worst of all - laryngospasm?
Desflurane and Isoflurane
T or F? N2O is contraindicated in a young female patient complains of severe PONV.
True.
Tor F. All inhlational anesthetics cause muscle relaxation?
False. N2O does not (it also does not trigger MH)
Which inhlational anesthetic oxidizes the Co atom in B12?
N20
Which inhlational anesthetic causes significant myocardial depression leading to up to a 50% decrease in BP and CO?
halothane
Which inhlational anesthetic inhibits methionine synthetase?How does it cause this and why does this matter?
N20. It matters because it effects the formation of the myelin sheath that protects neurons - this causes peripheral neuropathies and neurotoxicity.
It causes this b/c it oxidizes the Co atom in B12 which inactivates methionine synthetase .
You should probably remember this - esp the B12 part
Which inhalational anesthetic is associated with toxicity secondary to a desiccated CO2 absorbent leading to the increased production of carbon monoxide?
desflurane
T or F. N2O is flammable and supports combustion.
False. It does support combustion like O2 but it is not flammable
Which inhalational anesthetic increase HR?
Des and Iso
What is significant about Desfluranes vapor pressure?
the vapor pressure is very high (681 mmHg) and can actually boil at normal OR temps.
Because it vaporizes so easily, it makes it hard to control how much we deliver - this is why they use a heated vaporizer - it allows to control the concentration of the gas we deliver to the patient
(remember..High VP = high volatility = low BP)
T or F. Sevo provides enough muscle relaxation for intubating kids?
True
Which inhalational anesthetics have a sweet non-pungent odor?
Halothane and Nitrous
Why is N2O contraindicated in patients with a small bowl obstruction, PTX, or acute venous air embolism?
Nitrous is 35x more soluble in blood than nitrogen is and it diffuses out of blood into closed air spaces faster than air diffuses into blood - when a pt’s inspired gas mixture is switched from air (containing about 78% nitrogen) to an anesthetic mixture containing 70% N2O, the N2O will enter gas filled spaces 35x faster than nitrogen can exit - as a result, the volume and pressure within the space will increase
Also be aware of procedures that increase chances of N2O affecting pressures in the ear, eyes, and cranium
Why is N2O contraindicated in the 1st trimester of pregnancy?
It is a teratogen that can ause birth defects, especially in the first trimester.
