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 = ____%
6.00%
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
What does the term “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 hepatic blood flow .
Less commonly, massive hepatic necrosis/death is seen (Halothane Hepatitis). 20% of halothane (sevo is only 5%) is metabolzed in the liver to TFA (trifluoroacetic acid) and the increased fluoride levels are associated with hepatotoxicity
What does the term “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% of halothane (sevo is only 5%) is metabolzed in the liver to TFA (trifluoroacetic acid) and the increased fluoride levels are associated with hepatotoxicity
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 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
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 the 1st trimester of pregnancy?
It is a teratogen that can cause birth defects, especially in the first trimester.
T or F. A person who has had multiple surgeries in the past with no malignant hypethermia related complications has no risk of an MH reaction with anesthesia.
False. MH related deaths have occurred even though patients have undergone multiple prior uneventful surgeries.
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 increaseAlso be aware of procedures that increase chances of N2O affecting pressures in the ear, eyes, and cranium
What is the Gold Standard for a definitive diagnosis of MH?
Caffeine-halothane contracture test - requires muscle biopsy at a specialized biopsy center
What anesthetic agents can trigger MH?
All volatile anesthetic agents & Sux
remember..N2O is NOT a volatile gas
T or F. Genetic testing can definitively rule out MH, so if someone in your family has MH you should get tested.
False. Genetic testing cannot definitively rule out MH due to heterogeneity of mutations
What is used to treat MH and what is the dose?
Dantrolene 2.5mg/kg IV
This is after you stop the triggering agent!
Also want to have high O2 flows, active cooling, and treat acidosis and electrolyte imbalance
T or F. MH presents as sustained muscle contractions, including masseter muscle rigidity, that is not relieved with additional Sux or non-depolarizing NMBs.
True. There is an abnormal release of Ca within the skeletal muscles
T or F. If a patient has masseter muscle and peripheral muscle rigidity, you should assume it is MH and begin treatment.
True
T or F. Mild/transient masseter muscle rigidity is a normal response following administration of sux.
True
Describe the hypermetabolic state associated with MH.
Uncontrolled calcium release from the sarcoplasmic reticulum -> sustained myofibril contraction -> cells run out of ATP -> cell death
Inc EtCO2 despite hyperventilation
Heat production - temp will rise 1-2 degress q5min
Tachycardia, hypoxemia, acidosis, cardiac dysrythmias
*this is from a lecture from another class but I thought it was helpful in understanding why MH causes death
T or F. MH should be suspected if you have elevated EtCo2 despite hyperventilation?
True
T or F. The primary reason the use of sux is avoided in children is because of potential for undiagnosed MH.
False. It is because of the risk of undiagnosed muscular dystrophy (not true MH)
T or F. Neuroleptic Malignant Syndrome is triggered by sux and inhalational anestheic agents.
False. It is related to the administration of antipsychotic drugs
What is rhabdomyolysis?
condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure.
T or F. There is a strong correlation between patients who have experienced heat stroke and susceptibility for MH.
False. There is a small association between the two.
