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35 Cards in this Set
- Front
- Back
What are the functions of anesthesia?
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ANALGESIA
UNCONSCIOUSNESS AMNESIA MUSCLE RELAXATION REDUCTION OF REFLEX ACTIVITY IMMOBILITY |
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What are the True Gases
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Xenon
Nitrous Oxide |
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What are the volatile anethetics most commonly used today?
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Desflurane, Isofluran, Sevoflurane
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What was one of the major drawbacks of cyclopropane?
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Explosions
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What does potency correlate with r/t volatile anesthetics?
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Solubility in lipids
Oil Gas Partition Coefficient. |
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Substituting fluorine for chlorine does what?
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Increases Vapor Pressure
Isoflurane VP =240 mmHg Desflurane VP =669 mmHg Decreases Lipid Solubility/ Potency Isoflurane O:G= 99 Desflurane B:G= 18.7 Decreases Blood Solubility/ (Shorter onset and duration) Isoflurane B:G = 1.4 Desflurane B:G = 0.42 |
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What is the order of volatile anesthetics from most potent to least potent?
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Halothane (O:G 234) Most potent
Isofluorane (O:G 91) Sevoflurane (O:G 53) Desflurane (O:G 19) Least Potent |
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What happens to a volatile anesthetic when a halogen with a lower AMU is replaced with a halogen of a heavier amu?
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Vapor Pressure Decreases
Blood: Gas Solubility Increases (Onset and duration time get longer) Potency and lipid solubility increase. Potency is determined by: 1) what halogens are on the agent (heavier halogens are more potent) 2) Lipid solubility of the agent. Relative Potencies Halothane (Br/CL/F) > Isoflurane (F/Cl) > Desflurane (F) |
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What does oil/gas solubility indicate about a volative anethetic?
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It's potency.
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How does MAC of a volatile anesthetic relate to its solubility?
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The less lipid soluble the agent, the lower the potency, and the higher the MAC of that agent.
Agent MAC Oil/Gas Des 6-8% 19 - LEAST Sevo 2.4% 50 Iso 1.2% 91 Halo 0.75% 224 - MOST N2O 104 1.4 |
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What does increasing the number of halogen particles do in terms of arrhythmogenicity of that particular volatile anesthetic?
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It increases them.
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What is an alkane?
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An alkane is molecule compose only of carbon (C) and hydrogen (H) with no double or triple bonds. It is also saturated molecule because the C atom was fullly bonded with H atom.
There a many many different alkanes, however, the general formula for an alkane is always this: CnH2n+2 where "n" is an integer greater than or equal to 1. |
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Which is an ether? halothane or isofluorane
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Isofluorane
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Do ether molecules have more or less arrhythmogenic properties than other halogetated volatiles?
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Less because the Oxygen atom in their structure attenuate the arrythmogenic properties.
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What is the objective of GA? What is it that must happen to meet the expectations of GA?
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Achieve & maintain a constant and optimal brain partial pressure of the inhaled anesthetic
PA <=> Pa <=> Pcns The three will equilibriate over time. (6-10 min. ) Increase teh partieal pressure in the brain by increasing the partial pressure in the alveoli. |
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How is Desflurane metabolized?
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0.02% by oxidation (Phase I) of biotransformation.
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How is Isoflurane metabolized?
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0.2% by oxidation
Phase I of biotransformation Requires oxygen. |
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How is Sevoflurane metabolized?
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5-8% by oxidation (Phase 1 of biotransformation)
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How does the anesthesia machine impact uptake and distribution?
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There is some minimal degree of uptake by the rubber and plastic parts of the breathing circuit.
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What are the inhalation doses for N20?
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Induction: 50-70%
Maint.: 50-70% |
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What are the inhalation doses for Isoflurane?
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Induction:1-4%
Maint: 0.5-2% |
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What are the inhalation doses for Desflurane?
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Induction: 3-9%
Maint: 2-6% |
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What are the inhalation doses for Sevoflurane?
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Induction: 4-8%
Maint: 1-4% |
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What is the second gas effect?
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A phenomenon in which 2 anesthetics of varying onset speeds are adminstered together. A high concentration of a fast anesthetic such as N20 is adminsitered with a slower second gas anethetic. The slower gas achieves anesthetic levels more quickly than if it had been given alone.
(can help in cost savings with expensive volatile anesthetics) |
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How is Halothane metabolized?
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12-15% by oxidation & reduction
Phase 1 of biotransformation |
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How much of Nitrous oxide is metabolized?
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Only trace amounts.
(Pure gas) |
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What does blood solubility of an agent have to do with speed of onset?
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The more blood-soluble the agent (high blood-gas partition coefficient), the slower the onset of effect and the slower the patient goes to sleep. Thus a very soluble agent eg. ether will dissolve in large quantities in blood before the brain levels can rise sufficiently to produce anaesthesia.
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What is the blood/gas solubility coefficient?
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An indicator of an anesthetic's speed of onset and emergence. The higher the blood/gas solubility coefficient, the slower the anesthetic. The lower the blood/gas solubility coefficient, the faster the anesthetic.
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What happens when you substitute halogens for H+ ions in volatile anesthetics?
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Flammability is reduced and chemical stability is enhanced (Nagelhout p 100)
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In general, what does increasing the number of fluorine atoms to an anesthetic molecule do?
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Retards biodegradation.
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Desflurane is metabolized ____ as much as isoflurane.
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one tenth
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What trait of adipose tissue prevents over-sequestering of anesthetic agent during short or medium length procedures?
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It's relatively poor blood supply.
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Look at the Table 8-1 on page 94 in Nagelhout!
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Look at it!!!!!!!
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How do anesthetics move in the body?
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Down a concentration gradient.
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What is the oil/gas solubility coefficient?
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A measure of an anesthetic's potency. The higher the oil/gas solubility coefficient...the more potent the agent.
The higher the Oil : Gas solubility the more soluble the agent in lipids and the faster the uptake by the brain Increase O:G, increase potency, decrease MAC. Decrease O:G decrease potency, decrease MAC. |