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47 Cards in this Set
- Front
- Back
What are the 4 specific inhaled anesthetics to know?
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I don't say no
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What is I Don't Say No?
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-Isoflurane
-Desflurane -Sevoflurane -Nitrous oxide |
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How do the BGPC's of the inhaleds rank?
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Isoflurane = highest 1.5
Desflurane = lower .42 Sevoflurane = lower (like des) Nitrous oxd = lower .47 |
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So what will be the rates of induction and recovery from isoflurane?
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Moderate
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How is Isoflurane excreted?
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Unchanged - 99% from the lungs
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What are the clinical uses of Isoflurane?
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-Induction
-Maintainance (mostly this) |
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Why is Nitrous oxide often co-administered with Isoflurane?
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It reduces the dose of isoflurane needed
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Why would you want to reduce the dose of isoflurane needed?
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To reduce adverse side effects of isoflurane
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What are the 2 main types of side effects of isoflurane?
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-CV
-Respiratory |
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What 3 respiratory side effects are unique to Isoflurane?
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-Airway irritant - coughing
-Decreases TV -Increases RR |
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What is a respiratory side effect that is common to all volatile anesthetics and what does it lead to?
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Respiratory depression - leads to increased arterial PCO2
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What are 3 cardiovascular side effects of isoflurane?
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-Myocardial depression leading to hypotension
-Arrythmias -Cerebrodilation leading to increased ICP |
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How does Isoflurane cause arrythmias?
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It sensitizes the heart to catecholamines
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So what drugs should NOT be given to patients under Isoflurane anesthesia?
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Dopamine or Dobutamide
or Levodopa! |
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What is the blood:gas PC of Desflurane?
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LOW - .42
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So what sort of rate of induction and recovery is seen with Desflurane?
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Very rapid!
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What is needed for Desflurane administration and why?
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Special equipment to keep it in the liquid form - bc it is very volatile at room temp
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How is desflurane excreted?
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Predominantly unchanged at the lungs
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What does the very rapid rate of induction and recovery seen with Desflurane make it useful for?
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Outpatient surgeries!
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What steps in anesthesia therapy is Desflurane mainly used for and why?
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Maintainence - it causes coughing and bronchospasms in awake patients if used for induction.
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What other effect of Desflurane is of clinical use?
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It causes skeletal muscle relaxation
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How do the side effects of Desflurane compare to Isoflurane?
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-Similar CV effects (lowers BP)
-Worse respiratory irritant |
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What inhaled anesthetic is used most often in hospitals?
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Sevoflurane
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What sort of blood:gas PC does Sevoflurane have?
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Very low
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What is the main pharmacokinetic difference of Sevoflurane compared to Iso/Desflurane?
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~5% of administered doses of it are metabolized to fluoride ion in the liver
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Why is it unfortunate that 5% of Sevoflurane is metabolized to F- by the liver?
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Because it may cause renal damage
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What is the good thing about Sevoflurane compared to Iso and Desflurane?
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It causes less Respiratory depression and NO airway irritation
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How does the CV depression and lowering of BP compare between all 3 - iso/des/sevoflurane?
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All 3 are similar
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What are the clinical uses of Sevoflurane?
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-Induction
-Maintenance In both children and adults |
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Which inhaled anesthetic is a true gas?
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Nitrous oxide
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How does the fact that Nitrous Oxide is a true gas affect its pharmacokinetics?
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It is very insoluble in blood and other tissues so it equilibrates very rapidly
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So what kind of rate of induction and recovery is seen with NO2?
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Very rapid
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Why is nitrous oxide often coadministered with other inhaled anesthetics?
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When given in large volumes it increases the volume of uptake of a 2nd blood-soluble anesthetic.
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So what does coadministration of NO2 and other gas anesthetics allow for?
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Lower doses of the more irritating but stronger anesthetics, but with the same results as for higher doses by themselves.
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And how does Nitrous oxide cause concentration of other gases that are coadministered with it?
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By its rapid uptake from the alveolae
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What is an adverse effect of Nitrous oxide when it is discontinued?
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It causes DILUTION of oxygen
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So what do you have to do for patients when NO2 is discontinued?
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Put them on 100% o2
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How is Nitrous oxide excreted?
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99% thru the lungs
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How clinically useful is Nitrous oxide as an anesthetic?
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Weak
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What is required for full efficacy of NO2 as an anesthetic?
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Hyperbaric conditions
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What is the highest concentration of NO2 that can be given and why?
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80% due to oxygen requirements - you need at least 20% O2 to stay alive
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So what are the 2 main clinical uses of Nitrous oxide?
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-Sedation/analgesia in outpatient dentistry
-Adjunct to other inhalational anesthetics to reduce their dose |
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What is the conc of NO2 given as
-Sedative/analgesic in dentistry -Adjunct to other inhaled anesthetics |
Dentistry - 50%
Adjunct - 70% |
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What is the main side effect and contraindication for giving nitrous oxide?
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It can replace Nitrogen in an air-containing cavity; so contraindicated in pneumothorax
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What cardiac effects does Nitrous oxide have?
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-Negative inotrope
-Sympathomimetic - increases contractility/vasoconstricts |
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What are the respiratory effects of Nitrous oxide?
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Minimal except for O2 dilution during emergence
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What special care needs to be taken with Nitrous oxide?
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Avoid abuse - it carries an abuse liability
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