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23 Cards in this Set
- Front
- Back
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Note whether the following cause significant, some, or minimal CV effects:
enflurance, isoflurance, desflurance, nitrous oxide, halothane, sevoflurane Which can irritate the lungs and should be avoided in pulmonary dz? |
sig: halothane
minimal: nitrous oxide some: all others desflurane. |
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What is the key determinant of general anesthetic onset?
Thus, blood-solubility varies (directly/indirectly) with the induction rate of a given general anesthetic? |
Partial pressure in the CNS
indirectly. |
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Mechanical hyperventilation can _____ rate of anesthesia onset.
Depressed respiration by other drugs, e.g., opoids, can ____ onset. |
increase
slow |
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What type of relationship is there between pulmonary blood flow and general anesthesia induction rate? Why?
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inverse.
the more flow, the more blood is put into the "sink" for absorption. |
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If a general anesthetic diffuses into other tissues, that would ____ onset. It would correspondingly ____ recovery time.
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slow.
slow (it has to get back out of the tissue) |
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Which general anesthetic is unique in that it sensitizes myocardium to dysrhymias induced by catecholamines?
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halothane.
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How does halothane decrease CV function?
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Depressed force of myocardial contraction
Relaxed peripheral vascular smooth muscle Depressed baroreceptor reflex --> bradycardia NET RESULT: hypotension and decreased perfusion |
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What are the major and minor routes that eliminate general anesthetic?
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exhalation
- liver metabolism - kidney metabolism |
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Re: the elimination of general anesthetics from the body, what conditions make them more hepatotoxic?
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if hypoxia is present, the liver will convert these molecules into something that can cause damage.
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Which two general anesthetics generate fluoride ions in the liver?
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enflurane and sevoflurane
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Prolonged exposure to Nitrous oxide can cause what?
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megaloblastic anemia and peripheral neuropathies; both secondary to B12 deficiency.
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You start a pt on halothane. Pt becomes tachycardic, hypertensive, shows severe muscle regidity, hyperthermia, hyperkalemia, & acid base imbalance.
What's happening? What should you do? |
malignant hyperthermia, an acute emergency condition caused by an abnormal, sustained increase in free calcium in skeletal muscle.
Tx with dantrolene to block muscle calcium release, restore electrolyte balance, and reduce body temperature. |
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MAC is ____ proportional with general anesthetic potency.
Are MACs additive when tx'ing with more than one agent? What is 1.0 MAC defined as? |
inversely.
yes. 0.5 MAC N2O + 0.5 MAC isoflurane = same effect as 1.0 MAC isoflurane Conc’n of agent @ 1 atm. of inhaled gas mix preventing response to skin incision in 50% of patients |
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Are dose response curves flat or steep with inhaled anesthetics?
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steep... "big MAC attack" --> Cardiac arrest.
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Thiopental, methohexital, and thiamylal are all what? Characteristics?
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barbiturates
- ultra-short acting (unconsciousness in ~30sec) |
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Why would you use propofol? Is it a barbiturate?
When and why should you be concerned when using propofol? |
recovery rate even faster than barbiturates, thus used in same-day discharge cases.
no. in those with limited CV function - it causes a marked drop in BP. |
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What is an alternative to Propofol use in those with CV dz?
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Etomidate, unconsciousness in 3-5min. Only causes minimal BP drop.
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What are benzodiazepines? What type of amnesia do they cause?
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water soluble versions of these like midazolam (diazepam, lorazepam) are used in short dental/medical procedures.
anterograde amnesia. |
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How do barbiturates and benzodiazepines work?
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potentiate GABA on the GABA(a) Cl- ion channel.
--> hyperpolarization |
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What is ketamine and what does it do?
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NMDA receptor blockade that produces dissociative anesthesia. (sedation, analgesia, amnesia, disconnection from surroundings)
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Which injectable anesthetic can be of use in hypovolemic shock?
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ketamine, because an induction does can increase BP & CO.
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morphine, meperidine, fentanyl, remifentanil, etc. are all what?
What are alfentanil and remifentanil? |
opoids. They are excellent analgesics.
short-acting gentanyl analogs used in short surgical procedures. |
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How do inhaled general anesthetics exert their effects?
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hyperpolarization through activating Ligand GABA gated Cl- channels.
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