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Flashcards in Anesthesia Deck (17)
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1
Q

Halothane

A
  • Halogenated hydrocarbon inhalation
  • CNS effect: increase intracranial pressure
  • CV effects: Decreased myocardial contractility and stroke volume leading to lower arterial blood pressure; Sensitizes myocardium to catecholamines ↑ automaticity. Epi may trigger arrhythmia.
  • Malignant hyperthermia may occur with ALL inhalation anesthetics except nitrous oxide, most commonly seen with halothane.
  • Advantage: potent and cheap, no laryngospasm
2
Q

Isoflurane

A
  • Halogenated hydrocarbon inhalation
  • Advantage: potent, <10 min induction, less hepatotoxic and renal toxic than halothane
  • Disadvantage: smells bad, arrhythmias
3
Q

Desflurane

A

-Halogenated hydrocarbon inhalation

4
Q

Sevoflurane (7 fluorines)

A
  • Halogenated hydrocarbon inhalation (newer one)
  • High potency
  • Fast onset of action (low blood solubility) and rapid recovery
  • No metabolism
  • Almost perfect inhalation anesthetic
5
Q

Nitrous oxide

A
  • Low blood solubility (rapid onset)..2nd gas effect

- Disadvantage: MAC 104%, no muscle relaxing effect, diffusion hypoxia if rapidly discontinued

6
Q

Pentobarbital

A

-Injectable anesthetic

7
Q

Thiopental (Pentothal)

A
  • Injectable anesthetic
  • Rapid onset and short action
  • Facilitates GABA induced Cl- entry into neurons, leading to CNS depression
  • Use caution: anesthetic dose is b/t 50-75% of LD50
8
Q

Propofol

A
  • Injectable anesthetic
  • Rapid induction (50 s) and recover (4-8 minutes)
  • May be given alone to maintain anesthesia or used for induction as part of balanced anesthesia technique
  • Most significant respiratory effect is apnea!! Don’t walk out of room i.e Michael Jackson
  • May result in injection site pain
  • *DON’T USE FOR SLEEP, highest % of abuse is by anesthesiologists going to for a ‘cat nap’ 40% don’t wake up
9
Q

Midazolam (Versed)

A
  • Benzodiazepine
  • Facilitates GABA induced Cl- entry into neurons by increasing the frequency of opening of Cl- channels, leading to CNS depression
  • Most important for amnesia (anterograde)
  • Insufficient for anesthesia!!!
10
Q

Ketamine

A
  • Injectable anesthetic
  • Related to phencyclidine PCP
  • Causes dissociative anesthetic (patient appears to be awake, but they are totally unaware)- good for surgery on the back so you don’t need to get them hooked up to breathing apparatus i.e. they breathe on their own.
  • Principal drawback is the occurrence of emergence reactions (delirium and hallucinations)
  • *Abuse potential due to PCP like effect. Known as Special K on the street.
  • *Rapid action anti-depressant? Future..
11
Q

Fentanyl (Sublimaze) & Sulfentanyl (Sufenta)

A
  • Injectable anesthetic Opioid
  • High dose: hemodynamic stability, respiration must be maintained artificially and may be depressed into the postoperative period
  • Usually supplemented with inhalation anesthetic, benzodiazepine or propofal
12
Q

What are the 4 stages of anesthesia? (In general)

A
  1. Analgesia and amnesia (ends w/loss of consciousness); Good
  2. Delirium (begins with loss of consciousness, patients may become combative; get out of this as quickly as possible); Bad
  3. Surgical anesthesia (Plane I-IV: I light surgical IV excessive surgical); good
  4. Medullary depression (stage of reactive OD, patient can die); Bad OOPS
13
Q

How do you accomplish balanced anesthesia?

A
  • General anesthetic - Loss of awareness or consciousness
  • Benzodiazepine - Amnesia
  • Opioid – Analgesia, blunting autonomic NS
  • Neuromuscular blocker - Skeletal muscle relaxation
14
Q

What is the Partial pressure of oxygen needed?

A

21% (79% max can be anesthetic)

15
Q

What is the minimum alveolar concentration? (MAC)

A

Dose of anesthetic (vol%) producing surgical anesthesia in 50% of patient population (ED50).

  • Lowest MAC drugs are the most potent example: sevoflurane (1.71% of the mixture). Nitrous oxide requires 104%..NOT EFFECTIVE for anesthetic. Only for analgesia.
  • Need 1.3-1.5 MAC for light anesthesia, 2 MACs for deep anesthesia
16
Q

What is the difference between lipid solubility and blood solubility?

A

Lipid solubility: responsible for potency. Increased lipid solubility, increase potency. Also leaves slower.
Blood solubility: the more water soluble, the slower time of onset

17
Q

What is the second gas effect?

A

Rapid uptake of first anesthetic from alveoli into blood creates a negative pressure in alveoli

  • Draws in more of a second inhaled anesthetic agent whose alveolar uptake might otherwise be slow
  • Nitrous goes first, gets in fast, creates vacuum, sucks in halothane. Get out of 2nd stage quickly
  • Diffusion hypoxia is a risk with nitrous during recovery