Anesthesia Flashcards
What are the ideal characteristics of an anesthetic agent?
Quick onset
Few AEs
Rapidly reversible
What are the three objectives of general anesthesia (anesthetic triad)?
Hypnosis
Analgesia
Paralysis
How does an anesthesiologist decide which drug is best for each patient to achieve the triad?
Multiple drugs are used. If a single agent were used, the required dose would be too high
Differentiate anesthesia from conscious sedation.
Sedation: airway maintained - usually accomplished with ultra-short acting IV benzos (midazolam)
Anesthesia: loss of airway - multiple drugs to accomplish anesthetic triad
Describe the pre-procedure portion of anesthesia.
Anxiolysis, maybe a benzo (less common), hold inappropriate meds (NSAIDs, anticoagulants, etc.)
Describe the pre-operative period of anesthesia.
Assess patient condition and concurrent illnesses and drug therapy, IV access
List some medications that may be given in the pre-operative period of anesthesia.
Induction agents, antacids/prokinetics/PPIs s/p aspiration risk, drying agents (anti-Ach)
Describe the operative period of anesthesia
Induction –> opioid followed by propofol
Oxygenation and intubation
Maintenance –> volatile gas with oxygen, bolus opioids and paralytics PRN
Monitoring vital signs
What is an alternative to administering gasses for anesthesia?
Total propofol anesthesia usually administered with an opioid –> usually causes less N/V
Describe the post-operative portion of anesthesia.
Reveres paralysis (stigmines)
Extubation
Relief of pain and N/V
Are anesthetic agents lipophilic or hydrophilic? State why.
Lipophilic –> need to get into the CNS
Where in the CNS do most anesthetic agents act?
Midbrain –> mostly in the RAS system
Describe the minimum alveolar concentration (MAC).
Minimum dose of a gas required to make 50% of the population not respond the pain.
Describe what is meant by anesthetic agents being volatile.
When exposed to air, the liquid or powder form of the drugs becomes a gas
What two qualities would an ideal anesthetic gas have.
Non-irritating and non-flammable
Name and describe a rare life threatening AE of anesthetic gasses.
Malignant hyperthermia –> sudden release of intracellular calcium results in muscle contraction, hyperkalemia, and hyperthermia.
Treated with dantrolene, insulin, and D5W –> future anesthesia must exclude gasses
What is the most common use of nitrous oxide.
Dental procedures –> may be used as an adjunct in anesthesia so lower doses of more potent gasses may be used
What must nitrous oxide be mixed with?
Oxygen –> usually 50/50 mix
What AE is associated with long term use of nitrous oxide?
Megaloblastic changes to bone marrow causing methemoglobinemia
List 5 general anesthetic gasses discussed in class from most potent to least potent.
Halothane - MAC = 0.74% Isoflurane - MAC = 1.2% Enflurane - MAC = 1.7% Sevoflurane - MAC = 2.0% Desflurane - MAC = 6.0%
How is propofol administered and what are its uses?
IV - general anesthesia, conscious sedation, ICU agitation
What is propofol’s claim to fame?
Rapid on and rapid off
What is the major AE of propofol?
Hypotension –> reduces vascular tone by 10-20%
Why is propofol colored white and what are three reasons this is clinically significant?
The drug is not lipophilic so it is mixed with a soy-based lipid emulsion
Clinical - has egg so must be cautious in patients with egg allergies
Clinical - strict aseptic technique required because fat makes it more prone to bacteria
Clinical - the fat means it has calories that must be accounted for when calculating a patient’s nutrition administration
