Inhalational Anesthetic Agents Flashcards
What was the first ever inhalational anesthetic?
Nitrous oxide
Whats the difference between vapor and gas?
Vapor: liquid at STP, stored in bottles, and delivered via vaporizer
Gas: Gas at STP, stored in tanks, and delivered via flow meter
What is the saturated vapor pressure?
Maximum achievable concentration of molecules in a gaseous phase at a specific temperature
What affects saturated vapor pressure?
Agent specific, temperature specific
T/F Saturated vapor pressure is unaffected by altitude
TRUE
What is the definition of boiling point?
Temperature at which the saturated vapor pressure = atmospheric pressure
T/F Boiling point is unaffected by altitude
FALSE; boiling point decreases with altitude
T/F Isoflurane’s boiling point is near room temperature
FALSE; Desflurane is
What is gas movement driven by?
Partial pressure gradient across tissues
Chemical affinity for tissue (lipid solubility)
What is the partition coefficient?
indicates gas affinity for adjacent tissue at equilibrium
Gases relatively insoluble in blood have a LOW PC.
What are two ways that a vaporizer compensates for temperature differentiation?
1: Made of copper or bronze that has a high thermal conductivity
2: Device that alters carrier gas flow ratio (bimetallic strip)
A high MAC =
Low potency
What are things that will decrease MAC
Sedatives, analgesic, N2O (MAC sparing effect)
Old age, hypothermia, hypotension
What are factors that will increase MAC?
Hyperthermia, pediatric
What % of N2O needs to be used to see effects?
50%
T/F Nitrous oxide is very potent
FALSE, it has a very low potency
What are some of the advantages of N2O?
Analgesic properties, MAC sparing effect and does not cause hypotension
Why would you not want to use N2O on a ruminant?
Nitrous oxide diffuses in gas-filled cavities very readily; major problem
How would you make sure hypoxia didn’t occur when taking a patient off of N2O?
Flush high O2 flow for several minutes after turning N2O off.
Who are most at risk for N2O toxicity?
People exposed to chronic N2O.
What predisposing factors make Carbon monoxide production possible?
Dry soda lime
High NaOH concentration
T/F Isoflurane is more prone to Carbon Monoxide production than Desflurane
FALSE; other way around
What is malignant hyperthermia?
Life-threatening myopathy due to a genetic defect
What drugs is it possible to induce malignant hyperthermia?
All fluranes
