anesthetic drugs (inhalants) Flashcards
what are the major, minor and not in use yet inhalant anethetics
major use
- isoflurane
- sevoflurane
minor use
- desflurane
- nitrous oxide
not in use yet
- argon
partition coefficients - B/G and O/G
- isoflurane had higher B/G and O/G = waits longer to get induced and accumulates stronger and longer - need to flush out with O2 to wake naimal up)
- sevoflurane and desoflurane and N2O have lower B/G and O/G = induced quickly and washed out faster/animal wakes up faster)
understand design of desoflurane vaporizers
watch zoom recording
what are the CNS sites of action of inhalant anesthetics
spinal cord and brain stem
- inhibition of: sensory processing, nociceptive signaling, motor response to noxious stimulation
brain
- hypnosis & amnesia
- loss of consciousness
- analgesia
what is MAC
- minimum alveolar concentration
- the anesthetic concentration preventing motor response to a supramaximal moxious stimulus in 50 % of subjects
MAC dosing
- measure of potency
- given as vol. - % of Panes (mmHg)
- agent-specific
- species-specific
- correlates inversely with O/G part. coeff.
what are factors that decrease MAC value
- increasing age
- pregnancy (endogenous opioid release)
- hypothermia
- hypotension (MAP < 40 mmHg)
- CNS depressant drugs/analgesics
what are factors that increase MAC value
- hyperthermia
- hypernatremia
respiratory system adverse effects
- central respiratory depression
- decrease Vt: iso> sevo > des
- bronchodilation
adverse effects on CV system
- decrease MAP
- decrease systemic vascular resistance
- decrease myocardial contractility
adverse effects on the liver
- decrease in liver blood flow
- decreases drug metabolism by 50-70%
- hepatotoxicity
adverse effects on fetus
uteroplacental blood flow is decreased
sevoflurane - formation of compound A
lower flow rates make more compound A
what is balanced anethesia
concept using a combination of different agents and techniques to produce the four elements of anesthesia
- hypnosis and amnesia
- analgesia
- muscle relazation
- absence of somatic or autonomuc responses to noxious stimulation
what does lowing inhalant anesthetic dose do
- palpebral reflexes less suppressed
- hemodynamic parameteres (esp. arterial blood pressures (ABP) often closer to physiological values