Inhalation Agents Flashcards
Inhalation Agents MOA (3)
Volatile anesthetics primarily affect the function of ion channel and neurotransmitter receptor proteins in the membranes of nerve cells, which are lipid environments.
CNS ; GABAa stimulation produces supraspinal inhibition of transmission.
The Spinal Cord mediates immobility via inhibition of glycine channels.
Inhalation Agent Effects (4)
Unconsciousness : cerebral cortex, thalamus
Amnesia : amygdala , hippocampus
Analgesia: spinothalamic tract
Immobility : spinal cord receptors
Vapor Anesthetic Effects on Cardiac (4)
decrease BP, CO, SVR
+/- heart rate
Vapor Anesthetic Effects on Respiratory (2)
increase rate, decrease TV
Vapor Anesthetic Effects on Cerebral (2)
increase blood flow , decrease CMRO2
Vapor Anesthetic Effects on Muscular
Neuromuscular relaxation
Vapor Anesthetic Effects on Renal (2)
decrease blood flow and filtration rate
Vapor Anesthetic Effects on Hepatic
decrease blood flow
Vapor Anesthetic Effects on Metabolism (2)
slight decrease if normothermic
all are MH triggers
Isoflurane Class
Halogenated methyl ethyl ether
Isoflurane Vapor Pressure (pressure exerted by molecules from a volatile liquid that escape the liquid phase and become vapor, higher number= more molecules in vapor phase)
VP 239 mm Hg at 20 degrees C
Isoflurane MAC (relative potency)
MAC 1.17 in oxygen
Isoflurane B/G Coefficient (speed of onset, lower # = faster)
B/G = 1.4
Isoflurane Oil/Gas Coefficient (usually inversely related to MAC)
Oil /gas = 0.99
Isoflurane Considerations (3)
Not degraded
Non flammable
Irritating to airways
Desflurane Class
Fluorinated methyl ethyl ether