CH 4 Inhaled Anesthetics Comparative Pharmacology Flashcards
Which two inhaled anesthetics have a low blood and tissue solubility that permits more precise control over the induction of anesthesia and more rapid recovery when the drug is discontinued?
Desflurane and Sevoflurane
Reaction to N2O does not occur until ____% to ____% is inhaled
10% to 20% nitrous oxide is inhaled
Mental impairment is not detectable in volunteers breathing __________ of nitrous oxide or __________halothane
1,600 ppm (0.16%) nitrous oxide or 16 ppm (0.0016%) halothane
Drug-induced increases in CBF may ____________ intracranial pressure (ICP) in patients with space-occupying lesions
increase
Cerebral metabolic oxygen requirements are _______________ in parallel with drug-induced ______________in cerebral activity
decreases
decreases
What concentration of MAC increase the frequency and voltage on the EEG? (Excitement stage)
Volatile anesthetics in concentrations of <0.4 MAC
Cerebral metabolic oxygen requirements begin to decrease abruptly at about _______ MAC
0.4
What happens when volatile anesthetic approaches 1 MAC?
The frequency on the EEG decreases and maximum voltage occurs.
During administration of isoflurane, burst suppression appears on the EEG at about ________MAC, and at ________ MAC, electrical silence predominates
During administration of isoflurane, burst suppression appears on the EEG at about 1.5 MAC, and at 2 MAC, electrical silence predominates
____________ and _____________ cause dose-related changes in the EEG similar to those that occur with isoflurane
Desflurane and sevoflurane
1.5 MAC of isoflurane will cause
burst suppression
2 MAC of Isoflurane will cause
electric silence(isoelectric line)
What is the patients state on EEG when the MAC is 0?
WAKEFUL
What is the patients state on EEG when the MAC is 0.4
SEDATED
What is the patients state on EEG when the MAC is 0.8?
Unresponsive
What is the patients state on EEG when the MAC is 1.3?
Surgically anesthetized
What is the patients state on EEG when the MAC is 2?
Deeply anesthetized
How can volatile anesthetics affect evoked potentials?
Dose-related decreases in the amplitude and increases in the latency of the cortical component of median nerve somatosensory evoked potentials, visual evoked potentials, and auditory evoked potentials.
The decrease in amplitude is more marked than increase in latency
Mental Function and Awareness
Gaseous anesthetics may not be equally effective in preventing awareness.
0.4 MAC isoflurane prevents recall and responses to commands, whereas nitrous oxide requires greater than 0.5 to 0.6 MAC to produce similar effects.
Surgical stimulation may increase the anesthetic requirement to prevent awareness.
Volatile anesthetics administered during normocapnia in concentrations of >0.6 MAC produce
cerebral vasodilation, decreased cerebral vascular resistance, and resulting dose-dependent increases in CBF
Increase in CBF occurs despite concomitant decreases in cerebral metabolic requirements.
Which inhaled anesthetics increases the CBF?
Isoflurane = Desflurane> Sevoflurane
Which inhaled anesthetics do not affect CBF autoregulation?
ISO,DES & SEVO
What can counteract increases in ICP by volatile anesthetics?
Hyperventilation to decrease PaCO2 to about 30mmHg
Which inhaled anesthetic offers a degree of cerebral proctetion? from transient incomplete cerebral ischemia during carotid endarterectomy?
Isoflurane