inhalation anesthesia Flashcards
Define MAC.
minimum alveolar concentration (MAC), defined as the alveolar concentration of inhalation anesthetic that prevents movement in 50% of subjects in response to a noxious stimulus.
Of the four inhalants used in horses, rank in order of most potent to least potent, and their respective MACs.
halothane: 0.88%, isoflurane: 1.31%, sevoflurane: 2.31%, desflurane: 7.6%
T/F: The lower blood solubility of the modern inhalation anesthetics means that changes in anesthetic plane can be achieved more readily and onset or disappearance of clinical effects is faster.
True
How are modern inhalation anesthetics metabolized?
isoflurane, sevoflurane, and desflurane are metabolized by the liver
How does isoflurane compare to halothane in regard to changes in CO, SV, BP, and vascular peripheral resistance?
Isoflurane causes less depression of cardiac output and stroke volume than halothane, and it causes similar changes in blood pressure. Vascular peripheral resistance decreases with isoflurane more than with halothane
T/F: Isoflurane, sevoflurane, and desflurane lower blood pressure as a result of decreased peripheral resistance and tend to cause less depression of cardiac output and contractility than does halothane.
True
T/F: The effects of isoflurane and sevoflurane on cardiac output are very similar.
True
T/F: Desflurane does not depress cardiac output at 7.6%
True; Desflurane does not depress cardiac output at 1 MAC (7.6%)
Lidocaine is highly metabolized by the ______ and has a very _______ half-life.
liver; short
T/F: α2-adrenoreceptor agonists and especially medetomidine increase urine production, and catheterization of the urinary bladder after induction of anesthesia is mandatory.
True
T/F: Ketamine is a dissociative agent, which induces analgesia, amnesia, and immobility without depressing cardiovascular function.
True; there is some sympathetic stimulation, which might help to maintain cardiovascular function and respiratory function is only minimally impaired by ketamine
T/F: Boluses of α2adrenoreceptor agonists do not impair cardiopulmonary function
False; Boluses of α2adrenoreceptor agonists impair cardiopulmonary function considerably for 20 to 120 minutes at clinically used dosage rates. A bolus of medetomidine followed by a CRI results in a drop in heart rate and cardiac output for the first 10 minutes only.
T/F: Ketamine can provoke emergence reactions during the anesthetic recovery period characterized by muscle tremor and rigidity, mydriasis, oculogyric movements, sweating, excitation, ataxia, and schizophrenia-like behavior that can turn into a fatal event in horses.
True
T/F: Thrombophlebitis can occur especially with solutions containing 10% guaifenesin, and hemolysis has been reported after administering IV solutions containing a concentration greater than 10% of guaifenesin.
True
T/F: Guaifenesin provides good relaxation of laryngeal and pharyngeal muscles, produces relaxation of skeletal muscles, and at clinical doses does not affect diaphragmatic function. It preserve respiratory function, and exerts no significant effect on cardiac output and arterial blood pressure.
True
