inhaled anaesthetics

Question 1

Impact of physiologic and pharmacologic factors on minimal alveolar concentration (MAC)

Answer 1

-Increases in MAC
-Hyperthermia
-Excess pheomelanin production (red hair)
-Drug-induced increases in central nervous system catecholamine levels (cocaine, methamphetamine, amphetamine)
-Cyclosporine
-Hypernatremia

-Decreases in MAC
-Hypothermia
-Increasing age
-Preoperative medication
-Drug-induced decreases in central nervous system catecholamine levels
-α2 Agonists
-Acute alcohol ingestion
-Pregnancy
-Postpartum (returns to normal in 24-72 hours)
-Lidocaine
-Neuraxial opioids
-PaO2 <38 mm Hg
-Mean blood pressure <40 mm Hg
-Cardiopulmonary bypass
-Hyponatremia

-No change in MAC
-Anesthetic metabolism
-Chronic alcohol abuse
-Sex
-Duration of anesthesia
-PaCO2 15-95 mm Hg
-PaO2 >38 mm Hg
-Blood pressure >40 mm Hg
-Hyperkalemia or hypokalemia
-Thyroid gland dysfunction