ANESTHETIC CONSIDERATIONS IN PATIENTS WITH ACIDOSIS
Acidemia can potentiate the depressant
effects of most sedatives and anesthetic agents on the central nervous and
circulatory systems. Because most opi-oids are weak bases, acidosis can
increase the frac-tion of the drug in the nonionized form and facilitate
penetration of the opioid into the brain. Increased sedation and depression of
airway reflexes may pre-dispose to pulmonary aspiration. The circulatory
depressant effects of both volatile and intravenous anesthetics can also be
exaggerated. Moreover, any agent that rapidly decreases sympathetic tone can
potentially allow unopposed circulatory depression in the setting of acidosis.
Halothane is more arrhyth-mogenic in the presence of acidosis. Succinylcholine
should generally be avoided in acidotic patients with hyperkalemia to prevent
further increases in plasma [K+].