Which statement about vasopressors used with local anesthetics is NOT true?

Which statement about vasopressors used with local anesthetics is NOT true?

• A. LA blood levels are increased
• B. They decrease tissue perfusion
• C. They cause vasoconstriction
• D. They reduce bleeding by vasoconstriction

Answer: (A)

When a vasopressor is added to a local anesthetic, it causes vasoconstriction in the injection area through adrenergic receptor stimulation. This narrowing of vessels reduces local blood flow, which has several important effects: it decreases bleeding at the site, slows the systemic absorption of the anesthetic, and thereby prolongs the anesthetic’s effect. Because blood flow is reduced and absorption is slowed, the anesthetic’s blood levels are typically not increased; they are actually lower than they would be without the vasopressor. So the statement that local anesthetic blood levels are increased is not true. The other statements—that vasopressors cause vasoconstriction, that tissue perfusion is reduced, and that bleeding is reduced by vasoconstriction—are true.

When a vasopressor is added to a local anesthetic, it causes vasoconstriction in the injection area through adrenergic receptor stimulation. This narrowing of vessels reduces local blood flow, which has several important effects: it decreases bleeding at the site, slows the systemic absorption of the anesthetic, and thereby prolongs the anesthetic’s effect. Because blood flow is reduced and absorption is slowed, the anesthetic’s blood levels are typically not increased; they are actually lower than they would be without the vasopressor. So the statement that local anesthetic blood levels are increased is not true. The other statements—that vasopressors cause vasoconstriction, that tissue perfusion is reduced, and that bleeding is reduced by vasoconstriction—are true.