Which observation would be considered a positive test dose response to an epinephrine-containing local anesthetic solution?

Which observation would be considered a positive test dose response to an epinephrine-containing local anesthetic solution?

• A. Increase in systolic blood pressure by more than 15 mm Hg
• B. Decrease in heart rate by 10 bpm
• C. Seizure
• D. No response

Answer: (A)

When a small amount of epinephrine-containing local anesthetic enters the circulation, it produces a cardiovascular response that can be used to detect systemic absorption or inadvertent intravascular injection. Epinephrine stimulates alpha-1 receptors, causing vasoconstriction and an increase in blood pressure, and also stimulates beta-1 receptors, which can raise heart rate and contractility. A rise in systolic blood pressure by more than about 15 mmHg after administration is the classic positive test-dose response, indicating that epinephrine is having a systemic effect. A decrease in heart rate is not expected with epinephrine exposure; seizures would reflect local anesthetic toxicity at higher systemic levels rather than a routine test-dose response; and no response would suggest little to no systemic absorption.

When a small amount of epinephrine-containing local anesthetic enters the circulation, it produces a cardiovascular response that can be used to detect systemic absorption or inadvertent intravascular injection. Epinephrine stimulates alpha-1 receptors, causing vasoconstriction and an increase in blood pressure, and also stimulates beta-1 receptors, which can raise heart rate and contractility. A rise in systolic blood pressure by more than about 15 mmHg after administration is the classic positive test-dose response, indicating that epinephrine is having a systemic effect.

A decrease in heart rate is not expected with epinephrine exposure; seizures would reflect local anesthetic toxicity at higher systemic levels rather than a routine test-dose response; and no response would suggest little to no systemic absorption.