Which observation would NOT indicate intravascular injection with an epinephrine-containing caudal block solution?

Which observation would NOT indicate intravascular injection with an epinephrine-containing caudal block solution?

• A. Systolic blood pressure increase by 15 mm Hg
• B. Heart rate decrease by 10 bpm
• C. Ventricular extrasystoles
• D. Seizure

Answer: (B)

When epinephrine is mixed with local anesthetic for a caudal block, an intravascular injection dumps a surge of adrenaline into the circulation. That systemic exposure typically produces sympathetic signs: the heart rate goes up (beta-1 stimulation) and the systolic blood pressure rises (alpha-1 mediated vasoconstriction). You can also see electrical irritability in the heart, leading to ventricular extrasystoles, and in extreme cases CNS effects such as seizures due to high circulating epinephrine. So an observation of a decrease in heart rate would not fit this pattern. A drop in heart rate is not the expected result of intravascular epinephrine and would not indicate that the solution entered the bloodstream. In contrast, a rise in systolic blood pressure, the appearance of ventricular extrasystoles, or even a seizure are more consistent with intravascular distribution of epinephrine and would raise concern for intravascular injection.

When epinephrine is mixed with local anesthetic for a caudal block, an intravascular injection dumps a surge of adrenaline into the circulation. That systemic exposure typically produces sympathetic signs: the heart rate goes up (beta-1 stimulation) and the systolic blood pressure rises (alpha-1 mediated vasoconstriction). You can also see electrical irritability in the heart, leading to ventricular extrasystoles, and in extreme cases CNS effects such as seizures due to high circulating epinephrine.

So an observation of a decrease in heart rate would not fit this pattern. A drop in heart rate is not the expected result of intravascular epinephrine and would not indicate that the solution entered the bloodstream. In contrast, a rise in systolic blood pressure, the appearance of ventricular extrasystoles, or even a seizure are more consistent with intravascular distribution of epinephrine and would raise concern for intravascular injection.