Under 1.2 MAC of sevoflurane or isoflurane anesthesia, what is the maximum epinephrine dose (in micrograms) that can be injected submucosally without ventricular arrhythmias in a 70-kg patient?

Under 1.2 MAC of sevoflurane or isoflurane anesthesia, what is the maximum epinephrine dose (in micrograms) that can be injected submucosally without ventricular arrhythmias in a 70-kg patient?

• A. 100 µg
• B. 200 µg
• C. 350 µg
• D. 500 µg

Answer: (C)

Under general anesthesia with volatile agents like sevoflurane or isoflurane at about 1.2 MAC, the heart becomes more sensitive to catecholamines, so epinephrine can trigger ventricular arrhythmias if given in large submucosal doses. To reduce this risk, a maximum epinephrine dose of about 5 micrograms per kilogram is recommended. For a 70-kg patient, that totals 350 micrograms. So 350 µg is the highest dose that can be used safely in this setting. Doses much smaller than that (e.g., 100–200 µg) are below the limit, while a dose like 500 µg would exceed the limit and increase the risk of arrhythmias.

Under general anesthesia with volatile agents like sevoflurane or isoflurane at about 1.2 MAC, the heart becomes more sensitive to catecholamines, so epinephrine can trigger ventricular arrhythmias if given in large submucosal doses. To reduce this risk, a maximum epinephrine dose of about 5 micrograms per kilogram is recommended. For a 70-kg patient, that totals 350 micrograms. So 350 µg is the highest dose that can be used safely in this setting. Doses much smaller than that (e.g., 100–200 µg) are below the limit, while a dose like 500 µg would exceed the limit and increase the risk of arrhythmias.