An axillary block utilizing the transarterial approach with 0.5% bupivacaine and epinephrine (1:200,000) is performed in a 70-kg patient. Thirty mL is injected posterior to the axillary artery and 30 mL anterior to it. How many mg have been injected and was the maximum recommended dose exceeded?

An axillary block utilizing the transarterial approach with 0.5% bupivacaine and epinephrine (1:200,000) is performed in a 70-kg patient. Thirty mL is injected posterior to the axillary artery and 30 mL anterior to it. How many mg have been injected and was the maximum recommended dose exceeded?

• A. 150 mg bupivacaine, 150 µg epinephrine did not exceed maximum dose
• B. 150 mg bupivacaine, 150 µg epinephrine exceeded maximum dose
• C. 300 mg bupivacaine, 300 µg epinephrine did not exceed maximum dose
• D. 300 mg bupivacaine, 300 µg epinephrine exceeded maximum dose

Answer: (D)

The key concept is calculating total local anesthetic and vasoconstrictor doses and comparing them to weight-based safety limits. 0.5% bupivacaine contains 5 mg per mL. Injecting 60 mL gives 60 × 5 = 300 mg of bupivacaine. For a 70-kg patient, the maximum recommended dose of bupivacaine with epinephrine is about 3 mg/kg, which equals 210 mg. Therefore, 300 mg greatly exceeds this limit. Epinephrine at 1:200,000 delivers 5 µg per mL. With 60 mL, that's 60 × 5 = 300 µg, or 0.3 mg. The typical maximum single-dose limit for epinephrine with local anesthetics is around 0.2 mg (200 µg); 0.3 mg exceeds this as well. Thus, the regimen exceeds both the maximum bupivacaine dose and the maximum epinephrine dose.

The key concept is calculating total local anesthetic and vasoconstrictor doses and comparing them to weight-based safety limits.

0.5% bupivacaine contains 5 mg per mL. Injecting 60 mL gives 60 × 5 = 300 mg of bupivacaine. For a 70-kg patient, the maximum recommended dose of bupivacaine with epinephrine is about 3 mg/kg, which equals 210 mg. Therefore, 300 mg greatly exceeds this limit.

Epinephrine at 1:200,000 delivers 5 µg per mL. With 60 mL, that's 60 × 5 = 300 µg, or 0.3 mg. The typical maximum single-dose limit for epinephrine with local anesthetics is around 0.2 mg (200 µg); 0.3 mg exceeds this as well.

Thus, the regimen exceeds both the maximum bupivacaine dose and the maximum epinephrine dose.