You are performing a bilateral L3-L5 medial branch block followed by a diagnostic right SI joint injection on a 62-year-old, 58 kg woman with chronic axial low back pain. To improve her diagnostic information, you have drawn up 0.5% bupivacaine for the MBBs and plan to use additional bupivacaine for the SI joint injection. The total bupivacaine dose you have prepared is approaching the upper end of the weight-based maximum (~2 mg/kg for plain bupivacaine).