The safety of adding bupivacaine to the subcutaneous infiltration solution used for donor site harvest

Pain is a major problem for patients with burns. Donor sites are a significant source of this pain. In this investigation we hypothesized that bupivacaine infiltration of the donor site before skin harvest would prove to be a safe technique as determined by the measurement of blood levels of bupivacaine at various time intervals after infiltration. Fourteen patients were enrolled and studied. Average age was 14.3 +/- 3.1 years, weight was 43.1 +/- 9.1 kg, and donor site size was 6.3 +/- 2.0% TBSA. Mean dose of bupivacaine infused was 1.86 +/- 0.21 mg/kg. Maximum mean bupivacaine blood level was 0.39 +/- 0.09 microg/ml. The highest level measured in any one patient was 1.2 microg/ml; 4.0 microg/ml is considered to be the safe upper limit in children. Time to maximum blood level was 8.9 +/- 1.7 hours after infusion. Twelve of the 14 patients had measurable blood levels of bupivacaine at 24 hours after infusion. The maximum bupivacaine level was found to correlate significantly with both the mg/kg of bupivacaine infused (r =.60, P =.04) and the donor site size (r = 0.81, P = 0.002). Bupivacaine at a dose of slightly less than 1.9 mg/kg added to donor site infiltration solution is safe, as demonstrated by low blood levels and the absence of clinical signs of toxicity.