To the Editor:
In their excellent review, Dunn and Durieux1 examine the use of perioperative intravenous lidocaine as an analgesic adjunct. There are situations where additional local anesthetics may be used, thereby raising the concern of local anesthetic toxicity. Such situations include patients receiving either a transverse abdominis plane block, another regional nerve block, infiltration of the wound, or instillation into a joint. It may be possible if infiltration, instillation, a transverse abdominis plane block, or other regional nerve block is administered at the end of the case that intravenous lidocaine can be used during the case, hopefully accruing some benefit, and then turned off at the time of the block. It might be that the waning of the lidocaine infusion blood levels will be roughly matched by the rising blood levels from the block and toxicity would be unlikely. Are there any data to guide the decision to use intravenous lidocaine in these situations and to verify the safety of this approach? It would seem that if the blocks are administered at the beginning of the case, there may be a higher risk of local anesthetic toxicity, but with a working block, the lidocaine infusion would not be as helpful.
I would be hesitant to use intravenous lidocaine for large liposuction cases, because there can be large doses of local anesthetic administered in the tumescent solution that can potentially cause the blood level to rise to toxic levels. It would seem safe to use intravenous lidocaine during spinal, but not epidural, anesthesia, because the amount of local anesthetic administered in a spinal is small. If the epidural infusion is maintained postoperatively, intravenous lidocaine would not be as helpful. Are there any data that addresses these situations?
The author declares no competing interests.