Serum bupivacaine concentrations after intraarticular injection for pain relief after knee arthroscopy.

Intraarticular injection of local anesthetic drugs after arthroscopic knee surgery is used to provide postoperative analgesia. Toxic serum levels of bupivacaine have been reported after its use both in regional anesthesia and for intraarticular injection. The toxicity of the former is related to needle misplacement and the latter is presumed to be absorptive. This study evaluates the effect of tourniquet inflation and the addition of epinephrine on serum concentrations of bupivacaine after intraarticular injection. The results shows that the peak serum bupivacaine concentrations can be reduced by adding epinephrine and injecting it after tourniquet inflation.