Changing compatibility by temperature of local anesthetics with sodium bicarbonate

: We investigated the amount of 7% sodium bicarbonate which could be added to local anesthetics (bupivacaine, mepivacaine and lidocaine) without any precipitation when temperature was altered (5 degrees C, 25 degrees C, 40 degrees C). Precipitations occurred at any temperatures and with any dose of bupivacaine. Interestingly, the higher the temperature, the more frequently precipitation with mepivacaine and lidocaine occurred. This was probably because the solubility of the precipitate produced by the interaction of the base of local anesthetics with bicarbonate was reduced when the temperature increased.