BACKGROUND AND OBJECTIVES: Ropivacaine is the newest local anesthetic drug for clinical practice. Its structure is similar to levogyrous bupivacaine, therefore exibiting low toxicity. Little is known about plasma concentrations that can be reached in children after lumbar epidural administration of these drugs (including racemic bupivacaine). The aim of this study was to evaluate ropivacaine and bupivacaine plasma concentrations following successful lumbar epidural blocks in children, correlating them to known safe plasma levels. METHODS: Eight-one children of both genders, aged between 2 and 16 year, scheduled to undergo lower limbs surgeries, were randomly divided in two groups to receive lumbar epidural ropivacaine ( n = 41) or bupivacaine (n = 40), associated to general anesthesia. Venous blood samples were collected at times 0 (control), 5, 25, 40, 60, 120, 180 and 240 minutes. Ropivacaine and bupivacaine plasma concentrations were measured by gas chromatography. RESULTS: There was no statistically significant difference in anthropometric and physiological variables between groups. Mean ropivacaine and bupivacaine doses were 2.35 mg.kg-1 and 2.13 mg.kg-1 respectively, leading to peak plasma concentrations of 2.334 µg.ml-1 and 1.111 µg.ml-1 at 25 and 40 minutes respectively, both below the safety level of 3 µg.ml-1. CONCLUSIONS: Lumbar epidural administration of ropivacaine and bupivacaine in children, in doses below 3 mg.kg-1, result in efficient anesthetic blocks and safe plasma concentrations.
ANESTHETICS, Local; ANESTHETICS, Local; ANESTHETIC TECHNIQUES, Regional
