Scalp infiltration with bupivacaine in pediatric brain surgery

To evaluate whether local anesthetic scalp infiltration blunts hemodynamic responses to craniotomy in anesthetized children (age, 2-18 yr), two concentrations of bupivacaine (0.125% and 0.25%) with vasoconstrictor (epinephrine 1:400,000) were compared with control data when a solution of vasoconstrictor alone was injected. Arterial plasma levels of bupivacaine were measured by high-pressure liquid chromatography. Statistically significant increases in mean arterial pressure and heart rate above baseline measurements occurred in the control group during the period between scalp incision and dural reflection (P less than 0.05). Both concentrations of bupivacaine prevented these increases. Mean arterial pressure and heart rate during scalp incision and scalp reflection were significantly higher in the control group than in both bupivacaine groups (P less than 0.05). Peak bupivacaine plasma levels (mean +/- SD) occurred either 5 or 10 min after infiltration and were significantly higher in the 0.25% group (0.48 +/- 0.31 microgram/mL) than the 0.125% group (0.14 +/- 0.13 microgram/mL) (P less than 0.05). These results suggest that bupivacaine infiltration blocks the hemodynamic response to craniotomy. A concentration of 0.125% bupivacaine with 1:400,000 epinephrine is as effective as 0.25% bupivacaine with 1:400,000 epinephrine at reducing the hemodynamic response to craniotomy. Because the lower concentration of bupivacaine produces lower blood levels, we recommend 0.125% bupivacaine with 1:400,000 epinephrine as a useful, safe adjunct to general anesthesia in children undergoing craniotomy.