Effect of caudal block on sevoflurane requirement for lower limb surgery in children with cerebral palsy.

Summary Background:  Caudal block is a widely used technique for providing perioperative pain management in children. In this randomized double-blinded study, we evaluated the effects of preoperative caudal block on sevoflurane requirements in children with cerebral palsy (CP) undergoing lower limb surgery while bispectral index (BIS) values were maintained between 45 and 55. Methods:  52 children undergoing Achilles-tendon lengthening were randomized to receive combined general–caudal anesthesia (caudal group, n = 27) or general anesthesia alone (control group, n = 25). Caudal block was performed with a single dose of 0.7 ml·kg−1 of 1.0% lidocaine containing epinephrine at 5 μg·ml−1. The control group received no preoperative caudal block. The endtidal sevoflurane concentrations (ETsev) were adjusted every minute to maintain the BIS values between 45 and 55. Results:  The ETsev required to maintain the BIS values were not significantly different between the control and caudal groups after induction of anesthesia [2.1 (0.2) vs 2.2 (0.4); P = 0.773]. However, significantly higher ETsev was observed in the control group before surgical incision [2.0 (0.2) vs 1.8 (0.3); P = 0.013] and during the first 20 min after surgical incision [2.2 (0.3) vs 1.4 (0.3); P   0.05). In the caudal group, the caudal block was successful in 25 of 27 (92.6%) patients. Conclusions:  Caudal block effectively reduced sevoflurane requirements by 36% compared to general anesthesia alone in children with CP undergoing lower limb surgery while BIS values were maintained between 45 and 55.