[Dose requirement for caudal anesthesia in pediatric patient]

A series of 305 infants and children between 1 day to 14 years of age were operated upon using caudal anesthesia. We used 1% mepivacaine 1.2 ml.kg-1 to obtain a level of anesthesia above T10, 1.0 ml.kg-1 above L1, and 0.8 ml.kg-1 above S. Complete failure occurred in 4.3% of patients. We investigated the blood concentration of mepivacaine in 17 patients, and it ranged from 0.5 microgram.ml-1 to 5.0 micrograms.ml-1. In a two month old infant, weighing 6.7 kg, apnea and bradycardia occurred. This was managed by tracheal intubation and controlled ventilation. But there were no other severe complications. We also investigated the distance between C7 and sacral hiatus (D) in each case. The coefficients of correlation between D and height is 0.97, and high correlation existed also between D and body weight (r = 0.93). This confirms that body weight can be used as a parameter to determine the dose of local anesthetic agent. We conclude that this technique is a safe, reliable and simple way to produce surgical analgesia in infants and children.