The optimum concentration of levobupivacaine for intra‐operative caudal analgesia in children undergoing inguinal hernia repair at equal volumes of injectate

Summary Probit analysis was used to predict the median effective concentration (EC50) and the 95% effective concentration (EC95) values of levobupivacaine for caudal analgesia in children at equal volumes of injectate. Sixty children scheduled for inguinal herniorrhaphy were recruited. Anaesthesia was induced with sevofurane and nitrous oxide. Then caudal block (total volume of local anaesthetic 1 ml.kg−1) was performed. Patients randomly received one of six concentrations (0.08%, 0.10%, 0.12%, 0.14%, 0.16% or 0.18%) of levobupivacaine. Thereafter, inhalational anaesthetics were discontinued and intravenous midazolam 0.1 mg.kg−1 was administered to maintain sedation. The effective caudal analgesia was defined as an absence of gross movements and a haemodynamic (heart rate or blood pressure) reaction