A recent report has provided anaesthesiologists with reassuring data on the safety of caudal nerve block – sometimes called the "kiddie caudal" – for infants and young children undergoing surgery. But, reports Science Daily, an editorial in Anaesthesia & Analgesia draws attention to some important limitations of the study and to the need for further research on the safety and efficacy of this widely used paediatric anaesthesia technique. The database study reported a low overall complication rate, and no serious complications, in a very large series of caudal nerve blocks. "However, there are reasons to be cautious about interpretation of the data," according to the editorial by Drs Karen R Boretsky and James A DiNardo of Boston Children's Hospital. In caudal block, a small dose of local anaesthetic is injected into the base of the spine to numb feeling in the lower body. It is usually added to general anaesthesia in infants, with the aim of controlling pain after surgery while reducing the required dose of general anaesthetic. Dr Santhanam Suresh and colleagues of Northwestern University, Chicago, assessed the safety of surgery with "kiddie caudal" anaesthesia in 18,650 children, average age 14 months. The study used data from the Paediatric Regional Anesthesia Network (PRAN) – a centralised database collecting detailed information on regional anaesthesia techniques in children. The study reported a complication rate of less than 2%, with no serious or permanent complications. In their accompanying editorial, Boretsky and DiNardo raise some methodological concerns – particularly related to the use of the PRAN data. Like other large databases, PRAN lacks many key details on the patients' characteristics and the treatments they receive. That makes it difficult to evaluate some of the variations observed in the study, and to determine the true safety of the caudal nerve block procedure. For example, the study found significant variations in local anaesthetic dose. Suresh and co-authors suggest that about one-fourth of children are receiving "potentially toxic" doses – particularly younger children. But the variations in dose may be related to other factors, such as differences in the surgical procedures performed, according to Boretsky and DiNardo. They write, "Although it is true that proportionally higher doses were given in younger patients, the reason and significance of this finding are unclear." In addition, Boretsky and DiNardo question the study's definition of "potentially unsafe doses." They note that the only two children with systemic (generalised) toxic effects received doses well within standard guidelines. They also point out issues related to unexplained variations in dosing with different anaesthetics (ropivacaine versus bupivacaine) and the detection block failure – the most common complication. While the study adds to the evidence on the overall good safety record of caudal nerve block in infants and young children, further research is needed to address some of the unanswered questions that remain, Drs Boretsky and DiNardo believe. They conclude, "Despite the lack of evidence for complications, the article is not a carte blanche on the safety of the kiddie caudal."
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[link url="http://journals.lww.com/anesthesia-analgesia/pages/articleviewer.aspx?year=2015&issue=01000&article=00022&type=abstract"]Anaesthesia & Analgesia abstract[/link]
[link url="http://journals.lww.com/anesthesia-analgesia/Citation/2015/01000/_Kiddie__Caudal___Safe_but_More_to_Learn.6.aspx"]Anaesthesia & Analgesia editorial[/link]