Nerve block procedure is safe in children, report researchers

On analysis of more than 18,000 procedures, caudal nerve block in children has a complication rate of fewer than two percent, with little or no risk of long-term adverse effects, according to the report by Dr Santhanam Suresh and colleagues of Northwestern University, Chicago. But the study shows variation in the local anesthetic doses used for caudal block, raising concern about potential toxic effects.

Database Used to Assess Safety of Caudal Block in Children

In caudal block, a small dose of local anesthetic is injected into the base of the spine to numb feeling in the lower body. It is usually added to general anesthesia, with the aim of controlling pain after surgery while reducing the required dose of general anesthetic. Performed largely in infants, caudal block is "likely the most common regional anesthesia technique performed in children," the researchers write.

Dr Suresh and colleagues assessed safety outcomes in 18,650 children, average age 14 months, undergoing surgery with caudal block. The procedures were performed at 18 children's hospitals from 2007 to 2012. The study used data from the Pediatric Regional Anesthesia Network (PRAN) -- a centralized database collecting detailed information on practice patterns and complications of regional anesthesia techniques in children.

The overall estimated complication rate after caudal block was 1.9 percent. The risk of complications was somewhat higher in younger children. However, this was no longer significant after adjusting for the higher risk in awake children, compared to those under general anesthesia. There was no evidence that performing the procedure with ultrasound guidance reduced the risk of complications.

The most common complications were unsuccessful caudal block and complications related to incorrect needle placement. However, none of the reported complications led to lasting or permanent adverse effects. Serious complications such as cardiac arrest and seizure were rare, occurring in just 4 out of 18,650 children.

Large Variations in Anesthetic Dose

The study did find a large variation in the dose of local anesthetic used for caudal block. About one-fourth of children received a dose with the potential to cause toxic effects -- the use of such potentially toxic doses was higher in younger children.

Caudal block is a widely used regional anesthetic technique in infants and young children. Most previous studies have come from single hospitals, making it difficult to assess the risk of uncommon complications and adverse effects. The use of the cooperative PRAN database, combining data from many different hospitals, helps overcome this limitation.

The results support the safety of caudal block during surgery in children. The overall complication rate is low, while the risk of long-term adverse effects is very low. "The current study is, to the best of our knowledge, the largest study to demonstrate safety of a single regional anesthesia technique in children," Dr Suresh and coauthors write.

However, the results draw attention to variations in the local anesthetic doses used for caudal block, potentially increasing the risk of toxic effects. Further studies are needed to define the optimal local anesthetic dosage, as well as the pain-relieving effectiveness of caudal block for specific types of surgery.

"The PRAN database was a lot of work to create, but it is an important contribution to the safety of children undergoing anesthesia," comments Dr. Steven L. Shafer of Stanford University, Editor-in-Chief of Anesthesia & Analgesia. "This paper shows that caudal blocks for post-operative pain control are safe in children. It will help to guide physicians, and parents, in selecting the anesthetic that provides the best outcome for their kids."