The large majority of transversus abdominis plane blocks were ultrasound-guided. (Image source: Thinkstock)

The large majority of transversus abdominis plane blocks were ultrasound-guided. (Image source: Thinkstock)

Regional anesthesia has been thought of as the future of anesthesia, specifically targeting the area being operated on, and providing postoperative analgesia while decreasing intraoperative anesthetic requirements.  In this month’s issue of Anesthesia & Analgesia, Dr. Gildasio S. De Oliveira, Jr., Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, and colleagues from the PRAN network discuss the need for further research into the safety and dosing of transversus abdominis plane (TAP) blocks for postoperative analgesia in children in their article “Transversus Abdominis Plane Block in Children: A Multicenter Safety Analysis of 1994 Cases from the PRAN (Pediatric Regional Anesthesia Network) Database.”

As is the case with many studies done in children, safety concerns pose a barrier to large randomized trials. Therefore the authors used observational data as the first step toward a larger trial.  The data were collected by PRAN participating institutions from April 16, 2007 to December 19, 2012. The data were analyzed to document the incidence of complications and potential safety issues with this block.

Eligible study subjects were pediatric patients (<18 years) undergoing surgery who received a TAP block for postoperative analgesia. Only 2 complications were reported among the 1994 children who received a TAP block and were included in the analysis.  One complication was a vascular aspiration of blood before a local anesthetic injection, and the other was a peritoneal puncture.  The anesthesiologists recognized both complications.  Neither of complication resulted in additional intervention nor let to any sequelae.

One thousand eight hundred eighty-seven of the 1994 TAP blocks were done with ultrasound guidance. Only 49 were performed without ultrasound.  The majority of these blocks were done under general anesthesia.  The children who had their blocks done awake or sedated were generally older than children in whom the block was placed under general anesthesia.

The data documented a large variability in local anesthetic dose/weight.  The authors expressed concern that this variability may result in both underdosing and lack of efficacy, as well as overdosing and anesthetic toxicity.  One hundred thirty five of the 1944 patients received doses that could potentially be toxic. Further research should determine an appropriate age and weight-based dosing range for children.

This study uses observational data from a large database fed by multiple centers.  It is limited by the fact that it is observational and retrospective in nature.  Further study is warranted, ideally as a prospective randomized control trial, to document the safety and efficacy of TAP blocks in children.