SEATTLE -- Transverse abdominis plane (TAP) block was an effective opioid-sparing technique for postoperative pain management in patients undergoing bariatric surgery, according to a retrospective study.
Among patients given TAP blocks who underwent Roux-en-Y gastric bypass, postoperative use of opioid medication was decreased by 62.4%, and those who had sleeve gastrectomy used 59.9% less compared with patients on patient-controlled opioid anesthesia (P<0.0001 for both), reported Thomas C. Robertson, MD, of Carolinas Medical Center in Charlotte, N.C.
In addition, median length of stay in the hospital was 1.1 day for both gastric bypass and sleeve gastrectomy patients receiving TAP blocks (plus rescue narcotics as needed) compared with 2.2 and 1.8 days for the opioid-only group, which was also statistically significant (P<0.05), he reported at the here.
"Postoperative pain management in bariatric surgery is a challenge," he said during a plenary session at the meeting. One reason is that opioids have long been a foundation for postop pain, and with opioid-related deaths now outnumbering vehicle-related deaths in the United States, the need for non-opioid alternatives has grown.
"The side effects of opioids such as sedation and respiratory depression are particularly important in our bariatric patients because of the high prevalence of obstructive sleep apnea and the increased risk of respiratory depression, so we feel that multimodal anesthesia is important," he said.
Transverse abdominis plane block is an increasing popular regional anesthesia technique for abdominal surgery which involves injection of a local anesthetic between the internal oblique muscle and transverse abdominis muscle. The thorocolumbar nerves originating from T6 to L1 supply sensory nerves to this area, the anterior abdominal wall.
This technique has been shown to reduce rescue opioid use in bariatric procedures and cesarean sections, and to decrease opioid use both immediately in the recovery room and 24 hours postoperatively.
The TAP blocks used in this retrospective series, which included 440 patients, utilized liposomal bupivacaine, and because of its delivery system, it allows for continuous release of the local anesthetic for up to 72 hours, he explained.
The 30-day readmission rates in the TAP groups were 6.6% for patients having gastric bypass and 0.95% for those having the sleeve gastrectomy, while the corresponding rates for the opioid-only group were 7.5% and 4.9%.
"What was surprising was that pain scores did not change. In fact the TAP group had significantly increased pain scores at baseline and 12 hours, but at 24 hours pain scores were unchanged across all groups," Robertson said.
He noted that their analysis showed that the TAP block group had higher percentages of unreported pain scores, but that the retrospective nature of the study it was difficult to ascertain why this was.
"In conclusion, significant decreases in total morphine equivalents were seen for TAP block compared with patient-controlled opioid-only anesthesia, along with a statistically significant decrease in length of hospital stay. Pain scores were not decreased in this retrospective analysis, so a study with strict adherence to pain score collection is recommended," he stated.
Because the study was a retrospective chart review, not a randomized trial, unmeasured differences between patients receiving TAP block versus opioid anesthesia could have influenced the study results.