The use of a continuous transversus abdominis blockade (TAP) produced a significant decrease in opioid consumption, for a specific time interval, after open nephrectomy, according to research presented here at the 2017 Annual Meeting of the Canadian Anesthesiologists Society (CAS).
“The removal of a kidney is a big operation,” said Saifee Rashiq, MD, University Hospitals Multidisciplinary Pain Center, University of Alberta, Edmonton, Alberta. “Big surgery is painful. Because we do a lot of these operations, we are always looking for ways to do it better and make it less painful for patients.”
The researchers sought to determine if a surgically-placed TAP catheter, as part of a multimodal approach including patient-controlled analgesia, resulted in a decreased need for hydromorphone 48 hours after surgery following the admission of a patient to the post-anaesthesia care unit.
In the study, a group of patients underwent the TAP block followed by post-operative intermittent administration of 0.2% ropivacaine boluses through a TAP catheter (n = 24) while another group of patients received intermittent infusion of normal saline boluses through a TAP catheter after surgery (n = 24).
Pain scores at rest and at movement, nausea, vomiting and sedation, and time to ambulation were assessed, and hydromorphone use was measured at different time points after surgery.
Patients who received ropivacaine used less hydromorphone at all time intervals assessed, although there was only a statistically significant difference at 12 to 24 hours after surgery (4.13 mg vs 6.08 mg; P = .04).
In the 48-hour post-operative period, the incidence of nausea and vomiting after surgery was comparable in both arms.
“In retrospect, we did not study enough people,” said Dr. Rashiq. “If we had a bigger study, we might have seen a [statistically significant] difference. We have learned that we need to make sure the study has sufficient power.”
He said that his team continues to use the TAP blockade technique at their institution, noting it offers some benefit based on the data.