Opioid Use Less Using TAP Catheters Rather Than Epidural Catheters for Colorectal Surgery

Author: Bob Kronemyer

Anesthesiology News

Transversus abdominis plane (TAP) catheters were associated with significantly less use of morphine milligram equivalents (MMEs) compared with epidural catheters in patients undergoing open colorectal surgery who were part of an enhanced recovery after surgery (ERAS) program, according to a retrospective chart review.

“Our TAP catheter group received an average of 59 MMEs, while the epidural group received an average of 172 MMEs (P<0.005),” said lead author David Miller, BS, a second-year medical student at Albany Medical College, in New York.

“ERAS programs are still a relatively new concept in the United States, and I wanted to investigate if our ERAS program led to better patient outcomes, particularly in patients receiving TAP catheters for pain control versus patients receiving epidurals,” Miller said.

Figure. Transversus abdominis plane catheters are relatively easy to place.

Miller said single-injection TAP blocks have been around since the 2000s, but TAP catheters are newer, particularly at Albany Medical College. “I have always been a numbers person, so I was intrigued to analyze the quantifiable outcomes in our patients receiving TAP catheters as opposed to epidurals, including hospital length of stay, average cost, MMEs administered and average pain score,” he said.

Lengths of Stay Unaffected

The chart review consisted of patients booked under the ERAS colorectal surgery program from November 2016 through March 2018. Patients received either bilateral TAP catheters (n=52) or thoracic epidurals (n=24).

Besides the significant reduction in MMEs in the TAP catheter group, there was no difference in mean pain scores between the two groups: 4.54 for TAP catheters and 5.09 for epidurals (P=0.275).

“Given that epidurals block the somatic and visceral components of pain at the level of the spinal cord, one would predict that epidurals would provide better pain control compared to the TAP catheters, which only block the afferent intercostal nerves, and that patients receiving the TAP catheters would require more opiates to control their pain,” Miller said. “We were thus very surprised to discover that the TAP catheter group received nearly one-third the MMEs administered to our epidural patients. This is the opposite of what we expected.”

The study also found similar lengths of stay (5.41 days for TAP catheters vs. 5.71 days for epidurals; P=0.66) and total cost savings ($9,766 vs. $7,428, respectively; P=0.66).

To increase the efficacy and safety of TAP catheters in this patient population, Miller has noticed that having a dedicated ERAS team in charge of placing the TAP catheters can be beneficial. “This has allowed things to run much more smoothly and efficient, with fewer complications,” he said.

Relying less on opioids is especially noteworthy because of the opioid crisis, Miller noted. “It is of utmost importance that we try to decrease the number of opiates that patients receive in the hospital because hospital-prescribed opiates are often the first step in a patient becoming addicted,” he said.

Catheters Have Advantage of Being Easier to Place

Miller speculated that a major reason why TAP catheter patients were able to receive a fraction of traditional opioids was that expectations were set before surgery. “It was never our goal to reduce the level of pain to 0 (on a scale of 0-10), but rather to make patients comfortable and for them to get up and move as soon as possible, which speeds up recovery,” he said. “We wanted to give patients as little opiates as possible to avoid the negative side effects, such as constipation and altered mental status.”

Planting the seed in a patient’s mind early on that there are multiple alternative options than opioids to control pain was critical. “It would be very interesting to investigate this phenomenon in a future prospective controlled study,” Miller said.

“There is currently tremendous interest in improving perioperative pain control, limiting opioid exposure, and improving utilization of resources for hospital systems,” said Vinay Puttanniah, MD, the director of regional anesthesia and perioperative pain medicine in the Department of Anesthesiology and Critical Care Medicine at Memorial Sloan Kettering Cancer Center, in New York City. “This study is a good first look at the possibility of using TAP catheters perioperatively for the management of post-op pain after abdominal surgery.”

Dr. Puttanniah said although the study’s conclusions are interesting as an initial observation, “further study is required to help validate these findings. Going forward, appropriately powered randomized controlled trials studying the surgical and pain outcomes of patients having abdominal surgery with TAP catheters compared to patients having surgery with epidural analgesia would be helpful to decipher the best perioperative strategies for success.”

TAP catheters have the advantages of being relatively easy to place and are associated with an improved side effect and risk profile compared with epidurals, according to Dr. Puttanniah, “so the next step is to prove the efficacy in a more systematic fashion.”