Limited Role for Continuous Analgesic Pumps in Lap Sleeve Gastrectomy

In patients undergoing laparoscopic sleeve gastrectomy, a continuous infusion of local anesthetic via an anterior abdominal wall catheter does not improve pain control and does not reduce the use of narcotics or antiemetics, or decrease the hospital length of stay (LOS).

“Our study does not support the increased cost of using the continuous infusion [analgesic] catheters,” said Elaine Cleveland, MD, a general surgeon at William Beaumont Army Medical Center, in El Paso, Texas. She presented results from this randomized, double-blind, controlled trial at Obesity Week 2014 (abstract A102).

The proposed benefits of continuous analgesic infusion catheters include better pain control in the perioperative setting, which can reduce the use of narcotics and their associated side effects. “This can lead to a more comfortable recovery with faster return to normal activity, decreased length of stay and possibly decreased costs,” Dr. Cleveland said.

These benefits have been shown in several studies. In a randomized, placebo-controlled study involving 70 patients (J Am Coll Surg 2006;202:297-305), a continuous analgesia infusion pump of 0.5% bupivacaine after midline laparotomy reduced the average daily patient-controlled analgesia (PCA) morphine by 25 mg (33.7 vs. 60 mg; P=0.03). In a 21-patient, placebo-controlled study (Anesthesiology 2007;107:461-468), continuous administration of 0.2% ropivacaine for 48 hours after open colorectal resection for cancer reduced the average morphine used per day by 36 mg and decreased LOS, pain scores and antiemetic use.

Studies evaluating the use of these pumps in laparoscopic surgeries, however, have provided mixed results (Table 1), and to date, no studies have evaluated their use in laparoscopic surgery. To address this, surgeons at William Beaumont Army Medical Center randomized patients undergoing laparoscopic sleeve gastrectomy to receive either 0.2% ropivacaine or 0.9% normal saline via an intraoperatively placed continuous pain catheter. Dr. Cleveland said the pumps cost $710 and are placed in either the preperitoneal space or subcutaneous tissue.

Table 1. Sample of Trials Testing Continuous Analgesia Pumps Patient Population Trial Design Outcome 73 patients undergoing laparoscopic ventral hernia repair Continuous 0.5% bupivacaine vs. placebo No differences in postoperative pain scores, narcotic use, time to return of bowel function or hospital length of stay 30 patients undergoing laparoscopic adjustable gastric banding Continuous 0.375% bupivacaine vs. placebo No differences in shoulder pain, morphine requirements, or antiemetic requirements, but improvements were seen in subjective reports of pain by visual analog scale scores (1.8 vs. 3.5; P<0.046) 45 patients undergoing laparoscopic Roux-en-Y gastric bypass surgery Continuous 0.2% ropivacaine vs. placebo No significant differences in pain scores, morphine requirement or length of stay, but patients in the ropivacaine group were able to sit up a half-day sooner 40 patients undergoing laparoscopic Roux-en-Y gastric bypass surgery Bupivacaine pain pump vs. meperidine patient-controlled analgesia, discontinued at 06:00 h the following morning No significant differences in pain scores, nausea scores, gas pain scores, antiemetic use throughout their stay, or opioid use in the post-anesthesia care unit. Patients receiving bupivacaine had a dramatic decrease in opioid use from leaving the postanesthesia care unit to 06:00 h afterward (average meperidine by patient-controlled analgesia, 217 vs. 129 mg meperidine equivalents; P=0.008). Sources: Surg Endosc. 2009;23:2637-2643; Obes Surg. 2008;18:1581-1586; Surg Obes Relat Dis. 2010;6:181-184;Obes Surg. 2007;17:595-600.

Postoperatively, catheter flow rates were set at 7 mL per hour and patients received PCA with hydromorphone plus IV antiemetics. On the morning of postoperative day 1, patients were started on oral nausea and pain medications, and the catheter infusion rates were decreased to 4 mL per hour. Patients were discharged when they were ambulatory and oral medications could control their pain and nausea. After discharge, clinicians recorded total narcotic and total antiemetic use, pain scores, hospital LOS and adverse events.

To be enrolled in the study, patients had to have a body mass index (BMI) greater than 40, or greater than 35 with comorbidities. Patients were excluded if they had revision surgery, single-port surgery or an allergy to local anesthetic. Only 7% of patients in the study were male; the average age was roughly 35 years. The study was halted early after an interim analysis showed that an additional 20 patients would not change the outcomes.

The investigators found no benefit to the catheters. “The continuous infusion catheter provided no benefit regarding narcotic usage, pain scores, PCA attempts, antiemetic usage or hospital stay in the setting of laparoscopic sleeve gastrectomy,” Dr. Cleveland said (Table 2). Adverse events were minimal with no hypoxia or ileus in either group; urinary retention was identified in three patients, two in the ropivacaine group. Dr. Cleveland said the study was limited in that it was performed at a single institution and most of the patients were young females, which may not represent the typical bariatric surgery population.

Table 2. Comparison of Outcomes Between Patients Receiving Ropivacaine and Placebo   Ropivacaine Placebo P Value Total narcotic, morphine equivalents 51.8 55.17 0.63 Patient-controlled analgesia attempts 61.95 73.74 0.59 Ondansetron, mg 10.6 10.6 0.98 Promethazine, mg 11.7 6.83 0.10 Hospital time, h 37.45 38.19 0.77

So, why are analgesia pumps beneficial in open but not laparoscopic surgeries? “In open surgeries, the catheters are placed directly in the incision, delivering local anesthetic into the operative site. In laparoscopic surgeries, the catheters are placed near the incisions, but may not directly deliver anesthetic to these small trocar sites,” Dr. Cleveland noted. “Additionally, open surgeries tend to have increased pain compared to laparoscopic surgeries, and with that, local anesthetic can have a greater impact in reducing pain.”

Kelvin Higa, MD, director of minimally invasive and bariatric surgery, Fresno Heart and Surgical Hospital, in Fresno, Calif., said the study was important in an era when emphasis is placed on value-based care. “Today, the environment in which we practice is changing. As surgeons, we were only taught to think about quality at any cost, and now we are charged with talking about value … and cost-effectiveness. This research is something that any of us can do on a local level and can make a significant impact on the care of our patients.”