P408 - Hyperactive Intestinal Peaks Observed Within Hours After Colorectal Surgery Identify Patients Who Develop Postoperative Ileus

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Purpose/Background: The purpose of this study was to determine if the myoelectric activity recorded by a non-invasive, commercially available wireless patch system correlated with onset of postoperative ileus following colorectal surgery.

Methods/Interventions: In a single-arm, IRB-approved prospective study three commercially available wireless patches (Fig. 1A) that acquire electrical activity from gastrointestinal smooth muscle were placed on the anterior abdomen of 46 consenting, consecutively enrolled patients undergoing abdominal colorectal surgery using open (n=17), robotic (n=11) and laparoscopic (n=18) techniques. Cases of diverting loop ileostomy takedown were excluded. Patches were applied immediately following surgery and removed before hospital discharge or reoperation (n=2). All patients followed an enterprise-specific enhanced recovery protocol. The definition of ileus was lack of return of bowel movements by POD 5 and/or required placement of nasogastric tube either during index admission or after index discharge. Daily gut activity GutPrints (a histogram of the frequencies of all the peaks detected in 10-minute time windows) were created for every 4-hour period following surgery, averaged, and plotted for each of the groups. Peaks in the 8 to 12 cpm (cycles per minute) range were assigned to intestinal activity and the energy under the peaks were summed through day 1, day 2 and day 3 and compared between patients experiencing ileus vs. those not experiencing ileus. We secondarily analyzed results when dividing patients into those without any clinically observed postoperative bowel dysfunction, bowel dysfunction without ileus (nausea, vomiting, abdominal distention) and ileus causing index hospital stay > 5 days.

Results/Outcomes: Patch application was not associated with any adverse events. Peaks in the 8 to 12 cpm range were observed in all patients. Hyperactive intestinal activity was significantly higher in 11 patients developing postoperative ileus within 16 hours postoperatively (p=0.041) with a more pronounced difference at 20 and 24 hours (p=0.016 and p=0.013, respectively). Patients without ileus were associated with an average LOS of 3.4 days vs. 4 days for those with bowel dysfunction and 11 days for those with primary postoperative ileus. Their corresponding hyperactive 8-12 cpm peaks were significantly different within 12 hours following surgery and thereafter (fig. 1B,C).

Conclusion/Discussion: Non-invasive measurement of intestinal myoelectrical activity after colorectal surgery was safe and allowed early identification of patients with postoperative ileus. Patients with hyperactive peaks within the first few postoperative hours should not be discharged from the hospital or rapidly receive oral feeding. Future studies should assess if this technology can optimize selection of patients for early discharge or outpatient management while minimizing risk of readmission due to ileus.