Safety and Suitability of the SmartPill® after Abdominal Surgery: Results of the Prospective, Two-Armed, Open-Label PIDuSA Trial.

INTRODUCTION Postoperative ileus (POI) is a common complication after abdominal surgery. Until today, an evidence-based treatment of prolonged POI is still lacking, which can be attributed to the poor quality of clinical trials. Various different surrogate markers used to define POI severity are considered to be the cause of low-quality trials making it impossible to derive treatment recommendation. The SmartPill®, which is able to record pH values, temperature and pressure after ingestion, could be an ideal tool to measure transit times and peristalsis and therefore analyze POI severity. Unfortunately, the device has no approval for postoperative use due to safety concerns. The primary objective of the study is to determine safety of the SmartPill® in patients undergoing surgery. Secondary objectives were the quality of the recorded data and the suitability of the SmartPill® for analyzing intestinal motility after different surgical procedures. METHODS The PIDuSA Study is a prospective, 2-arm, open-label trial. At the end of surgery, the SmartPill® was applied to 49 patients undergoing abdominal surgery having a high risk for impaired intestinal motility and 15 patients undergoing extra-abdominal surgery. Patients were visited daily to access safety data of the SmartPill® on the basis of adverse and serious adverse events (AEs/SAEs). Suitability and data quality were investigated by analyzing data completeness and feasibility to determine transit times and peristalsis for all sections of the gastrointestinal tract. RESULTS In total, 179 AEs and 8 SAEs were recorded throughout the study affecting 42 patients in the abdominal (158 AEs) and 9 patients in the extra-abdominal surgery group (21 AEs, p = 0.061); none of them were device related. Primary capsule failure was observed in 5 patients, ultimately resulting in an impossibility of data analysis in only 3 patients (4.4%). 9% of the recorded data were incomplete due to the patient's incompliance in keeping the receiver close to the body. In 3 patients (4.4%), isolated small bowel transit could not be determined due to pH alterations as a result of prolonged POI. DISCUSSION Our study demonstrates that the use of the SmartPill® is safe after surgery but requires a reasonable patient compliance to deliver meaningful data. An objective analysis of transit times and peristalsis was possible irrespective of type and site of surgery in over 95% indicating that the SmartPill® has the potential to deliver objective parameters for POI severity in future clinical trials. However, in some patients with prolonged POI, analysis of small bowel transit could be challenging.