SmartPill® as an objective parameter for determination of severity and duration of postoperative ileus: study protocol of a prospective, two-arm, open-label trial (the PIDuSA study)

Abstract

Introduction: Postoperative ileus (POI) is a frequent complication after abdominal surgery (AS). Until today, neither a prophylaxis nor an evidence-based therapy exists. This originates from the absence of objective parameters evaluating the severity and duration of POI resulting in clinical trials of modest quality. The SmartPill(®), a capsule which frequently measures pH value, temperature and intraluminal pressure after swallowing, offers an elegant option for analysing gastrointestinal (GI) transit times and smooth muscle activity in vivo. As the use in patients in the first months after AS is not covered by the marketing authorisation, we aim to investigate the safety and feasibility of the SmartPill(®) immediately after surgery. Additionally, we analyse the influence of prokinetics and laxatives as well as standardised physiotherapy on postoperative bowel contractility, as scientific evidence of its effects is still lacking.

Methods and analysis: The PIDuSA study is a prospective, single-centre, two-arm, open-label trial. The SmartPill(®) will be applied to 55 patients undergoing AS having a high risk for POI and 10 patients undergoing extra-abdominal surgery rarely developing POI. The primary objective is the safety of the SmartPill(®) in patients after surgery on the basis of adverse device effects/serious adverse device effects (ADE/SADE). The sample size suggests that events with a probability of 3% could be seen with a certainty of 80% for at least once in the sample. Secondary objective is the analysis of postoperative intestinal activity in the GI tract in both groups. Furthermore, clinical signs of bowel motility disorders will be correlated to the data measured by the SmartPill(®) to evaluate its significance as an objective parameter for assessing POI severity. Additionally, effects of prokinetics, laxatives and physiotherapy on postoperative peristaltic activity recorded by the SmartPill(®) will be analysed.

Ethics and dissemination: The protocol was approved by the federal authority (94.1.05-5660-8976) and the local ethics committee (092/14-MPG). Findings will be disseminated through publications and conference presentations.

Trial registration number: NCT02329912; Pre-results.

Keywords: SmartPill®; physiotherapy; postoperative ileus; prokinetic substances; safety; wireless motility capsule.

Figure 1

SmartPill^®.

Figure 2

Analysis of gastrointestinal passage and peristaltic activity in a healthy man aged 37 years (A and C) and a woman aged 57 years after laparoscopic sigmoid resection demonstrating decelerated transit times (B and D). Gastric emptying time can be measured by a sudden increase in pH value (figure 2A, B). Small bowel passage is characterised by a slow pH increase followed by a sudden decrease at the ileocecal junction (figure 2B, C). Excretion of the SmartPill^® is determined by a sudden temperature drop and a loss of capsule signals (figure 2C, D). Furthermore, peristaltic activity can be analysed using frequency, minimum and maximum pressure of peristalsis as well as the motility index calculated by MotiliGI software. Exemplary, a highlighted period was added in figure 2C after using the ‘event button’, allowing an easy analysis of bowel contractions during the marked period.

Figure 3

Data receiver with ‘event button’.

Figure 4

Decelerated gastrointestinal transit times in patients with gastroparesis, intestinal bacterial overgrowth or liver cirrhosis compared with healthy probands.