Investigating the contextual modulation of postoperative gastrointestinal motility: a methodological feasibility...

Objective measurement of placebo effects on gastrointestinal function remains a methodological challenge, as most studies rely on patient-reported outcomes. Wireless motility capsule technology (SmartPill®) offers continuous, objective, in-vivo recording of motility parameters throughout the gastrointestinal tract, potentially providing physiological endpoints for placebo research. This methodological feasibility study, nested within the prospective PIDuSA trial, aimed to evaluate whether SmartPill®-based motility monitoring can be feasibly combined with a standardized contextually-enhanced drug administration protocol in patients following abdominal surgery.

A subgroup of six patients received laxatives (9 administrations) from a senior physician incorporating contextual moderators known to enhance placebo responses. Forty-three control group patients received standard administration by nursing staff (180 administrations). The SmartPill® continuously recorded gastrointestinal motility parameters. Primary outcome was the Motility Index calculated over three 30-min periods: baseline, early effect (30-60 min post-administration), and late effect (240-300 min post-administration). Clinical outcomes included stool passage and peristalsis development within 24 h.

The methodological approach proved feasible, although no consistent improvements in motility parameters were observed. The contextual intervention protocol was associated with descriptive trends toward improved clinical indicators like peristalsis on auscultation (77.8% vs. 55.6%) and stool passage (33.3% vs. 31.7%), but physiological parameters remained largely unchanged.

This feasibility study demonstrates that combining a standardized contextual intervention protocol with continuous SmartPill®-based gastrointestinal motility monitoring is operationally feasible in the postoperative setting. The approach successfully captured objective physiological data across all administrations, providing a preliminary methodological framework for future adequately powered trials investigating the modulation of gastrointestinal function by therapeutic context interventions. The absence of significant motility changes in this exploratory sample size does not allow conclusions regarding the presence or absence of contextual effects. We provide a detailed protocol description to facilitate replication and inform future study design.