Fecal microbiota transplantation for persistent feeding intolerance in critically ill patients: a prospective exploratory study

To evaluate the feasibility, safety, and preliminary efficacy of fecal microbiota transplantation (FMT) in improving persistent feeding intolerance (FI) in critically ill patients, with additional exploration of its effects on delirium and sleep. In this single-arm, open-label, prospective exploratory study, a large case series of 19 intensive care unit (ICU) patients with persistent FI received a standardized 3-day nasojejunal FMT as salvage therapy. FI improved in 89.5% (17/19) of patients, with a median time to improvement of 4 days. Enteral nutrition (EN) volume increased within 24 h after the first FMT compared with the preceding 24 h; however, the uncontrolled design precludes attribution of this temporal change to FMT alone. EN intake and prealbumin levels increased, while disease-severity scores (APACHE II and SOFA) and systemic inflammatory markers (CRP, NLR) decreased over follow-up. Microbiome analysis showed early compositional shifts, increased alpha diversity, changes in beta diversity, and detection of donor-associated taxa, including Bifidobacterium , Collinsella , Subdoligranulum , Bacteroides , and Megamonas , together with butyrate-producing Clostridia such as Lachnospiraceae and Ruminococcaceae . Immunological analysis revealed significant increases in CD8⁺ T cell and NK cell subsets. Delirium and sleep quality also improved significantly following FMT, with gut microbiota diversity positively correlated with sleep quality. Exacerbated fever occurred in 11/19 patients (57.9%), but only one patient had a temperature exceeding 38.5 ℃ during FMT; no severe organ dysfunction was attributed to FMT. This study provides preliminary evidence that FMT is feasible, has an acceptable safety profile, and may improve persistent FI in critically ill patients.