Fecal Microbiota Transplantation for the Treatment of ICU Delirium

Inclusion Criteria: * 1\. Age ≥ 18 years old, no ethnic or gender restrictions; * 2\. CAM-ICU-positive delirium; * 3\. Expected ICU stay ≥ 5 days after inclusion in the study; * 4\. Signed written informed consent. Exclusion Criteria: * 1\. Routine administration of antipsychotic medications: Conventional antipsychotic therapy refers to the daily ingestion or application of any sustained-release formulation (in any dosage form) of antipsychotic drugs with the ATC code N05A (in any form), including the following agents: 1. Typical antipsychotics: Chlorprothixene, Flupentixol, Haloperidol, Levomepromazine, Loxapine, Melperone, Perphenazine, Pericyazine, Pimozide, Prochlorperazine, Zuclopenthixol, Pimavanserin, Sulpiride. 2. Atypical antipsychotics: Amisulpride, Aripiprazole, Asenapine, Clozapine, Lurasidone, Olanzapine, Paliperidone, Quetiapine, Risperidone, Sertindole, Ziprasidone. However, the non-habitual administration of antipsychotic medications in the general ward prior to the patient's ICU admission (e.g., for the management of delirium) is deemed acceptable. Nevertheless, antipsychotic therapy should be discontinued upon the patient's ICU admission. * 2\. Severe systemic infection in the early stage of resuscitation, hemodynamic instability or insufficient tissue perfusion, and severe imbalance of water, electrolyte and acid-base. * 3\. Patients with a high risk of death within 5 days as judged by the clinician, or those whose treatment decisions are restricted. * 4\. Active major gastrointestinal bleeding, perforation, or other severe damage to the intestinal barrier. * 5\. Patients who cannot tolerate 50% of their caloric requirements through enteral nutrition due to severe diarrhea, significant fibrotic intestinal stenosis, severe gastrointestinal bleeding, or high-flow enteric fistula. * 6\. Planned or recent abdominal surgery (within 14 days). * 7\. Currently diagnosed with fulminant colitis or toxic megacolon. * 8\. Recently received high-risk immunosuppressive or cytotoxic drug treatment: such as rituximab, doxorubicin, or medium to high-dose corticosteroids (20 mg/d prednisone or higher) for more than 4 weeks. * 9\. Pregnant or lactating women. * 10\. Participated in other clinical trials as a subject within the past 3 months or at the time of enrollment. * 11\. Delirium assessment non applicable: this includes language barriers (patients with foreign language where delirium assessment cannot be confidently performed by the site staff), patients who are deaf, blind or aphasic. Comatose patients are not applicable for delirium assessment. Coma is defined by the following levels of consciousness: RASS -4 to -5. Further, RASS -3 may be considered as coma if this is the judgement of the treating physician. If a patient's coma is considered related to administration of sedative agents, an effort should be made to reduce or terminate the sedative treatment, according to the clinician's discretion. * 12\. Doubtful validity of informed consent: subjects with mental illness, intellectual disability, poor motivation, or other factors that limit the validity of informed consent for participation in this study.