The study is a case-controlled observational trial. Sixty patients will be divided into 2 groups depending on whether postoperative delirium or not. This study aims to characterise the gut microbiota in patients undergoing gastrointestinal surgery with postoperative delirium. The CAM-ICU (Confusion Assessment Method for Intensive Care Unit) was used for delirium assessment.

The study is a case-controlled observational trial. Sixty patients will be divided into 2 groups depending on whether postoperative delirium or not. This study aims to characterise the gut microbiota in patients undergoing gastrointestinal surgery with postoperative delirium. The CAM-ICU (Confusion Assessment Method for Intensive Care Unit) was used for delirium assessment.

General anesthesia was induced as follows: 0.3 mg kg-1 intravenous (IV) etomidate, 2 mg IV midazolam, 0.4 μg kg-1 IV sufentanil, and 0.2 mg kg-1 IV cisatracurium. Anesthesia was maintained with an end-tidal concentration of 2-3 vol% sevoflurane and 0.2-0.3 μg kg-1h-1 sufentanil to maintain the bispectral index between 40 and 60.

Inclusion Criteria:

• 1. ethnic Chinese;
• 2. age, 18 to 80 years old;
• 3. American Society of Anaesthesiologists (ASA) physical status I or II;
• 4. required Gastrointestinal Surgery

Exclusion Criteria:

• Cognitive difficulties
• Partial or complete gastrectomy
• Previous esophageal surgery
• Previous treated by radiotherapy or surgery
• Inability to conform to the study's requirements
• Deprivation of a right to decide by an administrative or juridical entity
• Ongoing participation or participation in another study <1 month ago

Patients Undergoing Gastrointestinal Surgery