The semi-sitting position is mainly applied after surgery for gastrointestinal perforation, acute purulent cholecystitis, acute gangrenous appendicitis, acute pelvic inflammatory disease and so on. At this time, there is still a large amount of inflammatory exudate in the abdominal cavity of the patient, and because the peritoneum has a strong absorption capacity, the fluid, pus, bacteria and toxins in the abdominal cavity can be absorbed into the blood, which can cause infectious shock in serious cases. At this time, if the patient takes a semi-sitting position, the fluid or pus in the abdominal cavity can flow downward into the pelvic cavity due to the effect of gravity. The absorption capacity of the pelvic cavity for toxins and bacteria is obviously weakened. At this time, if the amount of fluid and pus in the pelvic cavity is large, pus can also be aspirated by ultrasound-guided puncture, and female patients can also be aspirated by posterior fornix puncture to aspirate the fluid and pus in the pelvic cavity.