This study is a randomized, double-blinded, controlled design. In this study, low doses of S-ketamine were selected for surgury treatment in septic patients under general anesthesia , Meanwhile, activity of HO-1 protein , oxidative stress and inflammatory markers in serum are measured to evaluating the effects of S-ketamine Anesthetic on inflammatory response in septic patients undergoing abdominal surgury. In addition,It is very necessary to make use of the advantages of low-dose S-ketamine in anti-inflammation, and avoid the side effects of mental symptoms, so as to guide the new direction of perioperative clinical application of S-ketamine.

1. Title: Effect of S-ketamine Anesthetic on Inflammatory Response in Septic Patients Undergoing Abdominal Surgery

2. Research center: Single Center

3. The Design of the study: Randomized,double-blind, Controlled Trial

4. The population of the study: The main inclusion criteria are 18 years old or above,Patients with sepsis who need surgical treatment under general anesthesia and should be transferred to ICU for further treatment after surgery

5. Sample size: Enroll 50 patients (25 patients in each group)

6. Interventions: Participants in the test group received midazolam 0.05-0.1mg /kg, sufentanil 0.1-0.2ug/kg,Etomidate 0.1-0.2mg/kg, cisatracurium 0.15-0.3mg/kg, S-ketamine 0.125mg/kg (low dose) for Anesthesia induction, followed by an infusion of remifentanil 0.05-0.15ug/kg/min and S-Ketamine 0.125mg/kg/h (low dose) and continuous inhalation of sevoflurane at 2-3%.

   while participants in the control group was the same as the test group except for received the same volume of saline instead of S-ketamine.

   Intraoperative cisatracurium and sufentanil were added according to the circumstances.Bispectral index (BIS) was used to monitor the depth of anesthesia in two groups, and the BIS value was controlled to be 40-60, and the dose was adjusted according to the depth of anesthesia.

7. The aim of the research: To investigate the effect of S-ketamine Anesthetic on Inflammatory Response in Septic Patients Undergoing Abdominal Surgery

8. Outcome# 1) Primary outcome# the incidence of postoperative pulmonary complications 2)Secondary outcome#Inflammatory indicators: leukocyte, CRP, PCT levels;Inflammatory factors: IL-6, TNF-α, CC-16,activity of HO-1;Imaging diagnosis,such as chest X-ray,ultrasound;therapies for respiratory insufficiency,such as nasal cannula,face mask,postoperative noninvasive ventilation, re-intubation with postoperative mechanical ventilation;Incidence of postoperative adverse reactions such as restlessness, delirium, salivation, nausea, vomiting, respiratory depression, dizziness, etc;Length of stay in ICU

9. The estimated duration of the study#1-2years

Inclusion Criteria:

• Patients with sepsis requiring surgical treatment under general anesthesia should be transferred to ICU with endotracheal intubation for further treatment after surgery
• 18≤ age ≤85, gender and nationality is not limited
• Agree to participate in this study and sign the informed consent

Exclusion Criteria:

• Declined to participate in this study
• Patients in pregnancy or with drug allergy in this study
• Patient had chronic or acute respiratory ailments
• long-term preoperative continuous ventilatory support or oxygen dependency
• Patients are now being included in another study
• In the opinion of the attending physician or researcher, there are other conditions that are not appropriate for the study