LANCET: Relationship between anaesthetic depth and postoperative complications

There is a relationship between background and objectivestudies reporting anincrease in the depth of anesthesia and decreased survival rate after surgery; The purpose of this study was to compare the total cause of mortality in older patients who underwent major surgery with shallow or deep anaesthetic after one year of surgeryIn this international trial, researchers recruited patients 60 years of age and older, severely curly, surgically over 2 hours and expected to stay in hospital for at least 2 days in 73 centers in seven countriesBefore knowing the grouping, the anesthesiologist sets the appropriate mean arterial pressure (MAP) target range based on the patient's specific situation and determines whether the patient needs a regional anaesthetic as a joint anesthesiaRandomized group BIS targets are 50 and 35 (BIS 50 and BIS35, respectively)The main indicator is the total cause mortality rate within 1 year of surgeryresultsscreening patients at 73 medical centres in 7 countries between December 19, 2012 and December 12, 2017Of the 18,026 patients who met the criteria, 6644 were selected as subjects and randomly assigned to the treatment group or control group as intended treatment groups (3316 cases in BIS 50 groups and 3328 in BIS 35 groups)The median number of patients included at each test site was 48 cases (IQR 20-145) and the average age of patients was 72 years (SD 7)4221 (63%) were male, 2423 (37%) were female, 3107 (46%) were cancer surgery and 3,053 (46%) had abdominal surgeryBIS 50 groups of Maps were 3.5mmHg (4%) higher than in Group 35, and the use of volatile anesthetics decreased by 0.26MAC (30%)During anesthesia maintenance, the average MAC inhalation in 2602 patients (39%) was less than 0.7The one-year mortality rate was 6.5% (212) in the BIS 50 group, 7.2% (238 cases) in the BIS 35 group, HR 0.88 (95% CI 0.73-1.07), and the inter-group mortality rate was non-heterogeneous (HR 0.89, 0.74-1.07)BIS 50 group 954 cases (29%) occurred a level 3 adverse event, BIS 35 group 909 cases (27%) had a level 4 adverse event, BIS 50 group 265 cases (8%) had a level 4 adverse event, BIS 35 group 259 cases (8%)The most common adverse events are infections , vascular diseases , heart disease, and tumors concluded in patients with increased risk of complications after major surgery, the depth of anesthesia was not directly related to the mortality rate of 1 year after surgery