The Impact of Multimodal Brain Monitoring on Postoperative Outcomes in Elderly Patients Undergoing Major Abdominal Surgery

The incidence of ≥ 1 complication occurred from the extubation to the 30 th day postoperatively The definition of postoperative composite complications refers to the rate of occurrence of one or more complications from the time of anesthesia extubation to postoperative day 7 (or the day of discharge) and within 30 days after surgery. Postoperative complications are defined as adverse events of Clavien Dindo grade II or higher occurring in any system from postoperative day 1 to day 7 (or the day of discharge) and within 30 days after surgery.

Intraoperative stress hyperglycemia is defined as:

A condition diagnosed when a patient meeting all the following criteria:

Preoperative glycemic status:

Two or more fasting blood glucose measurements < 126 mg/dL (≈7.0 mmol/L) or Random blood glucose < 200 mg/dL (≈11.1 mmol/L) during hospitalization, With concurrent HbA1c < 6.5%;

Intraoperative finding:

Highest blood glucose level ≥ 140 mg/dL (≈7.8 mmol/L) when measured at:

1 hour after intubation and/or Upon completion of surgery.

Observe and record the incidence of intraoperative composite adverse events .

Adverse events include but are not limited to:

• Cardiovascular Complications:

• Hypotension

• Hypertension

• Severe Arrhythmia ④Acute Myocardial Ischemia

• Acute Myocardial Infarction ⑥Acute Pulmonary Embolism

• Acute Heart Failure ⑧Deep Vein Thrombosis
• Respiratory Complications:

• Pneumonia

• Acute Respiratory Distress Syndrome (ARDS)

• Pulmonary Edema ④Respiratory Failure ⑤Bronchospasm

⑥Atelectasis

⑦Pleural Effusion

• Neurological Complications:

①Intraoperative Awareness

②Acute Stroke

• Renal Complications:

• Acute Kidney Injury (AKI) ②Acute Renal Failure (ARF)

Record blood pressure before induction and immediately after completion of intubation, and calculate the magnitude of change.

Parameters to be recorded:

Duration of intraoperative hypotension；

Hypotension is defined as:

Mean arterial pressure < 65 mmHg or decrease of mean arterial pressure > 20% from preoperative baseline value.

Record the dosages of all medications administered during the intraoperative period, including but not limited to:

General anesthetics: Propofol, Remifentanil, Sufentanil, Oxycodone

Vasoactive agents:

• Norepinephrine
• Esmolol
• Urapidil
• Atropine
• Ephedrine
• Phenylephrine

Measure serum cortisol concentrations at the following time points:

Preoperatively and 24 hours postoperatively

Duration from anesthesia discontinuation to awake and duration from anesthesia discontinuation to extubation

The ratio of postoperative patients requiring transfer to either the Anesthesia Intensive Care Unit or Intensive Care Unit for any clinical indication, to the total number of surgical patients during the same period.

The duration from the end of surgery until the first activation of the patient controlled intravenous analgesia pump

Follow-up assessments will be performed by a single blinded and certified anesthesia practitioner at postoperative days 1-7 and day 30, with documentation of complications involving:

Cardiovascular system； Respiratory system； Digestive system； Nervous system； Urinary system； Infection-related complications,such as wound infection Postoperative complications are defined as adverse events of Clavien Dindo grade II or higher occurring in any system from postoperative day 1 to day 7 (or the day of discharge) and within 30 days after surgery.

the duration of patient stay in hospital

Observation and record the rate of secondary surgeries

Record the mortality within 30 days postoperatively.

Measure blood cardiac troponin I level at the following time points: Preoperatively and 24 hours postoperatively, measurement of cardiac troponin I exceeds the 99th percentile upper reference limit

Measure blood creatinine level at the following time points:

1 day before surgery, and 24 hours postoperatively;Acute kidney injury was defined according to the KDIGO criteria as the presence of any of the following: (1) an increase in serum creatinine by ≥26.5 μmol/L (0.3 mg/dL) within 48 hours; (2) an increase in serum creatinine to ≥1.5 times baseline within the previous 7 days; or (3) a urine volume <0.5 mL/kg/h for 6 consecutive hours.

surgical site infection refers to the proportion of surgical cases with surgical site infection (SSI) occurring from after surgery to before discharge, relative to the total number of surgical procedures performed on hospitalized patients during the same period. Postoperative wound infection is defined as an infection related to the surgical procedure and occurring near the surgical site within 30 days after surgery. Postoperative wound infections include: superficial incisional SSI, deep incisional SSI, and organ/space SSI.

Record heart rate before induction and immediately after completion of intubation, and calculate the magnitude of change.

Duration to postoperative first flatus time

Duration to postoperative first oral intake

Parameters to be recorded:

Minimum intraoperative mean arterial pressure ；

Parameters to be recorded:

Incidence of hypotension；

Hypotension is defined as:

Mean arterial pressure < 65 mmHg or decrease of mean arterial pressure > 20% from preoperative baseline value.

Duration of post-anesthesia care unit stay

Cumulative postoperative oxycodone dose

The duration of intraoperative wavelet index below 40 or Bispectral Index below 40

The duration of intraoperative pain threshold index higher than 70

Scores of Intake, Feeling nauseated, Emesis, physical Exam, and Duration of symptoms at 72 hours after surgery, Intake, Feeling nauseated, Emesis, physical Exam, and Duration of symptoms is a scoring system to evaluate the postoperative gastrointestinal function, if the score is higher than 6, it indicating gastrointestinal dysfunction.