Multisite Tissue Oxygenation Guided Perioperative Care in Cardiac Surgery

The primary outcome is a collapsed (one or more) composite of the following complications with a Clavien-Dindo grade II or greater arising within 30 days of randomization (randomization and surgery are performed on the same day). The patient is regarded as having the event of composite complications if any of the following complications occur (i.e., yes); otherwise, the patient is regarded as not having the event of composite complications. The percentage of patients having the event of composite complications will be used in the primary analysis.

• Brain complications (delirium, cognition decline, stroke);
• Cardiac complications (non-fatal cardiac arrest, myocardial injury, heart failure, new-onset symptomatic ventricular arrhythmia);
• Respiratory failure;
• Renal complications (AKI stages II and III);
• Infectious complications;
• Death.

Atrial fibrillation

A new diagnosis of AF per the current standard.

Postoperative delirium (assessed using CAM-ICU Worksheet for patients in PACU and ICU, or CAM for patients on the floor). The validated Chinese version will be used for assessment.

Delirium will be formally assessed as early in the morning as practical and early evening for the initial five postoperative days while patients remain hospitalized because this approach will detect nearly all postoperative delirium. Observed daytime delirium will be recorded and considered as an outcome. Delirium will not be evaluated the evening after surgery because confusion might result from residual anesthetic effects.

Postoperative cognitive decline (assessed using 30-points MoCA 7.1 version). The validated Chinese version will be used.

MoCA evaluates multiple cognitive domains including executive function and is widely used. Validated versions of MoCA are available in many languages including Chinese and German. A decrease of ≥2 points is associated with cognitive decline based on formal neuropsychological testing and considered a clinically meaningful reduction.

Length of hospital stay in days

Any stroke per current clinical diagnostic criteria arising during surgery or after surgery until postoperative day 30.

Cardiac complications include:

• non-fatal cardiac arrest (An absence of cardiac rhythm or presence of chaotic rhythm requiring any component of basic or advanced cardiac life support.)
• myocardial injury (Myocardial injury is defined as any myocardial infarction (i.e., 4th Universal Definition of myocardial infarction32), or any elevated troponin judged to be due to myocardial ischemia (i.e. without evidence of a non-ischemic etiology, e.g. chronic elevation, pulmonary embolism, sepsis, cardioversion, others) that occurred with the first 30 days after surgery.)
• heart failure (per current standard diagnostic criteria.)
• new-onset symptomatic ventricular arrhythmia (per current standard diagnostic criteria.)

Respiratory failure is defined as the requirement of respiratory support (intubation, CPAP or BiPAP, or high-flow oxygen (>10 L/min)) for acute respiratory insufficiency for more than 6 hours after surgery.

Renal complications in this study refers to acute Kidney Injury stages II and III diagnosed using the Kidney Disease Improving Global Guidelines (KDIGO).

Infectious complications include the following:

• Surgical site infection (deep surgical site):
• Surgical site infection (organ/space)
• Pneumonia
• Laboratory confirmed bloodstream infection
• Infection, source uncertain
• Sepsis Sepsis will be diagnosed per the Third International Consensus Definitions.38,39 The Task Force defines sepsis as a "life-threatening organ dysfunction due to a dysregulated host response to infection." Clinical diagnosis of organ dysfunction requires a two-point increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score, starting the day after surgery and continuing throughout hospitalization as shown below (adopted from Singer38).