The Million Anesthesia Cases Study (MACS) - a Cohort Study of Preoperative Fasting and Perioperative Outcomes

The co-primary outcome of PONV is defined as administration ≥ 1 antiemetic drug within 12 h postoperatively.

The co-primary outcome of intraoperative hypotension is defined as an area under the curve of intraoperative mean arterial pressure <65 mm Hg.

The co-primary outcome of perioperative AKI is defined as stage 1 or higher, based on Kidney Disease Improving Global Outcomes criteria (creatinine rise ≥ 0.3 mg/dl within 48 h or ≥ 1.5 times baseline) from postoperative day (POD) 0 until POD 7

Incidence of prolonged preoperative fasting for clear liquids is defined as fasting that exceeds the American Society of Anesthesiologists-recommended duration by a factor of 2 or more (≥ 4 hours).

Severity of prolonged clear liquid fasting is defined as the frequency of fasting duration that exceeds the currently recommended by 2x, 4x, 6x, etc.

Perioperative hypoglycemia: any blood glucose concentration < 70 mg/dL from 12 h before to 24 h after the procedure

Perioperative hyperglycemia is defined as any blood glucose concentration > 140 mg/dL from 12 h before to 24 h after the procedure.

Perioperative AKI stage 2 or higher is defined as creatinine at least twice the baseline level between POD0 to POD7.

Myocardial injury after noncardiac surgery is defined as increased cardiac troponin I above the 99th percentile within 3 days after surgery.

Perioperative pulmonary aspiration is defined as a clinical case of pulmonary aspiration confirmed either bronchoscopically (within 24h), radiologically (within 24h), or by visualization of aspirate in the airway/hypopharynx.