Risk of Oxygen During Cardiac Surgery Trial

brachial artery flow mediated dilation assessed when patient arrives in ICU after surgery. brachial artery flow mediated dilation is represented as the percent change in brachial artery diameter following 5 minutes of artery occlusion. The entire assessment takes place at ICU admission.

mitochondrial function in atrial myocardium estimated by quantifying adenylate kinase at the end of surgery and oxygen intervention

defined as any atrial fibrillation following surgery until hospital discharge assessed using continuous telemetry, rhythm strips, and electrocardiograms

plasma concentration of creatine kinase, myocardial band

Defined as new deficit on neurologic exam and confirmed with radiologic evidence occurring at any point prior to hospital discharge

Median change scores at the Short Blessed Scale (SBT) administered one-year following surgery. The SBT is a validated rating scale, administered by the clinician, measuring the cognitive performance. Sum Total (range 0-28) with 0 indicating no cognitive impairment and 28 indicating severe cognitive impairment.

reintubation

eGFR one year following surgery

Estimated by quantifying plasma concentration of plasminogen activator inhibitor-1 (PAI-1)

plasma free hemoglobin

TMH electron spin probe

The number of participants with acute brain dysfunction as assessed by the Confusion Assessment Method for the ICU (CAM-ICU) twice daily while patients are in the ICU or for first 3 postoperative days.

arterial lactate measured from arterial blood collected at ICU admission (immediately after arrival in ICU from operating room)

KDIGO acute kidney injury is defined as an increase in SCr ≥ 0.3 mg/dL (≥ 26.5 lmol/L) within 48 hours of surgery or 1.5 to 1.9 times baseline within 7 days of surgery

Urinary concentration of [TIMP2]*[IGFBP7] 6 hours after ICU admission

Urinary concentration of neutrophil gelatinase-associated lipocalin (NGAL) 6 hours after ICU admission.

CAT1H electron spin probe

hemoglobin O2 saturation summarized using SpO2 data continuously measured and recorded every minute during surgery. We calculated the median SpO2 throughout surgery using all the minute to minute values. For example, if a participant had a 5 hour (300 minutes) long surgery, the participant would have 300 SpO2 measurements. We calculated and report the median of those measurements.

partial pressure of oxygen in arterial blood measured from blood sampled at end of surgery, defined as following separation from cardiopulmonary bypass or completion of off-pump coronary artery bypass grafting (approximately 3-5 hours into surgery and intervention)

brain hemoglobin oxygenation using near-infrared spectroscopy (NIRS). The median percent changes from baseline (baseline measured at beginning of surgery when probes placed on forehead, prior to intervention) throughout surgery was calculated using cerebral oximetry measurements collected every minute throughout surgery. We calculated the difference between baseline and each measurement throughout surgery. For example, if a participant had a 5 hour (300 minutes) long surgery, the participant would have 300 cerebral oximetry measurements. We calculated and report the median of those measurements.

mixed venous O2 saturation, measured from blood sampled from pulmonary artery sampled at end of surgery, defined as following separation from cardiopulmonary bypass or completion of off-pump coronary artery bypass grafting (approximately 3-5 hours into surgery and intervention)

cardiac output (normalized to body surface area, i.e., cardiac index)

reactive hyperemia index measured at ICU admission (immediately after arrival in ICU from operating room). The reactive hyperemia index is a number generated by an endopat machine performing peripheral artery tonometry. The index ranges from approximately 1-3, where higher values indicate better vascular reactivity and endothelial function.

Effective concentration for 50% dilation acetylcholine dose response, tension wire myography from arterioles dissected from epicardial fat

Maximum percentage of arteriole dilation after increasing doses of acetylcholine measured using tension wire myography of arterioles dissected from epicardial fat. The fat sample was collected during surgery when heart is exposed approximately 2 hours into intervention.

Effective concentration for 50% dilation sodium nitroprusside dose response, tension wire myography from arterioles dissected from epicardial fat

Maximum percentage of arteriole dilation after increasing doses of sodium nitroprusside measured using tension wire myography of arterioles dissected from epicardial fat. The fat sample was collected during surgery when heart is exposed approximately 2 hours into intervention.

Effective concentration for 50% dilation cinaciguat dose response, tension wire myography from arterioles dissected from epicardial fat

Maximum percentage of arteriole dilation after increasing doses of cinaciguat measured using tension wire myography of arterioles dissected from epicardial fat. The fat sample was collected during surgery when heart is exposed approximately 2 hours into intervention.

Plasminogen activator inhibitor 1

E-selectin