2.3. Other definitions
The cardiac injury was defined as an increase in high-sensitive (HS) troponin I levels above the 99th-percentile upper reference limit.2 Acute kidney injury (AKI) was identified according to the Kidney Disease: Improving Global Outcomes definition.18Ventilator-associated pneumonia (VAP) was defined as pneumonia occurring more than 48 h after patients have been intubated and received mechanical ventilation. VAP was identified using a combination of positive culture results from respiratory specimen, clinical, laboratory, and radiological findings.19 Acute myocardial infarction was defined according to the fourth universal definition of myocardial infarction,20 and cardiologist confirmation.