Easy D _A O ₂ index: a novel hemodynamic risk factor for predicting mortality in surgical and critically ill patients

Background: Measurement of the arterial oxygen delivery index (DAO2I) requires substantial medical resources and invasive procedures. We proposed a novel hemodynamic parameter reflecting DAO2I, the Easy DAO2 index (EDI), and examined its association with mortality in non-cardiac surgical and critically ill patients. Methods: We retrospectively analyzed the data of 95,115 surgical cases from an Asian hospital and 90,420 intensive care unit (ICU) admissions from multicenter hospitals in the United States. EDI was the product of pulse pressure, heart rate, hemoglobin, and peripheral oxygen saturation, divided by body surface area, measured every 5 minutes during anesthesia and hourly for 24 hours post-ICU admission. We assessed the association between 7-day in-hospital mortality and duration of exposure to EDI values below the fifth percentile levels. Results: In non-cardiac surgical patients, mortality risk increased with duration of exposure below the low EDI threshold (adjusted odds ratio [aOR] 1.003 per minute; 95% CI 1.000-1.005). In critically ill patients, mortality risk increased with duration of exposure below the low EDI threshold (aOR 1.014 per hour; 95% CI 1.004-1.023). Conclusions: Low EDI values were independently associated with mortality in non-cardiac surgical and critically ill patients, suggesting that EDI may be a useful hemodynamic parameter for risk assessment.