Ramgopal S, Dezfulian C, Hickey RW, et al. - Researchers investigated the correlation of a high Pao₂ (hyperoxemia) at the time of presentation to the PICU with in-hospital mortality via performing a single-center observational study at quaternary-care PICU. Inclusion of encounters with a measured Pao₂ was done. The severity of illness upon presentation was determined via calculating a modified Pediatric Risk of Mortality IV score excluding Pao₂ for each encounter, calibrated for institutional data. Using logistic regression, they assessed if hyperoxemia (Pao₂ ≥ 300 torr [39.99 kPa]) in the 12 hours surrounding PICU admission was linked with in-hospital mortality. They identified 23,719 encounters; of these, 4,093 had a Pao₂ recorded in the period –6 to +6 hours after admission. In-hospital mortality was reported for 274 of 4,093 (6.7%). The outcomes revealed no correlation of a conventional threshold for hyperoxemia at presentation to the PICU with in-hospital mortality in a model using a calibrated acuity score. A significant association of extreme states of hyperoxemia (≥ 73.32 kPa) with in-hospital mortality was evident.