Is the Degree of Hypoxemia Driving Outcome or is it a Marker of Overall Organ Dysfunction in Acute Hypoxemic Respiratory Failure?

Background: Acute hypoxemic respiratory failure (AHRF) is the most common cause of admission in the intensive care units (UCIs) worldwide.

Objectives: The investigators will asess the value of mediation analysis (a statistical method to understand the mechanism or process through which an independent variable influences a dependent variable (prediction of early ICU death) via a mediator variable. This allows researcher to see the "how" and "why" of a causal link, respecting the timing relationships" o "maintaining appropriate time constants in patients with AHRF mechanically ventilated.

Methods: The investigators had a database with 2,000,000 anonymized and dissociated demographics and clinical data from 1,241 patients with AHRF enrolled in our PANDORA cohort (Prevalence AND Outcome of acute Respiratory fAilure) from 22 Spanish hospitals and funded by the ISCIII. The study was approved by the Ethics Committees for Clinical research of participating hospitals and informed consent was waived based on Spanish legislation for biomedical research (Royal Decrees 1090/2015 and 957/2020). The investigators will use mediation analysis (Baron & Kenny techniques) to clarify the association of extrapulmonary organ dysfunction and hypoxemia in the early prediction of ICU mortality. The investigators will analyze 1,241 patients mechanically ventilated with AHRF at the time of diagnosis, 1,193 with data at 24 hours, and 996 patients with data at 48 hours from a epidemiological study in Spain.