Stratification of the Acute Respiratory Distress Syndrome
Stratification of the Acute Respiratory Distress Syndrome
The American-European Consensus Conference (AECC) and the Berlin definitions of the Acute
 Respiratory Distress Syndrome (ARDS) could be adequate for epidemiologic studies, but it is
 not adequate for inclusion of patients into therapeutic clinical trials. Despite recent
 reports on the effects of standardized ventilator settings on PaO2/FIO2 and fulfillment of
 AECC and Berlin definitions of ARDS, it is still a matter of debate whether the assessment of
 hypoxemia at 24 hours is the most appropriate tool for stratifying lung severity in patients
 with ARDS. The investigators will perform an observational, multicenter, prospective audit in
 a network of intensive care units in Spain and China for validating and confirming that the
 assessment of hypoxemia at 24 hours after ARDS onset is the most valuable tool for
 stratifying and predicting outcome in patients with ARDS.
In 1994, the American-European Consensus Conference (AECC) defined ARDS as follows: 1) acute
 and sudden onset of severe respiratory distress, 2) bilateral infiltrates on frontal chest
 radiograph, 3) absence of left atrial hypertension or no clinical signs of left heart
 failure, and 4) severe hypoxemia, as PaO2/FiO2 ratio <200 mmHg, regardless of FIO2 or PEEP
 levels. Although this definition could be adequate for epidemiologic studies, it is not
 adequate for inclusion of patients into therapeutic clinical trials. In 2012, a proposal for
 updating the ARDS definition (the Berlin criteria) was published and an empirical
 classification was proposed according to three PaO2/FiO2 cut-off values at ARDS onset: severe
 (≤100 mmHg), moderate (>100-≤200), and mild (>200-≤300) on PEEP≥5 cmH2O. However, despite
 that there is sufficient evidence about the interactions between PEEP and FiO2, the Berlin
 criteria did not mandate the assessment of hypoxemia at 24 hours under standarized
 guidelines.

 The PaO2/FIO2 can be easily manipulated. Alterations in PEEP and FIO2 can dramatically change
 the PaO2/FIO2. Despite recent reports on the effects of standardized ventilator settings on
 PaO2/FIO2 and fulfillment of AECC definitions of ARDS, it is still a matter of debate whether
 the assessment of hypoxemia at 24 hours is the most appropriate tool for stratifying lung
 severity in patients with ARDS.

 The investigators will examine whether the assessment of hypoxemia at 24 h after ARDS
 diagnosis under standard guidelines for ventilatory management have an impact on the
 stratification of lung severity and on predicting mortality of ARDS patients in the intensive
 care unit.
Inclusion Criteria:

 -  Patients meeting the AECC definition for ARDS on PEEP greater or equal than 5 cmH2O
 (or the Berlin criteria for moderate and severe ARDS).

 Exclusion Criteria:

 -  None