Treatment of Acute Respiratory Failure in Acute Respiratory Distress Syndrome (ARDS) with PaO2/FiO2 ≤ 300

This protocol covers acute respiratory failure arising in the setting of acute respiratory distress syndrome (ARDS), specifically where the PaO2/FiO2 ratio is ≤ 300. The presentation is characterised by bilateral pulmonary involvement of acute onset, not attributable to cardiac failure or fluid overload alone.

Clinical scenario

ARDS is defined by the Berlin criteria: PaO2/FIO2 ratio ≤ 300 under PEEP or CPAP ≥ 5 cmH₂O; acute onset within one week; bilateral shadows on chest imaging; and respiratory failure not explained by cardiac failure or excess fluid alone. This protocol applies when all four criteria are met.

Treatment approach

Initial respiratory management in this setting may involve non-invasive support strategies — including high-flow nasal cannula oxygenation (HFNC) or noninvasive positive pressure ventilation (NPPV) — considered as alternatives to invasive positive pressure ventilation.

The full protocol specifies the decision criteria, clinical thresholds, and stepwise selection and escalation of respiratory support. Access below.

References

DOI: 10.1186/s40560-023-00658-3

The clinical diagnosis of ARDS is currently based on the Berlin definition: (1) PaO2/FIO2 ratio ≤ 300 under positive end-expiratory pressure (PEEP)/continuous positive airway pressure (CPAP) ≥ 5 cmHO2; (2) acute onset within a week; (3) bilateral shadows in the lung fields, and (4) respiratory failure that cannot be explained by cardiac failure or excess fluid alone.

Regarding ARDS, IPPV has been the gold standard; however, HFNC and NPPV are weakly recommended as alternative options to initial management in JRS/JSICM/JSRCM-GL2021.

As a result of the rapid spread and accumulation of evidence for high-flow nasal cannula oxygenation, it is now weakly recommended for the respiratory management of ARF in general and even for initial management of ARDS.

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