Acute respiratory distress syndrome classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Brian Shaller, M.D. [2]

Overview

According to the Berlin definition, ARDS may be classified by the severity of oxygenation deficit into three subtypes: mild, moderate, and severe.

Classification

ARDS may be classified according to the Berlin Definition into three mutually exclusive subtypes: mild, moderate, and severe. These levels of severity are based on the PF ratio, the degree of oxygenation relative to the fraction of oxygen participating in gas exchange. Data from the pooled cohorts demonstrated that mild, moderate, and severe ARDS were associated with increased 90-day mortality (27%, 32%, and 45%, respectively) and increased median duration of mechanical ventilation among survivors (5 days, 7 days, and 9 days, respectively).^[1]

The Berlin definitions of mild, moderate, and severe ARDS are as follows:

The Berlin Definition of Acute Respiratory Distress Syndrome
Oxygenation ^†
Mild	200 mm Hg < PaO₂/FiO₂ ≤ 300 mm Hg with PEEP or CPAP ≥ 5 cm H₂O ^‡
Moderate	100 mm Hg < PaO₂/FiO₂ ≤ 200 mm Hg with PEEP ≥ 5 cm H₂O
Severe	PaO₂/FiO₂ ≤ 100 mm Hg with PEEP ≥ 5 cm H₂O
^† If altitude is higher than 1000 m, the correction factor should be calculated as follows: [PaO₂/FIO₂ × (barometric pressure/760)]. ^‡ This may be delivered noninvasively in the mild ARDS group.

References

↑ ARDS Definition Task Force. Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E; et al. (2012). “Acute respiratory distress syndrome: the Berlin Definition”. JAMA. 307 (23): 2526–33. doi:10.1001/jama.2012.5669. PMID 22797452.

[pmid22797452-1] ARDS Definition Task Force. Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E; et al. (2012). “Acute respiratory distress syndrome: the Berlin Definition”. JAMA. 307 (23): 2526–33. doi:10.1001/jama.2012.5669. PMID 22797452.

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