BACKGROUND

Patients with multiple injuries are known to develop lung injury1 which can result in long-term disability or even death.2  A recent review of combat casualty deaths following admission to a hospital demonstrated that 8% of potentially preventable deaths are from multi-organ failure which includes ARDS.3  The purpose of this guideline is to review the diagnostic criteria for ARDS, to describe the frequency of this problem in combat casualties, and to recommend a series of management strategies to permit safe aeromedical evacuation of these patients.

Respiratory failure has been observed in combat casualties for over a century.  Some degree of ARDS occurs in between 26% and 33% of combat casualties.1,4,5  In a review of the DoD Trauma Registry (DoDTR), 152 patients with ARDS were identified over a 7 year period.6  Independent risk factors for ARDS included female sex, shock or tachycardia on presentation, and severe injury (Military Injury Severity Score (mISS) ≥25).  Patients with ARDS had a significantly increased risk of death as compared to intubated controls (12.8% vs. 5.9%, Odds Ratio 1.99, 95% confidence interval [1.12, 3.52], p=0.02).  Further analysis of this population identified that increased crystalloid infusion and Fresh Frozen Plasma (FFP) transfusion independently predicted ARDS.7

 

DEFINITIONS

             1. Mild ARDS = PaO2 to FiO2 ratio (P:F) of > 200 and ≤ 300.

             2. Moderate ARDS = P:F of >100 and ≤ 200.

             3. Severe ARDS = P:F of ≤ 100.