ARDS is a clinically heterogeneous syndrome, rather than a distinct disease. This
heterogeneity at least partially explains the difficulty in studying treatments for these patients
and contributes to the numerous trials of therapies for the syndrome that have not shown
benefit. Recent studies have identified different subphenotypes within the heterogeneous
patient population. These different subphenotypes likely have variable clinical responses to
specific therapies, a concept known as heterogeneity of treatment effect. Recognizing …