Infographic: visual explanation of the concepts of phenotypes, subphenotypes, and endotypes in ARDS. A phenotype denotes a group of patients that share a common syndrome, ARDS in this case. A subphenotype is a subset of patients within the phenotype that share specific features, such as clinical variables, outcomes, or responses to treatment or medical measures, that clearly differentiates this subgroup from others. An endotype is defined as a subgroup of patients within the subphenotype that have distinct biological mechanisms of the syndrome in common, such as gene expression and activated molecular pathways. For now, the definittion of endotypes in ARDS is purely hypothetical as we know little about underlying biology.