Serpa Neto A, et al. - Researchers ascertained if distinct biological phenotypes exist within surgical patients, as well as whether the development of postoperative pulmonary complications (PPCs) and subsequent dependence of intra-operative positive end-expiratory pressure (PEEP) differ between such phenotypes. Participants in the study were 242 subjects. Based on pre-operative plasma biomarker concentrations, patients at risk of PPCs and undergoing open abdominal surgery can be clustered. It was noted that the two identified phenotypes had different incidences of PPCs. No interaction was found between phenotype and PEEP level for the development of PPCs.