Post-operative pulmonary complications: Understanding definitions and risk assessment

Post-operative pulmonary complications (PPCs) can have severe consequences and their incidence is high. In recent years, PPCs have been the subject of numerous studies and articles, which have provided a great deal of information that is beneficial but that can cause confusion on a practical level. This review focusses on three main points: (1) the definitions of PPCs, which are heterogeneous and often vary from one report to another, despite emerging consensus; (2) the risk as reflected in the pool of PPC predictors, with each study identifying some but leaving us with a myriad of combinations; and (3) the many PPC prediction scores proposed, each with its strengths and limitations. We attempt to clarify the practical and research implications of the current situation.