Complications of severe pneumonia include infectious (e.g. catheter-related bloodstream infections, urinary tract infections, etc.) and non-infectious (e.g. myocardial infarction, arrhythmia, etc.). 1. Infectious: nosocomial infection is a common complication of severe pneumonia, such as catheter-related bloodstream infections, urinary tract infections, Clostridium difficile infections, and so on. 2. Non-infectious: severe pneumonia can cause cardiac stress, hypoxemia and inflammation, which can subsequently lead to acute cardiovascular events, including acute myocardial infarction, arrhythmia, congestive heart failure, pulmonary embolism and stroke. When severe pneumonia is present, it should be diagnosed and treated promptly to avoid delays that could lead to serious consequences.