New definitions for septic shock—a roadmap for a better clinical outcome?

Worldwide septic shock represents one of the most common causes for admission to intensive care units (ICU) (1). From a historical point of view, the primary criterion for the diagnosis of sepsis was progressive dysfunction of organ systems resulting from a proven infection. In 1991, a new set of terms and definitions was developed to define sepsis more precisely (2,3). The concept of the systemic inflammatory response syndrome (SIRS) was introduced with predefined diagnostic criteria. However, the SIRS definition reveals several major concerns. SIRS criteria are very common and therefore up to 90% of all patients being admitted to an ICU might fulfil them. Furthermore, SIRS criteria might be caused by several non-infectious diseases, such as a severe trauma, burns, pancreatitis, and ischemic reperfusion syndromes (4). In addition, septic shock was defined as a sepsis-induced arterial hypotension persisting despite adequate fluid substitution. The discrimination between severe sepsis and septic shock is critically important as it stratifies patients into groups with low and high risk of death. Especially septic shock reveals a highly variable mortality ranging from 30% to 80% across epidemiologic and therapeutic studies (1). This extreme variability has been attributed to an intrinsic heterogeneity of the different patients suffering from septic shock (1,5). Also non-equivalent definitions of severe sepsis or septic shock being applied in different studies might have influenced mortality rates (6-8). Due to the described inconsistencies the definitions of sepsis and septic shock were revised in 2001 (6).