A life threatening condition that arises when the bodys REPSONSE to infection causes injury to its own organs. The bodys response varies per person and is not necessarily correlated with the amount of insult someone undergoes. It is something we seeing in virtually all ICU patients; it is truly a core topic that you MUST have a in-depth understanding of. Inappropriately treating a septic patient early on can kill someone. As a trainee, you will go over the early definitions of sepsis and how to treat it; once you have a solid understanding of these, you can go over the newer definitions.
The word "sepsis" is derived from the Greek word that means "rot". In around 400 B.C., Hippocrates first described sepsis as "the decay of biologic materials in the colon leading to dysregulated body humors". Later, in 200 A.D. Galen - a physician who specialized in draining abscesses - described the "formation of pus" absolutely necessary for wound healing. It was a phenomenon that both the Romans and Greeks recognized - specifically, the Romans believed that invisible creatures within swamps released putrid fumes called "miasma" that caused infection. While they recognized the idea behind sepsis they incorrectly dealt with it by removing as many swamps as possible instead of stopping the spread of infection with handwashing/sterile technique.
Later, once germ theory was discovered (e.g. time of Pasteur), the idea of bacteria causing infection became more widespread and sepsis was known as systemic infections caused by an overwhelming amount of a pathogen ("blood poisoning").
Even later, as antibiotics made their way into the world people started realizing that even though we were removing the pathogen, people were still dying. Ultimately this started the idea that in sepsis the host is killing the host, not the pathogen.
The first general definition of sepsis was created in 1992 by SCCM/Chest. It was formed by an international consensus panel due to the high morbidly and mortality that sepsis held. They defined SIRS (systemic inflammatory response syndrome); severe sepsis (SIRS complicated by acute organ dysfunction) and septic shock (SIRS complicated by hypotension, hyperlactemia).
In 2001 Emmanuel Rivers came up with Early Goal Directed Therapy. This was the first standardized "guideline" on how to treat SIRS, severe sepsis and septic shock. It was derived from cardiac surgery "goal directed therapy" which had proven to decreased morbidity and mortality in post-surgical patients. This includes the three hour and six hour bundle.
In 2003, a 2nd consensus was held to look at the guidelines, specifically after they noticed SIRS had a low specificity for infected patients. In this definition they essentially agreed with the 1992 definition but removed sepsis; kept severe sepsis/septic shock.
The most recent guidelines, SEPSIS-3, was defined in February of 2016. These included newer information with the 1992 guidelines be much more outdated. SEPSIS-3 scraps the old definition and instead defines sepsis as "organ dysfunction secondary to a dysregulated host response to infection". It defines sepsis as a SOFA, or sequential organ failure assessment, score of 2 or more (or a qSOFA of >2/3), with the SOFA score being much more specific for infection than SIRS. It removes the idea of severe sepsis and defines septic shock as a LA>2 or MAP<65 after adequate fluid resuscitation.
Emcrit Podcast 169: Interview with Merv Singer: http://emcrit.org/podcasts/sepsis-3/