An expert 19-member task force convened by the Society of Critical Care Medicine (SCCM) and the European Society for Intensive Care Medicine (ESICM) has announced new definitions for sepsis and septic shock at the 45th annual Critical Care Congress currently taking place in Orlando, Florida. The new definitions, referred to as Sepsis-3, have also been published in the February 2016 issue of JAMA, available here.
This is the first time in over 2 decades that new definitions for sepsis and septic shock have been issued by the major critical care societies. These new definitions were designed to differentiate sepsis from uncomplicated infection and reflect new understanding of the pathophysiology, management and epidemiology of sepsis. Specifically, they aim to address limitations in the old definitions including “an excessive focus on inflammation, the misleading model that sepsis follows a continuum through severe sepsis to shock, and inadequate specificity and sensitivity of the systemic inflammatory response syndrome (SIRS) criteria,” according to the authors.
The new definition of sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. The Sepsis-3 task force unanimously considered the use of 2 or more SIRS criteria to identify sepsis as unhelpful, as these criteria do not necessarily indicate a dysregulated, life-threatening response, but rather inflammation, a normal host response to “danger” from infection and other insults. Instead, the new definition incorporates the requirement of life-threatening organ dysfunction in response to infection, and recommends the use of the Sequential Organ Failure Assessment (SOFA) score to detect patients at risk for such dysfunction, with a SOFA score ≥2 indicative of organ dysfunction (mortality risk of approx. 10% in a general hospital population with suspected infection). The authors did, however, stress that the SIRS criteria may still remain useful in the identification of infection. Given the incorporation of organ dysfunction in the basic definition of sepsis, the task force considers the previous definition of “severe sepsis” to be redundant and unnecessary.
In addition, the Sepsis-3 task force recommends the use of a new bedside clinical score termed quick-SOFA (qSOFA) to rapidly assess patients at risk for sepsis without the need for the extensive laboratory workup required by the full SOFA score. This test may be used as a rapid sepsis screening tool in the emergency department or in areas where medical resources are limited. Although not as robust as a full SOFA score of 2 or greater in identifying sepsis risk, the qSOFA may be used in lieu of the full SOFA score, or until it can be obtained, to prompt further investigation of organ dysfunction, initiation/escalation of therapy, or for referral to critical care or increased monitoring.
Quick SOFA: Positive if at least 2 of the following criteria are met:
- Respiratory rate of 22/minute or greater
- Altered mental status (GCS <13)
- Systolic blood pressure of 100 mm Hg or less
The new definition of septic shock is a subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality. The clinical criteria of septic shock are sepsis as newly defined plus persisting hypotension requiring vasopressors to maintain MAP ≥65 mm Hg and having a serum lactate level >2 mmol/L (18 mg/dL) despite adequate volume resuscitation. With these criteria, hospital mortality is in excess of 40%.
These new definitions and criteria are summarized in the table below.
New Sepsis-3 definitions and criteria for sepsis and septic shock
|Sepsis definition||A life-threatening organ dysfunction caused by a dysregulated host response to infection.|
|Sepsis clinical criteria||Suspected/documented infectionPLUSSOFA score ≥ 2
Positive qSOFA defined as 2 or more of the following criteria (HAT):
|Septic shock clinical criteria||Sepsis
Vasopressor therapy needed to maintain MAP ≥65 mm Hg
Lactate >2 mmol/L (18 mg/dL) despite adequate fluid resuscitation
The content of the Sepsis app will be updated over the coming days to reflect these new definitions and criteria.
Daniel Nichita, MD
The ESCAVO Team