Updated Consensus Definitions for Sepsis—Emphasis on End-Organ Dysfunction
By Martina M. McGrath, MD
January 19, 2017
In February 2016, a joint task force comprised of members of the Society of Critical Care Medicine and the European Society of Intensive Care Medicine published new consensus definitions of sepsis and septic shock. The aim was to reflect an updated understanding of the pathophysiology of sepsis and to develop a clinical tool to allow rapid identification of patients at risk of increased mortality. Several points worthy of note are outlined below:
- In the new definitions, emphasis is heavily placed on identification of an abnormal host response as opposed to the presence of infection in itself. Sepsis is defined as ‘life-threatening organ dysfunction caused by a dysregulated host response to infection’. An acute change in SOFA (Sequential Organ Failure Assessment) score ≥2 points due to infection denotes organ dysfunction in sepsis. Large epidemiologic studies have shown that a SOFA score of ≥2 is associated with a mortality risk of about 10 percent in hospitalized patients.
- The guidelines introduce the quick SOFA (qSOFA) criteria. qSOFA has three components and is a bedside assessment to identify patients at risk of prolonged ICU stay or in-hospital mortality. (See Table 1) For patients with infection who are not in the ICU setting, a score of ≥2 by either qSOFA or SOFA criteria, appear to have similar ability to predict poor outcomes. The advantage of qSOFA is its simplicity; SOFA scores require the results of lab tests and cannot be quickly measured or repeated as frequently as qSOFA. Correctly applied, qSOFA may be a useful clinical tool for intermediate-risk patients, those in EDs, or out-of-hospital settings to rapidly identify patients requiring more intensive intervention due to their increased risk of sudden deterioration and mortality. For patients already requiring ICU-level care, SOFA retains a greater predictive value for poor outcomes.
Table 1: Quick SOFA (qSOFA) Criteria · Respiratory rate ≥ 22breaths/min · Altered Mentation · Systolic blood pressure ≤ 100mmHg
- In the updated definitions, septic shock is defined as the need for vasopressors to maintain MAP >65 mmHg and a serum lactate >2mmol/L, despite adequate fluid resuscitation. Septic shock occurs where underlying circulatory, cellular, and metabolic abnormalities are sufficiently profound to lead to substantial increases in mortality. This group of patients has a predicted mortality of greater than 40 percent.
- Finally, the SIRS criteria have been removed. Consensus opinion was that the presence of SIRS criteria does not necessarily indicate a dysregulated, life-threatening response, but may simply indicate appropriate host response to infection. Therefore, SIRS criteria were not felt to be useful discriminating factors in identifying those patients at greatest risk of increased mortality. Similarly, the distinction between sepsis and severe sepsis was felt to be redundant and has also been removed.
Sepsis affects up to one million people in the US annually, and there is an urgent clinical need to improve early recognition. The guidelines have been crafted to be clinically relevant and broadly applicable, including in resource-poor settings. These guidelines are targeted to be a positive step at increasing early recognition of this common, but life-threatening, syndrome among the full range of health professionals.
The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). Singer et al, JAMA. 2016;315(8):801-810. doi:10.1001/jama.2016.0287
Dr. Martina McGrath is an Instructor in Medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston. Dr. McGrath is the Medical Editor for the Trends in Medicine blog.