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Defining Sepsis and Septic Shock


NEW YORK (Reuters Health) - The Sepsis Definitions Task Force, using expanded quantitative information, has updated its definitions for sepsis and septic shock and the clinical criteria underlying them.

Two reports and one summary communication published in JAMA February 23 detail the processes used to reach the consensus

definitions that have remained largely unchanged for more than two decades.

"The new definitions and clinical criteria of sepsis and septic shock are aimed to help clinicians at the bedside recognize these deadly syndromes and start therapy promptly," Dr. Christopher W. Seymour, from the University of Pittsburgh School of Medicine in Pennsylvania, told Reuters Health by email.

"After two years of deliberations and research, we were surprised to uncover the broad differences in how clinicians approach sepsis, and variety of criteria used in septic shock trials in the past decade. This mandated a re-examination of the criteria, strong efforts to speak a common language, and generate simple, easy to use criteria," Dr. Seymour said.

Dr. Seymour and colleagues recommended elimination of the terms sepsis syndrome, septicemia, and severe sepsis and settled on the definition of sepsis as "life-threatening organ dysfunction due to a dysregulated host response to infection."

They explored several sets of clinical criteria and their predictive validity for hospital mortality, including the Sequential Organ Function Assessment (SOFA), Logistic Organ Dysfunction System (LODS), systemic inflammatory response syndrome (SIRS), and a simplified qSOFA model that included Glasgow Coma Scale (GCS) score of 13 or less, systolic blood pressure of 100 mm Hg or less, and respiratory rate of 22/min or more (1 point each; score range, 0-3).

For intensive care unit encounters with suspected infection, SOFA came out on top, whereas for encounters with suspected infection outside of the ICU, qSOFA offered the best predictive validity for in-hospital mortality.

"Sepsis has no gold standard for diagnosis," Dr. Seymour said. "Given its complex pathophysiology and our evolving knowledge base, the current definition and criteria for sepsis represent a first step. Our field will need to continue to embark on improvements in the practicality, validity, and scientific rationale for sepsis definitions/criteria in future iterations."

He added,"We also hope that physicians recognize that, for the first time, these criteria derive from new data analyses in real patients. More than 700,000 encounters in 170 hospitals were studied to evaluate existing and new sepsis criteria."

Dr. Manu Shankar-Hari, from Guy's and St. Thomas' NHS Foundation Trust, London, UK, and colleagues reviewed 44 studies of septic shock involving 166,479 patients and used a Delphi process to arrive at the new consensus definition: "septic shock is defined as a subset of sepsis in which underlying circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than sepsis alone."

Dr. Shankar-Hari told Reuters Health by email, "The proposed definition for septic shock is a paradigm shift in illness concept. We wanted to provide consistency in diagnosing septic shock. The epidemiology of this illness as we measure currently is messy."

After examining six possible sets of clinical criteria, the group identified two criteria that proved most consistent with the proposed septic shock definition: hypotension requiring use of vasopressors to maintain mean blood pressure of 65 mm Hg or greater and having a serum lactate level greater than 2 mmol/L persisting after adequate fluid resuscitation.

In their summary report, Dr. Clifford S. Deutschman, from Hofstra-Northwell School of Medicine, Feinstein Institute for Medical Research, New Hyde Park, New York, and colleagues on the Task Force write, "The proposed criteria should aid diagnostic categorization once initial assessment and immediate management are completed. qSOFA or SOFA may at some point be used as entry criteria for clinical trials."

"Greater clarity and consistency will also facilitate research and more accurate coding," they add.

Dr. Edward Abraham, from Wake Forest School of Medicine, Winston Salem, North Carolina, who wrote an editorial related to these reports, told Reuters Health by email, "While the new definitions advance the field, particularly from an epidemiologic viewpoint and potentially in helping to identify the economic impact associated with sepsis and septic shock, they are only of limited help in defining care for an individual patient or in designing clinical trials to examine new therapies for sepsis."

"As noted in the editorial, more discriminatory definitions, based on specific cellular and genomic alterations, are necessary to truly affect care for individual patients and to assist in the development of novel therapeutic approaches to sepsis and septic shock," he said.

A number of organizations supported this research and a number of coauthors reported disclosures.

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