Sepsis is no longer defined as SIRS + a suspected source but rather “life-threatening organ dysfunction due to a dysregulated host response to infection”. This is according to the new guidelines released by the Sepsis-3 task force in 2016. By creating this new definition, they shift the focus of sepsis to the pathophysiology of the host’s response and related organ dysfunction and away from the inflammatory response (SIRS) which is incredibly nonspecific. The new definition relies on qSOFA and SOFA scores that were not designed to be used as sepsis screening tools (too late!) but rather predictors of mortality. They have also removed the category of “severe sepsis” and developed a new definition for identifying septic shock.
To validate these scores, Seymour, et al performed a retrospective cohort study looking at 1.3 million adult patient encounters between 2010 and 2012 in southwestern Pennsylvania in community and academic hospitals. Confirmatory analyses of the qSOFA score was performed on 706,399 external patients in order to include patients in different phases of acute care (outpatient, emergency department, inpatient), different countries (U.S. and Germany), and different types of infections (nosocomial and community). Suspected infection was identified in the electronic health records as the combination of use of antibiotic and test of body fluid cultures; from non-electronic health data, infection was determined on admission by administrative claims (ICD-9 criteria) or CDC criteria for hospital-acquired infection.
The researchers compared the SIRS criteria, the SOFA (Sequential [sepsis-related] Organ Failure Assessment) score, and the LODS (Logistic Organ Dysfunction) score. The primary outcome was mortality; the secondary outcome was ICU stays ≥ 3 days. They found that within the ICU, a SOFA increase of ≥ 2 had a statistically greater predictive validity compared to SIRS (p < .001); a SOFA score ≥ 2 has an overall mortality rate of 10%. Outside of the ICU, the simplified qSOFA had a statistically greater validity compared to SOFA (p < .001). Mortality comparisons of a positive vs. a negative SIRS screen had a 2 to-7-fold increase. Whereas, the comparison of a positive vs. negative SOFA screen had up to an 80-fold increase.
The benefits of the qSOFA are that patients can be assessed quickly and repeatedly in the clinical setting, laboratory testing is not required, and there validation for use outside of the ICU. The major drawback is that qSOFA is not validated as a screening tool, and if inappropriately used to screen for sepsis, clinicians may feel obligated to treat anyone with a positive qSOFA for sepsis. However, the authors at PulmCrit.org rightly point out that this is already happening with elevated serum lactate. Additionally, the criteria of qSOFA are not specific for sepsis: hypotension, AMS, and tachypnea have numerous potential causes, ranging from pain and anxiety to shock of another etiology. As with other clinical tools, it is prudent to not anchor a positive qSOFA to a diagnosis of sepsis without considering other more likely diseases in the differential diagnosis.
In conclusion, Sepsis-3 has undoubtedly rocked our world. Athough their guidelines require further prospective studies, this shouldn’t stop ED clinicians from utilizing the new sepsis criteria as part of their evaluation along with clinical gestalt. The SIRS criteria was far from perfect (AUROC 0.76 for mortality) and cumbersome (requires bloodwork for WBC). The qSOFA is fast, cheap, and appears to be more accurate (AUROC 0.81 for mortality), just the way we like things in the ED.
Farkas J, MD. “PulmCrit- Top Ten Problems with the New Sepsis Definition.” Weblog post. PulmCrit. EmCrit, 29 Feb. 2016. Web.
Haijian-Tilaki, K. “Receiver Operating Characteristic (ROC) Curve Analysis for Medical Diagnostic Test Evaluation.” Caspian J Intern Med 4.2 (2013): 627-35. Web.
Rezai S. “Sepsis 3.0.” Web blog post. R.E.B.E.L. EM. 24 Feb. 2016. Web.
“Sepsis Redefined.” Web blog post. FOAMCAST. 21 Feb. 2016. Web.
Seymour CW, Liu V, Iwashyna TJ, et al. Assessment of clinical criteria for sepsis: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). (JAMA, Feb 22, 2016).
Shankar-Hari M, Phillips G, Levy ML, et al. Assessment of definition and clinical criteria for septic shock: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). (JAMA, Feb 22, 2016).
Singer M, Deutschman CS, Seymour CW, et al:The Sepsis Definitions Task Force The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). (JAMA, Feb 22, 2016).
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