Diagnosing Sepsis in the Intensive Care Unit: A Retrospective Cohort Study

Abstract Background: Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. In the intensive care unit (ICU), organ dysfunction is common. The challenge lies in determining when organ dysfunction can be attributed to infection. We aimed to retrospectively determine what proportion of patients commenced on antibiotics for presumed sepsis in a mixed ICU had blood-culture positive sepsis, blood-culture negative sepsis, or an aseptic mimic. Methods: One hundred antibiotic naïve ICU patients who were clinically deemed to have an infection were enrolled. Retrospective interpretation of clinical history, biochemical, and microbiological data was performed by three clinicians from the fields of intensive care and infectious disease who aimed to differentiate infective from non-infective insults. Results: There was good interrater reliability amongst clinician assessors using this approach (Krippendorf’s alpha 0.868) for the retrospective diagnosis of infection. In the examined cohort, 35 percent of patients met the criteria of blood culture positivity and an additional 41 percent of patients were assessed as having probable blood culture negative sepsis. Twenty-four percent of patients were retrospectively determined to not have had sepsis. Conclusions: Misdiagnosis of infection as a cause for organ dysfunction in the ICU is common. The false attribution of organ dysfunction to infection in the ICU has significant clinical and research implications, and highlights the need for accurate point-of-care sepsis diagnostic tools.