Introduction: Early identification of sepsis significantly improves outcomes, suggesting a role for prehospital screening. An end-tidal carbon dioxide (ETCO2) value ≤ 25 mmHg predicts mortality and severe sepsis when used as part of a prehospital screening tool. Recently, the Quick Sequential Organ Failure Assessment (qSOFA) score was also derived as a tool for predicting poor outcomes in potentially septic patients. 

Methods: We conducted a retrospective cohort study among patients transported by emergency medical services to compare the use of ETCO2 ≤ 25 mmHg with qSOFA score of ≥ 2 as a predictor of mortality or diagnosis of severe sepsis in prehospital patients with suspected sepsis. 

Results: By comparison of receiver operator characteristic curves, ETCO2 had a higher discriminatory power to predict mortality, sepsis, and severe sepsis than qSOFA. 

Conclusion: Both non-invasive measures were easily obtainable by prehospital personnel, with ETCO2 performing slightly better as an outcome predictor.