title: A prehospital screening tool utilizing end-tidal carbon dioxide predicts sepsis and severe sepsis.
abstract: OBJECTIVE
  To determine the utility of a prehospital sepsis screening protocol utilizing systemic inflammatory response syndrome (SIRS) criteria and end-tidal carbon dioxide (ETCO2).
  
  
  METHODS
  We conducted a prospective cohort study among sepsis alerts activated by emergency medical services during a 12 month period after the initiation of a new sepsis screening protocol utilizing ≥2 SIRS criteria and ETCO2 levels of ≤25 mmHg in patients with suspected infection. The outcomes of those that met all criteria of the protocol were compared to those that did not. The main outcome was the diagnosis of sepsis and severe sepsis. Secondary outcomes included mortality and in-hospital lactate levels.
  
  
  RESULTS
  Of 330 sepsis alerts activated, 183 met all protocol criteria and 147 did not. Sepsis alerts that followed the protocol were more frequently diagnosed with sepsis (78% vs 43%, P < .001) and severe sepsis (47% vs 7%, P < .001), and had a higher mortality (11% vs 5%, P = .036). Low ETCO2 levels were the strongest predictor of sepsis (area under the ROC curve (AUC) of 0.99, 95% CI 0.99-1.00; P < .001), severe sepsis (AUC 0.80, 95% CI 0.73-0.86; P < .001), and mortality (AUC 0.70, 95% CI 0.57-0.83; P = .005) among all prehospital variables. Sepsis alerts that followed the protocol had a sensitivity of 90% (95% CI 81-95%), a specificity of 58% (95% CI 52-65%), and a negative predictive value of 93% (95% CI 87-97%) for severe sepsis. There were significant associations between prehospital ETCO2 and serum bicarbonate levels (r = 0.415, P < .001), anion gap (r = -0.322, P < .001), and lactate (r = -0.394, P < .001).
  
  
  CONCLUSIONS
  A prehospital screening protocol utilizing SIRS criteria and ETCO2 predicts sepsis and severe sepsis, which could potentially decrease time to therapeutic intervention.
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL; University of Central Florida College of Medicine, Orlando, FL. Electronic address: christopher.hunter@ocfl.net.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Hunter
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL; University of Central Florida College of Medicine, Orlando, FL.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Silvestri
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL.
authors.forename: George
authors.initials: G
authors.lastname: Ralls
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL.
authors.forename: Amanda
authors.initials: A
authors.lastname: Stone
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL.
authors.forename: Ayanna
authors.initials: A
authors.lastname: Walker
authors.affiliation: Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, FL; University of Central Florida College of Medicine, Orlando, FL.
authors.forename: Linda
authors.initials: L
authors.lastname: Papa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D012720:Severity of Illness Index; D018746:Systemic Inflammatory Response Syndrome / Q000175:diagnosis / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide