title: Accuracy of carbon monoxide in venous blood to detect smoking in male and female trauma patients.
abstract: BACKGROUND
  The determination of the smoking status should be part of the initial assessment in emergency or surgery patients, as preventive measures might reduce long-term morbidity. Next to self-report (not always possible or reliable) the use of biomarkers such as carbon monoxide (CO) has been recommended. Point-of-care CO-hemoglobin (CO-Hb) determination is routinely used in trauma settings. The aim of this study was to evaluate the accuracy and the best cut-off of CO-Hb in order to determine the smoking status in minimally injured patients in the emergency department.
  
  
  METHODS
  After informed consent and ethical committee approval 1283 minimally injured patients were assessed in the emergency department immediately after admission with a computer-based questionnaire including the 'Heaviness of Smoking Index' questionnaire. Venous blood sampling and point-of-care oximetry, including CO-Hb, was performed.
  
  
  RESULTS
  Median age of all patients (smokers: males: 399, females: 176; nonsmokers: males: 420, females: 288) was 33 years. According to the receiver operating characteristics CO-Hb had an excellent ability to differentiate between smokers and nonsmokers (area under the curve: males: 0.949, females 0.932). Optimal CO-Hb cut-off was 1.8% in males (specificity 95.7%, sensitivity 85.5%) and 1.6% in females (specificity 96.9%, sensitivity 80.1%).
  
  
  CONCLUSIONS
  CO-Hb was a good marker to detect current smoking in trauma patients. The cut-off of CO-Hb should be lowered to 1.6% in females and 1.8% in males.
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Anesthesiology and Intensive Care Medicine, Campus Virchow-Klinikum and Campus Charité Mitte, Charitéplatz 1, 10117 Berlin, Germany. tim.neumann@charite.de
authors.forename: Tim
authors.initials: T
authors.lastname: Neumann
authors.forename: Bruno
authors.initials: B
authors.lastname: Neuner
authors.forename: Edith
authors.initials: E
authors.lastname: Weiss-Gerlach
authors.forename: Falk
authors.initials: F
authors.lastname: Lippitz
authors.forename: Claudia D
authors.initials: CD
authors.lastname: Spies