title: Elevated carboxyhemoglobin: sources of carbon monoxide exposure.
abstract: BACKGROUND
  Inhalation of carbon monoxide (CO) can result in poisoning, with symptoms ranging from mild and nonspecific to severe, or even death. CO poisoning is often underdiagnosed because exposure to low concentrations goes unnoticed, and threshold values for normal carboxyhemoglobin vary according to different authors. The aim of our study was to analyze carboxyhemoglobin (COHb) levels in an unselected population and detect sources of CO exposure
  
  
  METHODS
  In a cross-sectional descriptive study, we analyzed consecutive arterial blood gas levels processed in our laboratory. We selected those with COHb≥2.5% in nonsmokers and ≥5% in smokers. In these cases a structured telephone interview was conducted.
  
  
  RESULTS
  Elevated levels of COHb were found in 64 (20%) of 306 initial determinations. Of these, data from 51 subjects aged 65±12 years, 31 (60%) of which were men, were obtained. Mean COHb was 4.0%. Forty patients (78%) were non-smokers with mean COHb of 3.2%, and 11 were smokers with COHb of 6.7%. In 45 patients (88.2%) we detected exposure to at least one source of ambient CO other than cigarette smoke.
  
  
  CONCLUSIONS
  A significant proportion of individuals from an unselected sample had elevated levels of COHb. The main sources of CO exposure were probably the home, so this possibility should be explored. The population should be warned about the risks and encouraged to take preventive measures.
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España.
authors.forename: Herminia
authors.initials: H
authors.lastname: Buchelli Ramirez
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España. Electronic address: enelllano@gmail.com.
authors.forename: Ramón
authors.initials: R
authors.lastname: Fernández Alvarez
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España.
authors.forename: Gemma
authors.initials: G
authors.lastname: Rubinos Cuadrado
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España.
authors.forename: Cristina
authors.initials: C
authors.lastname: Martinez Gonzalez
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España.
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodriguez Jerez
authors.affiliation: Unidad de Gestión Clínica de Pulmón, Servicio de Neumología, Hospital Universitario Central de Asturias, Oviedo, Asturias, España.
authors.forename: Pere
authors.initials: P
authors.lastname: Casan Clara
mesh_terms: D000368:Aged; D000393:Air Pollutants / Q000633:toxicity*; D016902:Air Pollution, Indoor; D002248:Carbon Monoxide / Q000633:toxicity*; D002263:Carboxyhemoglobin / Q000032:analysis*; D003296:Cooking; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D006798:Housing; D006801:Humans; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000097:blood; D013030:Spain; D011795:Surveys and Questionnaires; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin
keywords: Blood carbon monoxide levels; Carbon monoxide poisoning; Environmental carbon monoxide sources; Fuentes de exposición a monóxido de carbono; Intoxicación por monóxido de carbono; Niveles de monóxido de carbono en sangre