title: Increased arteriovenous carboxyhemoglobin differences in patients with inflammatory pulmonary diseases.
abstract: OBJECTIVE
  Exhaled carbon monoxide and arterial blood carboxyhemoglobin concentrations increase in inflammatory pulmonary diseases. The present study was undertaken to elucidate whether arteriovenous carboxyhemoglobin (a-vHb-CO) concentration differences are also useful to define the site of inflammation, either in the lung or organs other than the lung.
  
  
  METHODS
  We examined concentrations of carboxyhemoglobin in both arterial and peripheral venous blood and exhaled carbon monoxide in patients with acute pulmonary inflammation including bronchial asthma (n = 18) and pneumonia (n = 33), and those in patients with extrapulmonary inflammatory diseases, including acute pyelonephritis (n = 28) and active rheumatoid arthritis (n = 16).
  
  
  RESULTS
  The values of carboxyhemoglobin in both arterial and peripheral venous blood were significantly higher in patients with pulmonary and extrapulmonary inflammation compared with those in control subjects (n = 22). Furthermore, a-vHb-CO differences in patients with inflammatory pulmonary diseases were higher than those in patients with acute pyelonephritis and patients with rheumatoid arthritis, and than those in control subjects. The a-vHb-CO differences correlated with the WBC count of peripheral venous blood in patients with pneumonia. In patients with bronchial asthma, the a-vHb-CO differences inversely correlated with FEV(1), although they did not correlate with WBC count of peripheral venous blood. The a-vHb-CO differences in patients with acute pyelonephritis were higher than those in patients with active rheumatoid arthritis.
  
  
  CONCLUSIONS
  The present study suggests that a-vHb-CO differences may be a useful means to define the site of inflammation, either in the lung or organs other than the lung, in patients with a fever of unknown origin. The large a-vHb-CO differences may be caused by carbon monoxide production in pulmonary inflammation.
authors.affiliation: Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yasuda
authors.forename: Takahiko
authors.initials: T
authors.lastname: Sasaki
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Yamaya
authors.forename: Satoru
authors.initials: S
authors.lastname: Ebihara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Maruyama
authors.forename: Akio
authors.initials: A
authors.lastname: Kanda
authors.forename: Hidetada
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D001158:Arteries / Q000737:chemistry; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis; D001249:Asthma / Q000097:blood / Q000175:diagnosis; D001784:Blood Gas Analysis; D002263:Carboxyhemoglobin / Q000032:analysis / Q000378:metabolism*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D018836:Inflammation Mediators; D008297:Male; D011014:Pneumonia / Q000097:blood* / Q000175:diagnosis*; D011336:Probability; D011379:Prognosis; D011659:Pulmonary Gas Exchange; D011704:Pyelonephritis / Q000097:blood / Q000175:diagnosis; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014680:Veins / Q000737:chemistry
chemical_list: D018836:Inflammation Mediators; D002263:Carboxyhemoglobin