title: Carboxyhemoglobin and methemoglobin in asthma.
abstract: Nitric oxide (NO) and carbon monoxide (CO) are synthesized at high levels in asthmatic airways. NO can oxidize hemoglobin (Hb) to methemoglobin (MetHb). CO binds to heme to produce carboxyhemoglobin (COHb). We hypothesized that MetHb and COHb may be increased in asthma. COHb, MetHb, and Hb were measured in venous blood of healthy controls (n = 32) and asthmatics (n = 31). Arterial COHb and oxyhemoglobin were measured by pulse CO-oximeter. Hb, oxyhemoglobin, and deoxyhemoglobin were similar among groups, but arterial COHb was higher in asthmatics than controls (p = 0.04). Venous COHb was similar among groups, and thus, arteriovenous COHb (a-v COHb) concentration difference was greater in asthma compared with controls. Venous MetHb was lower in asthma compared to controls (p = 0.01) and correlated to venous NO (p = 0.009). The greater a-v COHb in asthma suggests CO offloading to tissues, but lower than normal MetHb suggests countermeasures to avoid adverse effects of high NO on gas transfer.
authors: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave/NC22, Cleveland, OH, 44195, USA.
authors: Robert
authors: R
authors: Naples
authors: Dan
authors: D
authors: Laskowski
authors: Kevin
authors: K
authors: McCarthy
authors: Emmea
authors: E
authors: Mattox
authors: Suzy A A
authors: SA
authors: Comhair
authors: Serpil C
authors: SC
authors: Erzurum
mesh_terms: D000328:Adult; D001158:Arteries; D001249:Asthma / Q000097:blood*; D001784:Blood Gas Analysis; D001944:Breath Tests; D002263:Carboxyhemoglobin / Q000032:analysis*; D016022:Case-Control Studies; D005260:Female; D005541:Forced Expiratory Volume; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D008706:Methemoglobin / Q000032:analysis*; D009569:Nitric Oxide / Q000097:blood; D010092:Oximetry; D010108:Oxyhemoglobins / Q000032:analysis; D014680:Veins; D014797:Vital Capacity
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D009569:Nitric Oxide; C100003:deoxyhemoglobin; D008706:Methemoglobin; D002263:Carboxyhemoglobin