title: Relationship of metabolic alkalosis, azotemia and morbidity in patients with chronic obstructive pulmonary disease and hypercapnia.
abstract: BACKGROUND
  Exacerbation of chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality, but the effect of metabolic compensation of respiratory acidosis (RA) on mortality is not fully understood.
  
  
  OBJECTIVE
  To investigate the relationship between metabolic compensation and mortality in COPD patients with RA.
  
  
  METHODS
  We prospectively investigated all COPD patients with RA admitted to the respiratory intensive care unit between February 2001 and March 2007. Two hundred and thirteen patients (159 male, 54 female; mean age 65 +/- 10.8 years) were divided into three groups (71 patients each) according to base excess (BE) levels: (1) low BE, (2) medium BE, and (3) high BE. H(+) concentration was calculated according to their standard formula and BE was calculated according to the Van Slyke equation.
  
  
  RESULTS
  The overall mortality rate was 24.9%. The group mortality rates were 32, 17 and 25% in the low, medium and high BE groups, respectively (p = 0.001). When patients were divided into three groups according to the HCO(3)(-) levels, the group mortality rate was 59.1% in the low HCO(3)(-) group and 19.8% in the high HCO(3)(-) group. Based on univariate analysis, six factors affecting mortality were identified. However, multivariate analysis showed that the levels of serum HCO(3)(-) (p = 0.013; OR: 0.552; CI: 0.345-0.882) and creatinine (p = 0.019; OR: 2.114; CI: 1.132-3.949) had an independent effect.
  
  
  CONCLUSIONS
  In patients with COPD exacerbation and hypercapnia, the development of sufficient metabolic compensation and adequate renal function significantly decreases mortality.
authors.affiliation: Respiratory Intensive Care Unit, Department of Chest Diseases, Medical Faculty, Eskisehir Osmangazi University, Eskisehir, Turkey. irfanucgun@hotmail.com
authors.forename: Irfan
authors.initials: I
authors.lastname: Ucgun
authors.forename: Funda
authors.initials: F
authors.lastname: Oztuna
authors.forename: Canan Eren
authors.initials: CE
authors.lastname: Dagli
authors.forename: Huseyin
authors.initials: H
authors.lastname: Yildirim
authors.forename: Cengiz
authors.initials: C
authors.lastname: Bal
mesh_terms: D018806:APACHE; D000368:Aged; D000472:Alkalosis, Respiratory / Q000378:metabolism* / Q000401:mortality; D001639:Bicarbonates / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000378:metabolism* / Q000401:mortality; D008297:Male; D015999:Multivariate Analysis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000401:mortality
chemical_list: D001639:Bicarbonates; D003404:Creatinine