title: Discontinuation of furosemide decreases PaCO(2) in patients with COPD.
abstract: OBJECTIVE
  To evaluate whether the discontinuation of furosemide treatment resulted in a decrease in PaCO(2) and an increase in daytime and nocturnal oxygenation.
  
  
  BACKGROUND
  Furosemide is widely prescribed in patients with COPD for the treatment of peripheral edema. It is known that furosemide causes a metabolic alkalosis. A diminished chemoreceptor stimulation may cause a decreased alveolar ventilation.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled, crossover trial.
  
  
  METHODS
  Department of Pulmonology, Rijnstate Hospital Arnhem, the Netherlands.
  
  
  METHODS
  Twenty patients with stable COPD (10 men; median age, 70 years [range, 58 to 81 years]; FEV(1) 35% predicted [range, 19 to 70% predicted]). Subjects were included if they had received furosemide, 40 mg/d, for the treatment of peripheral edema for at least a month and if they had a mean nocturnal arterial oxygen saturation (SaO(2)) < 92%. Patients with cardiac left and/or right ventricular dysfunction, sleep apneas, and patients receiving other diuretics, angiotensin-converting enzyme inhibitors, potassium or chloride replacement therapy, or long-term oxygen treatment were excluded.
  
  
  METHODS
  Furosemide was discontinued for 1 week and replaced by placebo treatment in the first or the second week.
  
  
  RESULTS
  Ventilation, daytime arterial blood gas levels, and nocturnal SaO(2) were measured at baseline, after 1, and after 2 weeks. Sixteen subjects completed the study. Ventilation increased from 10.4 L/min (range, 6.7 to 15.4 L/min) at baseline to 11.6 L/min (range, 8.7 to 14.0 L/min) after discontinuation of furosemide (p < 0.05). PaCO(2) decreased from 45 mm Hg (range, 35 to 64 mm Hg) to 41 mm Hg (range, 32 to 61 mm Hg; p < 0.01). Daytime and nocturnal oxygenation did not improve.
  
  
  CONCLUSIONS
  Although it does not improve oxygenation, the discontinuation of furosemide decreases PaCO(2) in patients with COPD.
authors.affiliation: Department of Pulmonary Diseases, Rijnstate Hospital Arnhem, The Netherlands. zonnebloem@compuserve.com
authors.forename: Folkert
authors.initials: F
authors.lastname: Brijker
authors.forename: Yvonne F
authors.initials: YF
authors.lastname: Heijdra
authors.forename: Frank J J
authors.initials: FJ
authors.lastname: van den Elshout
authors.forename: Hans Th M
authors.initials: HT
authors.lastname: Folgering
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001826:Body Fluids / Q000378:metabolism; D002248:Carbon Monoxide / Q000032:analysis*; D018592:Cross-Over Studies; D004232:Diuretics / Q000494:pharmacology*; D004311:Double-Blind Method; D004487:Edema / Q000188:drug therapy; D005260:Female; D005665:Furosemide / Q000494:pharmacology*; D006487:Hemostasis / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D010313:Partial Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012129:Respiratory Function Tests
chemical_list: D004232:Diuretics; D005665:Furosemide; D002248:Carbon Monoxide