Discontinuation of furosemide decreases PaCO(2) in patients with COPD.
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.
Brijker
Folkert
F
Department of Pulmonary Diseases, Rijnstate Hospital Arnhem, The Netherlands. zonnebloem@compuserve.com
Heijdra
Yvonne F
YF
van den Elshout
Frank J J
FJ
Folgering
Hans Th M
HT
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
D004232:Diuretics; D005665:Furosemide; D002248:Carbon Monoxide