title: Acetazolamide improves oxygenation in patients with respiratory failure and metabolic alkalosis.
abstract: BACKGROUND
  Coexistent respiratory failure and metabolic alkalosis is a common finding. Acidotic diuretics cause a fall in pH that may stimulate respiration.
  
  
  OBJECTIVE
  The purpose of the study was to evaluate the effectiveness of short-term treatment with acetazolamide for combined respiratory failure and metabolic alkalosis.
  
  
  METHODS
  A randomised, placebo-controlled and double-blind parallel group trial where oral acetazolamide 250 mg three times a day for 5 days were administered to patients hospitalised for respiratory failure because of a pulmonary disease (Pa O2 ≤ 8 kPa and/or Pa CO2 ≥ 7 kPa) who had concurrent metabolic alkalosis [base excess (BE) ≥ 8 mmol/L]. Pa O2 after 5 days was the primary effect variable. Secondary effect variables were Pa CO2 , BE and pH on day 5, and the total number of days in hospital.
  
  
  RESULTS
  Of 70 patients enrolled (35 in each group), data from 54 were analysed per protocol, while last observation carried forward was used for the remaining 16. During the 5-day treatment, Pa O2 increased on average 0.81 kPa in the placebo group and 1.41 kPa in the acetazolamide group. After adjustment for baseline skewness, the difference was statistically significant (adjusted mean difference 0.55 kPa, 95% confidence interval 0.03-1.06). Pa CO2 decreased in both groups, but the difference was not statistically significant. As expected, pH and BE decreased markedly in the acetazolamide group.
  
  
  CONCLUSIONS
  Acetazolamide may constitute a useful adjuvant treatment mainly to be considered in selected patients with respiratory failure combined with prominent metabolic alkalosis or where non-invasive ventilation is insufficient or infeasible.
authors.affiliation: Department of Pulmonary Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Ragnhild
authors.initials: R
authors.lastname: Gulsvik
authors.forename: Ingunn
authors.initials: I
authors.lastname: Skjørten
authors.forename: Kenneth
authors.initials: K
authors.lastname: Undhjem
authors.forename: Lars
authors.initials: L
authors.lastname: Holø
authors.forename: Anne
authors.initials: A
authors.lastname: Frostad
authors.forename: Eirunn Waatevik
authors.initials: EW
authors.lastname: Saure
authors.forename: Vasvija
authors.initials: V
authors.lastname: Lejlic
authors.forename: Sjur
authors.initials: S
authors.lastname: Humerfelt
authors.forename: Gunnar
authors.initials: G
authors.lastname: Hansen
authors.forename: Torgeir
authors.initials: T
authors.lastname: Bruun Wyller
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage*; D000368:Aged; D000369:Aged, 80 and over; D000471:Alkalosis / Q000188:drug therapy* / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage; D004311:Double-Blind Method; D004573:Electrolytes / Q000097:blood; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D000860:Hypoxia / Q000188:drug therapy / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000378:metabolism; D012131:Respiratory Insufficiency / Q000188:drug therapy* / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D004573:Electrolytes; D002245:Carbon Dioxide; D000086:Acetazolamide; D010100:Oxygen
keywords: acetazolamide; chronic obstructive pulmonary disease; hypoxia; metabolic alkalosis; respiratory failure