Effectiveness of acetazolamide for reversal of metabolic alkalosis in weaning COPD patients from mechanical ventilation.

PURPOSE: To evaluate the effects of a single daily dose of acetazolamide (ACET) on metabolic alkalosis and respiratory parameters in weaning chronic obstructive pulmonary disease (COPD) patients from invasive mechanical ventilation.
DESIGN: Case-control study.
SETTING: An 18-bed intensive care unit (ICU) in a university hospital. PATIENTS: Twenty-six intubated COPD patients with mixed metabolic alkalosis (serum bicarbonate >26 mmol/l and arterial pH >or=7.38) were compared with a historical control group (n = 26) matched for serum bicarbonate, arterial pH, age, and severity of illness at admission to ICU. ACET administration (500 mg intravenously) was monitored daily according to arterial blood gas analysis from readiness to wean until extubation.
RESULTS: ACET was administered 4 (1-11) days throughout the weaning period. Patients with ACET treatment significantly decreased their serum bicarbonate (p = 0.01 versus baseline) and arterial blood pH (p < 0.0001), increased their PaO(2)/FiO(2) ratio (p = 0.04), but did not change their PaCO(2) (p = 0.71). Compared with matched controls, administration of ACET did not improve arterial blood gas and respiratory parameters except PaO(2)/FiO(2) ratio (p = 0.03). ACET patients and their matched controls had similar duration of weaning. Extubation success rate was not significantly different between groups, and causes of reintubation were comparable.
CONCLUSIONS: ACET used at the dosage of 500 mg per day reduces metabolic alkalosis but has no benefit in terms of improving PaCO(2) or respiratory parameters in weaning COPD patients from mechanical ventilation.