Acetazolamide use in severe COPD exacerbations requiring invasive mechanical ventilation: impact on duration of mechanical ventilation

We read with interest the article titled “Effect of Acetazolamide vs. Placebo on Duration of Invasive Mechanical Ventilation Among Patients With Chronic Obstructive Pulmonary Disease: A Randomized Clinical Trial” by Faisy et al. (1) where the authors have and colleagues randomly assigned patients with chronic obstructive pulmonary disease (COPD) who required invasive mechanical ventilation to receive either acetazolamide 500 mg intravenously twice daily (1,000 mg if loop diuretics were also prescribed) or matching placebo up to 28 days. A total of 382 patients with COPD who were expected to receive mechanical ventilation for more than 24 hours to acetazolamide (500–1,000 mg, twice daily) or placebo, administered intravenously in cases of pure or mixed metabolic alkalosis. The main results were: among 382 randomized patients, 380 [mean age, 69 years; 272 men (71.6%); 379 (99.7%) with endotracheal intubation] completed the study. For the acetazolamide group (n=187), compared with the placebo group (n=193), no significant between-group differences were found for median duration of mechanical ventilation (–16.0 hours; 95% CI, –36.5 to 4.0 hours; P=0.17). For secondary outcomes, there is no difference in duration of weaning off mechanical ventilation (–0.9 hours; 95% CI, –4.3 to 1.3 hours; P=0.36), in changes of minute-ventilation (–0.0 L/min; 95% CI, –0.2 to 0.2 L/min; P=0.72), or partial carbon-dioxide pressure in arterial blood (–0.3 mmHg; 95% CI, –0.8 to 0.2 mmHg; P=0.25). However, the authors observed a significant daily changes of serum bicarbonate (between-group difference, –0.8 mEq/L; 95% CI, –1.2 to –0.5 mEq/L; P<0.001), in the number of days with metabolic alkalosis (between-group difference, –1 days; 95% CI, –2 to –1 days; P<0.001) and significantly increased in the PaO₂:FIO₂ ratio in the acetazolamide group’s. Other secondary outcomes also did not differ significantly between groups.