(1585) Acetazolamide Use in Patients With Respiratory Failure and Metabolic Alkalosis: A Meta-Analysis

Introduction: Respiratory failure often leads to hypercapnic respiratory acidosis and in turn, a compensatory metabolic alkalosis. Metabolic alkalosis decreases the respiratory drive hindering ventilator weaning which increases the duration of mechanical ventilation (MV) and hospitalization. Carbonic anhydrase inhibitors such as acetazolamide are often used to reverse this metabolic alkalosis. However, their utility in improving clinical outcomes such as duration of MV, hospitalization, and mortality in patients with respiratory failure and metabolic alkalosis is unclear.

Methods: We searched the following electronic sources from inception to July 2023: CENTRAL, MEDLINE, and PUBMED. Randomized clinical trials were included if they assessed mortality, duration of hospital stay or MV, change in PaCO2, PaO2, pH, or HCO3 levels. We used random-effects meta-analysis to calculate the pooled mean differences (pMD) between patients who received acetazolamide and those who did not.

Results: Among 817 articles identified, 17 articles, with an aggregate of 1,044 participants were included. The use of acetazolamide did not contribute to an increase or decrease in the mortality rate ( RR- 0.811; 95%CI: 0.522 to 1.261), duration of hospital stay (pMD: 0.109, 95%CI: -0.188 to 0.407) or duration of MV (pMD: 0.231, 95%CI: -0.747 to 0.285) despite significantly reducing the PaCO2 levels (pMD: -3.04mmHg, 95%CI: -0.587 to -0.021), HCO3 levels (pMD: -4.404meq/L, 95%CI: -7.131 to -1.678) and improving pH (pMD 0.619, 95%CI: -1.105 to -0.132).

Conclusions: Acetazolamide use in patients with respiratory failure and metabolic alkalosis significantly reverses the acid-base abnormality by decreasing the PaCO2 and the bicarbonate levels and improving the pH. However, it’s effect on clinically important outcomes such as duration of MV, hospitalization, and mortality rate is inconclusive, questioning the respiratory benefit offered by the use of acetazolamide. This could be due to the paucity of trials assessing these outcomes contributing to an inadequate statistical power to detect a difference. Well-designed multicenter randomized control trials assessing an important ventilatory measure such as duration of MV or ventilator weaning, are needed to further assess the effect of acetazolamide use on these outcomes.