Bicarbonate Fizzes Out: A Study of Intravenous Bicarbonate in Patients with COVID-19-Related Acute Respiratory Distress Syndrome (COVID-ARDS) and Kidney Failure

Background: Data supportive of bicarbonate use in acute metabolic acidosis is minimal, and data in mixed respiratory and metabolic acidosis is further lacking. Bicarbonate therapy has been theorized to temporarily reverse the adverse effects of metabolic acidosis but has no clear mortality benefit in critically ill patients. Furthermore, bicarbonate administration with concomitant severe respiratory acidosis could worsen underlying acidemia as CO2 is generated. During the COVID-19 pandemic, many patients developed sepsis and acute respiratory distress syndrome with mixed respiratory and metabolic acidosis. Sodium bicarbonate was frequently given to improve pH in these patients. We investigated the clinical effects of sodium bicarbonate in this population. Methods: Through a retrospective cohort study at Parkland Hospital spanning June 2020 to June 2023, we identified patients 18 years or older diagnosed with COVID-19 ARDS and renal failure requiring paralytics and renal replacement therapy (RRT) who received 300 millimoles mmol of bicarbonate in 24 hours in addition to alkali provided through RRT. Patients with significant increases in lactic acid were excluded. Through paired t-tests and linear regression we evaluated the effect of sodium bicarbonate on blood pH, pCO2, anion gap (AG), serum bicarbonate, vasopressor requirements, and tidal volumes. Results: In patients with respiratory failure and ARDS from COVID-19 who required RRT (n = 30), bicarbonate therapy was associated with a significant increase in pH and bicarbonate but no statistical change in pCO2, AG, minute ventilation (MV), and vasopressor requirements. Mortality of the studied population was 93%. Conclusion: In patients with fixed MV and combined metabolic and respiratory acidosis, sodium bicarbonate achieved the primary goal of raising pH without increasing pCO2 levels, but was not associated with clinically meaningful outcomes such as vasopressor reduction or decreased MV.