Bicarbonate use and mortality outcome among critically ill patients with metabolic acidosis: A meta analysis

Background: The use of sodium bicarbonate in the treatment of metabolic acidosis in critically ill subjects has long been a subject of debate. Despite empiric use in the setting of severe acidemia in critically ill patients, there is little data looking into the role of sodium bicarbonate in the treatment of severe metabolic acidosis in the intensive care unit (ICU) setting.

Methods: We conducted a comprehensive search of Pubmed and Cochrane Central Register of Controlled Trials addressing bicarbonate use in the metabolic acidosis in the intensive care unit (ICU) setting. We examined mortality as end point. Pooled odds ratios (OR) and their 95% confidence intervals (CI) were calculated for all outcomes using a random-effect model.

Results: The final search yielded 202 articles of which all were screened individually. A total of 11 studies were identified but 6 studies were excluded due to irrelevance in mortality outcome and methodology. Analysis was done separately for observational studies and randomized controlled trials. The pooled OR [95% CI] for mortality with bicarbonate use in the observational studies was 1.5 [0.62-3.67] with heterogeneity of 67%, while pooled OR for mortality in the randomized trials was 0.72 [0.49-1.05] (figure 2). In combining all studies, the pooled odds ratio was 0.93 95% [0.69-1.25] but with heterogeneity of 63%. After sensitivity analysis with removing the study done by Kim et al. 2013, heterogeneity was 0% with OR 0.8 [0.59-1.10].

Conclusion: There is no significant difference in mortality in the use of bicarbonate among critically ill patients with high anion gap metabolic acidosis predominantly driven by lactic acidosis.