Sodium Bicarbonate Supplementation May Be Harmful in Septic Patients with Severe Lactic Acidosis: A Retrospective Analysis

Background: Lactic acidosis is a common cause of metabolic acidosis in severely ill patients. Administrating sodium bicarbonate may be considered in lactic acidosis with pH <7.0, however the effect of sodium bicarbonate on mortality remains controversial. We aimed to evaluate the effect of sodium bicarbonate on mortality in patients with severe septic lactic acidosis. Methods: Single-center analysis was conducted from May 2011 to April 2021 at Dong-A University Hospital, Korea. We screened 1987 patients with initial pH<7.2, lactate<19.8mg/dL(2.2mmol/L), and positive blood culture. 695 patients with pCO2>45mmHg or without follow-up lactate were excluded. We classified 1292 patients into two groups depending on sodium bicarbonate supplementation. Results: Sodium bicarbonate group was 746 and control group was 545. Mean age was 66.8±13.3 years and male was 60.4%. Sodium bicarbonate group had significantly higher 7-day(25.2% to 15.0%) and 28-day(48.5% to 32.1%) mortality rate. More patients were treated with CKRT(continuous kidney replacement therapy), ventilator, and catecholamine in the sodium bicarbonate group. The difference of 7-day and 28-day mortality rate between two groups was prominent in patients below pH<7.0, whereas patients with pH 7.1-7.2 showed no difference of mortality rate. Similar results were shown in the Kaplan-Meier curve(Figure 1). Sodium bicarbonate was associated with 7-day(HR=1.800, p<0.001) and 28-day(HR=1.601, p<0.001) mortality in the Cox regression model. Sodium bicarbonate was only associated with 7-day(HR=2.245, p=0.034) and 28-day(HR=2.285, p=0.004) mortality in patients below pH<7.0. Conclusion: Administrating sodium bicarbonate may be harmful in septic patients with severe lactic acidosis. Sodium bicarbonate should be carefully administered in septic lactic acidosis even with pH<7.0.Figure 1. Kaplan-Meier Curve of 7 day Mortality