Serum Bicarbonate: Reconsidering the Importance of a Neglected Biomarker in Predicting Clinical Outcomes in Sepsis

• Published in: Curēus (Palo Alto, CA) Vol. 14; no. 4; p. e24012
• Main Authors: Paudel, Robin, Bissell, Brittany, Dogra, Prerna, Morris, Peter E, Chaaban, Said
• Format: Journal Article
• Language: English
• Published: United States Cureus Inc 10.04.2022; Cureus
• Subjects: Body mass index; Chronic obstructive pulmonary disease; Clinical outcomes; Hospitals; Infectious Disease; Intensive care; Internal Medicine; Kidney diseases; Mortality; Nephrology; Patients; Physiology; Sepsis; Ventilators; United States > US; clinical outcomes; predictive value; lactate; sofa score; sepsis; serum bicarbonate
• ISSN: 2168-8184; 2168-8184
• DOI: 10.7759/cureus.24012

Background Despite being an important pathophysiological component, information on the predictive value of serum bicarbonate level in sepsis is limited. Study design and method This is a single-centered retrospective study involving 4176 patients admitted to the medical ICU (MICU) with a diagnosis of sepsis. Patients were divided into two groups based on the presence or absence of chronic kidney disease (CKD) on admission: CKD and non-CKD, respectively. Each group was then divided into three sub-groups based on serum bicarbonate level at presentation (in mEq/l)- low (<22), normal (22-28), and high (>28). We compared the clinical outcomes between the sub-groups in each group, with in-hospital mortality as the primary endpoint. Secondary endpoints included vasopressor-free days, ventilator-free days, ICU-free days, and hospital-free days. Result In both the CKD and non-CKD groups, low serum bicarbonate was associated with significantly increased in-hospital mortality. There was no difference in the mortality between the sub-groups with normal and high serum bicarbonate. When adjusted for other known predictors of mortality, the association of low serum bicarbonate with increased in-hospital mortality was statistically significant only in the patient group with a Sequential Organ Failure Assessment (SOFA) score of ≥9. Additionally, the SOFA score had a better predictive value for in-hospital mortality, ICU-free days, and ventilator-free days when the serum bicarbonate level was <22. Interpretation Serum bicarbonate is a good predictor of clinical outcomes in sepsis and can be used along with other markers of sepsis to predict clinical outcomes.