The effects of the chloride:sodium ratio on acid-base status and mortality in septic patients

Background/aim: Calculation of the chloride: sodium (Cl-: Na+) ratio is proposed to enable a quick evaluation of the effect of Cl- and Na+ on the acid-base balance in critically ill patients. In the present study, the relationship of the Cl-: Na+ ratio of septic patients with acid-base status and ICU mortality were investigated. Materials and methods: In our two-center study, 434 patients who were diagnosed with sepsis were included. The patients were divided into three groups: low (< 0.75), normal (>= 0.75, < 0.80), and high (>= 0.80) Cl-: Na+ ratio groups. Patients' demographic data, blood gas values, length of ICU stay, and ICU mortality were recorded. Results: In the low and high groups, ICU mortality was significantly higher than in the normal group (29.3%, 37.1%) (P = 0.005). There was a negative correlation between the Cl-: Na+ ratio and each of HCO3-, standard base excess, and PaCO2 ( r(2) = 0.21, r(2) = 0.19, and r(2) = 0.17) ( P < 0.001 for each). In the multivariate analysis, the ICU mortality was increased 2.6-fold (1.2-5.8) by low Cl-: Na+ ratio (P - 0.019). Conclusion: The Cl-: Na+ ratio is a useful parameter for showing the relationship between Cl- and Na+ and their impact on acid-base status. Low Cl-: Na+ ratio at ICU admission can be used as a prognostic indicator for increased ICU mortality in septic patients.