IntroductionAcid-base disorder is an important issue that requires an urgent solution in the intensive care unit (ICU) (1). Stewart's physiochemical approach provides practical solutions for the understanding of metabolic acid-base disorders (2-4). However, this approach has limitations that prevent intensivists from completing a fast bedside assessment. Therefore, methods enabling fast and accurate bedside assessment are needed. Recently, simpler and more practical approaches, such as assessments of Cland Na + differences, Cl -:Na + ratio evaluation, and base excesschloride (BE Cl ) calculations, have been used (5,6). Duward et al. (6) evaluated acid-base disorders in accordance with pH, pCO 2 , and Clchanges. According to Duward et al. (6), the main reason for the changes in the HCO 3 pool is changes in Cl -. Moreover, Clmust always be interpreted together with Na + , and the simplest method of achieving this interpretation is calculation of the Cl -:Na + ratio. Hypochloremia or hyperchloremia should be considered in accordance with the Cl -:Na + ratio. Regardless of the individual Cland Na + concentrations, the Cl -:Na + ratio may be low or high. This notion makes the contribution of Clto acid-base disorder more comprehensible. It is indicated that a strong ion difference (SID) is related to mortality (7,8). Hypochloremia, hyperchloremia, and dysnatremia are also known to be associated with increased mortality (9-11). Thus, the Cl:Na + ratio can also be associated with increased mortality. In the present study, the relationship between the Cl -:Na + ratio in septic patients at ICU admission and each of the other components of the acid-base balance and ICU mortality was investigated.
Material and methods
Study designEthics committee approval was obtained from the Acıbadem University Medical Research Council for the present study. A total of 2691 patients admitted to the Acıbadem International Hospital ICU and Ataşehir Memorial ICU between 1 January 2006 and 31 December 2012 were retrospectively evaluated. Patients who were Background/aim: Calculation of the chloride:sodium (Cl -:Na + ) ratio is proposed to enable a quick evaluation of the effect of Cland 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 acidbase 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 HCO 3 -, standard base excess, and PaCO 2 (r 2 = 0.21, r 2 = 0.19, and r 2 = 0.17) (P < 0.001 for each). In the multivariate analysis, the ICU mortal...