Elevated strong ion gap: A predictor of the initiation of continuous renal replacement therapy in acute kidney injury

Abstract

BackgroundThere is no optimal timing for continuous renal replacement therapy (CRRT) in acute kidney injury (AKI). AKI is a reason for the increased unmeasured anions, which refers to the increased organic acids in the blood, and they can be detected by calculating strong ion gap (SIG). SIG level at the moment of the AKI diagnosis may be a predictor for the initiation of CRRT. MethodsPatients who were diagnosed with AKI in the first week of the intensive care unit (ICU) period were included in this prospective observational study. At the moment of the AKI diagnosis, blood gas samples were recorded, and SIG was calculated. ResultsThe median level of SIG at the moment of the AKI diagnosis of CRRT (+) patients was significantly higher than CRRT (-) patients (7.4 and 3.2 mmol L−1, respectively). In the multivariate Cox regression analysis, the likelihood of the initiation of CRRT was increased 1.16-fold (1.01-1.33) and 4.0-fold (1.9-8.7) by only 1 mmol L−1 increases in SIG and SIG ≥6 mmol L-1 at the moment of AKI diagnosis, respectively (p = 0.035 and p < 0.001). ConclusionsIncreased SIG at the moment of the AKI diagnosis in patients with AKI may be a predictive marker to initiate CRRT.