摘要：AbstractSerum creatinine (SCr) concentrations reflect kidney function in a patient. In an intensive care setting, SCr is used as a method to estimate Acute Kidney Injury (AKI). AKI occurs in a large portion of ICU admissions (Hoste et al. (2006)), and it can lead to devastating impacts on the body, including the development of interstitial and pulmonary edema, toxin accumulation, and excess mortality (Fry and Farrington (2006)). Previous papers have shown the benefits of utilizing an absolute scale for measuring SCr (Waikar and Bonventre (2009)) and the necessity to consider the impact of systemic volume changes on SCr (Pickering et al. (2013)). The present work develops a biologically-motivated low-order model of fluid volume and SCr. Volume is modeled with three interacting spatial compartments representing blood, interstitial fluid, and intracellular fluid; blood is further subdivided between plasma and liquid contained within the hematocrit (red blood cells). The 3-state SCr model uses similar structure, but lumps intracellular and interstitial volumes. Parameters are taken from the literature, where possible, or fitted to achieve physiological thresholds observed experimentally or anecdotally in the clinic. Simulation studies of dehydration and fluid overload across 6 days demonstrate the ability of this model to capture kidney function changes and the physiological responses encountered by ICU patients. Accounting for volume dynamics over a simulated 6-day time period of edema with 10% residual kidney function, this model finds a 23.2% difference in creatinine levels within the body versus a model that neglects volume difference.
