Acute kidney injury (AKI) is one of the most common serious complications in critically ill patients, and it is an independent risk factor for death. In recent years, renal replacement therapy (RRT) has become one of the routine treatments for AKI patients, however there is no accepted consensus on the optimal timing of RRT over the world. This paper reviewed the clinical studies carried out by researchers in the field of critical care and nephrology, thereby summarized and analyzed the related parameters of the optimal time to carry out, with the exception of previously acknowledged classic RRT indications such as hyperkalemia, severe metabolic acidosis, volume overload and so on. The feasible parameters such as serum creatinine (SCr), blood urea nitrogen (BUN), urine volume, the time admitted in the intensive care unit (ICU) and several standards distinguished AKI stages are discussed in order to find out the cutoff points of those parameters which were best for the patients' outcome, and to provide guidance of decision making for the optimal timing of RRT for AKI patients.

Objective To analyze the characteristics of change in plasma cholesterol level in patients with sepsis, and to explore its relationship with prognosis and its clinical significance. Methods A retrospective analysis was conducted. 568 patients with sepsis admitted to Department of Critical Care Medicine of Beijing Friendship Hospital Affiliated to Capital Medical University from August 2013 to August 2015 were enrolled, and 475 patients without sepsis hospitalized in the same period served as the control. The basic clinical data of the two groups were collected, and the results of blood fat and biochemical parameters were compared. The patients with sepsis were divided into death group and survival group, and risk factors influencing the prognosis of patients with sepsis were analyzed with multivariate logistic model regression analysis. Results Compared with non-sepsis patients, the levels of plasma total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) in the patients with sepsis were significantly lower [TC (mmol/L): 2.5±1.2 vs. 3.4±1.4, t = 4.274, P = 0.021; HDL-C (mmol/L): 1.6±0.9 vs. 2.5±0.8, t = 3.413, P = 0.018], and that of low density lipoprotein cholesterol (LDL-C) showed no statistically significant difference (mmol/L: 1.9±0.9 vs. 2.1±0.9, t = 0.749, P = 0.614). In the patients with sepsis, the patients in death group (n = 227) were older than those of the survival group (n = 341, years: 74.3±15.5 vs. 65.5±17.5, t = 4.037, P = 0.012), serum creatinine (SCr) was higher than that of survival group (μmol/L: 251.0±115.6 vs. 167.4±108.7, t = 3.254, P = 0.023), the levels of plasma TC, HDL-C and LDL-C were significantly lower than those of survival group [TC (mmol/L): 2.2±1.6 vs. 2.9±1.1, t = 3.057, P = 0.023; HDL-C (mmol/L): 1.4±0.8 vs. 1.9±0.8, t = 4.692, P = 0.016; LDL-C (mmol/L): 1.7±0.7 vs. 2.0±0.8, t = 2.541, P = 0.038]; there was no significant difference in the proportion of male, body mass index (BMI), based disease, intensive care unit (ICU) hospitalization time, the severity of the disease and other biochemical indexes between two groups. With single factor analysis with indicators of statistical significance as a covariate into binary logistic regression equation, the results show that age was the risk factor of death in patients with sepsis [odds ratio (OR) = 1.024, 95% confidence interval (95%CI) = 1.010-1.048, P = 0.009], and TC was the protective factor on the prognosis of patients with sepsis (OR = 0.747, 95%CI = 0.682-0.811, P = 0.013). Conclusions Plasma cholesterol levels in patients with sepsis were significantly lowered, and the levels in death group was significantly lower than that in the survival group. TC may be used as a clinical indicator to assess the outcome of patients with sepsis.