OBJECTIVES: Augmented renal clearance (ARC), in contrast to renal dysfunction, refers to enhanced renal elimination of circulating solutes compared to the expected baseline. Although patients may present with normal serum creatinine (Scr) levels, the incidence of ARC is high in intensive care unit (ICU) settings. ARC is associated with subtherapeutic exposure and treatment failure of renally cleared antibiotics. However, limited research exists on the incidence and risk factors of ARC in the ICU, and even fewer data are available specifically for neurological ICU (NICU). This study aims to determine the incidence and risk factors of ARC in neurocritically ill patients. METHODS: We retrospectively analyzed all available Scr data of neurocritical care patients admitted to the NICU of the Second Xiangya Hospital of Central South University between December 2020 and January 2023. Creatinine clearance (CrCl) was calculated using the Cockcroft-Gault equation. ARC was defined as a CrCl≥130 mL/(min·1.73 m²) sustained for more than 50% of the duration of the NICU stay. A total of 208 neurocritically ill patients were assigned into an ARC group (n=52) and a non-ARC (N-ARC) group (n=156). Clinical characteristics were compared between the 2 groups. Variables with P<0.05 in univariate analysis were included in binary Logistic regression to identify independent risk factors for ARC. RESULTS: The incidence of ARC among neurocritically ill patients was 25.00%. Of the 74 patients with normal CrCl, 20 (27.03%) gradually developed ARC during hospitalization. Compared with the N-ARC group, the patients of the ARC group were younger (P<0.001), with a higher proportion of females (P=0.048) and a lower admission mean arterial pressure (MAP) (P=0.034). Moreover, patients of the ARC group were commonly complicated with severe bacterial infections compared with the patients of the N-ARC group (P<0.001). In binary Logistic regression analysis, younger age (OR=0.903, 95% CI 0.872 to 0.935) and severe bacterial infections (OR=6.270, 95% CI 2.568 to 15.310) were significant predictors of ARC. CONCLUSIONS ARC is relatively common in the NICU. A considerable number of patients with initially normal renal function developed ARC during hospitalization. Younger age and concurrent severe bacterial infection are important risk factors of ARC in neurocritically ill patients.
Humans ; Risk Factors ; Female ; Male ; Retrospective Studies ; Creatinine/blood* ; Middle Aged ; Intensive Care Units ; Aged ; Adult ; Incidence ; Critical Illness ; Renal Elimination ; Kidney/metabolism*

Adding to the complexity of caring for critically ill patients is the fact that many of them have a creatinine clearance that exceeds 130 mL/min/1.73 m². This phenomenon, termed augmented renal clearance (ARC), has only recently been widely recognized and its pathogenesis remains incompletely understood. However, ARC has been shown to result in increased dose requirements for drugs that are primarily eliminated by renal excretion, including many antimicrobial agents and enoxaparin. Recognition of ARC is hampered by the fact that the standard creatinine-based equations used to estimate renal function are not accurate in this clinical setting and the diagnosis is best established using both serum and urine creatinine measurements to calculate clearance. So a high index of clinical suspicion and awareness is usually required before this step is taken to confirm the diagnosis of ARC.
Anti-Infective Agents ; Creatinine ; Critical Illness ; Diagnosis ; Enoxaparin ; Humans ; Renal Elimination

Vancomycin is a widely used glycopeptide antibiotic that requires therapeutic drug monitoring (TDM) owing to its narrow therapeutic window. It is primarily eliminated by renal excretion; thus, estimating the renal function of a patient is vital in the TDM of vancomycin. In patients with Duchenne muscular dystrophy (DMD), it is difficult to estimate the glomerular filtration rate using the serum creatinine level owing to the pathophysiological nature of the disease. Here, we report a case of a patient in whom TDM of vancomycin was performed, and explore the appropriate methods for evaluating renal function in patients with DMD based on serum levels of creatinine and cystatin C.
Creatinine ; Cystatin C ; Drug Monitoring* ; Glomerular Filtration Rate ; Humans ; Muscular Dystrophy, Duchenne* ; Renal Elimination ; Vancomycin*

Familial renal glycosuria (FRG) is an inherited disorder characterized by persistent glycosuria in the absence of hyperglycemia. It is caused by mutations in the sodium-glucose co-transporter, leading to increase in the renal excretion of glucose and sodium. However, there have been no studies on the role of fasting and postprandial changes in the urinary sodium excretion in patients with FRG. We report a case of renal glycosuria, which was confirmed by a SLC5A2 mutation via gene sequencing, and compared the postprandial urinary glucose and sodium excretion. A 26-year-old man sometimes experienced glycosuria on routine screening; however, other laboratory findings were normal. His fasting and postprandial urinary glucose excretion levels were 295mg/dL and 2,170mg/dL, respectively. The fasting and postprandial urinary sodium excretion levels were 200mEq/L and 89mEq/L, respectively. In patients with FRG, excessive diuresis might be prevented by a compensatory mechanism that reduces postprandial sodium excretion.
Adult ; Diuresis ; Fasting ; Glucose ; Glycosuria* ; Glycosuria, Renal ; Humans ; Hyperglycemia ; Mass Screening ; Renal Elimination ; Sodium ; Sodium-Glucose Transport Proteins

Lithium salts are being used increasingly to treat patient with affective disorders, especially acute mania, or bipolar manic-depressive illness. For therapeutic effect the lithium content must be maintained at or above a particular level. Lithium poisoning due to overdosage may be seen occasionally, and its course is determined primarily by the rate of renal lithium elimination. A search is therefore indicated for procedures that could raise the lithium clearance. In a number of reports renal lithium excretion has been studied in relation to the excretion of water, sodium, potassium and hydrogen, but effects of sodium or water on the lithium excretion has not yet been clarified. Hence the present study was undertaken to investigate the effects of corticosteroid on the excretion of lithium ion. The female rat (Sprague-Dowley), weighing from 200 to 300g, was injected with 50mg/kg of lithium chloride intraperitoneally, and then injected with graded dosage of fludrocortisones and dexamethasone in each group. During the injected rats were incubated in metabolic cage, 24 hour urine of rats were collected. At 24 hours after injection, the rats were sacrificed with guillotine, the blood were collected. And then the concentrations of Na⁺, K⁺, Li⁺ of collected urine and serum were checked by Flame photometer. The results are summarized as follows 1. Fludrocortisone decreased the serum concentration of lithium and increased the urinary excretion of lithium. 2. In the group treated with low dose of dexamethasone (0.1 mg/kg), the serum concentration of lithium was decreased and high dose of dexamethasone (1 mg/kg) increased the urinary excretion of lithium. 3. Fludrocortisone increased the urinary [Na⁺]/[K⁺] in serum and decreased [Na⁺]/[K⁺] inurine, but opposite effects were occurred in dexamethasone. By above results, it may be concluded that corticosteroid increased the urinary excretion of lithium and decreased the serum concentration of lithium, but it seems to be there in no relationship between these effects of corticosteroid and of the renal Na⁺ or K⁺ transport.
Adrenal Cortex Hormones* ; Animals ; Bipolar Disorder ; Dexamethasone ; Female ; Fludrocortisone ; Humans ; Hydrogen ; Lithium Chloride ; Lithium* ; Mood Disorders ; Poisoning ; Potassium ; Rats ; Renal Elimination* ; Salts ; Sodium ; Water