Urinausgabe

Urinausgabe, also referred to as urine output, denotes the volume of urine expelled by the kidneys into the bladder within a given time frame. In clinical practice, it is a fundamental parameter for assessing renal function, fluid balance, and hemodynamic status. Normal adult urine output ranges from 0.5 to 1 mL kg⁻¹ h⁻¹, corresponding to approximately 800–2 000 mL per day, although values may vary with age, sex, body size, and environmental conditions.

Measurement techniques include direct collection in calibrated containers, catheterization with suction bags, and electronic monitoring systems that record volume continuously. In intensive care units, hourly tracking is routine, allowing rapid detection of oliguria (output < 0.5 mL kg⁻¹ h⁻¹) or polyuria (output > 3 L per day), both of which can signal underlying pathology. Oliguric states may result from hypovolemia, renal artery obstruction, acute tubular necrosis, or drug toxicity, whereas polyuria is often associated with uncontrolled diabetes mellitus, diuretic therapy, or osmotic diuresis.

Urinausgabe is integrated into diagnostic criteria for acute kidney injury (AKI) and guides therapeutic decisions such as fluid resuscitation, vasoactive medication adjustment, and renal replacement therapy initiation. Normalization of urine output is frequently used as a clinical endpoint to evaluate treatment efficacy. In addition to volume, qualitative aspects—specific gravity, presence of protein, glucose, or blood—are assessed concurrently to provide a comprehensive picture of renal health. Accurate documentation and interpretation of urine output remain essential components of patient monitoring across diverse medical specialties.