Supplementary Material for: Urinary output of very low birth weight infants during the first weeks of life

Introduction:
Daily urinary output (UOP) serves as important tool to identify acute kidney injury (AKI) in preterm infants. However, reference values for UOP, especially stratified for gestational age, are missing.

Methods:
This retrospective single-center study assessed UOP during the first 28 days of life in 128 very low birth weight (VLBW) infants.

Results:
VLBW infants exhibit a highly dynamic daily UOP profile in the first 28 days of life with a maximum at day 12 with 4.78 ml/kg bodyweight/h. In the subcohort of 64 extremely low gestational age neonates (ELGAN), the highest UOP is measured during the second week of life. Infants born before 24 weeks of gestation have significantly higher UOP than more mature infants.

Conclusion:
UOP is dynamic in the postnatal period and differs significantly between gestational age cohorts in the subgroup of ELGANs. These data might point to an adaption of the UOP threshold for neonatal AKI in preterm infants.

引言：每日尿量（UOP）是识别早产儿急性肾损伤（AKI）的重要工具。然而，目前缺乏尿量的参考值，尤其是按胎龄分层的参考值。

方法：本回顾性单中心研究评估了128例极低出生体重（VLBW）婴儿出生后前28天的尿量。

结果：极低出生体重婴儿在出生后前28天的每日尿量变化极具动态性，第12天达到峰值，为4.78毫升/千克体重/小时。在64例极早期胎龄新生儿（ELGAN）亚组中，尿量峰值出现在出生后第二周。胎龄小于24周的婴儿尿量显著高于胎龄更大的婴儿。

结论：早产儿出生后尿量呈动态变化，且在极早期胎龄新生儿亚组中，不同胎龄队列间的尿量存在显著差异。这些数据提示，早产儿新生儿急性肾损伤的尿量阈值可能需要调整。