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Clinical Investigation

Poster Session II and Exhibits

(121) Evaluating the Association of Renal Tissue Oxygenation to Venous, Arterial, and Capillary Blood Gas Oxygen Saturation in Preterm Neonates

Thursday, September 18, 2025
2:00 PM - 3:00 PM CT

    Presenting Author(s)

  • Ria D. Patel, B.S.

    Medical Student
    University of Wisconsin School of Medicine and Public Health
    Madison, WI, United States

    • Co-Author(s)

  • Matthew W. Harer, MD

    Associate Professor
    University of Wisconsin School of Medicine and Public Health
    Madison, WI, United States

  • SS

    Shayla Schwingle, BS (she/her/hers)

    Clinical Research Coordinator II
    University of Wisconsin School of Medicine and Public Health
    Madison, Wisconsin, United States

Background: Between 18-48% of preterm neonates < 32 weeks’ gestation in the Neonatal Intensive Care Unit (NICU) are diagnosed with acute kidney injury (AKI), which has been associated with increased mortality and longer hospitalizations. Near-infrared spectroscopy (NIRS) is a non-invasive method of measuring renal tissue oxygenation, introducing the potential to detect and diagnose AKI earlier than increases in serum creatine or decreases in urine output. NIRS provides primarily a post-capillary assessment of oxygenation, believed to be about 75% venous, 20% arterial, and 5% capillary in the brain. However, the correlation of regional renal tissue oxygenation (RrSO2) to oxygen levels from venous (SvO2), arterial (SaO2), and capillary (ScO2) blood gases is not known.

Objectives: The aim of this study is to determine the association of (RrSO2) measured by NIRS to arterial, venous, and capillary blood gas oxygen levels in neonates born at < 32 weeks’ gestation.

Design/Methods: This is a secondary analysis of a prospective RrSO2 monitoring study in preterm neonates < 32 weeks’ gestation admitted to a single center level 3 NICU. RrSO2 was measured using INVOS 5100C NIRS monitors that were applied to the flank region within the first 96 hours of life. Renal tissue oxygenation was measured and recorded every 5 seconds. RrSO2 values were averaged over 1, 3, and 5 minutes at the time of each blood draw. Neonates with venous, arterial, and capillary blood oxygen levels measured during the time of NIRS monitoring were included in this study. Blood gas oxygen levels were collected: venous via umbilical venous catheter (UVC), arterial via umbilical arterial catheter (UAC), and capillary via heel stick. Proper UVC placement was confirmed on radiographic imaging; only properly placed UVC samples were used in this study. Descriptive statistics, Mann-Whitney U tests, and Spearman’s statistical analyses were performed to assess the relationships between RrSO2 and SvO2, SaO2, and ScO2. Statistical analysis was completed using Graph Pad Prism.

Results:

Conclusions: