Low Renal Oxygen Saturation at Near-Infrared Spectroscopy on the First Day of Life Is Associated with Developing Acute Kidney Injury in Very Preterm Infants

Abstract

Background: Acute kidney injury (AKI) is a frequent complication in preterm infants, and the identification of early markers of renal hypoperfusion is a chief challenge in neonatal intensive care units. Objectives: To describe the association between early markers of cardiovascular function and renal perfusion with AKI occurrence in a cohort of preterm infants < 32 weeks’ gestation. Methods: 128 infants were prospectively included from birth to discharge. During the first day of life, we assessed cardiovascular function, systemic and organ blood flow by Doppler ultrasound, and monitored cerebral and renal regional oxygen saturation (rSO₂) using near-infrared spectroscopy (NIRS). These measures were analyzed in relation to developing AKI and serum creatinine (SCr) peak from day 2 to 7 of life. Results: 12 of 128 infants presented with AKI (9.4%). SCr peak was 155.3 ± 30.2 µmol/L in infants with AKI versus 82.0 ± 16.5 in non-AKI infants (p < 0.001). Among all measures of cardiovascular function and renal perfusion, low mean cerebral and renal rSO₂ during the first day of life and a low resistive index at renal artery Doppler were significantly associated with developing AKI. After adjustment for possible confounding factors, low renal rSO₂ on the first day of life remained associated with a high SCr peak from day 2 to 7 of life. Conclusion: Low renal rSO₂ values during the first day of life correlate with developing AKI in preterm infants < 32 weeks’ gestation. NIRS monitoring of renal function during adaptation seems promising, and its very early use after birth to detect kidney hemodynamic dysfunction deserves further investigations.

Regional oxygen saturation and acute kidney injury in premature infants

“…The low renal rSO 2 levels were found to be associated with high serum creatinine values in the second to seventh days. 1 In our study, the low renal rSO 2 in the first hour of life was associated with high SCr values on the second to fourth days. Low renal rSO 2 values were found to be below the normal values reported in the literature.…”

“…5 The common pathophysiology in the neonatal AKI development is renal hypoperfusion and hypoxia. 1,2 Understanding the factors that cause this and determining this situation will enable the prediction of AKI development. The inhibition of AKI development will also improve the rates of mortality and morbidity of these vulnerable infants.…”

“…It is characterized by a decrease in the glomerular filtration rate (GFR), resulting in a fluid-electrolyte and an acid-base imbalance. 1 In neonatal intensive care units (NICU), the incidence of AKI is reported to be between 20% to 40%, and up to 48% for ≤29 weeks. 2,3 In clinical practice AKI is defined and classified according to increases in serum creatinine (SCr) levels.…”

“…5 The process, which begins with a decrease in renal flow, results in renal injury. 1,2 Near-infrared spectroscopy (NIRS) is a non-invasive method that measures tissue oxygenation in realtime by taking advantage of the difference between near-infrared light absorption of oxyhemoglobin and deoxyhemoglobin. 8 Its use in NICUs has increased in different fields of medicine.…”

Prenatal Endotoxin Exposure Induces Fetal and Neonatal Renal Inflammation via Innate and Th1 Immune Activation in Preterm Pigs

“…In the current study with preterm pigs, we demonstrated for the first time that CA, induced by IA LPS exposure, resulted in renal inflammation both at birth and 5 days after preterm birth with the involvement of innate and adaptive immune activation. Our data imply that prenatal insults may play a critical role in determining neonatal kidney outcomes and may explain the high incidence of AKI in preterm infants (46,(57)(58)(59)(60), although reduced gestational age at birth is also a risk factor (61).…”