Splanchnic-Cerebral Oxygenation Ratio Decreases during Enteral Feedings in Anemic Preterm Infants: Observations under Near-Infrared Spectroscopy

Abstract

Background: Anemia is common in premature infants. Due to risks with red blood cell transfusions, many anemic infants are not transfused. The implications of this pathophysiologic status, especially at times of increased metabolic demand (enteral feedings), is not well understood. Near-infrared spectroscopy (NIRS) allows for the noninvasive determination of regional oxygen saturations (rSO2) in tissues such as the brain and mesentery, giving insight into their oxygen sufficiency. Objective: We tested the hypothesis that during enteral feedings very low birth weight (VLBW) infants with a hematocrit ≤28% will experience a decrease in splanchnic rSO2 and splanchnic-cerebral oxygenation ratio (SCOR). Methods: This prospective, observational, 2-centered study included VLBW infants receiving full enteral feedings with a hematocrit ≤28%. Cerebral and splanchnic rSO2 were monitored via NIRS for 24 h. Average values were calculated for periods immediately preceding, during, and after each feeding. SCOR was calculated from these values (rSO2 splanchnic/rSO2 cerebral), and data were analyzed using a linear mixed effect model. Results: Fifty neonates with a median gestational age of 28 weeks (range 23-32), a birth weight of 1,118 ± 284 g (mean ± SD), and a hematocrit of 26 ± 2% (mean ± SD) were studied. During feedings, SCOR decreased significantly from baseline (0.72 ± 0.17 to 0.69 ± 0.17, p = 0.043). With feedings, there was a trend of decreased splanchnic rSO2 (47 ± 11 to 45 ± 10, p = 0.057) and no change in cerebral rSO2 (66 ± 8 to 66 ± 7, p = 0.597). Conclusions: VLBW infants with a hematocrit ≤28% had a decrease in SCOR and a trend towards decreased splanchnic rSO2 with enteral feedings.