Objective: Near-infrared spectroscopy is a noninvasive method of measuring local tissue oxygenation (StO2). Abdominal StO2 measurements in preterm piglets are directly correlated with changes in intestinal blood flow and markedly reduced by necrotizing enterocolitis. The objectives of this study were to use near-infrared spectroscopy to establish normal values for abdominal StO2 in preterm infants and test whether these values are reduced in infants who develop necrotizing enterocolitis.
Design: We conducted a 2-year prospective cohort study where we prospectively measured abdominal StO2 in preterm infants, to establish reference values for preterm infants, and compared the near-infrared spectroscopy values with preterm infants in the cohort that developed necrotizing enterocolitis.
Setting: Two neonatal ICUs: one at Texas Children's Hospital and the other at Ben Taub General Hospital in Houston, TX.
Patients: We enrolled 100 preterm infants (< 32 weeks' gestation and < 1,500 g birth weight) between January 2007 and November 2008.
Measurements and main results: Eight neonates with incomplete data were excluded. Mean abdominal StO2 in normal preterm infants (n = 78) during the first week of life was significantly higher than in those who later developed necrotizing enterocolitis (n = 14) (77.3% ± 14.4% vs 70.7% ± 19.1%, respectively, p = 0.002). An StO2 less than or equal to 56% identified preterm infants progressing to necrotizing enterocolitis with 86% sensitivity, 64% specificity, 96% negative predictive value, and 30% positive predictive value. Using logistic regression, StO2 less than or equal to 56% was independently associated with a significantly increased risk of necrotizing enterocolitis (odds ratio, 14.1; p = 0.01). Furthermore, infants with necrotizing enterocolitis demonstrated significantly more variation in StO2 both during and after feeding in the first 2 weeks of life.
Conclusions: This study establishes normal values for abdominal StO2 in preterm infants and demonstrates decreased values and increased variability in those with necrotizing enterocolitis. Abdominal near-infrared spectroscopy monitoring of preterm infants may be a useful tool for early diagnosis and guiding treatment of necrotizing enterocolitis.