Postprandial decline in abdominal regional oxygen saturation is associated with feeding intolerance in preterm infants: a prospective cohort study.

BACKGROUND

Feeding intolerance (FI) is a common morbidity in preterm infants, often preceding necrotizing enterocolitis (NEC). Near-infrared spectroscopy (NIRS) monitoring of abdominal regional oxygen saturation (A-rSO2) may detect impaired intestinal hemodynamics before clinical symptoms appear.

OBJECTIVE

To investigate the relationship between A-rSO2 patterns and feeding tolerance in preterm infants.

METHODS

A prospective observational cohort study of 30 preterm infants <37 weeks of gestation admitted at Dongguan Children's Hospital Affiliated to Guangdong Medical University between December 2020 to September 2021. A-rSO2 was measured pre-prandially (mean over a 10 min stable period) and post-prandially (mean commencing 30 min after feeding). Infants were stratified into FI (n = 7) and feeding tolerance (n = 23) groups based on clinical criteria. Univariate and multivariate logistic regression analyses were performed to identify factors associated with FI. Given the small sample size, the regression analysis is exploratory.

RESULTS

The incidence of FI was 23.3%, and NEC was 10%. Infants with FI had significantly lower gestational age (32.1 vs. 35.2 weeks, p = 0.003) and lower birth weight (1.76 vs. 2.43 kg, p = 0.008). Multivariate analysis identified lower gestational age [adjusted OR (aOR): 0.505, 95% CI: 0.286-0.891] and a postprandial decline in A-rSO₂ (aOR: 13.03, 95% CI: 1.352-125.6) as independent factors associated with FI. Conversely, preterm formula feeding was associated with a significantly reduced odds of FI (aOR: 0.055, 95% CI: 0.004-0.762). The exploratory model demonstrated good discrimination (AUC=0.867, 95% CI: 0.763-0.964) and adequate calibration (Hosmer-Lemeshow p = 0.612). At the optimal cutoff probability of 0.384, sensitivity was 85.7% and specificity 82.6%. Internal bootstrap validation confirmed model robustness (optimism-corrected C-statistic = 0.867). Infants with NEC (n = 3) demonstrated significantly lower preprandial oxygenation and a greater postprandial change in oxygenation index.

CONCLUSION

A postprandial decline in A-rSO2 may be a potential factor associated with feeding intolerance in preterm infants. NIRS monitoring of intestinal oxygenation provides a physiological indicator that warrants further investigation as a factor associated with gut dysfunction. These findings are hypothesis-generating and require validation in larger cohorts.