ABSTRACT
OBJECTIVE: To determine the utility of capillary blood ketone levels as an indicator of inadequate intake of breast milk in the early postnatal period. STUDY DESIGN: Levels of capillary blood beta-hydroxybutyrate (ßOHB), the main ketone body in the blood, were measured with a bedside ketone meter in 585 full-term neonates aged 48-95 hours who were breastfed exclusively. Relationships between weight-loss percentage, blood sodium, glucose, pH, partial pressure of carbon dioxide, base-deficit levels, and ßOHB levels were investigated. The diagnostic accuracy of ßOHB for predicting excessive weight loss (weight loss ≥10% of birth weight) and hypernatremic dehydration (blood sodium level ≥150 mEq/L) was determined. RESULTS: ßOHB levels were correlated positively with weight-loss percentage and blood sodium levels and were correlated negatively with blood glucose levels. The diagnostic accuracy of ßOHB was 0.846 (optimal cut off, 1.55 mmol/L; sensitivity, 80.9%, specificity, 74.0%) for predicting excessive weight loss and 0.868 (optimal cut off, 1.85 mmol/L; sensitivity, 94.3%; specificity, 69.9%) for predicting hypernatremic dehydration according to the area under the receiver operating characteristic curve. Multiple logistic analysis revealed that ßOHB and weight loss percentage were the only independent predictors of hypernatremic dehydration. Increases in ßOHB levels also were associated with worsening metabolic acidosis and hypocapnia. CONCLUSION: High ßOHB levels were associated with inadequate intake of breast milk in the early postnatal period. The use of bedside capillary blood ketone levels may be clinically useful as an indicator of dehydration, energy depletion, and acid-base imbalance in breastfeeding infants in the early postnatal period.