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Glucose production rate in extremely immature neonates (< 28 weeks) studied by use of deuterated glucose
Insights
Extremely premature infants (<28 weeks gestation) can produce glucose at rates comparable to full-term newborns. This study measured glucose production in these vulnerable infants shortly after birth.
Area of Science:
- Neonatal physiology
- Metabolic research
Background:
- Neonatal hypoglycemia is common in premature infants due to limited energy stores and immature metabolic systems.
- Infants born before 28 weeks gestation are particularly vulnerable to metabolic disturbances.
Purpose of the Study:
- To investigate the glucose production rate in newborn infants with gestational ages less than 28 weeks.
- To assess the metabolic capacity of extremely preterm infants in the early postnatal period.
Main Methods:
- Utilized stable isotope tracer (D-6,6-2H2-glucose) infused intravenously in 10 infants (25-26 weeks gestation).
- Measured plasma glucose concentration and isotopic enrichment via gas chromatography/mass spectrometry over 2 hours.
- Calculated glucose production rate using isotopic enrichment data.
Main Results:
- The mean glucose production rate was 6.1 +/- 1.5 mg.kg-1.min-1.
- Infants demonstrated a significant capacity for glucose production within the first 24 hours of life.
- Production rates were comparable to or exceeded those reported for term infants.
Conclusions:
- Extremely preterm infants (<28 weeks gestation) possess a notable capacity for endogenous glucose production shortly after birth.
- This finding challenges assumptions about the limited metabolic capabilities of these very immature neonates.
- Supports the understanding of glucose homeostasis in the critical early hours of life for extremely preterm infants.
Abstract:
Neonatal hypoglycemia is a frequent complication in immature infants. This may be due to small substrate stores, a high brain:body weight ratio, and immature enzyme systems. The purpose of the present study was to investigate the rate of glucose production in newborn infants with gestational ages of less than 28 wk. The subjects were 10 newborn infants delivered after 25 to 26 gestational wk. Their mean birth weight was 772 g (range 588-1000 g), and their mean postnatal age at the time of the study was 15 h (range 4-24 h). An isotopic compound (D-6,6-2H2-glucose) was given as a constant-rate i.v. infusion. In addition to dideuteroglucose, eight of the infants also received an i.v. infusion of unlabeled glucose at a rate of 1.4-2.6 mg.kg-1.min-1. Blood samples for determination of the concentration and isotopic enrichment of plasma glucose were obtained every 15 min in a 2-h period. Isotopic enrichment, measured by gas chromatography/mass spectrometry, was used for calculating the glucose production rate. The mean glucose production rate related to body weight (+/- SD) was 6.1 +/- 1.5 mg.kg-1.min-1. The results show that infants born at < 28 gestational wk have a capacity to produce glucose on their 1st d of life at rates close to or even exceeding those reported in term infants.