Failure to detect preterm infants at risk of hypoglycemia before discharge

Diagnosis and Management of Neonatal Hypoglycemia: A Comprehensive Review of Guidelines

Hypoglycemia represents one of the most frequent metabolic disturbances of the neonate, associated with increased morbidity and mortality, especially if left untreated or diagnosed after the establishment of brain damage. The aim of this study was to review and compare the recommendations from the most recently published influential guidelines on the diagnosis, screening, prevention and management of this common neonatal complication. Therefore, a descriptive review of the guidelines from the American Academy of Pediatrics (AAP), the British Association of Perinatal Medicine (BAPM), the European Foundation for the Care of the Newborn Infants (EFCNI), the Queensland Clinical Guidelines-Australia (AUS), the Canadian Pediatric Society (CPS) and the Pediatric Endocrine Society (PES) on neonatal hypoglycemia was carried out. There is a consensus among the reviewed guidelines on the risk factors, the clinical signs and symptoms of NH, and the main preventive strategies. Additionally, the importance of early recognition of at-risk infants, timely identification of NH and prompt initiation of treatment in optimizing the outcomes of hypoglycemic neonates are universally highlighted. All medical societies, except PES, recommend screening for NH in asymptomatic high-risk and symptomatic newborn infants, but they do not provide consistent screening approaches. Moreover, the reviewed guidelines point out that the diagnosis of NH should be confirmed by laboratory methods of BGL measurement, although treatment should not be delayed until the results become available. The definition of NH lacks uniformity and it is generally agreed that a single BG value cannot accurately define this clinical entity. Therefore, all medical societies support the use of operational thresholds for the management of NH, although discrepancies exist regarding the recommended cut-off values, the optimal treatment and surveillance strategies of both symptomatic and asymptomatic hypoglycemic neonates as well as the treatment targets. Over the past several decades, ΝH has remained an issue of keen debate as it is a preventable cause of brain injury and neurodevelopmental impairment; however, there is no clear definition or consistent treatment policies. Thus, the establishment of specific diagnostic criteria and uniform protocols for the management of this common biochemical disorder is of paramount importance as it will hopefully allow for the early identification of infants at risk, the establishment of efficient preventive measures, the optimal treatment in the first hours of a neonate's life and, subsequently, the improvement of neonatal outcomes.

Oral dextrose gel for the treatment of hypoglycaemia in newborn infants

BACKGROUND

Neonatal hypoglycaemia, a common condition, can be associated with brain injury. It is frequently managed by providing infants with an alternative source of glucose, often given enterally with milk-feeding or intravenously with dextrose solution, which may decrease breastfeeding success. Intravenous dextrose also often requires that mother and baby are cared for in separate environments. Oral dextrose gel is simple and inexpensive, and can be administered directly to the buccal mucosa for rapid correction of hypoglycaemia, in association with continued breastfeeding and maternal care. This is an update of a previous review published in 2016.

OBJECTIVES

To assess the effectiveness of oral dextrose gel in correcting hypoglycaemia in newborn infants from birth to discharge home and reducing long-term neurodevelopmental impairment.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase from database inception to October 2021.  We also searched international clinical trials networks, the reference lists of included trials, and relevant systematic reviews identified in the search.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs comparing oral dextrose gel versus placebo, no treatment, or other therapies for the treatment of neonatal hypoglycaemia in newborn infants from birth to discharge home.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data; they did not assess publications for which they were study authors. We contacted investigators to obtain additional information. We used fixed-effect models and the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included two studies conducted in high-income countries, involving 312 late preterm and at-risk term infants and comparing oral dextrose gel (40% concentration) to placebo gel. One study was at low risk of bias, and the other (an abstract) was at unclear to high risk of bias. Oral dextrose gel compared with placebo gel probably increases correction of hypoglycaemic events (rate ratio 1.08, 95% confidence interval (CI) 0.98 to 1.20; rate difference 66 more per 1000, 95% CI 17 fewer to 166 more; 1 study; 237 infants; moderate-certainty evidence), and may result in a slight reduction in the risk of major neurological disability at age two years or older, but the evidence is uncertain (risk ratio (RR) 0.46, 95% CI 0.09 to 2.47; risk difference (RD) 24 fewer per 1000, 95% CI 41 fewer to 66 more; 1 study, 185 children; low-certainty evidence). The evidence is very uncertain about the effect of oral dextrose gel compared with placebo gel or no gel on the need for intravenous treatment for hypoglycaemia (RR 0.78, 95% CI 0.46 to 1.32; RD 37 fewer per 1000, 95% CI 91 fewer to 54 more; 2 studies, 312 infants; very low-certainty evidence). Investigators in one study of 237 infants reported no adverse events (e.g. choking or vomiting at the time of administration) in the oral dextrose gel or placebo gel group (low-certainty evidence).  Oral dextrose gel compared with placebo gel probably reduces the incidence of separation from the mother for treatment of hypoglycaemia (RR 0.54, 95% CI 0.31 to 0.93; RD 116 fewer per 1000, 95% CI 174 fewer to 18 fewer; 1 study, 237 infants; moderate-certainty evidence), and increases the likelihood of exclusive breastfeeding after discharge (RR 1.10, 95% CI 1.01 to 1.18; RD 87 more per 1000, 95% CI 9 more to 157 more; 1 study, 237 infants; moderate-certainty evidence).   AUTHORS' CONCLUSIONS: Oral dextrose gel (specifically 40% dextrose concentration) used to treat hypoglycaemia in newborn infants (specifically at-risk late preterm and term infants) probably increases correction of hypoglycaemic events, and may result in a slight reduction in the risk of major neurological disability at age two years or older. Oral dextrose gel treatment probably reduces the incidence of separation from the mother for treatment and increases the likelihood of exclusive breastfeeding after discharge. No adverse events have been reported. Oral dextrose gel is probably an effective and safe first-line treatment for infants with neonatal hypoglycaemia in high-income settings.  More evidence is needed about the effects of oral dextrose gel treatment on later neurological disability and the need for other treatments for hypoglycaemia. Future studies should be conducted in low-and middle-income settings, in extremely and moderately preterm infants, and compare oral dextrose gel with other therapies such as intravenous dextrose. There are two ongoing studies that may alter the conclusions of this review when published.

Different glucose analyzers report different glucose concentration values in term newborns

BACKGROUND

The American Academy of Pediatrics and Pediatric Endocrine Society neonatal hypoglycemia guidelines based their glucose concentration treatment thresholds on studies that predominantly used Beckman and Yellow Springs Glucose Oxidase Analyzers. Currently, a majority (76%) of U.S. hospital laboratories utilizing glucose oxidase methodology use Vitros^® Glucose Analyzers. However, a bias of ~+5% between glucose concentrations from Beckman vs. Vitros Glucose Analyzers has been reported; this could have a clinically significant effect when using published guideline treatment thresholds.

METHODS

To determine if there is similar instrument bias between Beckman and Vitros Analyzers in reported glucose concentrations from term newborns, we compared plasma glucose concentrations measured within the first 3 h after birth by Beckman vs. Vitros Analyzers in a total of 1,987 newborns (Beckman n = 904, Vitros n = 1,083). Data were fit using nonlinear cubic spline models between collection time and glucose concentration.

RESULTS

The non-linear patterns of initial glucose concentrations (during the first 3 h after birth) as measured by Beckman and Vitros Analyzers paralleled each other with no overlap of the fit spline curve 95% confidence intervals, with an approximate +5 mg/dL constant bias. Additionally, in method comparison studies performed in the Chemistry Laboratory on adult samples, there was a +4.2-7.4 mg/dL measured glucose bias for the Beckman vs. Vitros Analyzer.

CONCLUSION

Glucose concentrations from term, appropriate size for gestational age newborns were about 5 mg/dL higher when measured by Beckman vs. Vitros Analyzers. Perhaps, concentrations of 45 mg/dL reported from Beckman Analyzers may be equivalent to 40 mg/dL from Vitros Analyzers. When managing neonatal hypoglycemia, it is important to know which analyzer was used and whether adjusting for potential instrument bias is necessary when following published guidelines.

The screening and management of newborns at risk for low blood glucose

Hypoglycemia in the first hours to days after birth remains one of the most common conditions facing practitioners across Canada who care for newborns. Many cases represent normal physiologic transition to extrauterine life, but another group experiences hypoglycemia of longer duration. This statement addresses key issues for providers of neonatal care, including the definition of hypoglycemia, risk factors, screening protocols, blood glucose levels requiring intervention, and managing care for this condition. Screening, monitoring, and intervention protocols have been revised to better identify, manage, and treat infants who are at risk for persistent, recurrent, or severe hypoglycemia. The role of dextrose gels in raising glucose levels or preventing more persistent hypoglycemia, and precautions to reduce risk for recurrence after leaving hospital, are also addressed. This statement differentiates between approaches to care for hypoglycemia during the 'transitional' phase-the first 72 hours post-birth-and persistent hypoglycemia, which occurs or presents for the first time past that point.

Le dépistage et la prise en charge des nouveau-nés à risque d’hypoglycémie

L’hypoglycémie entre les premières heures et les premiers jours suivant la naissance demeure l’une des principales affections qu’observent les praticiens du Canada qui s’occupent de nouveau-nés. Bien des cas vivent une transition physiologique normale à la vie extra-utérine, mais un groupe présente une hypoglycémie pendant une plus longue période. Le présent document de principes expose les principaux enjeux auxquels sont exposés les dispensateurs de soins néonatals, y compris la définition d’hypoglycémie, les facteurs de risque, les protocoles de dépistage, les valeurs de glycémie nécessitant une intervention et la gestion des soins pour cette affection. Les auteurs passent en revue le dépistage, la surveillance et les protocoles d’intervention pour mieux distinguer, prendre en charge et traiter les nouveau-nés à risque d’hypoglycémie persistante, récurrente ou marquée. Ils abordent également le rôle des gels de dextrose pour accroître la glycémie ou prévenir une hypoglycémie plus persistante, de même que les précautions à prendre pour réduire les risques de récurrence après le congé de l’hôpital. Le présent document de principes distingue les approches des soins de l’hypoglycémie pendant la « phase de transition » (les 72 premières heures de vie) de celles de l’hypoglycémie persistante, qui se manifeste ou est constatée pour la première fois après cette période.

Continuous glucose monitoring in neonates: a review

Continuous glucose monitoring (CGM) is well established in the management of diabetes mellitus, but its role in neonatal glycaemic control is less clear. CGM has provided important insights about neonatal glucose metabolism, and there is increasing interest in its clinical use, particularly in preterm neonates and in those in whom glucose control is difficult. Neonatal glucose instability, including hypoglycaemia and hyperglycaemia, has been associated with poorer neurodevelopment, and CGM offers the possibility of adjusting treatment in real time to account for individual metabolic requirements while reducing the number of blood tests required, potentially improving long-term outcomes. However, current devices are optimised for use at relatively high glucose concentrations, and several technical issues need to be resolved before real-time CGM can be recommended for routine neonatal care. These include: 1) limited point accuracy, especially at low or rapidly changing glucose concentrations; 2) calibration methods that are designed for higher glucose concentrations of children and adults, and not for neonates; 3) sensor drift, which is under-recognised; and 4) the need for dynamic and integrated metrics that can be related to long-term neurodevelopmental outcomes. CGM remains an important tool for retrospective investigation of neonatal glycaemia and the effect of different treatments on glucose metabolism. However, at present CGM should be limited to research studies, and should only be introduced into routine clinical care once benefit is demonstrated in randomised trials.

Retrospective evaluation of a national guideline to prevent neonatal hypoglycemia

BACKGROUND

Hypoglycemia is common in neonates and may cause adverse neurological outcomes. Guidelines should aim to prevent repeated hypoglycemic episodes in risk groups, but they are not usually stratified according to the severity of hypoglycemia risk, which may lead to inappropriate and redundant interventions. We evaluated the effect of a national prevention guideline stratified according to mild, moderate, and severe risks of hypoglycemia.

METHODS

From national registers, a population cohort of 22,725 neonates was identified retrospectively before and after implementation of a national guideline. Of these, 1900 had World Health Organization International Classification of Diseases 10 discharge diagnoses of hypoglycemia. Diagnoses indicating hypoglycemia risk [small/large for gestational age (SGA/LGA), asphyxia, prematurity, maternal insulin-treated diabetes mellitus] were recorded. Neonatal ward files were evaluated to validate hypoglycemia diagnoses. Adjusted odds ratios (aORs) were calculated, adjusting for sex, parity, SGA, LGA, preterm birth, and asphyxia, where relevant.

RESULTS

Primiparity and male sex were associated independently with hypoglycemia diagnosis [aORs, 1.29 (1.17-1.42) and 1.14 (1.03-1.26), respectively]. Overall incidence of hypoglycemia at discharge decreased from 9.4% to 5.5% after guideline implementation [aOR_change, 0.57 (0.50-0.64)]. Overall incidence of validated hypoglycemia decreased from 2.1% to 1.2% [aOR 0.59 (0.46-0.77), p<0.001]. By risk group, the hypoglycemia incidence decreased from 30.5% to 18.6% [aOR 0.52 (0.36-0.75)] among SGA neonates, from 25.8% to 16.4% [aOR 0.57 (0.42-0.76)] among preterm infants, and from 27.4% to 16.6% [aOR 0.63 (0.34-0.83)] among those with asphyxia. LGA neonates showed a decreased incidence in obstetric wards only. No significant change was observed for the diabetes group.

CONCLUSION

Stratification of hypoglycemia risk in a hypoglycemia prevention guideline was followed by decreased estimated hypoglycemia incidence, but no causative conclusion could be drawn. Prospective studies with risk stratification for hypoglycemia prevention are encouraged.

Responsive versus scheduled feeding for preterm infants

BACKGROUND

Feeding preterm infants in response to their hunger and satiation cues (responsive, cue-based, or infant-led feeding) rather than at scheduled intervals might enhance infants' and parents' experience and satisfaction, help in the establishment of independent oral feeding, increase nutrient intake and growth rates, and allow earlier hospital discharge.

OBJECTIVES

To assess the effect of a policy of feeding preterm infants on a responsive basis versus feeding prescribed volumes at scheduled intervals on growth rates, levels of parent satisfaction, and time to hospital discharge.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 1), MEDLINE via PubMed (1966 to 17 February 2016), Embase (1980 to 17 February 2016), and CINAHL (1982 to 17 February 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs that compared a policy of feeding preterm infants on a responsive basis versus feeding at scheduled intervals.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and undertook data extraction independently. We analysed the treatment effects in the individual trials and reported the risk ratio and risk difference for dichotomous data and mean difference (MD) for continuous data, with respective 95% confidence intervals (CIs). We used a fixed-effect model in meta-analyses and explored the potential causes of heterogeneity in sensitivity analyses. We assessed the quality of evidence at the outcome level using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We found nine eligible RCTs including 593 infants in total. These trials compared responsive with scheduled interval regimens in preterm infants in the transition phase from intragastric tube to oral feeding. The trials were generally small and contained various methodological weaknesses including lack of blinding and incomplete assessment of all randomised participants. Meta-analyses, although limited by data quality and availability, suggest that responsive feeding results in slightly slower rates of weight gain (MD -1.36, 95% CI -2.44 to -0.29 g/kg/day), and provide some evidence that responsive feeding reduces the time taken for infants to transition from enteral tube to oral feeding (MD -5.53, 95% CI -6.80 to -4.25 days). GRADE assessments indicated low quality of evidence. The importance of this finding is uncertain as the trials did not find a strong or consistent effect on the duration of hospitalisation. None of the included trials reported any parent, caregiver, or staff views.

AUTHORS' CONCLUSIONS

Overall, the data do not provide strong or consistent evidence that responsive feeding affects important outcomes for preterm infants or their families. Some (low quality) evidence exists that preterm infants fed in response to feeding and satiation cues achieve full oral feeding earlier than infants fed prescribed volumes at scheduled intervals. This finding should be interpreted cautiously because of methodological weaknesses in the included trials. A large RCT would be needed to confirm this finding and to determine if responsive feeding of preterm infants affects other important outcomes.

Insulin and glucagon levels of umbilical cord blood in appropriate for gestational age - preterm infants with or without postnatal hypoglycemia

PURPOSE

To determine whether serum insulin and glucagon levels of umbilical cord blood correlate with subsequent postnatal hypoglycemia in appropriate for gestational age (AGA) - preterm infants at different gestational ages (GAs).

METHODS

The serum insulin and glucagon levels of umbilical cord blood were measured using magnetic bead based multiplex immunoassay in 69 AGA - premature infants, stratified according to GA: GA 23-30 weeks, early preterm (EP, n=31); GA 31-34 weeks, late preterm (LP, n=38). Postnatal hypoglycemia was defined as a capillary glucose level <40 mg/dL within the first 60 minutes of life, regardless of GA.

RESULTS

The capillary glucose concentration in EP infants (65.5±21.2 mg/dL) was significantly higher than that of LP infants (55.9±17.3 mg/dL) (P=0.043). The serum glucagon level in EP infants (44.3±28.7 pg/mL) was significantly higher than that in LP infants (28.1±13.6 pg/mL) (P=0.006). There was not a significant difference in serum insulin level between EP and LP infants (372.7±254.2 pg/mL vs. 372.4±209.1 pg/mL, P=0.996). There was a significant difference in the serum glucagon level between infants with and without hypoglycemia (27.7±8.9 mg/dL vs. 36.8±24.6 mg/dL, P=0.036), but not in the serum insulin level (451.9±256.9 pg/mL vs. 357.4±222.2 pg/mL, P=0.211). Postnatal glucose concentration within the first 60 minutes of life had a significant positive correlation with serum glucagon levels (r=0.256, P=0.034), but not with serum insulin levels (r=-0.020, P=0.867).

CONCLUSION

Lower glucagon levels of cord blood were seen in premature infants with higher GA, which might contribute to the occurrence of postnatal hypoglycemia.

Oral dextrose gel for the treatment of hypoglycaemia in newborn infants

BACKGROUND

Neonatal hypoglycaemia, a common condition, can be associated with brain injury. It is frequently managed by providing infants with an alternative source of glucose, given enterally with formula or intravenously with dextrose solution. This often requires that mother and baby are cared for in separate environments and may inhibit breast feeding. Dextrose gel is simple and inexpensive and can be administered directly to the buccal mucosa for rapid correction of hypoglycaemia, in association with continued breast feeding and maternal care.

OBJECTIVES

To assess the effectiveness of dextrose gel in correcting hypoglycaemia and in reducing long-term neurodevelopmental impairment.

SEARCH METHODS

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Web of Science from inception of the database to February 2016. We also searched international clinical trials networks and handsearched proceedings of specific scientific meetings.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing dextrose gel versus placebo, no treatment or other therapies for treatment of neonatal hypoglycaemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data and did not assess publications for which they themselves were study authors.

MAIN RESULTS

We included two trials involving 312 infants. No data were available for correction of hypoglycaemia for each hypoglycaemic event. We found no evidence of a difference between dextrose gel and placebo gel for major neurosensory disability at two-year follow-up (risk ratio (RR) 6.27, 95% confidence interval (CI) 0.77 to 51.03; one trial, n = 184; quality of evidence very low). Dextrose gel compared with placebo gel or no gel did not alter the need for intravenous treatment for hypoglycaemia (typical RR 0.78, 95% CI 0.46 to 1.32; two trials, 312 infants; quality of evidence very low). Infants treated with dextrose gel were less likely to be separated from their mothers for treatment of hypoglycaemia (RR 0.54, 95% CI 0.31 to 0.93; one trial, 237 infants; quality of evidence moderate) and were more likely to be exclusively breast fed after discharge (RR 1.10, 95% CI 1.01 to 1.18; one trial, 237 infants; quality of evidence moderate). Estimated rise in blood glucose concentration following dextrose gel was 0.4 mmol/L (95% CI -0.14 to 0.94; one trial, 75 infants). Investigators in one trial reported no adverse outcomes (n = 237 infants).

AUTHORS' CONCLUSIONS

Treatment of infants with neonatal hypoglycaemia with 40% dextrose gel reduces the incidence of mother-infant separation for treatment and increases the likelihood of full breast feeding after discharge compared with placebo gel. No evidence suggests occurrence of adverse effects during the neonatal period or at two years' corrected age. Oral dextrose gel should be considered first-line treatment for infants with neonatal hypoglycaemia.

Responsive versus scheduled feeding for preterm infants

BACKGROUND

Feeding preterm infants in response to their hunger and satiation cues (responsive, cue-based, or infant-led feeding) rather than at scheduled intervals might enhance infants' and parents' experience and satisfaction, help in the establishment of independent oral feeding, increase nutrient intake and growth rates, and allow earlier hospital discharge.

OBJECTIVES

To assess the effect of feeding preterm infants on a responsive basis versus feeding prescribed volumes at scheduled intervals on growth, duration of hospital stay, and parental satisfaction.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 9, 2015), MEDLINE (1966 to September 2015), EMBASE (1980 to September 2015), and CINAHL (1982 to September 2015), conference proceedings, previous reviews, and trial registries.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs that compared a policy of feeding preterm infants on a responsive basis versus feeding at scheduled intervals.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and undertook data extraction independently. We analysed the treatment effects in the individual trials and reported the risk ratio and risk difference for dichotomous data and mean difference (MD) for continuous data, with respective 95% confidence intervals (CIs). We used a fixed-effect model in meta-analyses and explored the potential causes of heterogeneity in sensitivity analyses.

MAIN RESULTS

We found nine eligible RCTs including 593 infants in total. These trials compared responsive with scheduled interval regimens in preterm infants in the transition phase from intragastric tube to oral feeding. The trials were generally small and contained various methodological weaknesses including lack of blinding and incomplete assessment of all randomised participants. Meta-analyses, although limited by data quality and availability, suggest that responsive feeding results in slightly slower rates of weight gain (MD -1.4, 95% CI -2.4 to -0.3 g/kg/day), and provide some evidence that responsive feeding reduces the time taken for infants to transition from enteral tube to oral feeding (MD -5.5, 95% CI -6.8 to -4.2 days). The importance of this finding is uncertain as the trials did not find a strong or consistent effect on the duration of hospitalisation. None of the included trials reported any parent, caregiver, or staff views.

AUTHORS' CONCLUSIONS

Overall, the data do not provide strong or consistent evidence that responsive feeding affects important outcomes for preterm infants or their families. Some evidence exists that preterm infants fed in response to feeding and satiation cues achieve full oral feeding earlier than infants fed prescribed volumes at scheduled intervals. However, this finding should be interpreted cautiously because of methodological weaknesses in the included trials. A large RCT would be needed to confirm this finding and to determine if responsive feeding of preterm infants affects other important outcomes.

Instability of glucose values in very preterm babies at term postmenstrual age

OBJECTIVE

To determine if very preterm (VPT) babies are capable of maintaining glucose levels within normal ranges at or near term postmenstrual age.

STUDY DESIGN

Glucose levels were intermittently or continuously monitored during 48 hours in a cohort of 60 VPT infants near hospital discharge. Hypoglycemic (≤45 mg/dL, 2.5 mmol/L) and hyperglycemic (≥140 mg/dL or 7.8 mmol/L, severe if ≥180 mg/dL or 10 mmol/L) episodes were considered relevant if they lasted longer than 30 minutes. Feeding regimes followed current practice.

RESULTS

With intermittent capillary, 2 hypoglycemic values and another 3 that were abnormally high were detected. With continuous monitoring, 6 babies (10.0%) had isolated hypoglycemia ≤45 mg/dL (2.5 mmol/L) (3 of them reaching 40 mg/dL, 2.2 mmol/L), 14 (23.3%) had isolated hyperglycemia, and 8 (13.3%) had episodes of both. The mean duration of hypoglycemia per patient was 2.8 ± 2.9 hours and 4.68 ± 4.35 hours in the case of hyperglycemia, with 12 infants becoming severely hyperglycemic. Of the 12 severely hyperglycemic patients, 5 also developed severe hypoglycemia. No specific characteristics identified the hypoglycemic babies. A history of intrauterine growth restriction (P = .037) and female sex (P = .063) seemed to increase the risk of severe hyperglycemia.

CONCLUSIONS

VPT infants continue to have abnormal glucose values, especially hyperglycemia, by the time of hospital discharge. No specific factors identify babies at higher risk for hypoglycemia, and intrauterine growth restriction and female sex seemed to predispose to hyperglycemia.

Update on neonatal hypoglycemia

PURPOSE OF REVIEW

Neonatal hypoglycemia is one of the most common biochemical abnormalities encountered in the newborn. However, controversy remains surrounding its definition and management especially in asymptomatic patients.

RECENT FINDINGS

New information has been published that describes the incidence and timing of low glucose concentrations in the groups most at risk for asymptomatic neonatal hypoglycemia. Furthermore, one large prospective study failed to find an association between repetitive low glucose concentrations and poor neurodevelopmental outcomes in preterm infants. But hypoglycemia due to hyperinsulinism, especially genetic causes, continued to be associated with brain injury. New advances were made in the diagnosis and management of hyperinsulinism, including acquired hyperinsulinism in small for gestational age infants and others. Continuous glucose monitoring remains an attractive strategy for future research in this area.

SUMMARY

The fundamental question of how best to manage asymptomatic newborns with low glucose concentrations remains unanswered. Balancing the risks of overtreating newborns with low glucose concentrations who are undergoing a normal transition following birth against the risks of undertreating those in whom low glucose concentrations are pathological, dangerous, and/or a harbinger of serious metabolic disease remains a challenge.

Incidence of neonatal hypoglycemia in babies identified as at risk

OBJECTIVES

Routine blood glucose screening is recommended for babies at risk of neonatal hypoglycemia. However, the incidence of hypoglycemia in those screened is not well described. We sought to determine the incidence of hypoglycemia in babies identified as being at risk, and also to determine differences in incidence between at risk groups.

STUDY DESIGN

Infants (n = 514) were recruited who were born in a tertiary hospital, ≥35 weeks gestation and identified as at risk of hypoglycemia (small, large, infant of a diabetic, late-preterm, and other). Blood glucose screening used a standard protocol and a glucose oxidase method of glucose measurement in the first 48 hours after birth.

RESULTS

One-half of the babies (260/514, 51%) became hypoglycemic (<2.6 mM), 97 (19%) had severe hypoglycemia (≤2.0 mM), and 98 (19%) had more than 1 episode. The mean duration of an episode was 1.4 hours. Most episodes (315/390, 81%) occurred in the first 24 hours. The median number of blood glucose measurements for each baby was 9 (range 1-22). The incidence and timing of hypoglycemia was similar in all at risk groups, but babies with a total of 3 risk factors were more likely to have severe hypoglycemia.

CONCLUSIONS

Hypoglycemia is common amongst babies recommended for routine blood glucose screening. We found no evidence that screening protocols should differ in different at risk groups, but multiple risk factors may increase severity. The significance of these hypoglycemic episodes for long-term outcome remains undetermined.

Postnatal glucose homeostasis in late-preterm and term infants

This report provides a practical guide and algorithm for the screening and subsequent management of neonatal hypoglycemia. Current evidence does not support a specific concentration of glucose that can discriminate normal from abnormal or can potentially result in acute or chronic irreversible neurologic damage. Early identification of the at-risk infant and institution of prophylactic measures to prevent neonatal hypoglycemia are recommended as a pragmatic approach despite the absence of a consistent definition of hypoglycemia in the literature.

Describing hypoglycemia--definition or operational threshold?

Severe glucose deficiency leads to cerebral energy failure, impaired cardiac performance, muscle weakness, glycogen depletion, and diminished glucose production. Thus, maintenance of glucose delivery to all organs is an essential physiological function. Normal term infants have sufficient alternate energy stores and capacity for glucose production from glycogenolysis and gluconeogenesis to ensure normal glucose metabolism during the transition to extrauterine life and early neonatal period. Milk feedings particularly enhance glucose homeostasis. Energy sources often are low in preterm and growth restricted infants, who are especially vulnerable to glucose deficiency. Plasma glucose concentration is the only practical measure of glucose sufficiency, but by itself is a very limited guide. Key to preventing complications from glucose deficiency is to identify infants at risk, promote early and frequent feedings, normalize glucose homeostasis, measure glucose concentrations early and frequently in infants at risk, and treat promptly when glucose deficiency is marked and symptomatic.

Ad libitum or demand/semi-demand feeding versus scheduled interval feeding for preterm infants

BACKGROUND

Scheduled interval feeding of prescribed enteral volumes is current standard practice for preterm infants. However, feeding preterm infants in response to their hunger and satiation cues (ad libitum or demand/semi demand) rather than at scheduled intervals might help in the establishment of independent oral feeding, increase nutrient intake and growth rates, and allow earlier hospital discharge.

OBJECTIVES

To assess the effect of a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding prescribed volumes at scheduled intervals on growth rates and the time to hospital discharge.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2009), MEDLINE (1966 to Oct 2009), EMBASE (1980 to Oct 2009), CINAHL (1982 to Oct 2009), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials (including cluster randomised trials) that compared a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding at scheduled intervals.

DATA COLLECTION AND ANALYSIS

We used the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We found eight randomised controlled trials that compared ad libitum or demand/semi-demand regimens with scheduled interval regimes in preterm infants in the transition phase from intragastric tube to oral feeding. The trials were generally small and of variable methodological quality. The duration of the intervention and the duration of data collection and follow-up in most of the trials was not likely to have allowed detection of measurable effects on growth. Three trials reported that feeding preterm infants using an ad libitum or demand/semi-demand feeding regimen allowed earlier discharge from hospital (by about two to four days) but other trials did not confirm this finding.

AUTHORS' CONCLUSIONS

Limited evidence exists that feeding preterm infants with ad libitum or demand/semi-demand regimens allows earlier attainment of full oral feeding and earlier hospital discharge. This finding should be interpreted cautiously because of methodological weaknesses in the included trials. A large randomised controlled trial is needed to confirm this finding and to determine if ad libitum of demand/semi-demand feeding of preterm infants affects other clinically important outcomes.

Genetic variation in hepatic glucose-6-phosphatase system genes in cases of sudden infant death syndrome

Genetic deficiencies of the hepatic glucose-6-phosphatase system, either of the enzyme (G6PC1) or of the glucose-6-phosphate transporter (G6PT1), result in fasting hypoglycaemia. Low hepatic G6PC1 activities were previously reported in a few term sudden infant death syndrome (SIDS) infants and assumed to be due to G6PC1 genetic deficiencies. In preterm infants, failures of postnatal activation of G6PC1 expression suggest disordered development as a novel cause of decreased G6PC1 activity in SIDS. G6PC1 and G6PT1 functional and mutational analysis was investigated in SIDS and non-SIDS infants. G6PC1 hepatic activity was abnormally low in 98 SIDS (preterm, n=13; term, n=85), and non-SIDS preterm infants (n=35) compared to term non-SIDS infants (n=29) and adults (n=9). Mean glycogen levels were elevated, except in term non-SIDS infants. A novel G6PT1 promoter polymorphism, 259C --> T was found; the - 259*T allele frequency was greater in term SIDS infants (n=140) than in term control infants (n=119) and preterm SIDS infants (n=30). Heterozygous and homozygous prevalence of 259C --> T was 38.6% and 7.1%, respectively, in term SIDS infants. In cell-based expression systems, the presence of - 259T in the promoter decreased basal luciferase activity by 3.2-fold compared to - 259C. Glucose-6-phosphatase latency in hepatic microsomes was elevated (indicating decreased G6PT1 function) in heterozygous and homozygous - 259T states. Delayed postnatal appearance of hepatic glucose-6-phosphatase in infants makes them vulnerable to hypoglycaemic episodes and this may occur in some SIDS infants. However, SIDS may be an association of more complex phenotypes in which several genes interact with multiple environmental factors. A UK-wide DNA Biobank of samples from all infant deaths, with an accompanying epidemiological database, should be established by pathologists to allow cumulative data to be collected from multiple genetic investigations on the same large cohort of samples, with the aim of selection of the best combination of genetic markers to predict unexpected infant death.

Ad libitum or demand/semi-demand feeding versus scheduled interval feeding for preterm infants

BACKGROUND

Feeding preterm infants in response to their hunger and satiation cues (ad libitum or demand/semi demand) rather than at scheduled intervals might help in the establishment of independent oral feeding, increase nutrient intake and growth rates, and allow earlier hospital discharge.

OBJECTIVES

To assess the effect of a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding prescribed volumes at scheduled intervals on growth rates and the time to hospital discharge.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - March 2006), EMBASE (1980 - March 2006), CINAHL (1982 - March 2006), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials (including cluster randomised trials) that compared a policy of feeding preterm infants on an ad libitum or demand/semi-demand basis versus feeding at scheduled intervals.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors. The primary outcomes of interest were growth rates and age at hospital discharge.

MAIN RESULTS

We found seven randomised controlled trials that compared ad libitum or demand/semi-demand regimes with scheduled interval regimes in preterm infants in the transition phase from intragastric tube to oral feeding. The trials were generally small and of variable methodological quality. The duration of the intervention and the duration of data collection and follow up in most of the trials is not likely to have allowed detection of measurable effects on growth. The single trial that assessed growth for longer than one week found that the rate of weight gain was lower in the ad libitum fed infants [mean difference -3.30 (95% confidence interval -6.2 to -0.4) grams per kilogram per day]. Two trials reported that feeding preterm infants using an ad libitum or demand/semi-demand feeding regime allowed earlier discharge from hospital, but the other trials did not confirm this finding. We were not able to undertake meta-analyses because of differences in study design and in the way the findings were reported.

AUTHORS' CONCLUSIONS

There are insufficient data at present to guide clinical practice. A large randomised controlled trial is needed to determine if ad libitum of demand/semi-demand feeding of preterm infants affects clinically important outcomes. This trial should focus on infants in the transition phase from intragastric tube to oral feeding and should be of sufficient duration to assess effects on growth and time to oral feeding and hospital discharge.

Metabolic adaptation at birth

After birth, the neonate must make a transition from the assured continuous transplacental supply of glucose to a variable fat-based fuel economy. The normal infant born at term accomplishes this transition through a series of well-coordinated metabolic and hormonal adaptive changes. The patterns of adaptation in the preterm infant and the baby born after intrauterine growth restriction are, however, different to that of a full-term neonate, with the risk for former groups that there will be impaired counter-regulatory ketogenesis. There is much less precise linkage of neonatal insulin secretion to prevailing blood glucose concentrations. These patterns of metabolic adaptation are further influenced by feeding practices.

Identification of novel polymorphisms in the glucokinase and glucose-6-phosphatase genes in infants who died suddenly and unexpectedly

Sudden and unexpected infant deaths can be unexplained [sudden infant death syndrome (SIDS)] or explained (non-SIDS) but risk factors including lower birthweight are similar in both groups. Mutations in the glucokinase (GK) gene result in Maturity Onset Diabetes of the Young type 2 (MODY 2) and are associated with lower birthweight. Low hepatic glucose-6-phosphatase (G6PC1) expression occurs in both low birthweight and SIDS infants. We investigated whether polymorphisms are prevalent in the GK and G6PC1 genes in infants who died suddenly and unexpectedly. Mutation analysis was performed by polymerase chain reaction (PCR) and denaturing high-performance liquid chromatography (DHPLC) in samples from 126 infants who died suddenly and unexpectedly (78 SIDS, 48 non-SIDS) and from 70 healthy, living infants. G6PC1 promoter polymorphism significance was investigated by transfection of reporter gene constructs into a H4IIE cell line. Heterozygous GK polymorphisms were identified in 17.9% of SIDS and 20.8% of non-SIDS infants: two rare silent polymorphisms, Y215Y and S263S, in the coding region; a third rare polymorphism, -45G>A, in the hepatic promoter and the most prevalent polymorphism, c.484-29G>C, in a non-coding region upstream from the intron 4-exon 5 junction. A novel heterozygous polymorphism -77G>A in the G6PC1 promoter in 6.3% of non-SIDS and 2.9% of control infants decreased basal G6PC1 promoter activity (p<0.001). We describe three novel polymorphisms in the GK gene, S263S, -45G>A, and a common (14.3%) intronic substitution, c.484-29G>C, in infants who died suddenly and unexpectedly. We identified the first G6PC1 promoter polymorphism, which lowers expression, potentially increasing risk of hypoglycaemia and hence risk of sudden and unexpected death.

Glucose homeostasis in the newborn

Hepatic glucose production by glycogenolysis and gluconeogenesis is essential to maintain blood glucose levels, and the glucose-6-phosphatase system catalyses the terminal step of both pathways. Developmental delays in the postnatal up-regulation of hepatic glucose-6-phosphatase enzyme activity are common in preterm infants. Two groups of infants have been identified with failure of developmental regulation of glucose homeostasis. Firstly, up to 20% of preterm infants about to be discharged home are at risk of hypoglycaemia if a feed is delayed. Cortisol, corticotrophin and epinephrine levels are higher in the infants with severe and persistent hypoglycaemia, but insulin, glucagon and human growth hormone do not differ from normoglycaemic infants. Secondly, preterm infants with an inadequate glycaemic response to glucagon (30% at the time of discharge home) have relative fasting hyperglycaemia, hyperinsulinaemia, increased insulin:glucagon ratios and a lower insulin sensitivity index. Hormonal dysfunctions in preterm infants may contribute to failures in postnatal expression of hepatic enzymes.

Plasma catecholamines and the counterregulatory responses to hypoglycemia in infants: a critical role for epinephrine and cortisol

The purpose of this study was to define plasma catecholamine responses as part of the counterregulatory hormonal reaction to hypoglycemia in infants after a regular 3- to 4-h feed was omitted. Hormone levels were assessed once, at the end of the fast or at hypoglycemia. The 121 infants were subdivided into three groups for analysis: normoglycemia (n = 94, 78%); transient hypoglycemia (n = 11, 9%); or severe and persistent hypoglycemia (n = 16, 13%). The severe and persistent hypoglycemic group had significantly higher levels of cortisol and epinephrine than the normoglycemic group. Norepinephrine and glucagon levels did not differ between the groups. Human GH levels were higher in the transiently hypoglycemic group but not in the severe and persistent hypoglycemic group. Prefeed blood lactate levels differed significantly among the groups and were highest in the severe and persistent groups. Multiple regression analysis showed that cortisol levels were significantly higher in infants who had severe and persistent hypoglycemia. The counterregulatory hormonal response in infants to severe and persistent hypoglycemia was limited to elevations in only cortisol and epinephrine levels but did not involve glucagon or human GH. This limited hormonal response may also contribute to the frequent occurrence of hypoglycemia in these infants.

Cortisol and growth hormone responses to spontaneous hypoglycaemia in infants and children

AIMS

To evaluate responses of cortisol and growth hormone (GH) to spontaneous hypoglycaemia in infants and children.

METHODS

Retrospective review of laboratory and clinical data in paediatric patients investigated for suspected hypoglycaemia over a five year period. Thirty patients (16 aged <3 months) had hypoglycaemia confirmed by laboratory analysis (glucose <2.5 mmol/l) and were compared with 26 patients (11 aged <3 months) with glucose > or =2.5 mmol/l.

RESULTS

The commonest causes of hypoglycaemia were transient hyperinsulinism in infants <3 months and intercurrent infection in those >6 months of age. In both hypo- and non-hypoglycaemic patients, cortisol was positively (r(s) +0.66 and +0.68) and GH inversely (r(s) -0.65 and -0.75) correlated with age. Hypo- and non-hypoglycaemic infants <3 months had median cortisol concentrations of 205 and 116 nmol/l respectively compared with 1370 and 736 nmol/l in hypo- and non-hypoglycaemic children >6 months. Conversely, median GH was 46.5 and 51.2 mU/l in hypo- and non-hypoglycaemic infants compared with 14.3 and 12.1 mU/l in older hypo- and non-hypoglycaemic patients. Older non-hypoglycaemic patients with glucose levels below the glycaemic thresholds established for cortisol and GH secretion in adults had higher cortisol and GH concentrations than patients whose glucose levels exceeded these thresholds.

CONCLUSIONS

Cortisol and GH responses to spontaneous hypoglycaemia in children are highly age dependent. Young infants mount a poor cortisol response compared with older infants and children. Children older than 6 months may have glycaemic thresholds for cortisol and GH similar to those established for adults.

An inadequate glycaemic response to glucagon is linked to insulin resistance in preterm infants?

AIMS

To define clinical, metabolic, and hormonal characteristics of preterm infants relative to glucagon responsiveness.

METHODS

Two phase study of 78 preterm infants (25-36 weeks gestation) on regular four hourly feeds anticipating discharge home at 36 weeks mean corrected gestation. In phase 1 infants were fasted until hypoglycaemic, or maximally for eight hours. Endocrine and metabolic profiles were obtained at completion. Phase 2 was performed the following day. A feed was omitted and replaced by a bolus dose of intravenous glucagon (100 micro g/kg). Main outcome measures were measurements of blood glucose and lactate concentrations, taken immediately pre-glucagon, and thereafter every 15 minutes for 60 minutes. A rise in glucose concentration of >1 mmol/l (55 infants) was defined as an adequate response to glucagon. An inadequate glycaemic response was <1 mmol/l (23 infants).

RESULTS

Several differences in fasting blood glucose and hormone concentrations were identified in infants with an inadequate glycaemic response to glucagon compared to those with an adequate response: relative fasting hyperglycaemia (mean 3.7 v 3.3 mmol/l, p = 0.008); fasting hyperinsulinaemia (mean 4.3 v 2.6 mU/l, p = 0.014); an increased insulin:glucagon ratio (0.19 v 0.11, p = 0.014), and a lower insulin sensitivity QUICKI index (0.19 v 0.22, p = 0.04). There was no distinctive phenotype to reliably predict response to glucagon.

CONCLUSION

Some preterm infants show an inadequate glycaemic response to glucagon and have features suggestive of insulin resistance. The potential long term implications of such insulin resistance may have appreciable public health consequences.

Polymorphisms in genes involved in glucose metabolism in cases of sudden infant death syndrome

BACKGROUND

Infants with intra-uterine growth retardation have an increased risk of Sudden Infant Death Syndrome (SIDS). Hypoglycaemia is also significantly correlated with retardation of intra-uterine growth. A number of mutations in key proteins involved in regulation of blood glucose (e.g. glucokinase) have been found to result in reduced birth weight. Heterozygous mutations in the coding region of the glucokinase gene have been shown to cause MODY (a form of early onset Type II diabetes mellitus). The aim was to screen a cohort of SIDS and control infants who were either growth retarded or appropriately grown for gestational age to determine if any mutations and/or polymorphisms were present in the glucokinase gene.

METHODS

PCR, denaturing high performance liquid chromatography on an automated Transgenomic WAVE DNA fragment analysis system and DNA sequencing.

RESULTS

Genomic DNA was isolated from 129 infants who were either growth retarded or appropriately grown for gestational age. We found several rare novel polymorphisms in the glucokinase gene in the infant samples. However, none of the samples contained any of the mutations in the glucokinase gene previously reported in cases of MODY.

CONCLUSIONS

We have found rare novel polymorphisms in the glucokinase gene in the infant samples. In contrast in these samples, we have not found any examples of the previously reported mutations in the coding region of the glucokinase gene found in MODY. This clearly shows that while MODY babies are often small, MODY is not a common cause of either intra-uterine growth retardation or of SIDS.

Developmental disorders of glucose metabolism in infants

BACKGROUND

Developmental failures to adequately control postnatal blood glucose levels are common in the transition from fetal to infant life and can persist for many months. The standard method of functionally measuring hepatic glucose production and/or disordered glucose production is the response to a glucagon tolerance test.

METHOD

We adapted the standard glucagon tolerance test used for children and adults for use in preterm infants. 79 consecutive preterm infants gestational age range 25-36 weeks (mean 32.2 weeks), mean birth weight 1.66 kg admitted to the Neonatal Intensive Care Unit, Ninewells Hospital, Dundee and who survived to discharge home were recruited into the study. At the time of discharge home the characteristics of the group were as follows: adjusted mean gestational age 36.7 weeks, mean discharge weight 2.23 kg.

RESULTS

In this study of preterm infants the maximal increase in plasma glucose following administration of a glucagon tolerance test is 1.39 +/- 07 mmol/L, n = 78 (range 0-3.98 mmol/L).

CONCLUSIONS

An increase in plasma glucose of less than 4 mmol/L is considered abnormal in adults following administration of a fasting glucagon tolerance test. The responses of preterm infants and adults to glucagon are clearly different. The attenuated response to glucagon in the preterm infants is consistent with the low levels of hepatic glucose-6-phosphatase activity in premature infants as glucose-6-phosphatase is the terminal step of the two main pathways of liver glucose production.

Selecting an accurate point-of-care testing system: clinical and technical issues and implications in neonatal blood glucose monitoring

ISSUES AND PURPOSE

Rapid identification and treatment of glucose abnormalities is crucial in the prevention of potentially devastating neurological injury in neonates. Choice of a point-of-care glucose testing system must consider accuracy, clinical advantages, and data management capabilities.

CONCLUSIONS

The benefits and limitations of point-of-care testing must be weighed against the time delay of central laboratory testing.

PRACTICE IMPLICATIONS

Considerations in selecting a point-of-care blood glucose monitoring system include accuracy, precision, versatility, and the potential for cross infection and blood loss. When a system is selected, studies must be done to identify potential sources of error and confirm the utility and accuracy of the system in the identified population.

When it is more than transient neonatal hypoglycemia: hyperinsulinemia--a case study challenge

Persistent uncontrolled neonatal hypoglycemia may cause irreversible brain damage. Hyperinsulinemia is a rare cause of persistent hypoglycemia, diagnosed by excluding other etiologies. Inappropriately high fasting serum insulin levels with concurrent hypoglycemia confirm the diagnosis. Initial interventions for hyperinsulinemia are conservative. The first line of therapy is administration of adequate intravenous (i.v.) glucose to maintain serum or whole blood glucose levels at or greater than 40 mg/dl. When enteral feedings are tolerated, schedules and caloric concentration are adjusted. Pharmacologic therapy is added to facilitate weaning from i.v. glucose. The drug of first choice is diazoxide. Octreotide is added if diazoxide therapy fails. Partial or complete pancreatectomy is the final treatment option. Nursing care for infants with hyperinsulinemia must also focus on the support and education of families. Family education must be individualized and should cover feeding regimes, administration of medication, proper use of equipment, and care during illness.

Therapeutic insulin and hepatic glucose-6-phosphatase activity in preterm infants

BACKGROUND

Hepatic glucose-6-phosphatase activity is low at birth, and in term infants rises rapidly to adult levels. In contrast, in most preterm infants, it remains low postnatally making them vulnerable to repeated hypoglycaemic episodes, resultant cerebral damage, or risk of sudden and unexpected death.

AIMS

To investigate the clinical features of preterm infants with low glucose-6-phosphatase enzyme activity to determine the influencing factors.

METHODS

Clinical data from 36 preterm infants were correlated by stepwise multiple regression analysis with V(max) of hepatic glucose-6-phosphatase as the dependent variable.

RESULTS

The most significant correlation was with the administration of insulin (units/kg/h postnatal life) with lesser effects of respiratory distress syndrome and dopamine administration. The V(max) changes reflected changes in the level of expression of the glucose-6-phosphatase protein.

CONCLUSION

In a variety of animal models, hepatic glucose-6-phosphatase levels have been shown to decrease in response to insulin, which also decreases transcription of the glucose-6-phosphatase gene. The association of insulin administration with high levels of hepatic glucose-6-phosphatase activity and protein expression was therefore most unexpected. Results from model systems, or adults, must be extrapolated to the metabolism of preterm infants with caution.