Controversies regarding definition of neonatal hypoglycemia: suggested operational thresholds

The Accutrend sensor glucose analyzer may not be adequate in bedside testing for neonatal hypoglycemia

The aim of this prospective observational study was to compare a bedside test with the reference laboratory method in routine postnatal glucose monitoring. Term newborns with increased risk or clinical signs of hypoglycemia were screened with a bedside test. In case of a glucose value below 2.25 mmol/L, a second blood sample was taken and a duplicate glucose measurement done in the laboratory using a bedside test (Accutrend sensor) and the reference laboratory method (hexokinase method) at the same time and from the same sample. From 110 term newborns, 122 blood samples were obtained for duplicate measurements (median 1.69 mmol/L, SD 0.45 mmol/L). Of these 122, Accutrend correctly identified 97% as being <2.25 mmol/L by the laboratory method. A Bland-Altman plot revealed a mean underestimation of the Accutrend of only -0.09 mmol/L. However, due to high scattering, the maximal over- and underestimation was 0.89 and 1.39 mmol/L, respectively. Only 75% of the results from the Accutrend were within +/-20% of the result of the laboratory method. If the cut-off for low glucose concentrations was set 0.6 mmol/L higher for the bedside test as compared to the laboratory method, all patients except one would have been correctly identified as hypoglycemic.

CONCLUSION

When using the Accutrend sensor, single infants with even marked hypoglycemia might be missed. Some delay in receiving accurate measurements might be more helpful for clinical decisions and long-term outcome than immediate but potentially misleading results.

Cold stress and hypoglycemia in the late preterm ("near-term") infant: impact on nursery of admission

Late preterm infants (34-37 weeks gestation) pose unique challenges to physicians and nurses involved in their care after birth. They may be cared for in different units within hospitals after birth, including Neonatal Intensive Care Units, Newborn Nurseries, or rooming in with the mother. As a result of their gestational age and birth weight, the late preterm infant is often assessed quickly and triaged identical to term infants. Such practice can potentially result in a lack of attention to important components for successful transition after birth. Cold stress and hypoglycemia are the two important problems in late preterm infants which require immediate treatment. Thus, surveillance of these and other physiological variables is needed to insure that they do not affect successful adaptation during the early hours and days after birth.

Hypoglycemia in breastfed neonates

Healthy, full-term infants are programmed to make the transition from their intrauterine constant flow of nutrients to their extrauterine intermittent nutrient intake without the need for metabolic monitoring or interference with the natural breastfeeding process. Homeostatic mechanisms ensure adequate energy substrate is provided to the brain and other organs, even when feedings are delayed. The normal pattern of early, frequent, and exclusive breastfeeding meets the needs of healthy full-term infants. Routine screening or supplementation are not necessary and may harm the normal establishment of breastfeeding. Screening should be restricted to at-risk and symptomatic infants. Symptomatic infants need immediate assessment and intravenous glucose therapy, not forced feedings.

Hypoglycemia complicating dehydration in children with acute gastroenteritis

A study was done to estimate the prevalence of hypoglycemia among children with dehydration due to acute gastroenteritis, and to identify clinical variables associated with hypoglycemia in these children. A retrospective case series of children older than 1 month of age and younger than 5 years of age who presented to an urban children's hospital Emergency Department with acute gastroenteritis and dehydration was performed. Medical records were reviewed; demographic and clinical data, including pretreatment serum glucose concentrations, were recorded. There were 196 children comprising the study population. Eighteen children (9.2%) were hypoglycemic. The duration of vomiting was longer for the children with hypoglycemia (2.6 days, SD +/- 1.5) than for those without hypoglycemia (1.6, SD +/- 1.8), 95% CI 0.13 to 1.88. Hypoglycemia may complicate dehydration due to acute gastroenteritis in young children. Clinicians should examine the serum glucose concentration in these children.

Evaluation of the Glucometer Elite XL device for screening for neonatal hypoglycaemia

To prevent persistent neurodevelopment and physical growth deficits in neonatal care, it is mandatory to determine blood glucose levels as quickly and precisely as possible, preferably using micro-methods. However, most commercially available instruments have not been validated and approved for this purpose. The aim of this study was to validate the Glucometer Elite XL, a newly developed device for point-of-care testing (POCT). In samples from 869 newborn infants, glucose levels were simultaneously measured by the Glucometer Elite XL in whole blood and by an accepted clinical laboratory method in haemolysed blood using the ECA 2000 device. An acceptable method agreement was found between the POCT and the ECA 2000 method (mean difference 0.013 mmol/l, SD 0.69). As determined by regression analysis (Passing-Bablok), the slope was 1.086 with a y-intercept of -0.4 mmol/l ( r =0.959, P <0.05). The differences between measurement pairs of both assays versus the haematocrit were negligible. With a cut-off for hypoglycaemia at 2.6 mmol/l glucose in haemolysed blood, the sensitivity of the POCT device was 0.63 and specificity was 0.98. Raising the cut-off of the Glucometer Elite XL to 3.2 mmol/l, the sensitivity and specificity incremented to 1.0 and 0.89, respectively.

CONCLUSION

The Glucometer Elite XL instrument can be recommended for point-of-care blood glucose measurement in newborn infants if its character as a screening method is taken into account. To compensate deviating results, we advise to shift its cut-off for hypoglycaemia recognition to a safe threshold of 3.2 mmol/l. However, hypoglycaemia has to be confirmed by a valid glucose measurement in the clinical laboratory.

Blood glucose testing at alternate sites in newborn infants

AIM

To compare a method of testing at alternate skin sites (AST) with that of the usual heel-stick approach (SM) for determining blood glucose levels in newborn infants. Our other aims were to compare these methods as regards their accuracy, the pain caused by the procedures, the times taken to obtain a result and the possible delay in accurate test results using AST during rapid changes in blood glucose.

METHODS

One hundred and eighty-six preterm and term infants were enrolled. The blood glucose levels were determined by a standard bedside method (SM, HemoCue) and AST (Freestyle), which permitted blood samples to be taken from the arm or leg.

RESULTS

The levels of blood glucose ranged between 0.6 and 8.6 mmol/l. We found a significant correlation between SM and AST (r = 0.90, p < 0.001). The coefficient of variation was similar, pain was significantly less (median pain score 3.5 vs 7.5, p < 0.01) and the time taken to obtain a result significantly shorter (mean 35 vs 111 s, p < 0.01) with AST than with SM. No significant differences were found between these methods during rapid changes in the blood glucose levels.

CONCLUSION

AST, a relatively simple and painless method of determining blood glucose levels in newborn infants, is acceptably accurate and causes minimal blood loss.

The association between maternal obesity, glucose intolerance and hypertensive disorders of pregnancy in nondiabetic pregnant women

OBJECTIVE

The aim of this study is to evaluate whether pregnancy-induced hypertension (PIH) among nondiabetic patients is associated with glucose intolerance.

MATERIALS AND METHODS

A retrospective case-control study was designed including a study group who had pregnancy-induced hypertension or preeclampsia. Patients with normal pregnancy were used as a control group matched to cases by parity. Diabetic patients, nonsingleton pregnancies, and women without prenatal care were excluded. Data concerning fasting glucose levels, glucose challenge test (GCT), and oral glucose tolerance test (OGTT) were collected from patients' files.

RESULTS

There were 131 patients in each study group. The study group had significantly higher mean maternal age, mean GCT levels, and mean pregestational body mass index (BMI) (28.0 +/- 5.8 vs. 26.5 +/- 5.3, p = 0.02; 5.8 +/- 1.4 vs. 5.1 +/- 1.1 p = 0.0018; 26 +/- 5.1 vs. 23 +/- 4.0 p < 0.001, respectively) than the control group. Mean gestational age and birthweight were also significantly lower in the study group (38.5 +/- 2.1 vs. 39.4 +/- 1.7 p < 0.001; 2929 g +/- 614.7 vs. 3225 +/- 461.1 p < 0.001, respectively). Stratified analysis according to parity demonstrated that pregestational BMI, weight gain during pregnancy, and cesarean section (CS) were significantly higher in women with pregnancy-induced hypertension than in controls in all parity groups. Maternal age and mean GCT levels of women with pregnancy-induced hypertension were higher in all parity groups but statistically significant only among multiparous patients. Multiple logistic regression demonstrated that BMI, weight gain, and maternal age were independently associated with pregnancy-induced hypertension, while GCT level was not. Conclusions. Elevated pregestational BMI is an independent risk factor for development of pregnancy-induced hypertension (PIH). Its association with elevated GCT levels implies that even without overt diabetes, glucose intolerance may play a role in the pathogenesis of preeclampsia in obese patients.

Neonatal hypoglycaemia: clinical and legal aspects

Transiently low blood glucose levels are common in the neonatal period and may be considered a normal feature of adaptation to extrauterine life. There is no evidence that this causes brain injury in the absence of concurrent clinical manifestations. Conversely, persistent and severe hypoglycaemia may be associated with other underlying pathologies which themselves predispose to brain injury. Attribution of brain injury therefore requires demonstration of both 'significant' hypoglycaemia and a characteristic resulting pattern of brain injury. The prevention of hypoglycaemic brain injury requires early detection in infants considered 'at risk' and appropriate intervention. No single concentration of plasma glucose can be associated universally with either the appearance of clinical signs or causation of cerebral injury. For this reason we suggest that treatment be based upon 'operational thresholds' and guided by clinical assessment, not by the plasma glucose concentration alone. For example, the infant displaying neurological signs requires more urgent elevation of blood glucose concentration than the 'asymptomatic' one, regardless of the absolute plasma glucose value.

Hyperglycaemia and the very preterm baby

Neonatal hyperglycaemia, as usually defined (a whole blood glucose of >7 mmol/L), is common in the first week of life in babies born more than 12 weeks early. However, a review of a cohort of all such births in the north of England suggests that significant glycosuria is uncommon, and that there is no threat of an osmotic diuresis until the urine contains 2% glucose (by which time the blood glucose level almost always exceeds 15 mmol/L). The current statistical or epidemiological definition of hyperglycaemia (derived from data on term babies) needs to be replaced, for clinical purposes, by a more operationally relevant definition.

The Emergency Department Approach to Newborn and Childhood Metabolic Crisis

For most emergency medicine physicians, the phrases "newborn workup" and "metabolic disease" are, at best, uncomfortable. This article, however, provides a simple approach to the recognition,evaluation, and treatment of infants with all manners of metabolic issues, including hypoglycemia, inborn errors of metabolism, jaundice, and electrolyte abnormalities. The disorders are grouped based on symptomatology, and have simple guidelines for work-up and management, with an emergency department practitioner perspective in mind.

The investigation and management of neonatal hypoglycaemia

Assessment of neonatal glycaemic status requires accurate and reliable measurement of blood glucose concentrations. Most point-of-care technologies are, however, unsuitable for use in neonates. Although the definition of hypoglycaemia remains elusive, current knowledge allows adoption of pragmatic threshold blood glucose concentrations when clinical intervention should be considered. The vast majority of instances of neonatal hypoglycaemia are due to problems with the normal processes of metabolic adaptation after birth, and strategies to enhance the normal adaptive processes should help prevent such episodes. Further investigations and specific interventions should be considered when hypoglycaemia is of unusual severity or occurs in an otherwise low-risk infant.

The continuous glucose monitoring sensor in neonatal intensive care

OBJECTIVE

To determine the feasibility of continuous glucose monitoring in the very low birthweight baby requiring intensive care, as these infants are known to be at high risk of abnormalities of glucose control.

METHOD

Sixteen babies were studied from within 24 hours of delivery and for up to seven days.

RESULTS

The subcutaneous glucose sensors were well tolerated and readings were comparable to those on near patient whole blood monitoring devices.

CONCLUSION

Continuous glucose monitoring is practical in neonates, giving detailed information about glucose control.

Metabolic evaluation of the sick neonate

Inherited metabolic diseases are rare causes of neonatal morbidity, but they are associated with significant recurrence risks for the parents. Prompt identification and treatment of an infant with an inherited metabolic disease can minimize morbidity, mortality, and lifelong developmental problems. Diagnosis often requires specialized laboratory testing, but common laboratory tests can help identify those infants needing further evaluation. This paper reviews the laboratory abnormalities which can be found in various inherited metabolic diseases and can guide selection of specialized metabolic testing. Consultation with a metabolic specialist is essential for timely diagnosis and treatment to ensure the best possible outcome.

Dedicated neonatal retrieval teams improve delivery room resuscitation of outborn premature infants

BACKGROUND

Morbidity related to ineffective resuscitation and stabilization of premature infants is increased when delivery occurs outside tertiary perinatal centers. The regional neonatal transport team received extensive training to expand their scope of practice to include delivery room resuscitation allowing them to attend high-risk deliveries in community hospitals when maternal transfer was not possible.

OBJECTIVE

Compare the resuscitation and stabilization of premature infants when a specialized neonatal retrieval team (SNRT) is in attendance at delivery with immediate resuscitation and stabilization performed by the referral hospital team (RHT).

STUDY DESIGN

We assessed the impact of a specially trained neonatal transport team by comparing the initial resuscitation process, airway and vascular access skills, illness severity and patient stabilization in both groups.

RESULTS

Neonates resuscitated by the RHT were more likely to receive oxygen, mask CPAP, bag and mask ventilation and cardiac compressions for a significantly longer time period. Neonates resuscitated by the SNRT were intubated more promptly (8.5 minutes {1 to 22} vs 16 minutes {1 to 90}, p=0.035) following a fewer number of attempts. The endotracheal tube was correctly positioned on radiological assessment in 72% of cases in the SNRT group vs 38.1% in the RHT group (p<0.001). Many neonates had no vascular access (31%) and were profoundly hypothermic (38.5%) on arrival of the SNRT. Although there was no significant difference in maximum FiO(2) or oxygenation index, babies with respiratory distress syndrome resuscitated by the RHT were less likely to receive surfactant therapy (76.6 vs 34.4%, p=0.001). There was no difference in transport-related mortality between the groups

CONCLUSIONS

The presence of a highly skilled transport team at a high-risk preterm delivery improves the quality of neonatal resuscitation by increasing intubation success rates and achieving earlier vascular access. Neonates resuscitated by dedicated neonatal retrieval teams were less likely to become significantly hypothermic. Although the severity of RDS was similar neonates in the RHT were less likely to receive surfactant.

Neurodevelopmental outcome of hypoglycaemia in healthy, large for gestational age, term newborns

AIMS

To evaluate the effects of transient hypoglycaemia on the first day of life in 75 healthy term large for gestational age (LGA) infants, born to non-diabetic mothers, on their neurodevelopmental outcome at the age of 4 years.

METHODS

Screening for hypoglycaemia was performed 1, 3, and 5 hours after birth, and continued if blood glucose levels were low. Treatment with intravenous glucose for hypoglycaemia was started if hypoglycaemia was severe or symptomatic. Patients' development and behaviour was examined at the age of 4 years by the Denver Developmental Scale, a non-verbal intelligence test, and the Child Behaviour Check List.

RESULTS

There were no significant differences between children with neonatal normoglycaemia (n = 15) and hypoglycaemia (plasma glucose <2.2 mmol/l 1 hour after birth, or <2.5 mmol/l subsequently; n = 60) in Denver developmental scale scores and child behaviour checklist scores. Although total IQ did not differ between hypoglycaemic and normoglycaemic children, one subscale (reasoning) did (mean difference 9.3, 95% CI 1.3 to 17.2). The correlation between reasoning IQ and neonatal blood glucose levels was weak and not statistically significant. When other definitions for hypoglycaemia were applied, the difference in reasoning IQ was not found. There were no differences in any of the test scores between hypoglycaemic children who had and who had not been treated with intravenous glucose.

CONCLUSION

Transient mild hypoglycaemia in healthy, term LGA newborns does not appear to be harmful to psychomotor development at the age of 4 years.

Contemporary strategies in the diagnosis and management of neonatal hyperinsulinaemic hypoglycaemia

Congenital hyperinsulinism (CHI) is a genetically and phenotypically diverse syndrome. Key management issues involve early diagnosis by ensuring that appropriate samples are taken at the point of hypoglycaemia, prevention of recurrent hypoglycaemia, and detailed characterisation of the clinical, biochemical, and genetic features of each case. Infants with persistent diazoxide resistant CHI require evaluation at specialist referral centres equipped to differentiate those with focal (fo-HI) and diffuse (di-HI) pancreatic disease. Fo-HI is treated with selective pancreatic resection but di-HI is treated by surgery only if intensive medical management regimes are not efficacious.

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.

Infusionstherapie und Ernährung von Risikogruppen

Besondere Situationen erfordern ein besonderes Vorgehen. Während bisher das »Standardvorgehen« bezüglich der Ernährung von pädiatrischen Patienten dargestellt wurde, beschäftigt sich das vorliegende Kapitel mit »Sondersituationen« der pädiatrischen Infusionstherapie und Ernährung. Behandlungssituationen, die ein besonderes Vorgehen bei der Therapie oder spezielle Aufmerksamkeit bei der Anpassung der Ernährung erfordern, entstehen in der Regel durch 4 mögliche Situationen:

spezifische Physiologie von Patientengruppen (z. B. Früh- oder Neugeborene),

Auswirkungen von therapeutischen Maßnahmen (z. B. Operationen),

Pathophysiologie von Erkrankungen (z. B. angeborene Stoffwechselerkrankungen, Erkrankungen des onkologischen, rheumatischen oder atopischen Formenkreises, Anorexia nervosa, Bulimie oder Adipositas) oder

besondere körperliche Belastungen [z. B. (Leistungs-)Sport].

Bekannte Strategien werden systematisch und prägnant dargestellt und diskutiert.

Die Beschäftigung mit der Ernährung von »Risikogruppen« übt das Erkennen und den Umgang von potenziellen Gefahrensituationen bei der Verordnung von bilanzierter Ernährung. So sollte auch derjenige von dem Kapitel profitieren, der sich mit den behandelten Patientengruppen, Situationen, Erkrankungen üblicherweise nicht beschäftigen muss.

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.

Challenges of implementing Point-of-Care Testing (POCT) glucose meters in a pediatric acute care setting

OBJECTIVES

To investigate factors contributing to analytical bias in POCT glucose values generated by the NICU versus the core laboratory.

METHODS

The LifeScan Flexx hospital system glucose meters (SureStep) were used in precision and comparison studies between the NICU and laboratory (ABL715 and Vitros 950).

RESULTS

Analysis of 40 neonatal blood samples revealed a positive bias between the NICU glucose meters versus either the laboratory glucose meter or instrument (mean difference of 0.28 and 0.21 mmol/L, respectively). Linear regression analysis (R2 = 0.0584) of the difference in glucose results versus time elapsed between measurements indicated that the bias observed between the NICU and laboratory glucose meters was not due to in vitro glycolysis for samples transported on ice. Further analysis indicated that the bias appeared to be mostly operator driven, with different NICU operators exhibiting different mean biases. Increasing the amount of blood applied to the SureStep Pro test strip (e.g., 60 vs. 20 microL), led to higher values for glucose concentration for the same blood. Nearly 50% of all glucose values reported for the NICU were obtained by the SureStep Flexx glucose meters in a 3-month period following the introduction of POCT, yet the number of laboratory-reported glucose results for the same period increased by 21% as compared to the previous year.

CONCLUSIONS

Operator error appears to be a source of bias present between the NICU and laboratory, and despite glucose meter utilization in the NICU, the number of glucose measurements by the central laboratory increased after POCT introduction.

Endocrine disorders in the neonate

There is a significant amount of knowledge that has been gained in recent years in the study of endocrine disorders in the newborn. The explosion of genetic data shedding light on the origins of endocrine disease has expanded the level of diagnostic evaluation and management of these infants. This article provides a general review of endocrine disorders as they present in a newborn.

Symptomatic occipital lobe epilepsy following neonatal hypoglycemia

This study reports on the clinical, electrophysiologic, and neuroradiologic aspects of patients with epilepsy secondary to neonatal hypoglycemia. Fifteen patients with epilepsy and/or posterior cerebral lesions, and neonatal hypoglycemia were studied in the epilepsy clinic between February 1990 and March 2003. The mean age was 12 years. The different types of neonatal hypoglycemia were as follows: four patients had transitional-adaptive, seven classic transient, two secondary-associated, and two severe recurrent hypoglycemia. As to epilepsy, we recognized a larger group of 12 patients characterized by focal seizures and posterior abnormalities on the electroencephalogram, the majority of whom had a good outcome, and a second group of two patients presenting electroclinical features of encephalopathy with refractory seizures. All patients except two manifested parieto-occipital lesions on neuroradiologic images. Neurologic examination was normal in one patient. Six patients had microcephaly; eight manifested visual disturbances. Fourteen patients were mentally retarded. One had a pervasive developmental disorder. This study indicates neonatal hypoglycemia may cause posterior cerebral lesions, abnormal findings at neurologic examination, and symptomatic epilepsy, most frequently occipital lobe epilepsy, usually with a good prognosis, and occasionally epileptic encephalopathy with refractory seizures. MRI studies are essential to define the characteristics of cerebral lesions after neonatal hypoglycemia.

Evaluation of "point of care" devices in the measurement of low blood glucose in neonatal practice

BACKGROUND

Low blood glucose in newborns is difficult to detect clinically. Hence a reliable "point of care" device (glucometer) for early detection and treatment of low glucose is needed.

OBJECTIVE

To evaluate the performance of five readily available glucometers for the detection of low blood glucose in newborn infants.

METHOD

Glucostix measurements were taken for newborns with risk factors using a Reflolux S (Boehringer) glucometer. If the initial reading was low (< 2.6 mmol/l), further measurements were taken with two other glucometers (phase I, Advantage and Glucotrend (Roche); phase II, Elite XL (Bayer) and Precision (Abbott)), and plasma glucose was measured in the laboratory (Aeroset; Abbott).

RESULTS

Over 10 months, 101 specimens were collected from 71 newborns (57 in phase I; 44 in phase II). The Advantage glucometer usually overestimated blood glucose with a mean difference of 1.07 mmol/l (p < 0.01) at all low glucose ranges. The Glucotrend, Precision, and Elite XL glucometers performed better; the mean differences were not significantly different from the laboratory measured value (0.17 mmol/l (p = 0.37); -0.12 mmol/l (p = 0.13), and 0.24 mmol/l (p = 0.13) respectively). For detection of glucose concentrations < 2.6 mmol/l, the Precision glucometer had the highest sensitivity (96.4%) and negative predictive value (90%). For lower glucose concentrations (< 2.0 mmol/l), the Glucotrend glucometer performed even better (sensitivity 92.3%, negative predictive value 96.3%).

CONCLUSION

Point of care devices should have good precision in the low glucose concentration range, sensitivity, and accuracy for early detection of neonatal hypoglycaemia. None of the five glucometers was satisfactory as the sole measuring device. The Glucotrend and Precision glucometers have the greatest sensitivity and negative predictive value. However, confirmation with laboratory measurements of plasma glucose and clinical assessment are still of the utmost importance.

The role of parenteral lipids in supporting gluconeogenesis in very premature infants

We have previously demonstrated that very premature infants receiving glucose at 17 micromol/kg min plus appropriate supply of parenteral lipids (Intralipid) and amino acids (TrophAmine) maintained normoglycemia by glucose produced primarily via gluconeogenesis. The present study addressed the individual roles of parenteral lipids and amino acids in supporting gluconeogenesis. Fourteen premature infants (993 +/- 36 g 27 +/- 1 wk) (mean +/- SE) were studied for 8 h on d 5 +/- 1 of life. All infants were receiving standard TPN prior to the study. At start of study, the glucose infusion rate was decreased to approximately 17 micromol/kg min and either Intralipid (g + AA; n = 8) or TrophAmine (g + IL; n = 6) was discontinued. Data from 14 previously studied infants receiving glucose (approximately 17 micromol/kg min) + TrophAmine + Intralipid (g + AA + IL) are included for comparison. Gluconeogenesis was measured by [U-13 C]glucose, (g + AA) and (8 infants of the g + AA + IL group) or [2-13C]glycerol, (g + IL) and (6 infants of the g + AA + IL group). Infants studied by the same method were compared. Withdrawal of Intralipid resulted in decreased gluconeogenesis, 6.3 +/- 0.9 (g +AA) vs. 8.4 +/- 0.7 micromol/kg min (g + AA + IL) (p = 0.03). Withdrawal of TrophAmine affected neither total gluconeogenesis, 7.5 +/- 0.8 vs. 7.9 +/- 0.9 micromol/kg min nor gluconeogenesis from glycerol, 4.4 +/- 0.6 vs. 4.9 +/- 0.7 micromol/kg min (g+ IL and g + AA + IL groups, respectively). In conclusion, in parenterally fed very premature infants, lipids play a primary role in supporting gluconeogenesis.

Hypoglycemia complicating dehydration due to acute gastroenteritis

To identify clinical variables predictive of hypoglycemia in dehydrated children with acute gastroenteritis (AGE), clinical variables were recorded for dehydrated children younger than 5 years old with AGE before measuring serum glucose. One hundred and eighty-four children were enrolled; 62 with, and 122 without, hypoglycemia. Multivariate analysis identified variables associated with hypoglycemia. Female gender, neurologic symptoms of hypoglycemia, and a greater amount of vomiting vs. diarrhea were significantly associated with hypoglycemia. Clinical variables do not have adequate sensitivity and specificity to accurately predict which children with AGE have hypoglycemia. Glucose determination should be considered for these patients.

A prospective controlled study of neonatal morbidities in infants born at 36 weeks or more gestation to Women with diet-controlled gestational diabetes (GDM-class Al)

OBJECTIVE

Infants of gestational diabetes mellitus (GDM)-A1 women are unlikely to experience the marked excursion in maternal glucose levels that may characterize insulin-requiring GDM (class-A2) or insulin-dependent diabetes (IDDM). However, infants born to GDM-A1 women are traditionally managed like infants born to GDM-A2 or IDDM women.

AIMS

To examine monitoring protocols for infants of GDM-A1 women, and to examine the efficacy of early and frequent feedings to prevent and to treat hypoglycemia.

METHODS

A total of 92 of 101 infants born to GDM-A1 women (diabetic group) and 68 of 83 infants born to nondiabetic women (control group) at > or=36 weeks of gestation were prospectively monitored for the development of hypoglycemia and other morbidities. Blood glucose screening was performed in the diabetic group every 30-60 minutes three times, starting soon after birth and then at 3-hour intervals for 24 hours. Liberal feedings were started shortly after birth and provided every 3 hours for at least 24 hours. All women with GDM-A1 had an HbA1c measured before delivery.

RESULTS

Both the diabetic and control groups had similar demographics, including LGA incidence. Blood glucose readings before feedings were low (<40 mg/dl) in 24 of 92 infants (26.1%) from the diabetic group and in 20 of 68 control infants (29%). After the start of oral feedings, all but four diabetic and three control infants had subsequent glucose readings > or =40 mg/dl. No infant had symptoms of hypoglycemia and none from the diabetic group had birth trauma, hypoxic-ischemic encephalopathy, polycythemia, hypocalcemia, or hypomagnesemia. Hypoglycemic episodes in the infants from the diabetic group could be managed with oral feedings alone. Birth weight, gestational age, sex, Apgar scores, and maternal HbA1c levels could not predict low glucose readings on initial screening in infants from the diabetic group.

CONCLUSION

The incidence of hypoglycemia in infants born to GDM-A1 women at > or =36 weeks of gestation is similar to control infants born to nondiabetic women. Low blood glucose levels during the first few hours of life can be prevented or treated with early and frequent oral feeding.

Glucose and lipid metabolism in small for gestational age infants at 48 hours of age

OBJECTIVE

To study the consequences of low birth weight on glucose and lipid metabolism 48 hours after delivery.

METHODS

We studied 136 small for gestational age (SGA) and 34 appropriate for gestational age (AGA) term neonates who were born in Santiago, Chile. Prefeeding venous blood was obtained 48 hours after birth for determination of glucose, free fatty acids, beta-hydroxy butyrate, insulin, C-peptide, leptin, sex hormone-binding globulin, insulin-like growth factor-binding protein-1 (IGFBP-1), and cortisol.

RESULTS

SGA newborns had lower glucose (SGA versus AGA, median [interquartile range]: 3.6 mmol/L [2.9-4.1 mmol/L] vs 3.9 mmol/L [3.6-4.6 mmol/L]) and insulin levels (31.3 pmol/L [20.8-47.9 pmol/L] vs 62.5 pmol/L [53.5-154.9]) than AGA infants, and they had higher glucose/insulin ratios (13.9 mg/dL/uIU/mL [8.6-19.1 mg/dL/uIU/mL] vs 8.2 mg/dL/uIU/mL [4.6-14.1 mg/dL/uIU/mL]). SGA infants also had higher levels of IGFBP-1 (5.1 nmol/L [4.4-6.7 nmol/L] vs 2.9 nmol/l [1.4-4.2 nmol/L]), free fatty acids (0.72 mEq/L [0.43-1.00 mEq/L] vs 0.33 mEq/L [0.26-0.54 mEq/L]) and beta-hydroxy butyrate (0.41 mEq/L [0.15-0.91 mEq/L] vs 0.09 mEq/L [0.05-0.13 mEq/L]). Sex-hormone binding globulin levels were not significantly different between the 2 groups.

CONCLUSIONS

In early postnatal life, SGA infants display an increased insulin sensitivity with respect to glucose disposal but not with respect to suppression of lipolysis, ketogenesis, and hepatic production of IGFBP-1. It will be important to determine how these differential sensitivities to insulin vary with increasing age.

Hypoglycemia and the full-term newborn: how well does birth weight for gestational age predict risk?

OBJECTIVE

To determine whether anthropometric characteristics could be used to accurately predict risk of hypoglycemia in full-term newborns during the early post-birth period.

DESIGN

Descriptive, utilizing newborn anthropometric measurements singly and in combination to determine risk of neonatal hypoglycemia. The following measurements were obtained twice for each newborn: weight, head circumference, chest circumference, abdominal circumference, mid-arm circumference, thigh circumference, and length. The investigator was blind to all measurements except weight.

SETTING

Mothers' rooms or the newborn nursery in a community hospital.

INTERVENTIONS

All measurements were obtained twice, and a physical examination was completed on each newborn by the principal investigator. These newborns were classified as large-, average-, and small-for-gestational age, using a tool typically used in many newborn nurseries.

SAMPLE

One hundred fifty-seven full-term newborns (94 White and 63 African American).

MAIN OUTCOME MEASURES

The differences in anthropometric measurements by race and gender were calculated using two-way analysis of variance. The risk of hypoglycemia was calculated using logistic regression modeling.

RESULTS

There were significant differences in measurements by race and by gender. Additionally, there was a subset of newborns classified as average for gestational age who had an increased risk of hypoglycemia (OR = 4.17, 95% CI = 1.33-13.08). Newborns with a mid-arm circumference/head circumference ratio that varied from .26 to .29 have an odds ratio of 6.10 (95% CI = 1.89-19.66) for risk of hypoglycemia. Plotting a newborn's birth weight on a published fetal growth curve clearly did not accurately predict his or her risk of hypoglycemia.

CONCLUSIONS

These findings indicate that extremes in newborn birth weight are not always correctly defined, may vary by race and ethnic group, and may not be the best method for determining under- or overnourishment and risk of neonatal hypoglycemia.

Hypoglycemic injury to the immature brain

Despite the fact that hypoglycemia is an extremely common disorder of the newborn, consensus has been difficult to reach regarding definition, diagnosis, outcome, and treatment. With improved neuroradiologic techniques, such as MRI and PET scanning becoming increasingly available, studies to determine the correlation between hypoglycemia and outcome will help to clarify issues surrounding the effects of hypoglycemia on brain pathology. Long-term epidemiologic studies correlating the severity and duration of hypoglycemia with neurologic consequences are required, and can be complemented by appropriate parallel investigations in animal models of neonatal hypoglycemia.

Natural progress of blood glucose in full-term low-grade low-birthweight infants

BACKGROUND

Although various authors have suggested the risk of hypoglycemia in practical medicine for low-birthweight infants is exaggerated, convincing evidence using recent definitions of hypoglycemia is not documented.

METHODS

To evaluate the risk of hypoglycemia in low grade low-birthweight infants (LGLBWI) (2100 g < birthweight < 2500 g) whose only abnormality is low-birthweight, whole blood glucose (BGw) was measured five times (0, 0.5, 1, and 4 h after birth and just before the first bottle feeding) in 49 LGLBWI and 38 normal birthweight infants.

RESULTS

Whole blood glucose was not lower in LGLBWI with a gestational age of 38-40 weeks (GT38LGLBWI) than in normal birthweight individuals with a gestational age of 38-40 weeks at each of the five measuring times. No case of GT38LGLBWI, not even in small for gestational age infants, required treatment for hypoglycemia. The BGw was significantly lower in 37-week gestational age LGLBWI than in GT38LGLBWI at 0.5 h and 1 h after birth (P < 0.05). However, in all cases with low BGw value (below 30 mg/dL at 1 h after birth), BGw value increased naturally to the normal level 1.5 h after birth. No symptoms of hypoglycemia were observed.

CONCLUSIONS

In the care of hypoglycemia in LGLBWI, attention should be paid first to gestational age, namely, tendency to prematurity. In this study, however, no hypoglycemia that required treatment was found among full-term normal LGLBWI, even those who were small for gestational age. Frequent blood glucose measurement for those infants is therefore unnecessary.

Rate and risk factors of hypoglycemia in large-for-gestational-age newborn infants of nondiabetic mothers

OBJECTIVE

The purpose of this study was to investigate the rate of hypoglycemia in large-for-gestational-age infants of nondiabetic mothers in relation to maternal or neonatal risk factors.

STUDY DESIGN

Hospital charts of all term large-for-gestational-age infants born between 1994 and 1998 (n = 1136) were analyzed for the rate of neonatal hypoglycemia (capillary glucose level, < or =30 mg/dL) during the first 24 hours of life. Infants of women with preexisting or gestational diabetes mellitus were excluded (n = 180). Neonatal glucose testing was performed at 1 or 2 hours of life, with subsequent measurements every 4 to 6 hours. Maternal and neonatal parameters were compared between neonates with and without hypoglycemia, including recent oral glucose tolerance test values in those women who were tested (n = 358).

RESULTS

Of 956 infants, 69 infants (7.2%) were not tested for hypoglycemia. In the remaining 887 infants, hypoglycemia occurred in 142 infants (16%) within the first 24 hours of life. The incidence of hypoglycemia decreased sharply during the first few hours of life, from 9.2% within the first hour of life, to 3.5% between 2 to 5 hours (cumulative) of life, and 2.4% between 6 and 24 hours of life. Gestational age at delivery was the only neonatal parameter that differed significantly between infants with and without hypoglycemia (39.5 vs 39.3 weeks, P =.01). The antenatal 1-hour oral glucose tolerance test value was the only predictive maternal parameter (141.5 vs 163.0 mg/dL, P <.006). There was an incremental risk of hypoglycemia with increasing 1-hour oral glucose tolerance test values, with hypoglycemia rates of 2.5%, 9.3%, 22.0%, and 50.0% that were associated with maternal 1-hour glucose values of <120, 120-179, 180-239, and > or =240 mg/dL, respectively (P <.05, for all comparisons).

CONCLUSION

Routine glucose testing is indicated in large-for-gestational-age newborn infants of nondiabetic mothers. The 1-hour glucose value of the maternal oral glucose tolerance test is a fairly good predictor of subsequent neonatal hypoglycemia. A single elevated 1-hour value of > or =180 mg/dL markedly increases the risk of neonatal hypoglycemia.

An evaluation of three glucose meter systems and their performance in relation to criteria of acceptability for neonatal specimens

BACKGROUND

Prior to making a selection for our hospital, a pediatric institution, we deemed it necessary to evaluate, concurrently, three recently available glucose meter systems, claimed to be suitable for use with neonatal samples.

METHODS

Comparisons were with laboratory plasma analyses. Linearity and precision were also determined.

RESULTS

All meters gave linear responses. Precision determined using quality control material was acceptable. For an in-laboratory side-by-side evaluation, meter 1 showed a small bias but significant result scatter while meter 3 showed a negative bias; mean differences from reference (S.D.) were: -0.30 mmol/l (0.56), 0.06 mmol/l (0.39) and -0.49 mmol/l (0.35) for meters 1, 2 and 3, respectively. Clinical unit testing results gave mean differences from reference (S.D.) of: -0.19 mmol/l (0.56), 0.06 mmol/l (0.48) and -0.12 mmol/l (0.48) for meters 1, 2 and 3, respectively. Using +/- 15% of reference as acceptability thresholds, 61%, 79% and 72% of results for meters 1, 2 and 3 respectively, were within limits. At +/- 20%, the corresponding figures were 81%, 90% and 91%, respectively. All meters showed a sample-hematocrit effect with either negative (meters 1 and 3) or positive (meter 2) bias.

CONCLUSIONS

Regardless of the performance criteria chosen, meter 1 had the worst performance while meter 2 was slightly better in overall than meter 3. Based on performance, general characteristics and user feedback, meter 2 was selected by us. In light of our results, we nonetheless suggest that performance of the meters tested is less than ideal, especially in the context of clinical utility in neonates.

Plasma glucose levels in term infants who are appropriate size for gestation and exclusively breast fed

AIM

To evaluate the plasma glucose levels in normal, term infants who were appropriate size for gestational age (AGA) and exclusively breast fed, and to assess the influence of parity of the mother, mode of delivery, and time of feed on the glucose levels.

METHOD

A total of 200 healthy, term, AGA infants were longitudinally evaluated at 3, 6, 24, and 72 hours of life. Plasma glucose was estimated from heel prick capillary samples. The influence of mode of delivery, parity, and interval between feeds on plasma glucose was analysed.

RESULTS

There was no significant difference between the plasma glucose levels of the cohorts at any of the sampling time points. Parity, mode of delivery, and time since the last feed did not affect plasma glucose. Satisfactory glucose levels were maintained even when infants remained unfed up to 6 hours of age. Infants with plasma glucose concentrations less than 2.2 mmol/l at 3 hours of age were more likely to have low sugar concentration (< 2.5 mmol/l) at 72 hours (RR = 6.55, 95% confidence interval 3.93 to 10.92).

CONCLUSIONS

A term, breast fed infant may have its own distinct plasma glucose levels, showing no significant variation between 3 and 72 hours of age. Plasma glucose levels are satisfactorily maintained in normal term infants without resort to prelacteal feeds. Mode of delivery, parity of the mother, and interval between feeds did not influence plasma glucose. Biochemical thresholds for hypoglycaemia do not seem to be of practical importance in asymptomatic, normal, term, breast fed infants.

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.

Neonatal glucose metabolism: differential diagnoses, evaluation, and treatment of hypoglycemia

Hypoglycemia is one of the most common clinical care issues facing the neonatal practitioner. Increasing evidence indicates that neonatal hypoglycemia may have long-term neurologic effects. Care is complicated by the lack of a clearly defined threshold for hypoglycemia in term and preterm infants, however, and by highly variable clinical signs and symptoms. Furthermore, many infants with low blood glucose measurements do not exhibit obvious signs of impairment. The complexity of neonatal glucose metabolism is illustrated by the variety of conditions producing or associated with both neonatal hypo- and hyperglycemia. Maintenance of euglycemia is especially challenging in the sick or low birth weight neonate. This article defines euglycemia by its range and reviews the differential diagnoses and etiology of hypoglycemia--as well as the principles of its management--in the neonatal period.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

Didactic components of a comprehensive pediatric competency program

The infusion nurse specialist working with pediatric patients must demonstrate competencies related to all stages of child growth and development. In addition, specific skills requiring competency validation in the pediatric practice setting include calculation of pediatric dosages, maintaining fluid balance, use of specific devices, age-specific skills, and management of complications. This article presents a discussion of each of these areas as well as recommendations for methods of competency validation.

Glucose monitoring with long-term subcutaneous microdialysis in neonates

BACKGROUND

Microdialysis is a new approach for continuous monitoring of small molecules in the extracellular space, and hypoglycemia is a common problem in neonatal intensive care. The objective of this study was to evaluate subcutaneous microdialysis for long-term glucose monitoring in neonatal intensive care. We determined the relative recovery of the microdialysis system in vitro and in vivo, the stability of the relative recovery in vivo during long-term microdialysis, and the correlation between blood and dialysate concentrations of glucose and urea. Furthermore, we evaluated the sensitivity and specificy of subcutaneous microdialysis for the diagnosis of hypoglycemia.

PATIENT AND METHODS

Thirteen infants (10 neonates) with gestational ages of 30.2 to 45.6 weeks were investigated by microdialysis of subcutaneous adipose tissue and blood sampling. Subcutaneous microdialysis was performed for a median (range) duration of 9 (4-16) days.

RESULTS

The application was safe, even in extremely low birth weight infants (<1000 g) with scanty subcutaneous adipose tissue. The mean +/- standard deviation of the relative recovery in vitro was 101 +/- 3% for glucose and 100 +/- 2% for urea. Using urea as the internal standard, the mean relative recovery in vivo was 96.4 +/- 12.7% at the beginning and remained constant up to 16 days. The correlation between microdialysate and blood was significant for glucose (r = 0.88) and urea (r = 0.98). Subcutaneous microdialysis allowed the detection of asymptomatic hypoglycemias. The diagnostic sensitivity of a dialysate glucose </=2.9 mM to predict a blood glucose level </=2.8 mM was 92.3%, with 88.1% specificy. The positive predictive value with a 13.4% prevalence of a blood glucose </=2.8 mM was 54.5%, with a negative predictive value of 98.7% and an accuracy of 88.7%.

CONCLUSIONS

Subcutaneous microdialysis is a safe method, well suited for long-term glucose monitoring in neonates during intensive care. Subcutaneous microdialysis can be used to reduce blood loss and painful stress resulting from diagnostic blood sampling in high-risk neonates.

Hypoglycemia in the newborn

Since a universal definition for hypoglycemia is lacking, an operational threshold for initiating therapy has been defined. Hypoglycemia is encountered in a variety of neonatal conditions including prematurity, growth retardation and maternal diabetes. Since hypoglycemia may be asymptomatic, routine screening for this condition in certain high risk situations is recommended. Supervised breast-feeding may be a treatment option in asymptomatic hypoglycemia. However, symptomatic hypoglycemia should always be treated with a continuous infusion of parenteral dextrose. Neonates needing dextrose infusion rates above 12 mg/kg/m should be investigated for refractory causes of hypoglycemia. Hypoglycemia has been linked to poor neuro-developmental outcome and hence aggressive screening and treatment is recommended.

Screening for hypoglycemia in healthy term neonates: effects on breastfeeding

Transient hypoglycemia in the early neonatal period is a common adaptive phenomenon as the newborn changes from the fetal state of continuous transplacental glucose consumption to intermittent nutrient supply following cessation of maternal nutrition at birth. Research has demonstrated that in the term, healthy newborn, this dynamic process is self-limiting and is not considered pathologic. The American Academy of Pediatrics and the World Health Organization recommend that neonatal blood glucose screening be reserved for newborns who are at risk or symptomatic and conclude that universal hypoglycemia screening is inappropriate, unnecessary, and potentially harmful. Nevertheless, many hospital nurseries continue the clinical practice of routine early glucose screening on healthy, term newborns. This results in the misidentification of neonates captured while experiencing the normal, self-correcting physiologic blood glucose nadir who are then diagnosed with pathologic neonatal hypoglycemia. Subsequent to this misdiagnosis, further surveillance and unnecessary, aggressive treatment interventions will follow that are potentially harmful to the successful establishment of positive maternal-infant interactions and the breastfeeding experience. Research studies indicate that routine hypoglycemia screens, treatments, and interventions in the healthy infant are not evidence-based and result in a serious disruption of the initiation process and duration patterns of lactation. Using the perspective of the theory of technology dependency, this inquiry explores the potential adverse sequelae of inappropriate glucose screening in the healthy breastfeeding newborn and describes selected outcome variables including: 1) the consequences of early maternal-infant separation, 2) the influence of early formula supplementation on breastfeeding discontinuance rates, 3) the effect of separation and supplementation on the onset of lactogenesis, and 4) the impact of hospital staff and provider recommendations of formula supplementation on maternal confidence to independently nurture her baby.