Neonatal hypoglycemia, Part I: Background and definition

Relationship between serum insulin and point-of-admission blood glucose of ill neonates at a tertiary health facility in Nigeria

Introduction

Optimal glucose metabolism is important in neonatal survival especially in the first days of life. Insulin play a significant role in maintaining blood glucose homeostasis. This study set out to determine the serum insulin levels of ill neonates as related to their point-of-admission blood glucose estimation at the Wesley Guild Hospital, Ilesa, Nigeria.

Methods

Three hundred babies took part in the study. Blood glucose and serum insulin levels were assayed at admission using Accu-Chek Active glucometer^(R) and Accu-Ɔ-Bind ELISA Microwells^(R) respectively. Hyperglycaemia was defined as blood glucose ≥7mmol/L and hypoglycaemia as blood glucose <2.2mmol/L.

Results

The median (IQR) age of the babies was 10.0 (0.5 - 70.0) hours with male to female ratio of 1.5:1. Seventy-four (24.7%) were preterms and 35 (11.7%) were small-for-gestational age. The mean (SD) blood glucose level of the babies was 4.1(2.1) mmol/L with a range of 0.6-13.4mmol/L. Hyperglycaemia and hypoglycaemia were observed in 18(6.0%) and 40(13.3%) babies respectively. The median (IQR) serum insulin level was 9.8(3.0-35.3) μIU/ml. There was weak positive correlation between serum insulin and blood glucose levels of the babies (r = 0.197, p = 0.001). Birth asphyxia was associated with lower serum insulin, while probable sepsis with relatively higher levels.

Conclusion

Serum insulin level increases with increasing blood glucose in ill Nigerian babies at presentation to the hospital. Babies with asphyxia and sepsis particularly tend to have abnormal serum insulin at admission. Hyperinsulinaemia in ill babies may connote a compensatory mechanism to normalise abnormal blood glucose rather than playing significant role in its aetio-pathogenesis.

Evaluation of accuracy of FAD-GDH- and mutant Q-GDH-based blood glucose monitors in multi-patient populations

BACKGROUND

Glucose dehydrogenases have been highly promoted to high-accuracy blood glucose (BG) monitors. The flavin adenine dinucleotide glucose dehydrogenase (FAD-GDH) and mutant variant of quinoprotein glucose dehydrogenase (Mut. Q-GDH) are widely used in high-performance BG monitors for multi-patient use. Therefore we conducted accuracy evaluation of the GDH monitors, FAD-GDH-based GM700 and Mut. Q-GDH-based Performa.

METHODS

Different patients were enrolled: patients with and without diabetes, patients receiving respiratory therapies, hemodialysis (HD) and peritoneal dialysis (PD) patients, and neonates. The accuracy evaluation of FAD-GDH- and Mut. Q-GDH-based monitors referred to ISO 15197:2013 which applies new criteria for the minion accuracy requirements: more than 95% of the blood glucose readings shall fall within ±15mg/dL of the reference method at glucose concentration <100mg/dL and within ±15% of the reference method at glucose concentration ≥100mg/dL. Bland-Altman plots were used to evaluate the 2 GDH monitors as well.

RESULTS

Bland-Altman plots visualized excellent precision of the BG monitors. The 95% limit agreement of overall results for the FAD-GDH-based monitors was within ±12% and that for the Mut. Q-GDH-based monitors was from -10 to +17%. Both BG monitors met the accuracy requirements of ISO 15197:2013. The FAD-GDH-based monitor performed better with neonates and patients with and without diabetes, and the Mut. Q-GDH-based monitor performed better with HD and PD patients.

CONCLUSIONS

Analytical results prove that the GDH-based monitors tolerate a broad BG concentration range, are oxygen independent, have BG specificity, and have minimal interference from hematocrit. The GDH-based monitors are reliable for multi-patient use.

Neonatal glucose homeostasis

NEWBORNS ARE NURTURED in a uterine environment that provides and regulates their glucose supply. Once the umbilical cord is clamped and the maternal glucose supply is terminated, the neonate must begin glucose regulation. This regulation involves complex metabolic and hormonal pathways that may not be mature immediately after birth. A variety of factors influences maturation of these pathways, including developmental immaturity, gestational age, maternal influence, delivery history, and any existing disease processes.1 Management of glucose homeostasis is further complicated because a “normal” range for neonatal blood glucose values has not been clearly defined.2–6 The practitioner must be astute at identifying neonates at risk for glucose problems and intervene quickly because prolonged glucose imbalance can cause serious neonatal complications.

Clinical evaluation of bionime rightest GM310 biosensors with a simplified electrode fabrication for alternative-site blood glucose tests

BACKGROUND

Most processes for fabricating biosensors applied to screen-printed carbon electrodes (SPCEs) are complex. This study presents a novel one-step process for manufacturing electrodes for injection-molding biosensors.

METHODS

During the sensor-fabrication process, barrel-plated gold electrodes were inserted into an injection-molded base. The electrode directly touched the electrical contact of a meter. We analyzed technical measurements for this biosensor, including tests of the measurement range, within-run imprecision, and between-meter imprecision. In clinical trials, experienced technicians tested 3 alternative sites (fingertip, palm, and arm). The results were simultaneously compared with plasma values obtained with the hexokinase method on the Olympus AU640 instrument. Analytical results were evaluated according to International Standards Organization 15197 (ISO 15197:2003) criteria and by Clarke error grid analysis (EGA), and CVs were calculated to evaluate within-run imprecision.

RESULTS

The glucose measurement range was 0.6- 33.3 mmol/L (y = 0.96x + 0.07 mmol/L; r(2) = 0.9977). The CVs in the within-run imprecision test were 1.7%-3.5%, and the overall CV was 2.1%, indicating good reproducibility of results. The Student t-tests of mean values from 5 meters revealed statistically insignificant differences (P > 0.05). In clinical trials, the agreement of the Rightest GM310 meter results with those of a laboratory method complied with ISO 15197:2003 criteria. In the EGA, 100% of the values were within the acceptable zones (A + B), and the proportion of values within zone A exceeded 95%.

CONCLUSIONS

The Bionime Rightest GM310 meter applied a simplified process for biosensor fabrication and displayed acceptable performance for monitoring glucose concentrations at alternative test sites.

Glucose metabolism in the late preterm infant

Prematurity and low birth weight are important determinants of neonatal morbidity and mortality. A rising trend of preterm births is caused by an increase in the birth rate of near-term infants. Near-term infants are defined as infants of 34 to 36 6/7 weeks gestation. It is dangerous to assume that the incidence of hypoglycemia in the later preterm infant is similar to the infant born at full term. Although current methods for assessing effects of hypoglycemia are imperfect, the injury to central nervous system depends on the degree of prematurity, presence of intrauterine growth restriction (IUGR), intrauterine compromise, genotype, blood flow, metabolic rate, and availability of other substrates. Therefore, early recognition of glucose metabolic abnormalities pertaining to late preterm infants is essential to provide appropriate and timely interventions in the newborn nursery. Although many of the investigations have targeted full-term infants, premature infants inclusive of the extremely low birth weight infants and the intrauterine growth-restricted infants, adequately powered studies restricted to only the late preterm infants are required and need future consideration.

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.

Does maternal hypoglycemia during screening glucose assessment identify a pregnancy at-risk for adverse perinatal outcome?

OBJECTIVE

To determine the perinatal outcome in pregnancies with maternal hypoglycemia following a second trimester oral glucose challenge test (GCT).

STUDY DESIGN

Retrospective case-control study of pregnancies undergoing a second trimester 1-hour oral glucose challenge test (GCT). Hypoglycemic pregnancies (<88 mg/dl) were matched with pregnancies with 1-hour glucoses of >88 mg/dl. Antepartum, intrapartum, and neonatal outcomes were assessed.

RESULTS

Over 29 months, 334 hypoglycemic singleton pregnancies were matched with 334 controls. A greater number of special/neonatal intensive care unit (SCN/NICU) admissions occurred in the hypoglycemic group (48/334 (14.4%) vs 29/334 (8.7%) in the control group) (p=0.02). The SCN/NICU admission rate remained after controlling for maternal hypertension, smoking, and preterm birth (p=0.037). The development of pregnancy-induced hypertension in women with hypoglycemia 24/334 (7.2%) compared with euglycemic women 13/334 (3.9%, p<0.06) was not significant.

CONCLUSION

Admission to SCN/NICU is increased in pregnant women with hypoglycemia following a GCT.

Accuracy evaluation of a new glucometer with automated hematocrit measurement and correction

BACKGROUND

Blood glucose meters are widely used in point of care testing, however, many studies have shown inaccuracies in the glucose measurement due to a number of factors. The present study evaluated the accuracy of a new glucometer capable of simultaneous measurement of patient's hematocrit with algorithmic adjustment of glucose result. This meter was compared with a reference method and 2 other existing meters widely used in the market.

METHODS

Venous whole blood samples from healthy volunteers were pooled and reconstituted to produce 5 different hematocrit (30-60%) concentrations. Each hematocrit specimen was spiked to produce 4 different glucose (50-500 mg/dl) concentrations.

RESULTS

Hematocrit measured by the new meter correlated well with the reference method. Mean percentage error differences, compared to the reference method, showed obvious differences between existing meters across the wide hematocrit range at various glucose concentrations. The new meter showed a steady and consistent glucose concentrations compared to the reference method.

CONCLUSION

The new glucometer, which simultaneously measures hematocrit and performs automated correction for the hematocrit effect, provides a glucose result with improved accuracy. Its measurement of hematocrit from the same blood sample will eliminate the need for additional collection of blood or measurement using another method.

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.

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.

The impact of corticosteroids on the developing animal

Infants are subjected to both endogenous and exogenous corticosteroids in the pre- and postnatal periods. Stress to the mother before birth, or to the child postpartum, can give rise to high, chronic endogenous corticosteroid levels caused by activation of the hypothalamic-pituitary-adrenal (HPA) axis. Physician-administered exogenous corticosteroids are also used in the management of a wide spectrum of pre- and postnatal conditions. The long-term effects of corticosteroids in developing humans are not well known. Studies in animals, however, indicate that both natural stress and exogenous corticosteroids can have long-lasting and deleterious effects on the body, brain, behavior, and hypothalamic-pituitary-adrenal axis of developing infants. These data suggest that exogenous corticosteroids should be administered with caution, after careful benefit/risk analyses, and that, as far as possible, the developing brain should be protected against the effects of pre- and postnatal stress.

Glucose homeostasis in the micropremie

This article evaluates the current knowledge of the kinetics of glucose homeostasis in the micropremie. Glucose production, glucose use, and glucose oxidation are reviewed in detail. This article also evaluates the developmental regulation of glucose homeostasis relative to some of the fundamental differences known to exist in the neonate compared to the adult.

Effect of exogenous corticosteroids on the developing central nervous system: a review

Corticosteroid therapy is used in a variety of developmental clinical settings. Prenatally, maternal administration of corticosteroids is used primarily in the prevention of respiratory distress syndrome. Postnatally, corticosteroids are used to treat a variety of infant diseases such as autoimmune hemolytic anemia and hypoglycemia. Treatment regimes often involve repeated administration, on a weekly basis prenatally and daily postnatally, despite an absence of safety data from randomized clinical trials. A large number of animal studies, the majority of which used rodents, have shown that both repeated prenatal or neonatal administration of exogenous corticosteroids has a wide range of detrimental effects on the structure and function of the developing central nervous system (CNS). None of these studies included long-term follow-up. Despite the reported detrimental effects on CNS development, a number of animal studies have shown that pretreatment with corticosteroids nevertheless protect the brain from hypoxia-ischemic injury; however, clinically such treatment is no longer favored. Studies using large animal models and with long-term follow-up should be undertaken to establish the relative risks and benefits of the repeated application of exogenous corticosteroids.