Association of Cord Blood Glucose, Sodium, Potassium, and Calcium Levels With Neonatal Birth Asphyxia: A Hospital-Based Study

Context

Neonatal birth/perinatal asphyxia is a serious condition with the potential to cause damage to various tissues of the body especially the brain. Hypoxia can cause metabolic disturbances, which in turn can lead to imbalances in the levels of glucose, electrolytes, and calcium, which can further worsen the condition. Early detection of these biochemical derangements and immediate correction can prevent the complications and lifelong disabilities of birth asphyxia due to injury to vital organs particularly the brain. The aim is to assess any correlation between the cord blood glucose, electrolytes, and calcium levels and the severity of birth asphyxia.

Methods and material

In this study, 50 birth asphyxia neonates with birth weight >2.5 kg, and a 5-minute Apgar score ≤ 6 at birth with clinical evidence of asphyxia were compared with healthy neonates with birth weight > 2.5 kg, and a 5-minute Apgar score > 7. In all the cases and controls, cord blood glucose was estimated by glucose oxidase and peroxidase (GOD-POD) method, total calcium by Arsenazo method, and sodium and potassium were estimated by ion-selective Electrode (ISE) method using fully automated biochemistry analyzers.

Results

The mean cord blood concentrations of glucose, sodium, potassium, and calcium were significantly lower among birth asphyxia neonates in comparison with that of controls (p < 0.05). The correlation coefficient (r) for the study variables among cases indicates that there is a low to moderate positive correlation between the 5-minute Apgar score which is a measure of severity of birth asphyxia and cord blood concentrations of glucose, sodium, and calcium.

Conclusion

In our study, birth asphyxiated neonates were found to have statistically significant low levels of cord blood glucose and electrolytes like sodium and calcium except for potassium. There was a low to moderate positive correlation between cord blood glucose and electrolyte concentrations with the severity of birth asphyxia. Analysis of cord blood for these simple biochemical tests can help pediatricians in the active management of birth asphyxia cases.

Bioimpedance spectroscopy in the infant: effect of milk intake and extracellular fluid reservoirs on resistance measurements in term breastfed infants

BACKGROUND/OBJECTIVES

Bioimpedance spectroscopy is an accurate non-invasive method for measuring body composition in adults, but in infants it requires further testing and validation. Of the few studies of bioimpedance conducted in infants, none have comprehensively investigated the effect of milk intake volume. This study assessed the effect of the milk intake, feed duration and the volume of the infant's stomach and bladder on the resistance values pre-/post-feed to establish the feasibility of using these values interchangeably during data collection.

SUBJECTS/METHODS

Forty-eight breastfeeding infants were measured at 2, 5, 9 and/or 12 months (n=62 sessions) within 1-2 min before the start and after the end of breastfeed. Median (IQR) time between measurements was 24 (20.0-30.0) min. Resistance measurements at 0 and 50 kHz, and infinite frequency (R0, R50 and Rinf) and resistance of intracellular water (Ricw) were analysed with customised infant settings. Milk intake was measured by test weights. Free-water volumes and free-water change were determined from stomach and bladder volumes calculated from ultrasound images.

RESULTS

Small pre-to-post-feed changes (median (IQR): R0 -3.7 (-14.8, 14.3); R50 0.3 (-10.4, 15.0); Rinf 2.8 (-13.3, 35.5); Ricw 20.8 (-98.1, 290.9)) were not significantly different from zero (R0: P=0.92; R50: P=0.48; Rinf: P=0.32; Ricw: P=0.097). No significant effect of milk intake or free-water change was detected.

CONCLUSIONS

The lack of consistent change in resistance across a breastfeed provides flexibility in the timing of measurements of infants in the research setting, such that typically pre- and post-feed measures of resistance can be used interchangeably.

Estimation of fat-free mass in Asian neonates using bioelectrical impedance analysis

The aims of this study were to develop and validate a prediction equation of fat-free mass (FFM) based on bioelectrical impedance analysis (BIA) and anthropometry using air-displacement plethysmography (ADP) as a reference in Asian neonates and to test the applicability of the prediction equations in an independent Western cohort. A total of 173 neonates at birth and 140 at two weeks of age were included. Multiple linear regression analysis was performed to develop the prediction equations in a two-third randomly selected subset and validated on the remaining one-third subset at each time point and in an independent Queensland cohort. FFM measured by ADP was the dependent variable, and anthropometric measures, sex and impedance quotient (L2/R50) were independent variables in the model. Accuracy of prediction equations was assessed using intra-class correlation and Bland-Altman analyses. L2/R50 was the significant predictor of FFM at week two but not at birth. Compared with the model using weight, sex and length, including L2/R50 slightly improved the prediction with a bias of 0·01 kg with 2 sd limits of agreement (LOA) (0·18, -0·20). Prediction explained 88·9 % of variation but not beyond that of anthropometry. Applying these equations to the Queensland cohort provided similar performance at the appropriate age. However, when the Queensland equations were applied to our cohort, the bias increased slightly but with similar LOA. BIA appears to have limited use in predicting FFM in the first few weeks of life compared with simple anthropometry in Asian populations. There is a need for population- and age-appropriate FFM prediction equations.

Predictive performance of a gentamicin population pharmacokinetic model in neonates receiving full-body hypothermia

BACKGROUND

Population pharmacokinetic (popPK) models derived from small pharmacokinetics (PK) studies in neonates are often underpowered to detect clinically important characteristics that drive dosing. External validation of such models is crucial. In this study, the predictive performance of a gentamicin popPK model in neonates receiving hypothermia was evaluated.

METHODS

A previously published gentamicin popPK model was developed in neonates with hypoxic ischemic encephalopathy undergoing hypothermia using a retrospective single-institution (University of California-San Francisco) data set. The predictive performance of this model was evaluated in an external retrospective data set from the University of California-San Francisco (validation A) and another from Duke University (validation B). Both institutions used the same hypothermia protocol and collected similar clinical and PK data. Gentamicin dosing and samples were collected per routine care. Predictive performance was evaluated by quantifying the accuracy and precision of model predictions and using simulation-based diagnostics to detect bias in predictions.

RESULTS

Forty-one neonates (n = 18 validation A; n = 23 validation B) with median (range) gestational age of 40 weeks (33-42) and birth weight of 3.3 kg (1.9-4.6) and 76 samples (55% troughs, 33% and 28% drawn at 24 and 36 hours after dose, respectively) were analyzed. The model adequately predicted gentamicin concentrations from the same institution (validation A; median average fold error = 1.1 and numerical prediction distribution error P > 0.05) but underpredicted concentrations from the outside institution (validation B; median average fold error = 0.6 and numerical prediction distribution error P < 0.05).

CONCLUSIONS

The model demonstrated adequate predictive performance for an external data set in the same institution but not from an outside institution. Larger sample sizes, use of data from multiple institutions, and external evaluation in development of popPK models in neonates may improve generalizability of dosing recommendations arising from single-institution studies.

Reference intervals and age-related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

OBJECTIVE

To determine the reference interval for various venous analyte concentrations using a point-of-care (POC) analyzer in healthy, 4-84-day-old puppies and identify any age-specific variations in the values as compared with adults.

DESIGN

A prospective cohort study.

SETTING

University teaching hospital.

ANIMALS

Clinically healthy dogs; 68 puppies and 30 adults.

MEASUREMENTS AND MAIN RESULTS

Samples were collected by jugular venipuncture from 68 clinically healthy puppies at 4, 10, 12, 16, 28, 70, 77, and 84 days of age and once each from 30 clinically healthy adult dogs. Blood samples (n = 287) were analyzed within 5 minutes of collection using an automated POC analyzer. Reference intervals for puppies at various ages were estimated using a bootstrap sampling approach. The analytes that were closest to the adult values were pH and bicarbonate. On days 4 and 10 the pH for puppies was higher than the adults while the HCO3 was higher than the adults only on day 4. HCT on day 4 approximated adult values but fell to a nadir on day 28 before rising toward adult levels. At all time points, sodium, chloride, and ionized magnesium concentrations were lower than adult values, and potassium and ionized calcium were higher than adult values. Glucose was similar to adult values on day 4 but was above adult values at all other time points. Blood urea nitrogen (BUN) was higher in puppies until day 28 when it became lower than in adults. BUN levels remained lower than adults through day 84.

CONCLUSIONS

Variations exist between puppies and adults for venous POC analyzer results. Adult reference intervals should not be used for puppies as this might cause misinterpretation of the results.

Fetal Laboratory Medicine: On the Frontier of Maternal–Fetal Medicine

BACKGROUND

Emerging antenatal interventions and care delivery to the fetus require diagnostic support, including laboratory technologies, appropriate methodologies, establishment of special algorithms, and interpretative guidelines for clinical decision-making.

CONTENT

Fetal diagnostic and therapeutic interventions vary in invasiveness and are associated with a spectrum of risks and benefits. Fetal laboratory assessments are well served by miniaturized diagnostic methods for blood analysis. Expedited turnaround times are mandatory to support invasive interventions such as cordocentesis and intrauterine transfusions. Health-associated reference intervals are required for fetal test interpretation. Fetal blood sampling by cordocentesis carries substantial risk and is therefore performed only when fetal health is impaired, or at risk. When the suspected pathology is not confirmed, however, normative fetal data can be collected. Strategies for assurance of sample integrity from cordocenteses and confirmation of fetal origin are described. After birth, definitive assessment of prenatal environmental and/or drug exposures to the fetus can be retrospectively assessed by analysis of meconium, hair, and other alternative matrices. A rapidly advancing technology for fetal assessment is the use of fetal laboratory diagnostic techniques that use cell-free fetal DNA collected from maternal plasma, and genetic analysis based on molecular counting techniques.

SUMMARY

Developmental changes in fetal biochemical and hematologic parameters in health and disease are continually delineated by analysis of our collective outcome-based experience. Noninvasive technologies for fetal evaluation are realizing the promise of lower risk yet robust diagnostics; examples include sampling and analysis of free fetal DNA from maternal blood, and analysis of fetal products accessible at maternal sites. Application of diagnostic technologies for nonmedical purposes (e.g., sex selection) underscores the importance of ethical guidelines for new technology implementation.

Using enteral sterile water feeds for hypernatremia in extremely low birth-weight infants

Extremely low birth-weight infants are prone to fluid and electrolyte imbalance due to multiple etiologies. Hypernatremia can occur in this gestational age group during the first week of life. One therapy that many NICUs initiate to treat hypernatremia is enteral sterile water feeds (SWFs). The use of free water is an adjunct therapy in place of large volumes of intravenous fluids. This article presents a review of renal physiology and 3 case studies of infants, less than 27 weeks' gestational age and less than 1000-g birth weight, treated with SWFs for hypernatremia. Commonalities and differences in treatment are addressed. There is limited evidence-based research using enteral SWFs for the treatment of hypernatremia.

Factors affecting postnatal changes in serum creatinine in preterm infants with gestational age <32 weeks

OBJECTIVE

The Aim of this study was to investigate maternal and neonatal factors associated with serum creatinine (SeCr) changes in a representative cohort of preterm newborns during their first week of life.

STUDY DESIGN

Retrospective study. All the infants born less than 32 weeks of gestational age (GA) and cared for in our neonatal intensive care unit between January 2001 and December 2005 were eligible for the analysis. Epidemiological data of all mother-infant pairs and neonatal SeCr values were recorded.

RESULT

A total of 652 infants were studied. Multivariate regression analysis showed that the main independent factors associated with high SeCr at day 1 were hypertensive disease of pregnancy (P<0.0001) and advancing hour of life (P<0.0001), with minimal contribution of placental abruption (P<0.05) and higher GA (P<0.05). Lower GA (P<0.0001) and ibuprofen-treated patent ductus arteriosus (PDA; P<0.0001) were the main analyzed factors independently associated with higher SeCr peak (defined as the highest SeCr during the week), with less contribution of respiratory distress syndrome (P<0.01) and early onset infection (P<0.05). In infants with hemodynamically significant PDA (hsPDA) SeCr before ibuprofen administration was higher when compared to GA-matched controls without hsPDA (P< 0.0001).

CONCLUSION

SeCr peak was inversely correlated to GA in preterm infants born less than 32 weeks of GA. Neonatal rather than maternal morbidity affected SeCr peak. In hsPDA, SeCr increase preceded ibuprofen administration.

Fluid and electrolyte management in the premature infant

Caring for the premature infant in the NICU requires knowledge and understanding of the physiologic adaptation to extrauterine life and how prematurity affects that transition. Nurses play an integral role in managing fluid and electrolyte balance in these infants. This article addresses postnatal adaptation and all aspects of fluid and electrolyte management of the preterm infant.

The pig as an experimental model for elucidating the mechanisms governing dietary influence on mineral absorption

This review highlights the similarities between pigs and humans and thereby the value of the porcine human nutritional model, and reviews some of the more recent applications of this model for nutritional research.

[Metabolism of potassium in preterm infants]

During the first days of life, hyperkalemia can affect 30 to 60% of very low birth weight infants free of acute renal insufficiency (i.e. nonoliguric hyperkalemia). The place of the kidney in the regulation of the potassium homeostasis of VLBW remains badly specified.

OBJECTIVE

To evaluate the rate and the mechanisms of hyperkalemia in infants born at less than 32 weeks' gestation.

METHODS

A prospective study was conducted in 33 preterm infants (BW=1289+/-382 g; GA=28.8+/-1.7 weeks). Fifteen consecutive 8-hour urine collections were performed for each infant from the 8th hour of life (495 periods). A plasma sample was obtained at the end of each urine collection. Sodium, potassium and creatinine were measured in urine and blood samples as often as possible.

RESULTS

Plasma potassium concentrations varied significantly over the 15 successive periods with an initial value (P1) of 4.55+/-0.80 mmol/l, a peak on P3 (4.94+/-0.81 mmol/l) and the lowest value on P13 (3.88+/-0.42 mmol/l). Hyperkalemia (plasma potassium>6.0 mmol/l) was observed in 4 infants (12%) and in 1.2% of the periods. The cumulative potassium balance (output-input) was negative over the first 7 periods (-1.97 mmol/kg), and afterwards became positive (from P8 to P15:+1.57 mmol/kg). Over the first 3 days, plasma potassium concentrations were positively correlated (p<0.01) with urinary excretion of potassium, clearance of potassium, fractional excretion of potassium, and negatively with endogenous creatinine clearance.

CONCLUSION

In the first days of life, very low birth weight infants present an increase in kalemia associated with a negative potassium balance indicating a intracellular to extracellular potassium shift rather than a lower renal potassium excretion.

A new rapid radiological procedure for routine teratological use in bone ossification assessment: a supplement for staining methods

BACKGROUND

Presently, bone ossification is assessed by the study of single-stained fetal bones (alizarin red-S) or double-stained bones and cartilaginous structures (alcian blue followed by alizarin red-S). Both methods, especially double-staining, are labor-intensive, time-consuming, and provide qualitative information regarding skeleton ossification. Quantitative evaluation of ossification is more difficult and is usually based on determination of calcium and other minerals in the bone by means of atomic absorption spectrometry. Here we introduce a simple new method that allows quantitative determination of skeleton ossification before routine staining examination.

METHODS

Fetuses delivered by laparotomy on the 16th and 21st day of gestation as well as 1-day-old rat pups were examined. The fetuses and pups were prenatally subcutaneously exposed to sodium valproate or to physiological saline. Lateral, prone, and supine digital radiograms of each fetus were taken using the Digora-Soredex digital radiography system and the Planmeca Intra intraoral X-ray machine. According to the best visualization, the data concerning vertebra were analyzed. All the fetuses were then routinely double-stained using alcian blue and alizarin red-S.

RESULTS

Malformations of axial skeleton (rib, sternum, and thoracic and sacral vertebra) were found in valproate-treated groups. Unlike cartilage malformations, the bone changes were detected in similar frequency in radiological and staining methods. Differences in densities according to the degree of ossification in the vertebral arches and bodies at different levels of the vertebral column, between drug-treated and negative control groups were noted.

CONCLUSIONS

The preliminary results suggest that digital radiography examination is a useful method in determining delaying of skeleton ossification not detectable by other methods. It balances qualitative and quantitative aspects of the presently used methods and is also simple, objective, fast, and relatively inexpensive.