Metabolic acidosis in the first 14 days of life in infants of gestation less than 26 weeks

Hyperbilirubinemia screening and treatment in neonates born prior to 35 weeks of gestation

BACKGROUND

Guidelines on when to screen for neonatal hyperbilirubinemia apply to infants born at 35 weeks or later of gestation. It is unknown whether infants born earlier would benefit from similar guidelines. Our objective was to examine hyperbilirubinemia screening and phototherapy prescription among early preterm infants during the first 6 days of life.

METHODS

We reviewed the charts of 193 infants born prior to 35 weeks of gestation who were admitted to a tertiary care NICU in Southeastern Ontario in 2018-2019. Information on total serum bilirubin (TSB) measurements over each 12-hour interval during the first six days of life and the treatment decision (no treatment, initiate, continue, or stop phototherapy) was extracted. We also examined what proportion of infants were prescribed phototherapy during each 12-hour interval.

RESULTS

Of 1006 TSB measurements performed over the first 6 days of life, 605 were done to determine whether phototherapy should be initiated. Treatment was prescribed in 275 instances (45%). A higher proportion of infants born prior to 28 weeks of gestation required phototherapy in the first 12 hours of life (37%) compared to those born at 28-32 weeks (20%) and 33-34 weeks (5.7%).

CONCLUSIONS

Our results suggest that TSB measurements are often poorly timed to detect treatment need in infants born prior to 35 weeks of gestation. This unnecessarily increases the risk of complications from phlebotomy and is an ineffective use of health care resources. There is a need to develop guidelines to optimize hyperbilirubinemia screening among early preterm infants.

An Extremely Preterm Infant Born at 23 Weeks' Gestation With an Interrupted Aortic Arch Complex: A Case Report

We present a case of an infant male born at 23 weeks' gestation with an interrupted aortic arch (IAA) complex. We treated the patient with hypoxic gas ventilation to address developing systemic undercirculation in the acute postnatal phase. As the symptoms of bronchopulmonary dysplasia evolved, hypoxic gas ventilation was no longer required to stabilize the hemodynamics. The patient was discharged home after undergoing the palliative surgical procedure of bilateral pulmonary artery banding and ductus arteriosus stent implantation. Although he suffered from pulmonary hypertension, it was controllable with oxygen supplementation and pulmonary vasodilators. There are limited therapeutic options available for extremely preterm infants with critical congenital heart defects (CHDs). Hypoxic gas ventilation might be considered as one of the options, with its risks taken into account, to manage extremely preterm infants with CHDs with pulmonary overcirculation before performing surgical interventions.

Risk factors and machine learning prediction models for bronchopulmonary dysplasia severity in the Chinese population

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in extremely preterm neonates. The outcome and clinical burden vary dramatically according to severity. Although some prediction tools for BPD exist, they seldom pay attention to disease severity and are based on populations in developed countries. This study aimed to develop machine learning prediction models for BPD severity based on selected clinical factors in a Chinese population.

METHODS

In this retrospective, single-center study, we included patients with a gestational age < 32 weeks who were diagnosed with BPD in our neonatal intensive care unit from 2016 to 2020. We collected their clinical information during the maternal, birth and early postnatal periods. Risk factors were selected through univariable and ordinal logistic regression analyses. Prediction models based on logistic regression (LR), gradient boosting decision tree, XGBoost (XGB) and random forest (RF) models were implemented and assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

We ultimately included 471 patients (279 mild, 147 moderate, and 45 severe cases). On ordinal logistic regression, gestational diabetes mellitus, initial fraction of inspiration O2 value, invasive ventilation, acidosis, hypochloremia, C-reactive protein level, patent ductus arteriosus and Gram-negative respiratory culture were independent risk factors for BPD severity. All the XGB, LR and RF models (AUC = 0.85, 0.86 and 0.84, respectively) all had good performance.

CONCLUSIONS

We found risk factors for BPD severity in our population and developed machine learning models based on them. The models have good performance and can be used to aid in predicting BPD severity in the Chinese population.

Metabolic acidosis during continuous glucagon therapy for neonatal hypoglycemia

Objectives

Refractory neonatal hypoglycemia may be treated with glucagon infusions, which have been associated with thrombocytopenia and hyponatremia. After anecdotally noting metabolic acidosis during glucagon therapy in our hospital, an outcome not previously reported in the literature, we aimed to quantify occurrence of metabolic acidosis (base excess >-6) as well as thrombocytopenia and hyponatremia during treatment with glucagon.

Methods

We performed a single-centre retrospective case series. Descriptive statistics were used and subgroups compared with Chi-Square, Fisher's Exact Test, and Mann-Whitney U testing.

Results

Sixty-two infants (mean birth gestational age 37.2 weeks, 64.5% male) were treated with continuous glucagon infusions for median 10 days during the study period. 41.2% were preterm, 21.0% were small for gestational age, and 30.6% were infants of diabetic mothers. Metabolic acidosis was seen in 59.6% and was more common in infants who were not born to diabetic mothers (75% versus 24% in infants of diabetic mothers, P<0.001). Infants with versus without metabolic acidosis had lower birth weights (median 2,743 g versus 3,854 g, P<0.01) and were treated with higher doses of glucagon (0.02 versus 0.01 mg/kg/h, P<0.01) for a longer duration (12.4 versus 5.9 days, P<0.01). Thrombocytopenia was diagnosed in 51.9% of patients.

Conclusions

In addition to thrombocytopenia, metabolic acidosis of unclear etiology appears to be very common with glucagon infusions for neonatal hypoglycemia, especially in lower birth weight infants or those born to mothers without diabetes. Further research is needed to elucidate causation and potential mechanisms.

Normal Anion-Gap Metabolic Acidosis in an Extremely Preterm Neonate

Extremely preterm neonates (< 28 wk) are at risk of metabolic complications like hypocalcemia, hypophosphatemia, hyponatremia, and metabolic acidosis. Many of these complications are often the result of prematurity per se, while some of them may be the result of prolonged parenteral nutrition. Most of the complications occur in the initial few weeks of hospital stay, but hyponatremia, hypocalcemia, and hypophosphatemia may persist for longer periods of time. Optimizing enteral nutrition along with fortification helps in promoting optimal growth and overcoming the aforementioned problems. The authors report one such extremely preterm neonate with hyperchloremic metabolic acidosis, the cause of which is uncommon and not reported previously in the literature.

The effects of sodium bicarbonate infusion on cerebrovascular function in newborn pigs

BACKGROUND

Sodium bicarbonate (NaHCO₃) is no longer recommended by the Neonatal Resuscitation Program (NRP), but is still being used by some neonatologists. The effects of NaHCO₃ on cerebral hemodynamics are unclear. Therefore, we investigated the effects of NaHCO₃ on cerebral blood flow (CBF) and cerebrovascular function using a newborn piglet model.

METHODS

Newborn pigs were anesthetized, intubated, and ventilated. Cranial windows were implanted to evaluate changes in pial arteriolar diameters (PADs) as a surrogate for CBF during a 4-h intravenous infusion of 3% NaHCO₃. Cerebrovascular reactivity to vasodilators and vasoconstrictors was investigated during vehicle control and during NaHCO₃ infusion.

RESULTS

NaHCO₃ infusion caused significant and progressive pial arteriolar vasoconstrictions. During NaHCO₃ infusion, cerebrovascular reactivity was preserved. Adding vasodilators decreased cerebral vasoconstriction, while adding vasoconstrictors exaggerated cerebral vasoconstriction.

CONCLUSIONS

Intravenous infusion of NaHCO₃ over 4 h caused progressive vasoconstriction of pial arterioles. Cerebrovascular function evaluated by the responses of pial arterioles to physiologically relevant vasoconstrictors and vasodilators was preserved during NaHCO₃ infusion. A notable additional reduction of PADs was observed during NaHCO₃ infusion in the presence of vasoconstrictors. Extrapolating our findings to human neonates should alarm the clinicians that using NaHCO₃ in neonates may cause cerebral hypoperfusion.

IMPACT

Cerebral vasoconstriction occurs during slow infusion of 3% diluted NaHCO₃. Cerebral vasoconstriction is exaggerated when another vasoconstrictor is added during NaHCO₃ infusion. Cerebrovascular function is preserved during NaHCO₃ infusion. Clinicians should be aware of the risk of cerebral hypoperfusion with NaHCO₃ infusion in vulnerable neonates.

Hemodynamic considerations in preterm infants born at less than 25 weeks gestation

As survival rates continue to improve for infants born at less than 25 weeks gestation, delineating normal cardiovascular physiology from pathophysiology becomes much more challenging. With a paucity of 'normative' data for such infants, an over-reliance on studies at older gestations can result in a 'best guess' approach. Here we offer a pragmatic approach to these diagnostic challenges from a cardiovascular viewpoint. An appreciation of the unique physiology, from the immature myocardium and altered vascular tone to an innately large patent ductus arteriosus is essential, as is a thorough history for case specific contributing factors. We explore the additional difficulties in achieving a balance between minimal handling at the bedside and delineating important objective markers of perfusion. Finally, we discuss treatment approaches including inotrope therapy and patent ductus treatment, acknowledging the limited data available to guide these decisions.

Use of intravenous sodium bicarbonate in neonatal intensive care units in Italy: a nationwide survey

Background

Metabolic Acidosis (MA) is a disturbance of the acid-base balance that can occur in preterm and critically ill term neonates due to different etiologies. Intravenous sodium bicarbonate (SB) has been traditionally used to correct such unbalance, despite the lack of evidence about its safety and efficacy. In literature, reported undesirable effects of treatment with SB in neonates include worsening of intracellular acidosis, impairment of myocardial function, cerebral blood flow fluctuations and intracranial hemorrhage. A national survey was conducted by the Neonatal Pharmacotherapy Study Group of the Italian Society of Neonatology with the aim to assess and describe attitudes and practices concerning the use of SB, particularly for the treatment of MA in Italian NICUs.

Methods

A questionnaire regarding treatment of MA and SB prescription habits was sent to the directors of 120 Italian NICUs from June 2017 to March 2018.

Results

The survey response rate was 97.5% (117/120 centers). Findings showed that in 55% of the surveyed NICUs (64/117 units) it is common practice to correct MA with intravenous SB. On the other hand, the remaining 45% of the units try to solve the metabolic disturbances adopting different approaches (improving perfusion, adjusting ventilation parameters or increasing blood volume). Moreover, to prevent the occurrence of MA, 37.6% of the NICUs (44/117) include buffer salts (lactate, acetate or both) in parenteral nutrition prescriptions. SB is also used as a treatment for other conditions, mainly pathologies with bicarbonate loss and tubular acidosis (respectively in 53.8 and 32.5% of the NICUs).

Conclusion

This survey showed how SB is a commonly used treatment for MA in more than half of Italian NICUs, with indications and prescription criteria that significantly vary across centers. Based on current knowledge, it is reasonable to suggest that the management of neonatal MA should be firstly directed to identify the underlying disorders. Thus, the use of SB should be reserved only for selected cases, also considering the severity of SB adverse effects and the lack of evidence about its efficacy. Guidance for the management of MA is required to harmonize practices and reduce the use of potentially inappropriate and unsafe treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13052-021-00955-3.

Autism risk linked to prematurity is more accentuated in girls

INTRODUCTION

Prematurity has been identified as a risk factor for Autism Spectrum Disorder (ASD). The link between Autism Spectrum Disorder (ASD) and birth-week has not been strongly evidenced. We evaluated the correlation between the degree of prematurity and the incidence of autism in a cohort of 871 children born prematurely and followed from birth. The cohort was reduced to 416 premature infants born between 2011-2017 who were followed for 2-14 years, and analyzed according to birth week (degree of prematurity), and according to gender.

RESULTS

43 children (10.3%) received a definite diagnosis of ASD. There was a significant correlation between birth week and the risk of ASD, with 22.6% of children diagnosed with ASD when born at 25 weeks, versus 6% of ASD diagnoses at 31 weeks of prematurity. For children born after 32 weeks, the incidence decreased to 8-12.5%. A strong link was found between earlier birth week and increased autism risk; the risk remained elevated during near-term prematurity in boys. A correlation between early birth week and an elevated risk for ASD was seen in all children, but accentuated in females, gradually decreasing as birth week progresses; in males the risk for ASD remains elevated for any birth week.

CONCLUSION

A statistically significant increase in rates of autism was found with each additional week of prematurity. Females drove this direct risk related to degree of prematurity, while males had an elevated risk throughout prematurity weeks, even at near-term. We recommend including ASD screening in follow up of infants born prematurely, at all levels of prematurity.

Renal aspects of metabolic acid-base disorders in neonates

Acid-base homeostasis is one of the most tightly regulated systems in the body. Maintaining the acid-base balance is particularly challenging for preterm infants and growing neonates. The kidney, which represents the crucial ultimate line of defense against disturbances of acid-base balance, undergoes a complex maturation process during the transition from a fetal to an extra-uterine environment. This review article summarizes the physiology of acid-base regulation by the immature human kidney and discusses disorders of acid-base balance, such as metabolic acidosis, respiratory acidosis, metabolic alkalosis, and respiratory alkalosis. In conditions of metabolic acidosis, the serum anion gap and the urinary anion gap can be useful tools to define the nature of the acidosis. Metabolic acidosis can reflect a decrease in glomerular filtration rate, or be the consequence of selective disorders of proximal or distal tubular function. Most tubulopathies associated with metabolic acidosis observed in neonates are primary, hereditary, isolated tubulopathies. Proximal renal tubular acidosis is characterized by bicarbonate wasting, while the distal types of renal tubular acidosis are secondary to distal acidification defects. All tubulopathies are associated with hypokalemia, with the exception of type 4 hyperkalemic distal renal tubular acidosis. The transporter defects in the various acid-base tubulopathies are now well defined. Treatment of the acidosis varies according to the site and mechanism of the defect. Chronic renal tubular acidosis or alkalosis severely impair growth and calcium metabolism. Early rational therapeutic intervention can prevent some of the consequences of the disorders and improves the prognosis.

Newborn Metabolic Profile Associated with Hyperbilirubinemia With and Without Kernicterus

Our objective was to assess the relationship between hyperbilirubinemia with and without kernicterus and metabolic profile at newborn screening. Included were 1,693,658 infants divided into a training or testing subset in a ratio of 3:1. Forty‐two metabolites were analyzed using logistic regression (odds ratios (ORs), area under the receiver operating characteristic curve (AUC), 95% confidence intervals (CIs)). Several metabolite patterns remained consistent across gestational age groups for hyperbilirubinemia without kernicterus. Thyroid stimulating hormone (TSH) and C‐18:2 were decreased, whereas tyrosine and C‐3 were increased in infants across groupings. Increased C‐3 was also observed for kernicterus (OR: 3.17; 95% CI: 1.18–8.53). Thirty‐one metabolites were associated with hyperbilirubinemia without kernicterus in the training set. Phenylalanine (OR: 1.91; 95% CI: 1.85–1.97), ornithine (OR: 0.76; 95% 0.74–0.77), and isoleucine + leucine (OR: 0.63; 95% CI: 0.61–0.65) were the most strongly associated. This study showed that newborn metabolic function is associated with hyperbilirubinemia with and without kernicterus.

Bone status in preterm infant: influences of different nutritional regimens and possible markers of bone disease

OBJECTIVE

The objective of this study was to evaluate possible influences of parenteral nutrition on growth and bone development in preterms and to search for markers of bone status.

STUDY DESIGN

Metacarpus bone transmission time (mc-BTT) was performed at birth, 21 days and 36 weeks of gestational age (GA) in preterms, receiving two different nutritional regimens, together with biochemical analysis.

RESULT

A total of 234 patients were studied. Newborns with aggressive nutrition had significantly better growth rate and higher values of mc-BTT until discharge. Mc-BTT at day 21 correlates positively with nutritional intakes and phosphatemia; lower limb length positively correlated with mc-BTT (P<0.01). Newborns with low energy intake in the first week of life (<70 kcal kg(-1) per day) and low serum phosphate level (<1.4 mmol l(-1)) at 21 days had lower mc-BTT at 36 weeks of GA (P<0.01).

CONCLUSION

Aggressive parenteral intakes in preterms improve growth and bone status in the short-medium term, suggesting that early nutrition could influence bone development.

Quality of life of individuals born preterm: a systematic review of assessment approaches

PURPOSE

To review the existing literature regarding factors associated with quality of life (QoL) of individuals who were born preterm. The review focuses on assessment approaches and information sources.

METHODS

A systematic review of empirical studies published in PubMed, PsycARTICLES, PsycINFO, LILACS, and SciELO databases between 2007 and 2015. Search terms were chosen that relate preterm birth to QoL.

RESULTS

Twenty-two articles were included. Of these, ten investigated QoL in children, six investigated adolescents, and six investigated adults. All studies used generic instruments to assess QoL. There was a high rate of parental report to assess QoL in studies of children. Adolescent and adult studies most often assessed QoL through self-report. Parents of children who were born preterm reported worse QoL for their children compared with parents of children born full term. Teenagers and adults who were born preterm self-reported more positive outcomes in their QoL. The main risk factors associated with worse QoL in children who were born preterm were congenital malformations, mechanical ventilation during the neonatal phase, cognitive impairments, behavioral problems, physical disabilities, low family income, and black race.

CONCLUSIONS

Agreement between parents and children about QoL in preterm individuals was lower in younger age groups compared with older age groups. The differences in QoL throughout the different age groups may have arisen because of developmental changes or differences in the source of information used (i.e., parent report or self-report). We recommend that QoL assessments in children born preterm should consider both parent report and self-report.

Effect of blood transfusion on intestinal blood flow and oxygenation in extremely preterm infants during first week of life

BACKGROUND

Extremely preterm infants receive frequent blood transfusions in the first week of life. The aim of this study was to measure the effect of blood transfusion on intestinal blood flow and oxygenation during the first week of life in extremely preterm infants.

STUDY DESIGN AND METHODS

Superior mesenteric artery (SMA) peak systolic velocity (PSV) and diastolic velocities were measured 30 to 60 minutes before and after transfusion. Splanchnic tissue hemoglobin index (sTHI), splanchnic tissue oxygenation index (sTOI), and splanchnic fractional tissue oxygen extraction (sFTOE) were measured continuously from 15 to 20 minutes before to after transfusion along with vital variables.

RESULTS

Twenty infants were studied (median gestational age, 26 weeks). Ten infants were partially fed (15-68 mL/kg/day). Heart rate and SaO2 remained unaltered; blood pressure increased significantly (p < 0.01) after transfusion. Mean SMA PSV (p = 0.63) and diastolic velocity (p = 0.65) remained unaltered. Mean pretransfusion SMA PSV was similar in partially fed (0.78 m/sec) compared to unfed infants (0.52 m/sec; p = 0.06) and the response to transfusion was not dissimilar. There was a significant increase in sTHI (mean difference, 32.3%; p < 0.01) and sTOI (14.6%; p = 0.03) and decrease in sFTOE (22.1%; p < 0.01) after transfusion. There was no significant difference in sTHI or sTOI between fed and unfed infants and their response to transfusion.

CONCLUSIONS

Blood transfusion increased blood pressure and intestinal tissue oxygenation but did not alter blood flow velocities. Partial feeding had no impact on intestinal blood flow and tissue oxygenation changes.