Early Mortality and Morbidity in Infants with Birth Weight of 500 Grams or Less in Japan

FIVE-YEAR VISUAL OUTCOME OF TREATMENT FOR RETINOPATHY OF PREMATURITY IN INFANTS WEIGHING <500 G AT BIRTH: A Multicenter Cohort Study From J-CREST

PURPOSE

To investigate the 5-year treatment outcomes of retinopathy of prematurity in infants <500 g birth weight and compare laser and anti-vascular endothelial growth factor therapies.

METHODS

A multicenter retrospective study comprised 24 eyes of 13 patients treated for Type 1 retinopathy of prematurity, followed for 5 years. Initial treatment was laser and anti-vascular endothelial growth factor in 13 and 11 eyes, respectively. Data collected included sex, birth characteristics, retinopathy of prematurity characteristics at the time of treatment, best-corrected visual acuity (BCVA), spherical equivalent, and astigmatism at 5 years posttreatment.

RESULTS

Median BCVA was 0.15 logarithm of the minimum angle of resolution (interquartile range, 0.0-0.5). Snellen BCVA was ≥20/40 in 73% and ≥20/20 in 27% of eyes. Median spherical equivalent was -2.37 (interquartile range, -6.1 to -0.1); 75% had myopia (≤-0.5 D), and 25% had high myopia (≤-6.0 D). Median astigmatism was 1.25 (interquartile range, 0.9-3.0); 46% had ≥1.5 D. Anti-vascular endothelial growth factor-treated eyes showed less myopia ( P < 0.009), with no BCVA or astigmatism difference ( P = 0.997, P = 0.271) compared with laser-treated eyes.

CONCLUSION

One-quarter of the eyes exhibited good visual acuity (Snellen BCVA of ≥20/20) 5 years after retinopathy of prematurity treatment. Refractive errors were common. Anti-vascular endothelial growth factor therapy may be superior to laser therapy in myopic refractive error.

Divergent neurodevelopmental profiles of very-low-birth-weight infants

BACKGROUND

Advanced perinatal medicine has decreased the mortality rate of preterm infants. Long-term neurodevelopmental outcomes of very-low-birth-weight infants (VLBWIs) remain to be investigated.

METHODS

Participants were 124 VLBWIs who had in-hospital birth from 2007 to 2015. Perinatal information, developmental or intelligence quotient (DQ/IQ), and neurological comorbidities at ages 3 and 6 years were analyzed.

RESULTS

Fifty-eight (47%) VLBWIs received neurodevelopmental assessments at ages 3 and 6 years. Among them, 15 (26%) showed DQ/IQ <75 at age 6 years. From age 3 to 6 years, 21 (36%) patients showed a decrease (≤-10), while 5 (9%) showed an increase (≥+10) in DQ/IQ scores. Eight (17%) with autism spectrum disorder or attention-deficit hyperactivity disorder (ASD/ADHD) showed split courses of DQ/IQ, including two with ≤-10 and one with +31 to their scores. On the other hand, all 7 VLBWIs with cerebral palsy showed DQ ≤35 at these ages. Magnetic resonance imaging detected severe brain lesions in 7 (47%) of those with DQ <75 and 1 (18%) with ASD/ADHD.

CONCLUSIONS

VLBWIs show a broad spectrum of neurodevelopmental outcomes after 6 years. These divergent profiles also indicate that different risks contribute to the development of ASD/ADHD from those of cerebral palsy and epilepsy in VLBWIs.

IMPACT

Very-low-birth-weight infants (VLBWIs) show divergent neurodevelopmental outcomes from age 3 to 6 years. A deep longitudinal study depicts the dynamic change in neurodevelopmental profiles of VLBWIs from age 3 to 6 years. Perinatal brain injury is associated with developmental delay, cerebral palsy and epilepsy, but not with ASD or ADHD at age 6 years.

Antenatal prediction models for outcomes of extremely and very preterm infants based on machine learning

PURPOSE

Predicting individual risks for adverse outcomes in preterm infants is necessary for perinatal management and antenatal counseling for their parents. To evaluate whether a machine learning approach can improve the prediction of severe infant outcomes beyond the performance of conventional logistic models, and to identify maternal and fetal factors that largely contribute to these outcomes.

METHODS

A population-based retrospective study was performed using clinical data of 31,157 infants born at < 32 weeks of gestation and weighing ≤ 1500 g, registered in the Neonatal Research Network of Japan between 2006 and 2015. We developed a conventional logistic model and 6 types of machine learning models based on 12 maternal and fetal factors. Discriminative ability was evaluated using the area under the receiver operating characteristic curves (AUROCs), and the importance of each factor in terms of its contribution to outcomes was evaluated using the SHAP (SHapley Additive exPlanations) value.

RESULTS

The AUROCs of the most discriminative machine learning models were better than those of the conventional models for all outcomes. The AUROCs for in-hospital death and short-term adverse outcomes in the gradient boosting decision tree were significantly higher than those in the conventional model (p = 0.015 and p = 0.002, respectively). The SHAP value analyses showed that gestational age, birth weight, and antenatal corticosteroid treatment were the three most important factors associated with severe infant outcomes.

CONCLUSION

Machine learning models improve the prediction of severe infant outcomes. Moreover, the machine learning approach provides insight into the potential risk factors for severe infant outcomes.

Neurodevelopment and physical measurements in infants with birthweight of 500 grams or less

BACKGROUND

In infants born weighing ≤500 g, little has been studied about the association between neurodevelopmental prognosis and growth. This study aimed to evaluate the association between neurodevelopmental impairment (NDI) and z-scores of physical measurements in infants born weighing ≤500 g.

METHODS

A single-center, retrospective cohort study in a level IV neonatal intensive care unit in Japan. Infants born weighing ≤500 g between 2010 and 2019 were eligible. Z-scores in weight, length/height, and head circumference at birth, due date (or discharge), 6 and 18 months of corrected age, and 3 years of age were compared between infants with and without NDI at 3 years of age. Three infants with severe intraventricular hemorrhage or periventricular leukomalacia were excluded from the comparison analyses. NDI was defined as having a developmental quotient of ≤70, cerebral palsy, visual impairment, or hearing impairment.

RESULTS

Of 22 eligible infants, the incidence of NDI at 3 years of age was 54.5%. The z-score was significantly smaller in the NDI group (n = 10) than that in the non-NDI group (n = 9) in head circumference at birth (median, -1.94 vs. -0.75; Z = 0.54; p = 0.020), and in height at 18 months of corrected age (median, -2.84 vs. -1.79; Z = 0.58; p = 0.013) and 3 years of age (median, -2.02 vs. -1.21; Z = 0.47; p = 0.046).

CONCLUSIONS

NDI at 3 years of age was associated with a small head circumference z-score at birth, height at 18 months of corrected age, and height at 3 years of age in infants born weighing ≤500 g.

Protecting the brain of the micropreemie

Advances in perinatal care have seen substantial improvements in survival without disability for extremely preterm infants. Protecting the developing brain and reducing neurodevelopmental sequelae of extremely preterm birth are strategic priorities for both research and clinical care. A number of evidence-based interventions exist for neuroprotection in micropreemies, inclusive of prevention of preterm birth and multiple births with implantation of only one embryo during in vitro fertilisation, as well as antenatal care to optimize fetal wellbeing, strategies for supporting neonatal transition, and neuroprotective developmental care. Avoidance of complications that trigger ischemia and inflammation is vital for minimizing brain dysmaturation and injury, particularly of the white matter. Neurodevelopmental surveillance, early diagnosis of cerebral palsy and early intervention are essential for optimizing long-term outcomes and quality of life. Research priorities include further evaluation of putative neuroprotective agents, and investigation of common neonatal interventions in trials adequately powered to assess neurodevelopmental outcome.

Outcomes in extremely low birth weight (≤500 g) preterm infants: A Western Australian experience

BACKGROUND AND AIM

Extremely preterm (EP) infant survival has significantly improved with advanced neonatal care; however outcomes of infants born with birth weight (BW) ≤500 g remain poor. We aimed to review outcomes of this cohort in our institution.

METHODS

Retrospective study of all inborn preterm infants born at ≥22 weeks gestational age (GA) and weighing ≤500 g between January 2001-December 2017. Outcomes included short-term morbidity, mortality, neurodevelopmental impairment and growth up to five years of age.

RESULTS

Of a total 438 eligible infants, 92 livebirths were admitted to intensive care [median (range) GA: 24 (22-30) weeks; median (IQR) BW: 427.5 (380-499) grams]. Majority [78/92 (84.7%)] were small for gestational age (SGA). In 50% of non-survivors, median (IQR) age of death was 3.5 (1-17.5) days with no late deaths. Medical morbidities were common. Follow-up, including standardised cognitive assessments, was available for 41/46 (89%) infants. At a median age of 5.06 years, 17/41 (41.5%) had moderate-severe disability; non-statistically higher in SGA compared to appropriate for gestational age/AGA (48.6% vs. 33.3%) group. Cerebral palsy (4/41; 10%), deafness needing amplification (1/41; 2.4%) were noted. Weight (32/41, 78%) and height (27/41, 66%) of most children remained at >2 SD below normal.

CONCLUSIONS

In a cohort of preterm infants weighing ≤500 g at birth, 50% survived after admission to intensive care. Medical morbidities were common and 54% were free from moderate to severe disability at five years. SGA infants had higher rates (48.6%) of moderate to severe disability. Ongoing suboptimal growth in childhood is common.

Respiratory and Gastrointestinal Management of an Infant with a Birth Weight of 258 Grams

Today, more infants weighing less than or equal to 300 g are born, and they survive because of the improvements in neonatal care and treatment. However, their detailed clinical course and neonatal intensive care unit management remain unknown due to their low survival rate and dearth of reports. A male infant was born at 24 weeks and 5 days of gestation and weighed 258 g. The infant received 72 days of invasive and 92 days of noninvasive respiratory support, including high-frequency oscillatory ventilation with volume guarantee and noninvasive neurally adjusted ventilatory assist. Meconium-related ileus was safely treated using diatrizoate. Although the infant was diagnosed with severe bronchopulmonary dysplasia and retinopathy of prematurity requiring laser photocoagulation, he had no other severe complications. He was discharged 201 days postdelivery (3 months of corrected age) with a weight of 3.396 kg. Although managing infants weighing less than or equal to 300 g is difficult, our experience shows that it is possible by combining traditional and modern management methods. The management of such infants requires an understanding of the expected difficulties and adaptation of existing methods to their management. The management techniques described here should help improve their survival and long-term prognosis.

Clinical Impact of Heritable Thrombophilia on Neonatal-Onset Thromboembolism: A Nationwide Study in Japan

OBJECTIVE

To clarify the incidence and genetic risk of neonatal-thromboembolism, we conducted a nationwide study exploring the impact of thrombophilia on neonatal-thromboembolism in Japan.

STUDY DESIGN

A questionnaire survey was conducted for perinatal centers in Japan, focusing on the clinical expression, genotype, treatment, and outcome of patients who developed thromboembolism within 28 days of birth from 2014 to 2018.

RESULTS

The estimated incidence of neonatal-thromboembolism was 0.39 cases per 10 000 live births. Intracranial lesions and purpura fulminans occurred in 66 and 5 of 77 patients, respectively. Fifty-eight (75.3%) infants presented within 3 days after birth. Four (5.2%) died, and 14 (18.2%) survived with disability. At the diagnosis, <20% plasma activity of protein C was noted in 16 infants, protein S (in 2), and antithrombin (in 1). Thirteen genetic tests identified 4 biallelic and 5 monoallelic protein C-variants but no protein S- or antithrombin-variants. Protein C-variants had purpura fulminans (P < .01), ocular bleeding (P < .01), positive-family history (P = .01), and death or disability (P = .03) more frequently than others. Protein C-variants were independently associated with disability (OR 5.74, 95% CI 1.16-28.4, P = .03) but not death. Four biallelic variants had serious thrombotic complications of neurologic disability, blindness, and/or amputation. Three monoallelic variants survived without complications. The only protein C-variant death was an extremely preterm heterozygote infant.

CONCLUSIONS

Monoallelic protein C-variants had a higher incidence of neonatal-thromboembolism than biallelic variants. Thrombophilia genetic testing should be performed in the setting of neonatal-thromboembolism and low protein C to identify the underlying genetic defect.

Survival and Morbidities in Infants with Birth Weight Less than 500 g: a Nationwide Cohort Study

BACKGROUND

This study aimed to investigate the survival and morbidities of infants in the Korean Neonatal Network (KNN) with birth weight (BW) < 500 g.

METHODS

The demographic and clinical data of 208 live-born infants with a BW < 500 g at a gestational age of ≥ 22 weeks who were treated in the neonatal intensive care units of the KNN between 2013 and 2017 were reviewed.

RESULTS

The survival rate of the infants was 28%, with a median gestational age and BW of 243/7 weeks (range, 220/7-336/7) and 440 g (range, 220-499), respectively. Multivariable Cox proportional hazards analysis demonstrated that survival to discharge was associated with longer gestation, higher BW, female sex, singleton gestation, use of any antenatal corticosteroids, and higher Apgar scores at 5 minutes. The overall survival rates were significantly different between the BW categories of < 400 g and 400-499 g. However, there was no significant difference in the incidence of any morbidity between the BW groups. Half of the deaths of infants with BW < 500 g occurred within a week of life, mainly due to cardiopulmonary and neurologic causes. The major causes of death in infants after 1 week of age were infection and gastrointestinal disease. Among the surviving infants, 79% had moderate to severe bronchopulmonary dysplasia, 21% underwent surgical ligation of patent ductus arteriosus, 12% had severe intraventricular hemorrhage (grade III-IV), 38% had sepsis, 9% had necrotizing enterocolitis (stage ≥ 2), and 47% underwent laser treatment for retinopathy of prematurity. The median length of hospital stay was 132 days (range, 69-291), and 53% required assistive devices at discharge.

CONCLUSION

Despite recent advances in neonatal intensive care, the survival and morbidity rates of infants with BW < 500 g need further improvement.

Considerable mortality and morbidity in neonates born below 500 gram

Data evaluating mortality and morbidity in infants born ≤500 g are scarce and show wide variability. To support counselling and decision‐making, we analysed neurodevelopmental outcome in all neonates ≤500 g birth weight.

Retrospective analysis including preterm infants with a birth weight ≤500 g and a gestational age >22 weeks born at a single tertiary perinatal centre between 2010 and 2017.

Of 59 live births, 88% received standard care. Birth weight ranged from 318 to 500 g and gestational age from 23 to 29 weeks. 56% of neonates were born ≤3rd percentile and 42% of treated infants survived. Neurodevelopmental outcome was available in 91% of patients and was evaluated using Bayley Scales of Infant Development at two years. 50% showed a favourable mental development (normal or mild impairment), 75% a favourable motor development and 45% a favourable outcome in both outcome subcategories. When additionally considering visual and hearing disability and, or, cerebral palsy level ≥2 according to the Gross Motor Function Classification System 35% had a good neurodevelopmental outcome.

Survival rate was 37% for all live births and 42% for infants with standard care. More than one‐third of survivors showed no significant neurodevelopmental impairment at two years.

An Association between Maternal Occupations and Low Birth Weight Infants in Japan from 1995 to 2015

Differences in low birth weight rate depending on maternal socioeconomic characteristics have not yet been demonstrated using the Vital Statistics in Japan; therefore, this study aimed to investigate these differences according to maternal occupations. “Report of Vital Statistics: Occupational and Industrial Aspects” and the Vital Statistics in Japan were used every five years from 1995 to 2015. Nine types of occupations were compared. The low birth weight rate was calculated according to maternal occupations and year. Also, the standardized low birth weight ratio was obtained by dividing the number of low-birth-weight infants for each maternal occupation by an expected number of low birth weight infants. The standardized low birth weight ratio for manual workers was the highest among all occupations from 2000 to 2015, and it was significantly higher than one throughout the years. The ratio for clerical workers was also significantly higher than one from 1995 to 2010. Whereas, the ratio for farmers was significantly lower than one in most of the years. It was suggested that health guidance and prenatal care are particularly needed for manual workers, and a study investigating the differences in prenatal characteristics among maternal occupations is necessary for finding a reason for disparity.

Gestation-Based Viability-Difficult Decisions with Far-Reaching Consequences

Most clinicians rely on outcome data based on completed weeks of gestational of fetal maturity for antenatal and postnatal counseling, especially for preterm infants born at the margins of viability. Contemporary estimation of gestational maturity, based on ultrasounds, relies on the use of first-trimester scans, which offer an accuracy of ±3-7 days, and depend on the timing of the scans and the measurements used in the calculations. Most published literature on the outcomes of babies born prematurely have reported on short- and long-term outcomes based on completed gestational weeks of fetal maturity at birth. These outcome data change significantly from one week to the next, especially around the margin of gestational viability. With a change in approach solely from decisions based on survival, to disability-free survival and long-term functional outcomes, the complexity of the parental and care provider's decision-making in the perinatal and postnatal period for babies born at less than 25 weeks gestation remains challenging. While sustaining life following birth at the margins of viability remains our priority-identifying and mitigating risks associated with extremely preterm birth begins in the perinatal period. The challenge of supporting the normal maturation of these babies postnatally has far-reaching consequences and depends on our ability to sustain life while optimizing growth, nutrition, and the repair of organs compromised by the consequences of preterm birth. This article aims to explore the ethical and medical complexities of contemporary decision-making in the perinatal and postnatal periods. We identify gaps in our current knowledge of this topic and suggest areas for future research, while offering a perspective for future collaborative decision-making and care for babies born at the margins of viability.

[Risk factors for endotracheal intubation during resuscitation in the delivery room among very preterm infants]

OBJECTIVE

To explore the risk factors for endotracheal intubation during resuscitation in the delivery room among very preterm infants.

METHODS

A retrospective analysis was performed for 455 very preterm infants who were admitted to the neonatal intensive care unit from January 2017 to December 2019. They were divided into an intubation group (n=79) and a non-intubation group (n=376) according to whether endotracheal intubation was performed during resuscitation. The risk factors for endotracheal intubation during resuscitation were evaluated by multivariate logistic regression analysis.

RESULTS

The intubation rate was 17.4% (79/455). Compared with the intubation group, the non-intubation group had significantly higher gestational age, birth weight, and rates of caesarean birth, delayed cord clamping (DCC), resuscitation quality improvement, regular use of antenatal glucocorticoids in mothers and premature rupture of membranes > 18 hours (P < 0.05), but significantly lower rates of maternal gestational diabetes mellitus, placental abruption, placenta previa or placenta previa status, and maternal thyroid dysfunction (P < 0.05). Regular use of antenatal glucocorticoids in mothers (OR=0.368, P < 0.05) and DCC (OR=0.222, P < 0.05) were protective factors against intubation during resuscitation, while younger gestational age, birth weight < 750 g, maternal gestational diabetes mellitus, and placenta previa or placenta previa status were risk factors for intubation during resuscitation (P < 0.05).

CONCLUSIONS

Very preterm infants with younger gestational age, birth weight < 750 g, maternal diabetes mellitus, placenta previa or placenta previa status may have a higher risk for endotracheal intubation after birth. The regular use of antenatal glucocorticoids and DCC can reduce the risk of intubation during resuscitation in very preterm infants.

Germinal Matrix-Intraventricular Hemorrhage: A Tale of Preterm Infants

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a common intracranial complication in preterm infants, especially those born before 32 weeks of gestation and very-low-birth-weight infants. Hemorrhage originates in the fragile capillary network of the subependymal germinal matrix of the developing brain and may disrupt the ependymal lining and progress into the lateral cerebral ventricle. GM-IVH is associated with increased mortality and abnormal neurodevelopmental outcomes such as posthemorrhagic hydrocephalus, cerebral palsy, epilepsy, severe cognitive impairment, and visual and hearing impairment. Most affected neonates are asymptomatic, and thus, diagnosis is usually made using real-time transfontanellar ultrasound. The present review provides a synopsis of the pathogenesis, grading, incidence, risk factors, and diagnosis of GM-IVH in preterm neonates. We explore brief literature related to outcomes, management interventions, and pharmacological and nonpharmacological prevention strategies for GM-IVH and posthemorrhagic hydrocephalus.

Loop Ileostomy in Europe's Tiniest Male Newborn for Meconium-Related Ileus

With the advances of neonatology, the survival rate for "live-born periviable fetuses" weighing < 300 g, a subgroup of extremely low birth weight (BW) infants, has improved over the past 10 years. Meconium-related ileus (MRI) represents an early postnatal hazard, and, if medical evacuation fails, a surgical challenge in such immature babies. We report the interdisciplinary management of surgically treated MRI in a newborn with a BW of 273 g. According to the worldwide database held by the University of Iowa, he is registered as the tiniest male newborn in Europe. The boy was born in the 25th gestational week by cesarean section after a triplet pregnancy with twin-twin transfusion syndrome, him being the donor. He had a BW of 273 g, whereas his brothers had a BW of 740 g and 722 g. Cardiopulmonary stabilization and ventilation were successful. He developed MRI unresponsive to medical treatment. On day 14 of life, a minilaparotomy was performed in the right lower quadrant to externalize a loop of the distal ileum in a no-touch technique. Despite the small diameter of only 2 mm, a standard loop ileostomy could be fashioned. There were no intra- or postoperative abdominal complications. Bowel function and weight gain were adequate and the ileostomy was closed electively 5 months later at a body weight of 3.5 kg. In summary, minilaparotomy and loop ileostomy placement were effective to treat surgical MRI in Europe's tiniest male newborn. With the advances of neonatology, pediatric surgery reaches new frontiers as well.

Case Report: Intact Survival of a Marginally Viable Male Infant Born Weighing 268 Grams at 24 Weeks Gestation

We report the case of a preterm small for gestational age male infant born at 24 weeks of gestation with a birth weight of 268 g who was discharged from our hospital without the requirement for home oxygen therapy or tube feeding. He did not experience severe intraventricular hemorrhage, periventricular leukomalacia, hearing disability, or any other serious complications. At that time (February 2019), according to the University of Iowa's Tiniest Babies Registry, he was the tiniest male infant in the world to survive without any serious complications other than severe retinopathy of prematurity that required laser therapy. Although the survival rate of infants with extremely low birth weight is improving worldwide, a high mortality rate and incidence of severe complications remain common for infants weighing <300 g at birth, particularly in male infants. In recent years, there have been frequent discussions regarding the ethical and social issues involved in treating extremely preterm infants weighing <400 g. Despite the challenges, reports of such infants surviving are increasing. Neonatal medicine has already achieved great success in treating infants weighing 400 g or more at birth. However, lack of evidence and experience may make physicians reluctant to treat infants weighing less than this. The present case demonstrates that intact survival of a marginally viable male infant with a birth weight of <300 g is possible with minimal handling and family involvement beginning shortly after birth. Our detailed description of the clinical course of this case should provide invaluable information to physicians around the world who treat such infants. This report will aid in the progress of neonatal medicine and help to address many of the social and ethical issues surrounding their care.

Case Report: Treatment of Extremely Preterm Infants With Birthweight Below 300 g: Case Series

Reports on the birth of infants weighing <300 g are quite rare and little is known about the best practices in treating such micropreemies. Therefore, we report here on three cases of low birthweight infants weighing <300 g, of whom two infants survived. The birthweights and gestational ages were ranging 279-293 g and 22 + 6/7 - 23 + 6/7 weeks, respectively. All the infants had severe fetal growth restriction and prematurity. The infant in case 1 died of hepatic rupture, perhaps due to birth trauma, which emphasized the need for less invasive obstetric procedures including en caul delivery. The infant in case 2 managed to survive through severe prematurity secondary to hydrops fetalis. However, complications followed soon as tracheal granulation tissue was formed with neurodevelopmental impairment. The infant in case 3 was born recently and her clinical course was less remarkable without severe complications, despite having the least gestational age and birthweight among the three patients. The improved care protocols for extremely low birthweight infants over these years through experiential learning including that with cases 1 and 2 may have ensured the better outcome of case 3. Accumulating evidence and recording the experience of such cases with continuous constructive discussion can contribute to better outcomes and appropriate parental counseling for extremely small babies in the future.

Frühgeborene an der Grenze der Lebensfähigkeit (Entwicklungsstufe S2k, AWMF-Leitlinien-Register Nr. 024/019, Juni 2020)

Redaktionskomitee Federführende Fachgesellschaft

Transcutaneous blood gas monitoring among neonatal intensive care units in Japan

BACKGROUND

This study aimed to investigate the utility of transcutaneous (tc) measurements of partial pressure of oxygen (tcPO₂ ) and carbon dioxide (tcPCO₂ ) monitoring in neonatal intensive care units (NICUs) in Japan.

METHODS

At the end of 2016,we sent a survey questionnaire on tc monitoring to all 106 NICUs registered with the Japanese Neonatologist Association. The questions included usage, subjects, methods, management, and the practical usefulness of tc monitoring.

RESULTS

The questionnaire was returned by 69 NICUs (65.1% of response rate). Seventeen institutions (24.6%) measured both tcPCO₂ and tcPO₂ , and 42 (60.9%) measured tcPCO₂ alone. Transcutaneous PCO₂ or tcPO₂ monitoring was applied for "pre-viable" infants born at 22-23 weeks' gestational age (18.6% vs 23.5%), and infants of <500 g birthweight (30.5% vs 17.6%). The tcPCO₂ and tcPO₂ monitoring was started at birth in 49.2% and 70.6% of the newborn infants, respectively. The temperature of the sensor was set at <38°C for tcPCO₂ in 54.3% and >42°C for tcPO₂ in 58.9% of NICUs. The accuracy for tcPO₂ was rated as good in 35.3% or moderate in 64.7%, of institutions but or for tcPCO₂ as 1.7% or 93.2%of institutions , respectively.

CONCLUSION

Transcutaneous monitoring was widely, but limitedly, used for preterm infants. The lower temperature of the tcPCO₂ sensor compared to that reported in other developed countries might compromise the accuracy but increase the feasibility of tc monitoring in Japan.

Adult-Onset Diseases in Low Birth Weight Infants: Association with Adipose Tissue Maldevelopment

Low birth weight (LBW) infants have higher risk of developing insulin resistance and its comorbidities later in life. The concept of “developmental origins of health and disease” suggests that intrauterine and postnatal environments have an important role in increasing these risks. The risk of such adult-onset diseases in LBW infants might be associated with adipose tissue maldevelopment including altered body composition and increased amount of visceral fat, which is the same mechanism as that in children and adults with metabolic syndrome. However, LBW infants often have different characteristics: they are not always overweight or obese over their life course. The inconsistency might be associated with the thrifty phenotype, which is produced in response to impaired growth potential and decreased lean body mass. LBW infants tend to be obese within the limits of impaired growth potential. Through our previous investigations evaluating longitudinal changes in adiponectin levels at an early stage of life, we speculated that probably, the intrauterine life of term infants or the period up to term-equivalent age in preterm infants might be the key age for the development of adipose tissues including fat cells. Because of that, we hypothesized that the smaller number of adipocytes in LBW infants might be associated with overloading of single adipocytes and impaired adipose tissue expandability. The possible mechanisms are discussed from the perspective of adipose tissue maldevelopment in LBW infants.

Late-Onset Circulatory Collapse and Risk of Cerebral Palsy in Extremely Preterm Infants

OBJECTIVE

To investigate whether the development of postnatal, late-onset refractory hypotension, referred to as late-onset circulatory collapse, was associated with an increased risk of developing cerebral palsy (CP) at 3 years of age in extremely preterm infants.

METHODS

In this historical cohort study, infants who were born at 22-27 weeks of gestation from 2008 to 2012 in the Neonatal Research Network of Japan were eligible. The study sample consisted of 3474 infants (45.6% of 7613 potentially eligible infants) who were evaluated at 36-42 months of age. Late-onset circulatory collapse was defined as a clinical diagnosis of late-onset circulatory collapse requiring treatment with corticosteroids. We compared the neurodevelopmental outcomes between infants with and without late-onset circulatory collapse.

RESULTS

Late-onset circulatory collapse was diagnosed in 666 of the infants studied. Infants with late-onset circulatory collapse had a higher incidence of CP than those without late-onset circulatory collapse (18.0% vs 9.8%; P < .01). In multivariable logistic analysis, late-onset circulatory collapse was independently associated with CP (aOR, 1.52; 95% CI, 1.13-2.04) and developmental quotient score of <50 (OR, 1.83; 95% CI, 1.23-2.72).

CONCLUSIONS

Late-onset circulatory collapse may be a relatively common event occurring in extremely preterm infants and an independent risk factor for CP at 3 years of age.

Perinatal factors associated with bubbly/cystic appearance in bronchopulmonary dysplasia: a nationwide, population-based cohort study in Japan

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains one of the most serious morbidities associated with preterm birth. Previous study reported that bubbly/cystic appearance on chest X-rays in the neonatal period is the strongest determinant of impaired lung function at school age in BPD patients.

AIMS

To determine perinatal risk factors for bubbly/cystic appearance on chest X-rays in extremely premature infants with BPD exposed to histological chorioamnionitis histological chorioamnionitis (hCAM).

STUDY DESIGN

Multicenter retrospective cohort study.

SUBJECTS

We analyzed 1369 extremely premature infants with severe hCAM who were admitted to the neonatal intensive care units participating in the Neonatal Research Network, Japan (NRNJ) Neonatal research network Japan.

OUTCOME MEASURES

Perinatal characteristics were compared and logistic regression analysis was performed for multivariate risk factor assessment.

RESULT

Infants with bubbly/cystic appearance on chest X-rays underwent longer duration of invasive mechanical ventilation and required inhaled nitric oxide and home oxygen therapy more frequently. Low gestational age (odds ratio 1.244; 95% confidence interval 1.139-1.359) and preterm premature rupture of membranes (odds ratio 1.507; 95% confidence interval 1.200-1.893) were significant risk factors.

CONCLUSION

Low gestational age and preterm premature rupture of membranes were independent risk factors for bubbly/cystic appearance in extremely premature infants with BPD following exposure to severe hCAM.

Recurrent intestinal ischemia following surgery for gastric and duodenal perforations: a case report

Background

Extremely low birth weight (ELBW) is a risk factor for various gastrointestinal complications. In the recent decades, advances in medicine have increased the survival of ELBW infants with necrotizing enterocolitis (NEC). To our knowledge, there have been no reports of neonates or infants developing simultaneous gastric and duodenal perforations and later developing NEC. We report a case of an extremely low birth weight infant (ELBWI) who developed both gastric and duodenal perforations at the same time and developed NEC after operation for gastric and duodenal perforations.

Case presentation

The patient was a female infant with ELBW who developed both gastric and duodenal perforations at the same time and developed NEC after operation for gastric and duodenal perforations. After birth, endotracheal intubation was performed. However, barotrauma occurred during positive pressure ventilation, resulting in a large area of emphysema in the left lower lung field, leading to collapse of the left lung. This giant bulla may have compressed the pulmonary vein, possibly resulting in pulmonary venous thrombosis (PVT). This episode could have triggered simultaneous gastric and duodenal perforations. In addition, we hypothesized that PVT caused acute arterial ischemia, leading to the development of NEC. The infant was started on heparin for anticoagulation. Later, the infant developed non-immunoglobulin E (IgE)-mediated gastrointestinal food allergies (non-IgE-GI-FAs). The giant bulla associated with barotrauma might have caused PVT, resulting in arterial emboli and multiple simultaneous gastrointestinal perforations.

Conclusions

Anticoagulation therapy with heparin for acute arterial thrombosis is effective for preventing the development of short bowel syndrome. Duodenal and intestinal surgery probably acted as risk factors for the subsequent development of non-IgE-GI-FAs. The infant had been stabilized at the time of writing this report.

Successful conservative treatment of intestinal perforation in VLBW and ELBW neonates: a single centre case series and review of the literature

Background

The current standard treatment of neonates with intestinal perforation is surgery. However, the mortality rate after surgical treatment for intestinal perforation is very high for very low birth weight (VLBW) and extremely low birth weight (ELBW) neonates. In this review, conservative treatment of pneumoperitoneum among VLBW and ELBW neonates is investigated.

Methods

Between January 2015 and December 2017, data from all of the VLBW and ELBW neonates with pneumoperitoneum who survived without surgical treatment were collected from Shenzhen Maternity and Child Healthcare Hospital in Guangdong, China. Twenty-two neonates with birth weight less than 1500 g were diagnosed with pneumoperitoneum. Following careful evaluation and discussion, eleven were treated conservatively and this was successful in eight. Details of the eight neonates including birth weight, gestational age, gender, risk factors, time of the perforation, treatment and prognosis were retrospectively recorded. A literature review was performed of previously reported cases that had used conservative treatment.

Results

The median gestational age and birth weight of the eight neonates were 27^+ 1 weeks (range 24w^+ 3 to 31w^+ 6) and 855 g (range 650 g to 1440 g), respectively. Pneumoperitoneum was confirmed by X-ray in all at a median of 8 days of life. They received full parenteral support for a median of 22 days. All eight neonates received a combination of piperacillin-tazobactam and meropenem as first-choice antibiotics, two of them also received fluconazole as anti-fungal medication. Median duration of hospitalisation was 80 days.

Conclusions

Conservative treatment with careful surveillance may be a practical choice for the VLBW and ELBW neonates with intestinal perforation. Further studies are needed for confirmation.

Feeding interval and use of donor breast milk for very low birthweight infants: A nationwide survey in Japan

BACKGROUND

Enteral feeding is critical for postnatal growth of very low birthweight infants (VLBWI); however, a standard feeding strategy has not been established in Japan. A 2- or 3-h feeding interval is generally used, but no clear evidence supports either approach. Additionally, there is no nationwide breast milk bank in Japan and no consensus exists on the use of donor breast milk (DBM). To clarify the current feeding strategies for VLBWI in Japan, we undertook a nationwide survey.

METHODS

We sent a questionnaire to the 382 NICUs included in the Neonatal Research Network in Japan. We sought information on NICU size, number of admissions, necrotizing enterocolitis (NEC) incidence, feeding interval, and use of DBM.

RESULTS

We received responses from 217 NICUs (56.8%), including 76 tertiary centers and 140 regional centers. We only analyzed data obtained from tertiary perinatal centers with a high response rate (77.6%) owing to the insufficient response rate of lower-level facilities (<50%). Most NICUs (71.1%) used a 3-h feeding interval. Only 9.2% used a 2-h interval for all VLBWI. Most NICUs (64.5%) never used DBM, which is not routinely pasteurized. DBM was used in 27 NICUs (35.5%), with and without limitations. Data from 14,233 VLBWI were analyzed; 258 infants (1.8%) were diagnosed with NEC from 2011 to 2015. The incidence of NEC was higher in NICUs that used a 2-h interval (2.7%) than in others. No association was found between NEC and the use of DBM. The NEC incidence did not differ between centers using the most common strategy of a 3-h interval without DBM and those using other strategies.

CONCLUSION

Most NICUs in Japan use a 3-h feeding interval and do not use DBM for VLBWI. Further prospective studies including multiple confounders are required to clarify the relationship between feeding strategy and the incidence of NEC.

Association of perinatal factors of epilepsy in very low birth weight infants, using a nationwide database in Japan

OBJECTIVE

To determine clinical features of very low birth weight infants (VLBWIs) who had developed epilepsy by age 3 years.

STUDY DESIGN

Multicenter cohort study using the Neonatal Research Network of Japan database. We analyzed clinical variables of 8431 VLBWIs who had recorded data of neurological sequelae at age 3 years. Logistic regression identified the association between variables and development of epilepsy.

RESULT

One hundred and forty-three (1.7%) infants developed epilepsy, 683 (8.1%) showed cerebral palsy (CP), and 1114 (13.2%) had psychomotor delay. Epilepsy was associated with history of sepsis [adjusted odds ratio (AOR) 3.23], severe intraventricular hemorrhage (IVH; AOR 5.13), and cystic periventricular leukomalacia (PVL; AOR 12.7). Severe IVH and cystic PVL were also frequently associated with CP and psychomotor delay.

CONCLUSION

Severe IVH and cystic PVL are strongly associated with development of epilepsy, as well as other neurological sequelae, and are potential critical therapeutic targets.

Neonatal Outcomes in Extremely Preterm Newborns Admitted to Intensive Care after No Active Antenatal Management: A Population-Based Cohort Study

OBJECTIVE

To evaluate the association between active antenatal management and neonatal outcomes in extremely preterm newborns admitted to a neonatal intensive care unit (NICU).

STUDY DESIGN

This population-based cohort study was conducted in 25 regions of France. Infants born in 2011 between 22^0/7 and 26^6/7 weeks of gestation and admitted to a NICU were included. Infants with lethal congenital malformations or death in the delivery room were excluded. A multilevel multivariable analysis was performed, accounting for clustering by mother (multiple pregnancies) and hospital plus individual characteristics, to estimate the association between the main exposure of no active antenatal management (not receiving antenatal corticosteroids, magnesium sulfate, or cesarean delivery for fetal indications) and a composite outcome of death or severe neonatal morbidity (including severe forms of brain or lung injury, retinopathy of prematurity, and necrotizing enterocolitis).

RESULTS

Among 3046 extremely preterm births, 783 infants were admitted to a NICU. Of these, 138 (18%) did not receive active antenatal management. The risk of death or severe morbidity was significantly higher for infants without active antenatal management (crude OR, 2.60; 95% CI, 1.44-4.66). This finding persisted after adjustment for gestational age (OR, 2.08; 95% CI, 1.19-3.62) and all confounding factors (OR, 1.86; 95% CI, 1.09-3.20).

CONCLUSIONS

The increased risk of severe neonatal outcomes for extremely preterm babies admitted to a NICU without optimal antenatal management should be considered in individual-level decision making and in the development of professional guidelines for the management of extremely preterm births.

Neurodevelopmental Outcomes in Infants With Birth Weight ≤500 g at 3 Years of Age

OBJECTIVES

To determine neurodevelopmental outcomes at 3 years of age in children born with a birth weight (BW) of ≤500 g.

METHODS

Infants who were born with a BW of ≤500 g from 2003 to 2012 in the Neonatal Research Network of Japan and survived to discharge from the NICU were eligible in this study. The study population consisted of 460 children (56.7% of 811 surviving infants) who were evaluated at 36 to 42 months of age. Neurodevelopmental impairment (NDI) was defined as having cerebral palsy, visual impairment, hearing impairment, or a developmental quotient score of <70.

RESULTS

The overall proportion of NDI was 59.1% (95% confidence interval [CI]: 54.6%-63.5%). The trend revealed no significant change during the study period. In a multivariate modified Poisson regression analysis, NDI was associated with severe intraventricular hemorrhage (adjusted risk ratio [RR]: 1.42; 95% CI: 1.19-1.68; P < .01), cystic periventricular leukomalacia (adjusted RR: 1.40; 95% CI: 1.13-1.73; P < .01), severe necrotizing enterocolitis (adjusted RR: 1.31; 95% CI: 1.07-1.60; P < .01), surgical ligation for patent ductus arteriosus (adjusted RR: 1.29; 95% CI: 1.09-1.54; P < .01), and male sex (adjusted RR: 1.19; 95% CI: 1.01-2.40; P = .04).

CONCLUSIONS

This cohort showed that neurodevelopmental outcomes of infants with a BW of ≤500 g have not improved from 2003 to 2012. Multivariate analysis revealed that severe intracranial hemorrhage and cystic periventricular leukomalacia were the strongest risk factors for NDIs. Our data suggested that measures aimed at reducing neurologic morbidities will be important for improving outcomes of infants with a BW of ≤500 g.

Favorable outcomes of adequate laser photocoagulation and salvage bevacizumab treatment for aggressive posterior retinopathy of prematurity

Purpose

To evaluate the effect of salvage therapy with bevacizumab after laser photocoagulation for infants with recurrence of zone I aggressive-posterior retinopathy of prematurity (AP-ROP).

Methods

This was a retrospective case series documenting the 2-year outcomes of 8 patients diagnosed with zone I AP-ROP and treated with bevacizumab for recurrence after laser photocoagulation. Prior to intravitreal bevacizumab, additional laser treatment was performed when any skip areas on the avascular retina remained. Anatomical and functional outcomes were evaluated.

Results

The median gestational age at birth was 23.7 weeks and the median birth weight was 541.5 g. The median time of initial laser treatment and intravitreal bevacizumab treatment were 32.1 weeks and 36.7 weeks' postmenstrual age, respectively. All 14 eyes developed a normal macular appearance and all 8 patients had visual responses. Visual acuity was measurable in 13 eyes (92%) between the chronological ages of 12–24 months.

Conclusions

and Importance: Adequate laser treatment and salvage intravitreal bevacizumab achieved favorable anatomical and functional outcomes in AP-ROP patients with recurrence.

An International Comparison of Death Classification at 22 to 25 Weeks' Gestational Age

OBJECTIVES

To explore international differences in the classification of births at extremely low gestation and the subsequent impact on the calculation of survival rates.

METHODS

We used national data on births at 22 to 25 weeks' gestation from the United States (2014; n = 11 144), Canada (2009-2014; n = 5668), the United Kingdom (2014-2015; n = 2992), Norway (2010-2014; n = 409), Finland (2010-2015; n = 348), Sweden (2011-2014; n = 489), and Japan (2014-2015; n = 2288) to compare neonatal survival rates using different denominators: all births, births alive at the onset of labor, live births, live births surviving to 1 hour, and live births surviving to 24 hours.

RESULTS

For births at 22 weeks' gestation, neonatal survival rates for which we used live births as the denominator varied from 3.7% to 56.7% among the 7 countries. This variation decreased when the denominator was changed to include stillbirths (ie, all births [1.8%-22.3%] and fetuses alive at the onset of labor [3.7%-38.2%]) or exclude early deaths and limited to births surviving at least 12 hours (50.0%-77.8%). Similar trends were seen for infants born at 23 weeks' gestation. Variation diminished considerably at 24 and 25 weeks' gestation.

CONCLUSIONS

International variation in neonatal survival rates at 22 to 23 weeks' gestation diminished considerably when including stillbirths in the denominator, revealing the variation arises in part from differences in the proportion of births reported as live births, which itself is closely connected to the provision of active care.

Trends in Mortality and Morbidity in Infants Under 500 Grams Birthweight: Observations from Our Neonatal Intensive Care Unit (NICU)

BACKGROUND In our previous study, some changes were presented in obstetric care and we studied the morbidity and mortality trends of infants with <500 grams birth weight. Several neonatal protocol changes occurred during the study period. The aim of this study was to analyze the changes in mortality and morbidity of premature infants in light of changing neonatal protocols. MATERIAL AND METHODS We performed a retrospective study of premature infants with <500 grams birth weight, born at our department between 2006 and 2015. We divided the study period into two 5-year epochs and compared mortality and morbidity rates. We calculated the duration of mechanical ventilation and non-invasive respiratory support, and also investigated the potential impact of the differences in clinical practice. RESULTS The survival rate was 30.8% during first epoch, which was significantly lower than the 70.4% survival rate during second epoch. There was no difference in the rate of complications between the 2 epochs. The total number of ventilator and non-invasive ventilation days was significantly lower in the second epoch. CONCLUSIONS We found significant differences in survival rates but no change in the incidence of morbidities between the 2 epochs. Therefore, although the number of neonates surviving with morbidities has increased, so did the number of those with intact survival. The increased survival of infants born with <500 grams birth weight is not associated with increased rate of morbidities. Protocol changes may have contributed to these findings; however, in a retrospective study it is not possible to separate the impact of individual changes.

Outcomes of infants with a birthweight less than or equal to 500 g in Northern England: 15 years experience

AIM

We aimed to evaluate mortality and short-term neonatal morbidity of babies born ≤500 g cared for in the Northern Neonatal Network over a 15-year period.

METHOD

Using regional databases, we identified all live-born babies ≥22 weeks gestation and ≤500 g, in North East England and North Cumbria from 1998 to 2012. We quantified major neonatal morbidities and survival to one year.

RESULTS

We identified 104 live-born babies ≥22 weeks gestation and ≤500 g (birth prevalence 0.22/1000), of which 49 were admitted for intensive care. Overall one-year survival was 11%, but survival for those receiving intensive care was 22%. There was significant short-term neonatal morbidity in survivors, in particular retinopathy of prematurity and chronic lung disease.

CONCLUSION

Survival of babies born weighing ≤500 g in this cohort remains poor despite advances in neonatal care, with considerable short-term neonatal morbidity in survivors. This could be due to a combination of attitudes and a rather conservative approach towards resuscitation and intensive care, and the intrinsic nature of these tiny babies.