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.

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.

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

OBJECTIVE: To assess the short-term prognosis of Japanese infants with a birth weight (BW) of ≤500 g. STUDY DESIGN: Demographic and clinical data were reviewed for 1473 live born infants with a BW ≤500 g at gestational age ≥22 weeks who were treated in the 204 affiliated hospitals of the Neonatal Research Network of Japan between 2003 and 2012. RESULTS: Survival to hospital discharge occurred in 811 of 1473 infants (55%; 95% CI 53%-58%). The survival rates of BW ≤300 g, 301-400 g, and 401-500 g were 18% (95% CI 10%-31%), 41% (95% CI 36%-47%), and 60% (95% CI 57%-63%), respectively. In a multivariable Cox proportional hazards analysis, antenatal corticosteroid use (adjusted hazard ratio: 0.68; 95% CI 0.58-0.81; P < .01), cesarean delivery (0.69; 95% CI 0.56-0.85; P < .01), advanced gestational age per week (0.94; 95% CI 0.89-0.99; P = .02), BW per 100-g increase (0.55; 95% CI 0.49-0.64; P < .01), Apgar score ≥4 at 5 minutes (0.51; 95% CI 0.43-0.61; P < .01), and no major congenital abnormalities (0.38; 95% CI 0.29-0.51; P < .01) were associated with survival to discharge. Despite the improved survival rate over the 10-year study period (from 40% in 2003 [95% CI 30%-51%] to 68% in 2012 [95% CI 61%-75%]), at least 1 severe morbidity was present in 81%-89% of the survivors. CONCLUSIONS: Improvements in perinatal-neonatal medicine have improved the survival, but not the rate of major morbidities, of infants with a BW ≤500 g in Japan.

Inflammation in the neonatal period and intrauterine growth restriction aggravate bronchopulmonary dysplasia.

BACKGROUND: To investigate the hematological features of infants with bronchopulmonary dysplasia (BPD) and their relationships with clinical severity. METHODS: This prospective observational study enrolled 73 BPD patients from a total of 331 infants with a birth weight of <1500 g from 2005 to 2013. The clinical severity of BPD was defined by the duration of oxygen supplementation and positive pressure ventilation (PPV) in line with the diagnostic criteria of BPD. The hematological status and cytokine levels were surveyed from blood samples at birth and at 2 and 4 weeks of life. RESULTS: Thirty-four (46.6%) cases were classified as "moderate-to-severe" BPD. Small-for-gestational-age (SGA) was associated with the severity of BPD (OR: 5.05; 95% CI: 1.45 to 17.2). The CRP level at 2 weeks (partial regression coefficient [rc]: 21.8; 4.01 to 39.7) and the neutrophil count at 4 weeks (0.005; 0.001 to 0.007) were positively correlated with the oxygenation period. The PPV period was found to be correlated with the CRP level at 2 weeks (27.2; 14.9 to 39.5), and the neutrophil count (0.003; 0.001 to 0.004) at 4 weeks. CONCLUSION: The aggravation of BPD was associated with both SGA at birth and inflammation during neonatal period.

A nationwide survey on tracheostomy for very-low-birth-weight infants in Japan.

OBJECTIVES: Tracheostomy is indicated for very-low-birth-weight infants (VLBWIs) with prolonged respiratory problems during the perinatal period. The objective of this study is to clarify the epidemiology and risk factors in VLBWIs with tracheostomy after birth in Japan. METHODS: A total of 40 806 VLBWIs were registered in the Neonatal Research Network of Japan database from 2003 to 2012. Among them, 34 674 infants (85%) survived over 28 days after birth and were subjected to this study. The clinical variables at birth, outcomes at hospital discharge and associated factors for tracheostomy were examined. RESULTS: The proportion of VLBWIs with tracheostomy did not increase during the study period (mean 36 cases per year, 0.93%). The rate of in-hospital death over 28 days after birth did not differ between tracheostomized and non-tracheostomized infants (2/324, 0.6% vs 314/34 350, 0.9%). Tracheostomized infants more frequently had severe or moderate bronchopulmonary dysplasia (BPD) (75.5% vs 26.0%, P < 0.01) and longer hospitalization (229 days vs 83 days, P < 0.01) than non-tracheostomized infants. Tracheostomized patients showed higher comorbidities with hypoxic ischemic encephalopathy (odds ratio [OR] 10.98, P < 0.01), muscular disease (OR 10.95, P < 0.01), severe or moderate BPD (OR 7.79, P < 0.01), chromosomal abnormality (OR 4.43, P < 0.01) or sepsis (OR 1.78, P < 0.05) at hospital discharge than non-tracheostomized patients. CONCLUSION: We demonstrated the non-increasing rate in tracheostomy for VLBWIs and such cases were associated with an excellent survival in Japan. These data provide evidence that more attentive care must be practiced in order to reduce the pulmonary and neuromuscular burdens of VLBWIs at birth.

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.

Congenital Ewing sarcoma in retroperitoneum with multiple metastases.

A 7-day-old Japanese female showed the absence of spontaneous movement in her both legs. MRI revealed tumors in the retroperitoneum invading into the spinal canal, the left cerebral hemisphere and the right eyeball. Histological examination of retroperitoneal tumor revealed the sheets of undifferentiated small round cells with hyperchromatic nuclei and scanty cytoplasm. EWS-FLI1 fusion gene was detected by RT-PCR, indicating Ewing sarcoma. She received chemo-radiotherapy and survived for 2 years and 10 months despite the multiple metastases at initial presentation.

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.

An Elevation of Serum Ferritin Level Might Increase Clinical Risk for the Persistence of Patent Ductus Arteriosus, Sepsis and Bronchopulmonary Dysplasia in Erythropoietin-Treated Very-Low-Birth-Weight Infants.

BACKGROUND: The substantial risk of iron overload is not routinely monitored in most of the neonatal intensive care units (NICUs) in Japan; however, blood transfusion is an essential strategy for successfully treating preterm low-birth-weight infants. OBJECTIVE: The aim of this study was to investigate the iron status and clinical features of infants with a birth weight of <1,500 g, i.e. very-low-birth-weight infants (VLBWIs). METHODS: This prospective observational study enrolled 176 (82.6%) patients from a total of 213 VLBWIs admitted to our NICU from 2009 to 2014. Clinical information was collected including maternal records and infant morbidity and treatment. Management strategies including enteral iron supplementation, erythropoietin administration and blood transfusion were allowed according to the consensus in Japan. The hematological status was surveyed from birth to 12 postnatal weeks of age. The iron status was determined according to serum iron, unbound iron-binding capacity and serum ferritin. The definition of hyperferritinemia was set as a value of ≥500 ng/ml. RESULTS: Twenty-four (13.6%) infants displayed hyperferritinemia. A multiple logistic analysis selected 3 associated factors of hyperferritinemia: surgical ligation for patent ductus arteriosus, sepsis and moderate or severe states of bronchopulmonary dysplasia. We also verified that the value of ferritin was significantly correlated with those of aspartate transaminase, creatine kinase and C-reactive protein according to a multilinear regression analysis. After excluding the ferritin data of these outliers, we did not observe any factors associated with hyperferritinemia. CONCLUSIONS: Hyperferritinemia might be associated with oxygen radical diseases and susceptibility to infection.