Comparative analysis of foetal and neonatal growth curves.

INTRODUCTION: Our aim was to determine which foetal or neonatal growth curves discriminate the probability of dying of newborns with low birth weight for their gestational age (small for gestational age, SGA) and sex (weight < 10th percentile) and to establish the curves that are presumably most useful for monitoring growth through age 10 years. MATERIAL AND METHODS: The analysis included every neonate (15 122) managed in our hospital (2013-2022) and all neonates born preterm before 32 weeks (6913) registered in the SEN1500 database (2019-2022). We considered most useful those curves with the highest likelihood ratio (LR) for dying with or without a history of SGA in each subgroup of gestational ages. Theoretically, the optimal curves for monitoring growth would be those with a higher R2 in the quantile regression formulas for the 50th percentile. RESULTS: The growth curves exhibiting the strongest association between SGA and hospital mortality are the Intergrowth fetal curves and the Fenton neonatal curves in infants born preterm before 32 weeks. However, the optimal curves for premature babies and neonates overall were those of Olsen and Intergrowth. The most useful curves to monitor anthropometric values alone until age 10 years of age are the longitudinal Intergrowth curves followed by the WHO standards, but if a single reference is desired from birth through age 10 years, the best option is the Fenton curves followed by the WHO standards. CONCLUSIONS: The Intergrowth reference provides the most discriminating foetal growth curves. In neonatal clinical practice, the optimal references are the Fenton followed by the WHO charts.

Lung Microbiota and Ventilator-Associated Pneumonia in the Neonatal Period.

The lung microbiota is a complex community of microorganisms that colonize the respiratory tract of individuals from, or even before, birth. Although the lungs were traditionally believed to be sterile, recent research has shown that there is a diversity of bacterial species in the respiratory system. Knowledge about the lung microbiota in newborns and its relationship with bacterial infections is of vital importance to understand the pathogenesis of respiratory diseases in neonatal patients undergoing mechanical ventilation. In this article, the current evidence on the composition of the lung microbiota in newborns will be reviewed, as well as the risks that an altered microbiota can impose on premature newborns. Although advances in neonatal intensive care units have significantly improved the survival rate of preterm infants, the diagnosis and treatment of ventilator-associated pneumonia has not progressed in recent decades. Avoiding dysbiosis caused by inappropriate use of antibiotics around birth, as well as avoiding intubation of patients or promoting early removal of endotracheal tubes, are among the most important preventive measures for ventilator-associated pneumonia. The potential benefit of probiotics and prebiotics in preventing infectious, allergic or metabolic complications in the short or long term is not clearly established and constitutes a very important field of research in perinatal medicine.

Improved efficiency in the management of newborns with infectious risk factors by the sepsis risk calculator and clinical observation.

OBJECTIVE: To evaluate the efficiency of the sepsis risk calculator and the serial clinical observation in the management of late preterm and term newborns with infectious risk factors. METHOD: Single-center, observational, two-phase cohort study comparing the rates of neonates born ≥35 weeks' gestation, ≥2000 g birthweight, and without major congenital anomalies, who were screened and/or received antibiotics for early-onset neonatal sepsis risk at our center during two periods, before (January/2018-June/2019) and after (July/2019-December/2020) the implementation of the sepsis risk calculator. RESULTS: A total of 1796 (Period 1) and 1867 (Period 2) patients with infectious risk factors were included. During the second period, tests to rule out sepsis were reduced by 34.0 % (RR, 95 %CI): 0.66 (0.61, 0.71), blood cultures by 13.1 %: 0.87 (0.77, 0.98), hospital admissions by 13.5 %: 0.86 (0.76, 0.98) and antibiotic administration by 45.9 %: 0.54 (0.47, 0.63). Three cases of early-onset neonatal sepsis occurred in the first period and two in the second. Clinical serial evaluation would have detected all true cases. CONCLUSIONS: The implementation of a sepsis risk calculator in the management of newborns ≥35 weeks GA, ≥2000 g birthweight, without major congenital anomalies, with infectious risk factors is safe and adequate to reduce laboratory tests, blood cultures, hospital admissions, and antibiotics administration. Serial clinical observation, in addition, could be instrumental to achieve or even improve this goal.

Morbidity and Mortality of Very-Low-Birthweight Twin Infants according to Their Sex and the Sex of the Co-Twin: A Retrospective Cohort Study.

INTRODUCTION: The concept of male disadvantage regarding the prognosis of premature newborns was introduced more than half a century ago, and it has been corroborated over time. However, the influence of the sex of one twin on the outcomes of the other has yielded contradictory results. OBJECTIVE: The aim of the study was to determine if, in twin pregnancies of VLBW infants, the outcomes of one twin are modified by the sex of the co-twin. METHODS: A multicentre retrospective study of a cohort of infants admitted to the collaborating units of the Spanish SEN1500 neonatal network was conducted. Liveborn VLBW twin infants, from 23+0 to 31+6 weeks of gestational age (GA), admitted from 2011 to 2020 were included. Outborn patients, infants with major congenital anomalies, and cases with only one twin admitted were excluded. The main outcomes were survival until first hospital discharge, survival without moderate or severe bronchopulmonary dysplasia (BPD), survival without major brain damage (MBD), and survival without major morbidity. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were calculated. RESULTS: 2,111 twin pairs were included. Male infants exhibited worse outcomes than females (IRR; 95% CI) regarding survival (0.96; 0.94, 0.98), survival without moderate or severe BPD (0.89; 0.86, 0.93), survival without MBD (0.94; 0.91, 0.97), and survival without major morbidity (0.87; 0.81, 0.93). Differences disappeared when the co-twin was a female infant: survival (1.00; 0.97, 1.03), survival without moderate or severe BPD (0.96; 0.91, 1.01), survival without MBD (0.99; 0.95, 1.04), and survival without major morbidity (0.94; 0.85, 1.03). Results for female infants did not change significantly with co-twin sex. CONCLUSIONS: Among VLBW twins from 23+0 to 31+6 weeks of GA, male infants have higher risk of morbidity and mortality overall. In cases of pregnancies with different-sex foetuses, males seem to improve their results, while these do not change for females. The underlying mechanism of this influence deserves further investigation.

Birth order and morbidity and mortality to hospital discharge among inborn very low-birthweight, very preterm twin infants admitted to neonatal intensive care: a retrospective cohort study.

OBJECTIVE: To know the association of birth order with the risk of morbidity and mortality in very low-birthweight (VLBW) twin infants less than 32 weeks' gestational age (GA). DESIGN: Retrospective cohort study. SETTING: Infants admitted to the collaborating centres of the Spanish SEN1500 neonatal network. PATIENTS: Liveborn VLBW twin infants, with GA from 23+0 weeks to 31+6 weeks, without congenital anomalies, admitted from 2011 to 2020. Outborn patients were excluded. MAIN OUTCOME MEASURES: Respiratory distress syndrome (RDS), patent ductus arteriosus, bronchopulmonary dysplasia (BPD), necrotising enterocolitis, major brain damage (MBD), late-onset neonatal sepsis, severe retinopathy of prematurity, survival and survival without morbidity. Crude and adjusted incidence rate ratios were calculated. RESULTS: Among 2111 twin pairs included, the second twin had higher risk (adjusted risk ratio (aRR) of RDS (aRR 1.08, 95% CI 1.03 to 1.12) and need for surfactant (aRR1.10, 95% CI 1.05 to 1.16). No other significant differences were found, neither in survival (aRR 1.01, 95% CI 0.99 to 1.03) nor in survival without BPD (aRR 1.02, 95% CI 0.99 to 1.05), survival without MBD (aRR 1.02, 95% CI 0.99 to 1.06) nor in survival without major morbidity (aRR 0.97, 95% CI 0.92 to 1.03). However, second twins born by caesarean section (C-section) after a vaginally delivered first twin had less overall survival and survival without MBD. CONCLUSION: In modern perinatology, second twins are still more unstable immediately after birth and require more resuscitation. After admission to the neonatal intensive care unit, they are at increased risk of RDS, but not other conditions, except for second twins delivered by C-section after a first twin delivered vaginally, who have decreased overall survival and survival without major brain injury.

Management of neonates with 35 weeks of gestational age or more with infectious risk factors at birth: opportunities for improvement.

OBJECTIVES: The Northern California Kaiser-Permanente Neonatal Sepsis Risk Calculator (SRC) has proved to be safe and effective in reducing laboratory tests, hospital admissions, and administration of antibiotics to patients at risk of early-onset neonatal sepsis (EONS). Many studies have focused on maternal chorioamnionitis as the principal risk factor for EONS. We wanted to know if the use of the SRC could be equally efficient in the context of several other infectious risk factors (IRF), in addition to chorioamnionitis, such as intrapartum maternal fever, GBS colonization and/or prolonged rupture of membranes (PROM). METHODS: Systematic study of neonates with ≥35 weeks gestational age (GA), born in our tertiary university hospital during a period of 18 months. Patients were retrospectively assessed with the SRC and its recommendations were compared with the actual management. A bivariate analysis of perinatal interventions, and outcomes was performed. RESULTS: A total of 5,885 newborns were born during the study period and 1783 mothers (31%) had at least one IRF. The incidence of culture-proven EONS was 0.5‰. The use of the SRC would have reduced laboratory evaluations (CBC and CRP) from 56.2 to 23.3%, and blood cultures, hospital admissions and antibiotic therapy from 22.9 to 15.5%, 17.8 and 7.6%, respectively. The management based on patients' symptoms would have shown a reduction to 7.5% in all the outcomes of interest. CONCLUSIONS: Both, the SRC and the management based on clinical findings, are safe and efficient to reduce the number of analytical studies, hospital admissions and administration of antibiotics to neonates with IRF.

Effects of public health measures during the SARS-CoV-2 pandemic on the winter respiratory syncytial virus epidemic: An interrupted time series analysis.

BACKGROUND: Public health measures (PHM) designed to contain the spread of COVID-19 pandemic have influenced the epidemiological characteristics of other viral infections. Its impact on acute RSV bronchiolitis in infants of ≤24 months old has not been systematically studied in our setting. OBJECTIVES: To describe the monthly pattern of visits to the Paediatric Emergency Department (PED) of patients 0 to 14 years of age, the rate of patients diagnosed with RSV acute bronchiolitis per thousand inhabitants of 0 to 24 months, and the rate of them requiring hospital admission during the winter 2020-2021, in the context of local and national COVID-19 restrictions and compare them to the four previous seasons. METHODS: Interrupted time series analysis of patients assisted in the PED and diagnosed with or admitted for RSV acute bronchiolitis in a tertiary University Hospital from January 2016 to February 2020 (pre-intervention period) and from March 2020 to June 2021 (post-intervention period). INTERVENTION: Preventive PHM implemented by the Spanish government weighted by the Containment and Health Index of the Oxford COVID-19 Government Response Tracker. RESULTS: The intervention was followed by an immediate reduction of the rate of visits to the PED of -19.5 (95% confidence interval [CI] -24.0, -14.9) per thousand, and the rate of diagnoses and admissions for RSV acute bronchiolitis of -44.3 (95% CI -73.8, -14.8) and -1.4 (95% CI -2.7, -0.1) per thousand, respectively, with a delayed rebound. CONCLUSIONS: After the implementation of PHM to prevent the spread of SARS-CoV-2 infection, an immediate and important decline in the visits to the PED was observed, with an upward change thereafter. There was also an initial reduction in the diagnoses of and admissions by RSV acute bronchiolitis. An upward trend was observed six to nine months after the usual time of the winter RSV epidemic, coinciding with the relaxation of the preventive PHM.

Intercenter variability and factors associated with survival without bronchopulmonary dysplasia in extremely preterm newborns.

Background: Variability in clinical practice may influence morbidity and mortality in extremely preterm infants. We aimed to know if there are differences in survival and survival without bronchopulmonary dysplasia (BPD) in extremely preterm infants in Spanish tertiary hospitals and the potential associated factors.Methods: Fifteen hospitals from the SEN1500 network were studied. The overall rate of survival without BPD was 61.4%. Hospitals with extreme results were grouped for comparison (Group 1; N = 2480 versus Group 2; N = 2367). A bivariate analysis of the characteristics of patients and perinatal interventions was carried out and the probability of survival without BPD was studied by Cox regression.Results: Survival (79.0 versus 72.9%; p < .001) and survival without BPD (72.5 versus 49.1%; p < .001) were greater in Group 1. Higher gestational age, birth weight, and female sex were associated with better outcomes. Oxygen administration (aHR: 0.868 [95%CI: 0.782, 0.964]; p=.008) and intubation (aHR: 0.767 [95%CI: 0.701, 0.839]; p < .001) in delivery room were associated with lower survival without BPD. The occurrence of patent ductus arteriosus (PDA), sepsis and/or necrotizing enterocolitis (NEC) was independently associated with worse outcomes. After adjusting for confounders, the probabilities of survival without BPD were significantly higher among patients in Group 1: aHR: 1.557 [95% CI: 1.458, 1.662]; p < .001.Conclusions: Among the studied hospitals, we found great variability in clinical practice and in the rates of survival and survival without BPD. A more conservative approach to the use of oxygen and respiratory support seems to be related to an increase in survival without BPD. Complications such as PDA, sepsis, and/or NEC decrease survival without BPD. Other variables not included in the present study could be relevant and deserve further study.

Variations in the number of births by day of the week, and morbidity and mortality in very-low-birth-weight infants / Variações no número de partos por dia da semana e morbidez e mortalidade em neonatos com muito baixo peso ao nascer

Abstract Objective: To know the distribution of births of very low birth weight infants by day of the week, and whether this distribution affects the morbidity and mortality in this group of patients. Methods: This was a retrospective analysis of data collected prospectively in the Spanish SEN1500 network (2002-2011). Outborn infants, patients with major congenital anomalies, and those who died in the delivery room were excluded. Births were grouped into "weekdays" and "weekends." A multivariate logistic regression analysis was conducted to evaluate the independent effect of the birth moment on outcomes, and Cox regression for survival. Results: Out of a total of 27,205 very low birth weight infants born at and/or admitted to the participating centers, 22,961 (84.4%) met inclusion criteria. A reduction of 24% in the number of births was observed during the "weekends" compared with "weekdays". In the raw analysis, patients born on weekends exhibited higher morbidity and mortality (mortality rate: 14.2% vs. 16.5%, p < 0.001), but differences were no longer significant after adjusting for confounding factors. Conclusions: The present results suggest that current care practices reduce the proportion of births during the weekends and tend to cluster some high-risk births during this period, increasing crude morbidity and mortality. However, after adjusting for confounding factors, the differences disappear, suggesting that overall care coverage in these centers is appropriate.

Resumo Objetivo: Conhecer a distribuição dos partos de neonatos com muito baixo peso ao nascer durante a semana e se essa distribuição afeta a morbidez e a mortalidade nesse grupo de pacientes. Método: Esta é uma análise retrospectiva de dados coletados prospectivamente na rede espanhola SEN1500 (2002-2011). Foram excluídos neonatos nascidos em outro local, pacientes com grandes anomalias congênitas e pacientes falecidos na sala de parto. Os partos foram agrupados em "Dias úteis" e "Final de semana". Foi realizada uma análise de regressão logística multivariada para avaliar o efeito independente do parto sobre os resultados e uma regressão de Cox para avaliar a sobrevida. Resultados: Do total de 27.205 neonatos com muito baixo peso ao nascer nascidos e/ou internados nos centros participantes, 22.961 (84,4%) atenderam aos critérios de inclusão. Houve uma redução de 24% no número de partos no "Final de semana" em comparação com os "Dias úteis". Na análise bruta, os pacientes nascidos em finais de semana apresentaram maior morbidez e mortalidade (Taxa de mortalidade: 14,2% em comparação a 16,5%, p < 0,001), porém as diferenças não eram mais significativas após o ajuste aos fatores de confusão. Conclusões: Nossos resultados sugerem que as práticas atuais de atendimento reduzem a proporção de partos em finais de semana e tendem a agrupar alguns partos de alto risco nesse período, aumentando a morbidez e mortalidade brutas. Contudo, após o ajuste aos fatores de risco, as diferenças desaparecem, sugerindo que a cobertura de atendimento geral em nossos centros é adequada.

Variations in the number of births by day of the week, and morbidity and mortality in very-low-birth-weight infants.

OBJECTIVE: To know the distribution of births of very low birth weight infants by day of the week, and whether this distribution affects the morbidity and mortality in this group of patients. METHODS: This was a retrospective analysis of data collected prospectively in the Spanish SEN1500 network (2002-2011). Outborn infants, patients with major congenital anomalies, and those who died in the delivery room were excluded. Births were grouped into "weekdays" and "weekends." A multivariate logistic regression analysis was conducted to evaluate the independent effect of the birth moment on outcomes, and Cox regression for survival. RESULTS: Out of a total of 27,205 very low birth weight infants born at and/or admitted to the participating centers, 22,961 (84.4%) met inclusion criteria. A reduction of 24% in the number of births was observed during the "weekends" compared with "weekdays". In the raw analysis, patients born on weekends exhibited higher morbidity and mortality (mortality rate: 14.2% vs. 16.5%, p<0.001), but differences were no longer significant after adjusting for confounding factors. CONCLUSIONS: The present results suggest that current care practices reduce the proportion of births during the weekends and tend to cluster some high-risk births during this period, increasing crude morbidity and mortality. However, after adjusting for confounding factors, the differences disappear, suggesting that overall care coverage in these centers is appropriate.

Neural breathing patterns in preterm newborns supported with non-invasive neurally adjusted ventilatory assist.

OBJECTIVE: To characterize the neural breathing pattern in preterm infants supported with non-invasive neurally adjusted ventilatory assist (NIV-NAVA). STUDY DESIGN: Single-center prospective observational study. The electrical activity of the diaphragm (EAdi) was periodically recorded in 30-second series with the Edi catheter and the Servo-n software (Maquet, Solna, Sweden) in preterm infants supported with NIV-NAVA. The EAdiPeak, EAdiMin, EAdiTonic, EAdiPhasic, neural inspiratory, and expiratory times (nTi and nTe) and the neural respiratory rate (nRR) were calculated. EAdi curves were generated by Excel for visual examination and classified according to the predominant pattern. RESULTS: 291 observations were analyzed in 19 patients with a mean GA of 27.3 weeks (range 24-36 weeks), birth weight 1028 g (510-2945 g), and a median (IQR) postnatal age of 18 days (4-27 days). The distribution of respiratory patterns was phasic without tonic activity 61.9%, phasic with basal tonic activity 18.6, tonic burst 3.8%, central apnea 7.9%, and mixed pattern 7.9%. In addition, 12% of the records showed apneas of >10 seconds, and 50.2% one or more "sighs", defined as breaths with an EAdiPeak and/or nTi greater than twice the average EAdiPeak and/or nTi of the recording. Neural times were measurable in 252 observations. The nTi was, median (IQR): 279 ms (253-285 ms), the nTe 764 ms (642-925 ms), and the nRR 63 bpm (51-70), with a great intra and inter-subjects variability. CONCLUSIONS: The neural breathing patterns in preterm infants supported with NIV-NAVA are quite variable and are characterized by the presence of significant tonic activity. Central apneas and sighs are common in this group of patients. The nTi seems to be shorter than the mechanical Ti commonly used in assisted ventilation.

Perinatal risk factors for pneumothorax and morbidity and mortality in very low birth weight infants.

AIM: To determine the perinatal risk factors for pneumothorax in Very-Low-Birth-Weight (VLBW) infants and the associated morbidity and mortality in this population. METHODS: Retrospective analysis of data collected prospectively from a cohort of VLBW neonates assisted in our Unit (2006-2013). We included all consecutive in-born patients with ≤ 1500 g, without severe congenital anomalies. Perinatal history, demographics, interventions and clinical outcomes were collected. Associations were evaluated by logistic regression analysis. RESULTS: During the study period, 803 VLBW infants were assisted in our Unit, of whom 763 were inborn. Ten patients (1.2%) died in delivery room, and 18 (2.2%) with major congenital anomalies were excluded. Finally, 735 (91.5%) neonates were included in the study. Seventeen (2.3%) developed pneumothorax during the first week of life [median (IQR): 2 (1-2) days]. After correcting for GA and other confounders, prolonged rupture of membranes [aOR =1.002 (95% CI 1.000-1.003); p = 0.040] and surfactant administration [aOR = 6.281 (95% CI 1.688-23.373); p = 0.006] were the independent risk factors associated with pneumothorax. Patients with pneumothorax had lower probabilities of survival without major brain damage (MBD): aOR = 0.283 (95% CI = 0.095-0.879); p = 0.029. CONCLUSIONS: Pneumothorax in VLBW seems to be related to perinatal inflammation and surfactant administration, and it is significantly associated with a reduction in the probabilities of survival without MBD.

End-of-Life Care and Survival without Major Brain Damage in Newborns at the Limit of Viability.

BACKGROUND: The probabilities of survival and survival without major brain damage (MBD) are low in newborns at the limit of viability. Survival without MBD constitutes a major concern for parents and professionals. OBJECTIVES: To know the probabilities of survival without MBD in newborns ≤26 weeks' gestational age (GA) relative to the total number of survivors, whether these probabilities vary with GA, and how end-of-life (EoL) decisions influence these results. METHODS: We included all live-inborn patients of 22-26 weeks' GA, without major congenital anomalies, born in collaborating centers of the Spanish SEN1500 Network (2004-2010). MBD was defined as the presence of severe intraventricular hemorrhage and/or periventricular leukomalacia. RESULTS: A total of 3,371 patients were born alive, 3,236 of whom were admitted to the neonatal intensive care unit (NICU). Survival without MBD was 44.4% among patients admitted to the NICU, increasing from 12.5% at 22 weeks to 57.9% at 26 weeks' GA. The proportion of survivors without MBD relative to the total number of survivors was 81.1%, and it was independent of GA. EoL decisions preceded one-third of all deaths and were more frequent among the most immature patients. CONCLUSIONS: The proportion of survivors without MBD, when referred to the total number of survivors, is relatively high and is independent of GA. EoL decisions after the occurrence of MBD seem to play an important role in this respect. These results support the attitude of "giving an opportunity" even to the most immature patients, if this is in accordance with the parents' wishes.