Body Size, Cerebral Blood Flow, Ambient Temperature, and Relative Brain Temperatures in Newborn Infants under Incubator Care.

Subtle changes in body temperature affect the outcomes of ill newborns. However, the temperature profile of neonatal brains remains largely unknown. In open-cot care, increased cerebral perfusion is correlated with higher superficial brain temperatures. This study investigated the dependence of brain temperature (relative to rectal temperature) on ambient temperature, body size, cerebral perfusion, and metabolism in infants receiving incubator care. Rectal, scalp, and brain temperatures, superior vena cava flow, and brain oxygenation were assessed using echocardiography, thermo-compensatory temperature monitoring, and near-infrared spectroscopy in 60 newborns. These infants had a mean postconceptional age of 36.9 (2.2) weeks and weighed 2348 (609) g at the time of evaluation. The ambient temperature was maintained at 30.0 (1.0) °C. A higher rectal temperature was associated with greater postconceptional age (p = 0.002), body weight (p < 0.001), and head circumference (p < 0.001). Relative scalp, superficial brain, and deep brain temperatures were associated with smaller head circumference (p < 0.001, p = 0.030, and p = 0.015, respectively) and superior vena cava flow (p = 0.002, p = 0.003, and p = 0.003, respectively). In infants receiving incubator care, larger head sizes and increased brain perfusion were associated with lower relative scalp and brain temperatures. When considered alongside previous reports, cerebral perfusion may contribute to maintaining stable cerebral tissue temperature against ambient temperature changes.

Furin Regulates the Alveolarization of Neonatal Lungs in a Mouse Model of Hyperoxic Lung Injury.

Despite advances in treatment options, such as corticosteroid administration and less invasive respiratory support, bronchopulmonary dysplasia (BPD) remains an important prognostic factor in preterm infants. We previously reported that furin regulates changes in lung smooth muscle cell phenotypes, suggesting that it plays a critical role in BPD pathogenesis. Therefore, in this study, we aimed to evaluate whether it regulates the alveolarization of immature lungs through activating alveolarization-driving proteins. We first examined furin expression levels, and its functions, using an established hyperoxia-induced BPD mouse model. Thereafter, we treated mice pups, as well as primary myofibroblast cell cultures, with furin inhibitors. Finally, we administered the hyperoxia-exposed mice pups with recombinant furin. Immunofluorescence revealed the co-expression of furin with alpha-smooth muscle actin. Hyperoxia exposure for 10 d decreased alveolar formation, as well as the expression of furin and its target, IGF-1R. Hexa-D-arginine administration also significantly inhibited alveolar formation. Another furin inhibitor, decanoyl-RVKR-chloromethylketone, accumulated pro-IGF-1R, and decreased IGF-1R phosphorylation in myofibroblast primary cultures. Finally, recombinant furin treatment significantly improved alveolarization in hyperoxia-exposed mice pups. Furin regulates alveolarization in immature lungs. Therefore, this study provides novel insights regarding the involvement of furin in BPD pathogenesis, and highlights a potential treatment target for ameliorating the impact of BPD.

A New Quantitative Triage System for Hospitalized Neonates to Assist with Decisions of Hospital Evacuation Priorities.

INTRODUCTION: Hospitalized neonates are vulnerable to natural and man-made disasters because of their persistent requirement for medical resources and may need to be evacuated to safe locations when electricity and medical gas supply become unreliable. In Japan, a triage system for hospitalized neonates, or the Simple Triage and Rapid Treatment for Neonates, Revised (START-Neo-R), has been used to determine whether neonates are in suitable conditions for transportation. However, this scale is not useful to determine the evacuation order of neonates because a considerable number of evacuees are classified into the same categories. STUDY OBJECTIVE: To solve this problem, a novel triage system, Neonatal Extrication Triage (NEXT) was developed. This study tested the validity and reproducibility of both triages and compared them with a standardized prognostic scoring system for hospitalized neonates, the Neonatal Therapeutic Intervention Scoring System (NTISS). METHODS: In this retrospective observational study, physicians and nurses independently assessed each neonate hospitalized at a tertiary neonatal intensive care unit (NICU) twice weekly using NEXT and START-Neo-R. The NEXT system comprises six questionnaires regarding medical resources required during transition and transportation, providing composite scores on a 12-point scale. The START-Neo-R classified neonates into five levels based on the severity of disease and dependence on medical care. Inter-rater reliability of both systems was assessed using Cohen's kappa coefficient, whereas the criterion validity with NTISS was assessed using Spearman's correlation coefficient. RESULTS: Overall, 162 neonates were assessed for 49 days, resulting in triage data for 1,079 accumulated patients. Both NEXT scores and START-Neo-R ranks were well-dispersed across different levels without excessive accumulation in specific categories. Inter-rater reliability of NEXT (kappa coefficient, 0.973; 95% confidence interval, 0.969-0.976) and START-Neo-R (kappa coefficient, 0.952; 95% confidence interval, 0.946-0.957) between physicians and nurses was sufficiently high. The correlation coefficient of NEXT and START-Neo-R scores with NTISS scores were 0.889 (P <.001) and 0.850 (P <.001), respectively. CONCLUSIONS: Both START-Neo-R and NEXT had good reproducibility and correlation with the severity of neonates indicated by NTISS. With its well-dispersed scores across different levels, the NEXT system might be a powerful tool to determine the priority of evacuation objectively.

Validation of actigraphy in hospitalised newborn infants using video polysomnography.

Actigraphy has been established as a reliable sleep assessment tool in adults; however, its utility in newborns remains unknown. Validation of actigraphy in newborns may provide a significant insight into the physiological and pathological acquisition process of mature diurnal sleep patterns and subsequent morbidities in both newborns and their mothers. Thus, the present study aimed to evaluate the accuracy of sleep-wake detection by overnight actigraphy in a cohort of newborns. Simultaneous recording of polysomnography and actigraphy data was performed in 40 newborns admitted to a tertiary neonatal intensive care unit (NICU). A mixed-effects logistic regression model to explain the sleep state identified by polysomnography was employed using the actigraphic activity score as a fixed independent variable and the individual newborn's identity as a random effect. To evaluate the usefulness of the actigraphic activity score as a surrogate marker of sleep, a receiver operating characteristic (ROC) curve analysis was performed using the variables that were used in the mixed-effects logistic regression model, and the area under the curve (AUC) was assessed. The results showed that polysomnography-determined sleep epochs were associated with a smaller activity index on actigraphy (odds ratio per 10 activity indices increase 0.81, 95% confidence interval [CI] 0.79-0.84). The AUC for the ROC curve was 0.87 (95% CI 0.87-0.88, range 0.54-0.99). An activity score of 124 showed the maximum overall accuracy (90.2%, 95% CI 87.7-92.1). Our present study suggests that sleep-wake states of NICU-hospitalised newborns can be precisely determined using actigraphy on the ankle.

Temporal inversion of the acid-base equilibrium in newborns: an observational study.

BACKGROUND: A considerable fraction of newborn infants experience hypoxia-ischaemia and metabolic acidosis at birth. However, little is known regarding the biological response of newborn infants to the pH drift from the physiological equilibrium. The aim of this study was to investigate the relationship between the pH drift at birth and postnatal acid-base regulation in newborn infants. METHODS: Clinical information of 200 spontaneously breathing newborn infants hospitalised at a neonatal intensive care centre were reviewed. Clinical variables associated with venous blood pH on days 5-7 were assessed. RESULTS: The higher blood pH on days 5-7 were explained by lower cord blood pH (-0.131, -0.210 to -0.052; regression coefficient, 95% confidence interval), greater gestational age (0.004, 0.002 to 0.005) and lower partial pressure of carbon dioxide on days 5-7 (-0.005, -0.006 to -0.004) (adjusted for sex, postnatal age and lactate on days 5-7). CONCLUSION: In relatively stable newborn infants, blood pH drift from the physiological equilibrium at birth might trigger a system, which reverts and over-corrects blood pH within the first week of life. Given that the infants within the study cohort was spontaneously breathing, the observed phenomenon might be a common reaction of newborn infants to pH changes at birth.

Promoting sound development of preterm infants in the name of developmental neuroscience: Beyond advanced life support and neuroprotection.

Despite the increased survival opportunities for extremely preterm infants, their long-term cognitive outcomes remain poor, with increased incidence of cognitive impairments in childhood and reduced opportunities to attend higher education in young adulthood compared to their term-born peers. Given that a considerable fraction of preterm infants develop cognitive impairments even without apparent sentinel events at birth and cerebral lesions on MRI assessed at term equivalent age, future strategies to improve the outcome may need to address cerebral dysfunction, which cannot be explained by the classical understanding of the injury cascade triggered by hypoxia-ischaemia around birth. Developmental care has been proposed to minimize neurodevelopmental impairments related to preterm birth. However, considerable modes of cares, environmental settings and procedures provided by the developmental care of current style appear to offer little benefit to the sound development of infants. Although it is obvious that advanced life support and neuroprotective treatments fall far short in compensating for the burden of preterm birth, researchers need to make further effort to fill the knowledge gap in the cerebral function of foetuses and newborn infants before establishing evidence-based developmental care. Clinicians need to develop an ability to translate the findings from basic and translational studies incorporating their potential biases and limitations. Care for newborn infants needs to be reassessed, including but not limited to developmental care, in the context that any sensory input and motor reaction of preterm infants may ultimately affect their cognitive functioning.