Multichannel esophageal signals to monitor respiratory rate in preterm infants

Background Apnea of prematurity cannot be reliably measured with current monitoring techniques. Instead, indirect parameters such as oxygen desaturation or bradycardia are captured. We propose a Kalman filter-based detection of respiration activity and hence apnea using multichannel esophageal signals in neonatal intensive care unit patients. Methods We performed a single-center observational study with moderately preterm infants. Commercially available nasogastric feeding tubes containing multiple electrodes were used to capture signals with customized software. Multichannel esophageal raw signals were manually annotated, processed using extended Kalman filter, and compared with standard monitoring data including chest impedance to measure respiration activity. Results Out of a total of 405.4 h captured signals in 13 infants, 100 episodes of drop in oxygen saturation or heart rate were examined. Median (interquartile range) difference in respiratory rate was 0.04 (−2.45 to 1.48)/min between esophageal measurements annotated manually and with Kalman filter and −3.51 (−7.05 to −1.33)/min when compared to standard monitoring, suggesting an underestimation of respiratory rate when using the latter. Conclusions Kalman filter-based estimation of respiratory activity using multichannel esophageal signals is safe and feasible and results in respiratory rate closer to visual annotation than that derived from chest impedance of standard monitoring.

Preterm disparities between foreign and Swedish born mothers depend on the method used to estimate gestational age. A Swedish population-based register study

This study aims to examine whether disparities in gestational age outcomes between foreign and Swedish-born mothers are contingent on the measure used to estimate gestational age and, if so, to identify which maternal factors are associated with the discrepancy. Using population register data, we studied all singleton live births in Sweden from 1992–2012 (n = 1,317,265). Multinomial logistic regression was performed to compare gestational age outcomes classified into very (<32 weeks) and late preterm (32–36 weeks), term and post-term derived from the last menstrual period (LMP) and ultrasound estimates in foreign- and Swedish-born women. Compared to Swedish-born women, foreign-born women had similar odds of very preterm birth (OR: 0.98 [95% CI: 0.98, 1.01]) and lower odds of moderately preterm birth (OR: 0.95 [95% CI: 0.92, 0.98]) based on ultrasound, while higher risks based on LMP (respectively, OR: 1.10 [95% CI: 1.07, 1.14] and 1.09 [95% CI: 1.06, 1.13]). Conclusions on disparities in gestational age-related outcomes by mother’s country of origin depend on the method used to estimate gestational age. Except for very preterm, foreign-born women had a health advantage when gestational age is based on ultrasound, but a health disadvantage when based on LMP. Studies assessing disparities in very preterm birth by migration status are not affected by the estimation method but caution should be taken when interpreting disparities in moderately preterm and preterm birth rates.

Prematurity and postnatal alterations in intermittent hypoxaemia

Intermittent hypoxaemia (IH) events are well described in extremely preterm infants, but the occurrence of IH patterns in more mature preterm infants remains unclear. The objective of this study was to characterise the effect of gestational age on early postnatal patterns of IH in extremely (<28 weeks), very (28–<32 weeks) and moderately (32–<34 weeks) preterm infants. As expected, extremely preterm infants had a significantly higher frequency of IH events of longer durations and greater time with hypoxaemia versus very and moderately preterm infants. In addition, the postnatal decrease in IH duration was comparable in the very and moderately preterm infants. This progression of IH events should assist clinicians and families in managing expectations for resolution of IH events during early postnatal life.

Moderately and Late Preterm Infants: Short- and Long-Term Outcomes From a Registry-Based Cohort

Background: While most studies on the association of preterm birth and cerebral palsy (CP) have focused on very preterm infants, lately, attention has been paid to moderately preterm [32 to &lt;34 weeks gestational age (GA)] and late preterm infants (34 to &lt;37 weeks GA).Methods: In order to report on the outcomes of a cohort of moderately and late preterm infants, derived from a population-based CP Registry, a comparative analysis of data on 95 moderately preterm infants and 96 late preterm infants out of 1,016 with CP, was performed.Results: Moderately preterm neonates with CP were more likely to have a history of N-ICU admission (p = 0.001) and require respiratory support (p &lt; 0.001) than late preterm neonates. Birth weight was significantly related to early neonatal outcome with children with lower birth weight being more likely to have a history of N-ICU admission [moderately preterm infants (p = 0.006)/late preterm infants (p &lt; 0.001)], to require ventilator support [moderately preterm infants (p = 0.025)/late preterm infants (p = 0.014)] and not to have neonatal seizures [moderately preterm infants (p = 0.044)/late preterm infants (p = 0.263)]. In both subgroups, the majority of children had bilateral spastic CP with moderately preterm infants being more likely to have bilateral spastic CP and less likely to have ataxic CP as compared to late preterm infants (p = 0.006). The prevailing imaging findings were white matter lesions in both subgroups, with statistically significant difference between moderately preterm infants who required ventilator support and mainly presented with this type of lesion vs. those who did not and presented with gray matter lesions, maldevelopments or miscellaneous findings. Gross motor function was also assessed in both subgroups without significant difference. Among late preterm infants, those who needed N-ICU admission and ventilator support as neonates achieved worse fine motor outcomes than those who did not.Conclusions: Low birth weight is associated with early neonatal problems in both moderately and late preterm infants with CP. The majority of children had bilateral spastic CP and white matter lesions in neuroimaging. GMFCS levels were comparable in both subgroups while BFMF was worse in late preterm infants with a history of N-ICU admission and ventilator support.

Renal morphology and glomerular capillarisation in young adult sheep born moderately preterm

Preterm birth (delivery <37 weeks of gestation) is associated with impaired glomerular capillary growth in neonates; if this persists, it may be a contributing factor in the increased risk of hypertension and chronic kidney disease in people born preterm. Therefore, in this study, we aimed to determine the long-term impact of preterm birth on renal morphology, in adult sheep. Singleton male sheep were delivered moderately preterm at 132 days (~0.9) of gestation (n = 6) or at term (147 days gestation; n = 6) and euthanised at 14.5 months of age (early adulthood). Stereological methods were used to determine mean renal corpuscle and glomerular volumes, and glomerular capillary length and surface area, in the outer, mid and inner regions of the renal cortex. Glomerulosclerosis and interstitial collagen levels were assessed histologically. By 14.5 months of age, there was no difference between the term and preterm sheep in body or kidney weight. Renal corpuscle volume was significantly larger in the preterm sheep than the term sheep, with the preterm sheep exhibiting enlarged Bowman’s spaces; however, there was no difference in glomerular volume between groups, with no impact of preterm birth on capillary length or surface area per glomerulus. There was also no difference in interstitial collagen levels or glomerulosclerosis index between groups. Findings suggest that moderate preterm birth does not adversely affect glomerular structure in early adulthood. The enlarged Bowman’s space in the renal corpuscles of the preterm sheep kidneys, however, is of concern and merits further research into its cause and functional consequences.

Parenting Behavior at 18 Months Predicts Internalizing and Externalizing Problems at 6 Years in Moderately Preterm and Full Term Children

Moderately preterm born children (MPT) are at increased risk for behavior problems compared to full term born (FT) children. MPT children may receive less optimal parenting, and in response, may develop behavior problems. Our aims were to examine whether parenting behavior and mother–child interaction quality mediate the association between birth status and child behavior problems. Participants were 120 MPT children and 100 FT children. At 18 months of age, mothers reported on their parenting behavior (support and structure), and mother–child interaction (sensitivity and limit-setting) was observed. At 6 years of age, mothers reported on children’s behavior problems. Using structural equation modeling, birth status was found to predict attention problems, but not internalizing and externalizing problems. Mothers of MPT children set less appropriate limits than mothers of FT children at 18 months of age. More maternal structure at 18 months predicted fewer internalizing and externalizing problems, but not attention problems, at 6 years. These associations between parenting behavior, mother–child interaction quality, and child behavior problems were similar for MPT and FT children. Our findings indicate that maternal structure in toddlerhood is an important predictor of later internalizing and externalizing problems for both MPT and FT children.

Right ventricular morphology and function analysis in moderately preterm-born young adults

Background Previous studies have shown that prematurity leads to altered right ventricular (RV) geometry and performance with persistent impairments in RV systolic function in young adulthood. It is unknown to what extent pulmonary physiology impacts these findings. Purpose To better quantify known alterations in RV morphology and function in preterm-born young adults and to determine to what extent these changes are influenced by the pulmonary circulation. Methods A total of 101 normotensive preterm-born (n=47, mean gestational age 32.8±3.2 weeks) and term-born (n=54) young adults were recruited. Echocardiography and cardiovascular magnetic resonance (CMR) imaging were performed to characterise RV morphology, RV function, pulmonary hemodynamics and RV-pulmonary arterial vascular (PA) coupling. CMR cine images were used to create a 3D computational atlas of the RV geometry and principal component analysis was undertaken to identify the key modes of shape variation. Spirometry was performed to assess lung function. Results RV CMR revealed a higher absolute and indexed RV mass (P&lt;0.05) and lower ejection fraction (54.90±5.17 versus 57.48±4.39%, P=0.008) in young adults born preterm. RV end-diastolic areas and volumes for CMR and echocardiography were lower in preterm-born compared to term-born young adults (P≤0.001). Principal component analysis of the computational atlas defined the anatomical modes of the RV geometry, with mode 1 accounting for 25.3% of the population variance. Preterm and term cohorts showed significant differences (P&lt;0.001) in mode 1, which represented a smaller and shorter RV cavity in the preterm group (Figure 1). Measurements of RV function by echocardiography, including RV fractional area of change (FAC) and tricuspid annular plane systolic excursion (TAPSE), were lower in preterm-born compared to term-born adults (P&lt;0.05). Despite lower pulmonary artery acceleration times (PAAT) in those born preterm (141.1±15.1 versus 159.2±21.6msec, P&lt;0.001), indicating increased pulmonary vascular resistance, the RV remained coupled to its pulmonary circulation (TAPSE/PAAT: 0.13±0.02 versus 0.14±0.03m/sec, P=0.153). Reduced RV performance in preterm-born individuals remained significant when adjusting for pulmonary function parameters (P&lt;0.05). Conclusions Multimodality cardiac imaging demonstrated that moderately preterm-born young adults exhibit structural and functional RV alterations, independent of lung physiology. Their RV remains hemodynamically coupled to its pulmonary circulation despite higher RV afterload, lower RV function and altered morphology. Figure 1. Statistical shape model of the RV Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Toddlers’ Language Development: The Gradual Effect of Gestational Age, Attention Capacities, and Maternal Sensitivity

Language development in toddlerhood forms the foundation for speech and language comprehension throughout childhood. Children born moderately preterm are at increased risk for problems in receptive and expressive language functioning, and they may need specific support or interventions. To understand the underlying mechanisms of language development, an integrated model of gestational age, attention capacities, and maternal sensitivity was examined in relation to receptive and expressive language functioning in toddlerhood. Our sample included 221 children (gestational age between 32–41 + 6 weeks; 54.7% born moderately preterm; 51.6% boys; 69.1% highly educated mothers). At 18 months (corrected age), attention capacities were measured using an eye-tracking procedure and maternal sensitivity was observed during mother-child interaction. Language was assessed at 24 months (corrected age). Results showed children with a higher gestational age scored higher on receptive language. This association was direct, as well as indirect through the child’s alerting attention. Expressive language was related to maternal sensitivity. Gestational age and alerting attention capacities specifically were related to language comprehension, whereas maternal sensitivity was related to speech. As language comprehension and speech in toddlerhood show different associations with biological, child, contextual, and regulation factors, they should be viewed as separate constructs in research and practice.