Sleep related breathing disorders and indications for polysomnography in preterm infants

Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease, associated with premature birth, that arises during the infantile period. It is an evolving disease process with an unchanged incidence due to advancements in neonatal care which allow for the survival of premature infants of lower gestational ages and birth weights. Currently, there are few effective interventions to prevent BPD. However, careful attention to BPD phenotypes and comprehensive care provided by an interdisciplinary team have improved care. Interventions early in the disease course hold promise for improving long-term survival and outcomes in adulthood for this high-risk population.

Sleep as a driver of pre- and postnatal brain development

In 1966, Howard Roffwarg proposed the ontogenic sleep hypothesis, relating neural plasticity and development to rapid eye movement (REM) sleep, a hypothesis that current fetal and neonatal sleep research is still exploring. Recently, technological advances have enabled researchers to automatically quantify neonatal sleep architecture, which has caused a resurgence of research in this field as attempts are made to further elucidate the important role of sleep in pre- and postnatal brain development. This article will review our current understanding of the role of sleep as a driver of brain development and identify possible areas for future research. IMPACT: The evidence to date suggests that Roffwarg's ontogenesis hypothesis of sleep and brain development is correct. A better understanding of the relationship between sleep and the development of functional connectivity is needed. Reliable, non-invasive tools to assess sleep in the NICU and at home need to be tested in a real-world environment and the best way to promote healthy sleep needs to be understood before clinical trials promoting and optimizing sleep quality in neonates could be undertaken.

Respiratory polygraphy in children with bronchopulmonary dysplasia: a retrospective study

BACKGROUND

Periodic assessment of the need for oxygen supplementation and/or mechanical ventilation in children with severe bronchopulmonary dysplasia (BPD) is crucial. The aim of the study was to analyze the indications and results of respiratory polygraphies (RP) performed in preterm infants with BPD followed at a tertiary university hospital.

METHODS

All subjects <5-year-old with BPD who had a RP between September and February 2018 were included. The indications and results of RP and consequent medical management were analyzed.

RESULTS

Fourteen infants (9 females, mean gestational age 27.6±3.3 weeks) underwent a RP at mean age of 26.4±19.4 months. Five subjects were evaluated for the need of long-term respiratory support (RS), 3 started continuous positive airway pressure (CPAP), 2 were weaned from RS. Four subjects underwent RP for suspected obstructive sleep apnea (OSA), one started on CPAP. Central apnea syndrome (CSA) was confirmed in 2 subjects and one was started on non-invasive ventilation. RP allowed safe tracheostomy decannulation in 2 subjects. Finally, RP was normal in one subject who had a brief resolved unexplained event.

CONCLUSIONS

RP represents an important tool for the evaluation of children with BPD and leads to important therapeutic decisions.

Assessment of obstructive sleep apnoea in children: What are the challenges we face?

There is an increasing demand for the assessment of sleep-disordered breathing in children of all ages to prevent the deleterious neurocognitive and behaviour consequences of the under-diagnosis and under-treatment of obstructive sleep apnoea [OSA]. OSA can be considered in three broad categories based on predominating contributory features: OSA type 1 [enlarged tonsils and adenoids], type II [Obesity] and type III [craniofacial abnormalities, syndromal, storage diseases and neuromuscular conditions]. The reality is that sleep questionnaires or calculations of body mass index in isolation are poorly predictive of OSA in individuals. Globally, the access to testing in tertiary referral centres is comprehensively overwhelmed by the demand and financial cost. This has prompted the need for better awareness and focussed history taking, matched with simpler tools with acceptable accuracy used in the setting of likely OSA. Consequently, we present key indications for polysomnography and present scalable, existing alternatives for assessment of OSA in the hospital or home setting, using polygraphy, oximetry or contactless sleep monitoring.

What Are the Factors Affecting Total Sleep Time During Video Polysomnography in Infants?

OBJECTIVE

The aim of the study is to investigate factors affecting total sleep time (TST) during infant polysomnography (PSG) and assess if <4 hours of TST is sufficient for accurate interpretation.

STUDY DESIGN

Overall, 242 PSGs performed in 194 infants <6 months of chronological age between March 2013 and December 2015 were reviewed to identify factors that affect TST, including age of infant, location and timing of study, presence of medical complexity, and presence of nasal tubes. A continuum of apnea-hypopnea index (AHI) in relation to TST was reviewed. Data were examined in infants who had TST <4 hours and low AHI.

RESULTS

Greater TST (p < 0.001) was noted among infants during nocturnal PSGs, at older chronological and post-menstrual ages, and without medical complexity. The presence of nasogastric/impedance probes reduced TST (p = 0.002). Elevated AHIs were identified even in PSGs with TST <4 hours. Short TST may have affected interpretation and delayed initial management in one infant without any inadvertent complications.

CONCLUSION

Clinical factors such as PMA and medical complexity, and potentially modifiable factors such as time of day and location of study appeared to affect TST during infant PSGs. TST < 4 hours can be sufficient to identify high AHI allowing physician interpretation.

KEY POINTS

· Less than 4 hours of TST is enough for interpretation of infant polysomnography.. · Shorter TST appears related to infant age, medical complexity, and higher apnea-hypopnea index.. · Modifiable factors seen with higher TST were time of day, environment, and presence of nasal tubes..

The Impact of Preterm Birth on Sleep through Infancy, Childhood and Adolescence and Its Implications

There is emergent literature on the relationship between the development of sleep-wake cycles, sleep architecture, and sleep duration during the neonatal period on neurodevelopmental outcomes among children born preterm. There is also a growing literature on techniques to assess sleep staging in preterm neonates using either EEG methods or heart and respiration rate. Upon discharge from hospital, sleep in children born preterm has been assessed using parent report, actigraphy, and polysomnography. This review describes the ontogeny and measurement of sleep in the neonatal period, the current evidence on the impact of preterm birth on sleep both in the NICU and in childhood and adolescence, and the interaction between sleep, cognition, and social-emotional outcomes in this population.

Weaning oxygen in infants with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease commonly seen in preterm infants as the sequelae following respiratory distress syndrome. The management of evolving BPD aims to minimise lung injury and prevent the impact of hypoxia and hyperoxia. Proposed morbidities include respiratory instability, pulmonary hypertension, suboptimal growth, altered cerebral oxygenation and long-term neurodevelopmental impairment. The ongoing management and associated morbidity present a significant burden for carers and healthcare systems. Long-term oxygen therapy may be required for variable duration, though there is a lack of consensus and wide variation in practise when weaning supplemental oxygen. Furthermore, a shift in care towards earlier discharge and community care underlines the importance of a structured discharge and weaning process that eliminates the potential risks associated with hypoxia and hyperoxia. This review article describes recent evidence outlining oxygen saturation reference ranges in young infants, on which structured guidance can be based.

The relationship between preterm birth and sleep in children at school age: A systematic review

Premature birth (before 37 weeks of gestation) has been linked to a variety of adverse neurological outcomes. Sleep problems are associated with decreased neurocognitive functioning, which is especially common in children born preterm. The exact relationship between prematurity and sleep at school age is unknown. A systematic review is performed with the aim to assess the relationship between prematurity and sleep at school age (5th to 18th year of life), in comparison to sleep of their peers born full-term. Of 347 possibly eligible studies, nine were included. The overall conclusion is that prematurity is associated with earlier bedtimes and a lower sleep quality, in particular more nocturnal awakenings and more non-rapid eye movement stage 2 sleep. Interpretations and limitations of the review are discussed. Moreover, suggestions for future research are brought forward, including the need for a systematic approach with consistent outcome measures in this field of research. A better understanding of the mechanisms that influence sleep in the vulnerable group of children born preterm could help optimize these children's behavioral and intellectual development.

Retrospective analysis of inpatient polysomnogram characteristics and discharge outcomes in infants with bronchopulmonary dysplasia requiring home oxygen therapy

RATIONALE

Little is known about the polysomnogram (PSG) characteristics in infants with bronchopulmonary dysplasia (BPD), especially severe BPD, who do not need home ventilatory support but are at increased risk for chronic hypoxia and are vulnerable to its effects.

OBJECTIVE

This study aims to assess PSG characteristics and change in discharge outcomes in premature infants with BPD who required oxygen therapy at discharge.

METHODS

This is a retrospective chart review of premature infants with BPD who were admitted to a quaternary newborn and infant intensive care unit from January 1, 2012 to December 31, 2015 and who underwent polysomnography before discharge.

MEASUREMENTS AND MAIN RESULTS

Data from 127 patients were analyzed. The median gestational age of our patients was 26 weeks and 1 day (interquartile range [IQR]: 24.71, 28.86). The majority of the patients had moderate-to-severe BPD. The median obstructive apnea-hypopnea index was 5.3 events/h (IQR: 2.2, 10.1). The median oxygen desaturation index was 15.7 events/h (IQR: 4.7, 35). Nadir oxygen saturation measured by pulse oximeter was 81% (IQR: 76-86) and the arousal/awakening index was 21.9 (IQR: 13.3-30.9). No statistically significant difference was noted between severe and nonsevere BPD groups for PSG characteristics. However, average end-tidal CO₂ was significantly higher in the severe BPD group (p = .0438). Infants in the severe BPD group were intubated longer than infants with nonsevere BPD (p = .0082). The corrected gestational age (CGA) at the time of discharge (CGA-PSG) and PSG (CGA-DC) was higher in severe BPD patients but not statistically different. The majority of premature infants who underwent a PSG were discharged home with oxygen, and 69% required a titration of their level of support based on results from the PSG.

CONCLUSION

Our results highlight the presence of abnormal PSG characteristics in BPD patients, as early as 43 weeks CGA. These findings have not been previously described in this patient population prior to initial discharge from the hospital. A severe BPD phenotype tends to be associated with higher respiratory morbidity compared with a nonsevere BPD phenotype for the comparable CGA. PSG, when available, may be helpful for individualizing and streamlining treatment in preparation for discharge home and mitigating the effects of intermittent hypoxic episodes.

Behavioral-state development and sleep-state differentiation during early ontogenesis

Sleep is a key process in neurodevelopment and essential for the maturation of fundamental brain functions. Premature birth can disturb the initial steps of sleep maturation, which may contribute to the impairment of neurodevelopment. It is thus fundamental to understand the maturation of the various sleep states and the quality of cerebral function in each vigilance state, as well as the development of sleep cyclicity, in at-risk neonatal infants, particularly those born premature. The objective of this review is to provide a precise description of sleep states and cycles and their rhythmic organization in premature and term newborns according to their gestational age. Technical aspects of polysomnography, which requires a high level of expertise in neonates, are also described. Principles of the visual interpretation of polysomnography, including the simultaneous analysis of behavioral (spontaneous motricity and eye movements), polysomnographic parameters (electro-oculogram, electrocardiogram, respiration), and electroencephalography patterns are presented. The neurophysiology of sleep ontogenesis and its interaction with brain maturation are discussed, highlighting the crucial role of sleep states and their duration in premature newborns. In particular, the involvement of myoclonic twitches in functional connectivity in sensorimotor development is discussed. Indeed, sleep quality, determined by combined polysomnographic parameters, reflects either normal or pathological developmental processes during the neonatal period. The fundamental place of neurophysiological explorations in the early detection of sleep disorders is discussed, as well as their potential consequences on neurodevelopmental care to improve the prevention of neurodevelopmental impairment.

Comparison of sleep problems between term and preterm born preschool children

OBJECTIVES

Sleep disorders are common problems among all age groups. If sleep problems detected in childhood are not resolved successfully, they become sleep disorders and a chronic state. In this study, we aimed to compare sleep problems between preterm-born and term-born preschool-age children.

METHODS

In the cross-sectional study, children were grouped according to whether they were born preterm or at term. The preterm group included 137 children aged four to six years. The control group comprised 145 age-matched term-born preschool children. The prenatal, natal, demographical, and clinical characteristics of preterm- and term-born preschool-age children were compared. The Children's Sleep Habits Questionnaire (CSHQ) was used to identify sleep problems. The total score and subscores of the CSHQ were compared between the groups.

RESULTS

The percentage of gastroesophageal reflux (GER) symptoms and obstructive sleep apnea (OSA) symptoms were significantly higher in the preterm group. According to the cutoff point of the CSHQ, 97 children in the preterm group (70.8%) and 88 children in the control group (60.7%) had a sleep disorder. The total score of the CSHQ was significantly higher in the preterm group compared with the control group; however, the scores of the subscales were similar between the groups. In the regression analysis, a significant association was found between being born preterm and having sleep disorder (β = 0.308, OR = 1.36, p = 0.04).

CONCLUSIONS

Our study reported a high percentage of sleep problems in preterm-born preschool children. We suggest that prematurity is associated with sleep problems even if the etiology of sleep problems is heterogeneous. Symptoms regarding GER and OAS should be investigated, and precautions, such as prohibiting maternal cigarette smoking, should be taken in preterm infants.

Evaluation of maturity of sleep states in preterm infants using conventional and amplitude-integrated electroencephalography

OBJECTIVE

To determine whether sleep state maturity can be estimated accurately using conventional electroencephalography (cEEG) or amplitude-integrated electroencephalography (aEEG) features concerning sleep in neurologically unimpaired preterm infants.

METHODS

A total of 51 preterm infants were monitored with cEEG-polygraphy and simultaneous aEEG. Sleep state maturity of EEG corresponded to specific postmenstrual age (PMA). PMA on cEEG was blindly estimated according to cEEG patterns (indicated as background continuity, frequencies, and voltages) as well as developmental markers in specific states. PMA on aEEG was blindly estimated based on the cycling score (cycling representing sleep state transitions) according to a pre-established scoring system.

RESULTS

A total of 51 EEGs recorded between 32 and 37 weeks PMA were analysed. A significant relationship between estimated PMA (ePMA) and actual chronological PMA (cPMA) was shown by linear regression both on cEEG (r = 0.93, β = 0.98, 95% confidence interval (CI) 0.87-1.09, p < 0.001) and aEEG (r = 0.85, β = 0.83, 95% CI 0.69-0.98, p < 0.001). The estimation gap (defined as ePMA minus cPMA) was between -2 and +2 weeks both on cEEG and aEEG. The percentage of estimation gap between -1 and +1 weeks was 96% for cEEG, which was higher than the estimate of 88% for aEEG.

CONCLUSION

Estimated maturity of sleep state was well correlated with cPMA both on cEEG and aEEG. PMA corresponding to state maturity could be estimated within two weeks of actual cPMA using either of these two tools. However, cEEG had higher accuracy compared with aEEG in the evaluation of sleep state maturity.

Newborn Sleep: Patterns, Interventions, and Outcomes

Sleep is a necessary function of life. Fetuses and neonates spend most of their day sleeping, making it paramount to place emphasis on adequate and optimal sleep. As the current body of literature continues to expand, we have increased our understanding of sleep and its role in development. Sleep disturbances, particularly early in life can affect all aspects of health such as neurological development, emotional well-being, and overall growth. This article aims to provide a primer on sleep development from fetal life into the neonatal period, discuss sleep in both the home and hospital settings, explore the tools used to measure sleep, and review common interventions applied to those infants experiencing poor sleep. Lastly, there is a mention of long-term outcomes and how early recognition and implementation of measures could help to improve overall growth and development throughout childhood. [Pediatr Ann. 2020;49(2):e82-e87.].

Non-invasive Ventilation for Children With Chronic Lung Disease

Advances in medical care and supportive care options have contributed to the survival of children with complex disorders, including children with chronic lung disease. By delivering a positive pressure or a volume during the patient's inspiration, NIV is able to reverse nocturnal alveolar hypoventilation in patients who experience hypoventilation during sleep, such as patients with chronic lung disease. Bronchopulmonary dysplasia (BPD) is a common complication of prematurity, and despite significant advances in neonatal care over recent decades its incidence has not diminished. Most affected infants have mild disease and require a short period of oxygen supplementation or respiratory support. However, severely affected infants can become dependent on positive pressure support for a prolonged period. In case of established severe BPD, respiratory support with non-invasive or invasive positive pressure ventilation is required. Patients with cystic fibrosis (CF) and advanced lung disease develop hypoxaemia and hypercapnia during sleep and hypoventilation during sleep usually predates daytime hypercapnia. Hypoxaemia and hypercapnia indicates poor prognosis and prompts referral for lung transplantation. The prevention of respiratory failure during sleep in CF may prolong survival. Long-term oxygen therapy has not been shown to improve survival in people with CF. A Cochrane review on the use NIV in CF concluded that NIV in combination with oxygen therapy improves gas exchange during sleep to a greater extent than oxygen therapy alone in people with moderate to severe CF lung disease. Uncontrolled, non-randomized studies suggest survival benefit with NIV in addition to being an effective bridge to transplantation. Complications of NIV relate mainly to prolonged use of a face or nasal mask which can lead to skin trauma, and neurodevelopmental delay by acting as a physical barrier to social interaction. Another associated risk is pulmonary aspiration caused by vomiting whilst wearing a face mask. Adherence to NIV is one of the major barriers to treatment in children. This article will review the current evidence for indications, adverse effects and long term follow up including adherence to NIV in children with chronic lung disease.

Effects of a supportive care bundle on sleep variables of preterm infants during hospitalization

Sleep is important for preterm infants' brain development, but they are frequently exposed to painful procedures in the neonatal intensive care unit (NICU) that disturb their sleep cycle and affect their growth. The purpose of this study was to examine the prolonged effects of a supportive care bundle (modulation of the infants' states, non-nutritive sucking, facilitated tucking, and oral sucrose feeding) on preterm infants' sleep variables (sleep efficiency, total sleep time, sleep latency, and frequency of wake bouts) during hospitalization. The team recruited 65 preterm infants (gestational age at birth 28-36 weeks, average birth weight 1,652 g) from a Level III NICU at a medical center in Taiwan. Infants were randomly assigned to one of two treatment conditions to be administered while receiving intrusive procedures: (1) control condition (usual care, including routine procedures, positioning, and gentle touch); or (2) intervention condition in which the supportive care bundle was added to usual care. Sleep variables were measured using actigraphy for a baseline of three continuous days on the 6th to 8th days after birth and again for 3 continuous days when infants weighed ≧1,950 g. Two forms of generalized estimating equation analyses with control of significant covariates were used for data analysis. The supportive care bundle not only significantly increased sleep efficiency and total sleep time but also significantly decreased duration of sleep latency and frequency of wake bouts. These results provide evidence to support the incorporation of the supportive care bundle into NICU clinical practice during intrusive procedures.

Sleep Disturbances in Newborns

The purpose of this review is to serve as an introduction to understanding sleep in the fetus, the preterm neonate and the term neonate. Sleep appears to have numerous important roles, particularly in the consolidation of new information. The sleep cycle changes over time, neonates spend the most time in active sleep and have a progressive shortening of active sleep and lengthening of quiet sleep. Additionally, the sleep cycle is disrupted by many things including disease state and environment, and the amplitude integrated EEG can be a useful tool in evaluating sleep, and sleep disturbances, in neonates. Finally, there are protective factors for infant sleep that are still being studied.