Polysomnographic findings in 320 infants evaluated for apneic events

Management and outcomes of obstructive sleep apnea in infants

OBJECTIVE

To characterize the clinical characteristics of infants with obstructive sleep apnea (OSA), define the resolution rate of infant OSA, and identify factors associated with OSA resolution.

METHODS

We identified infants diagnosed with OSA via retrospective chart review at less than one year of age at a tertiary care center. We identified patient comorbidities, flexible or rigid airway evaluations, surgical procedures, and oxygen/other respiratory support administration. We identified infants as having resolved OSA based on clinical or polysomnogram resolution. We compared the frequency of comorbid diagnoses and receipt of interventions in infants with resolved versus non-resolved OSA by χ² analysis.

RESULTS

83 patients were included. Prematurity was found in 35/83 (42%), hypotonia-related diagnoses in 31/83 (37%), and craniofacial abnormalities in 34/83 (41%). Resolution was observed in 61/83 (74%), either clinically or by polysomnogram, during follow up. On χ² analysis, surgical intervention was not associated with likelihood of resolution (73% versus 74% in those without surgical intervention, p = 0.98). Patients with airway abnormalities on flexible or rigid evaluation were less likely to have OSA resolution than those without (63% versus 100%, p = 0.010), as were patients with hypotonia-related diagnoses (58% versus 83%, p = 0.014). In patients with laryngomalacia, there was no association of supraglottoplasty with increased resolution (88% with supraglottoplasty versus 80% without, p = 1.00).

CONCLUSIONS

We identified a group of infants with OSA with diverse comorbidities. There was a high rate of resolution. This data can assist with treatment planning and family counselling for infants with OSA. A prospective clinical trial is needed to better assess consequences of OSA in this age.

Developmental respiratory physiology

Various developmental aspects of respiratory physiology put infants and young children at an increased risk of respiratory failure, which is associated with a higher rate of critical incidents during anesthesia. The immaturity of control of breathing in infants is reflected by prolonged central apneas and periodic breathing, and an increased risk of apneas after anesthesia. The physiology of the pediatric upper and lower airways is characterized by a higher flow resistance and airway collapsibility. The increased chest wall compliance and reduced gas exchange surface of the lungs reduce the pulmonary oxygen reserve vis-à-vis a higher metabolic oxygen demand, which causes more rapid oxygen desaturation when ventilation is compromised. This review describes the various developmental aspects of respiratory physiology and summarizes anesthetic implications.

ERS statement on obstructive sleep disordered breathing in 1- to 23-month-old children

The present statement was produced by a European Respiratory Society Task Force to summarise the evidence and current practice on the diagnosis and management of obstructive sleep disordered breathing (SDB) in children aged 1-23 months. A systematic literature search was completed and 159 articles were summarised to answer clinically relevant questions. SDB is suspected when symptoms or abnormalities related to upper airway obstruction are identified. Morbidity (pulmonary hypertension, growth delay, behavioural problems) and coexisting conditions (feeding difficulties, recurrent otitis media) may be present. SDB severity is measured objectively, preferably by polysomnography, or alternatively polygraphy or nocturnal oximetry. Children with apparent upper airway obstruction during wakefulness, those with abnormal sleep study in combination with SDB symptoms (e.g. snoring) and/or conditions predisposing to SDB (e.g. mandibular hypoplasia) as well as children with SDB and complex conditions (e.g. Down syndrome, Prader-Willi syndrome) will benefit from treatment. Adenotonsillectomy and continuous positive airway pressure are the most frequently used treatment measures along with interventions targeting specific conditions (e.g. supraglottoplasty for laryngomalacia or nasopharyngeal airway for mandibular hypoplasia). Hence, obstructive SDB in children aged 1-23 months is a multifactorial disorder that requires objective assessment and treatment of all underlying abnormalities that contribute to upper airway obstruction during sleep.

Sleep disordered breathing in bronchopulmonary dysplasia

BACKGROUND

There are limited data on the effect of bronchopulmonary dysplasia (BPD) on sleep disordered breathing (SDB). We hypothesized that both the severity of prematurity and BPD would increase the likelihood of SDB in early childhood. Our secondary aim was to evaluate the association of demographic factors on the development of SDB.

METHODS

This is a retrospective study of patient factors and overnight polysomnogram (PSG) data of children enrolled in our BPD registry between 2008 and 2015. Association between PSG results and studied variables was assessed using multiple linear regression analysis.

RESULTS

One-hundred-forty children underwent at least one sleep study on room air. The mean respiratory disturbance index (RDI) was elevated at 9.9 events/hr (SD: 10.1). The mean obstructive apnea-hypopnea index (OAHI) was 6.5 (9.1) events/hr and the mean central event rate of 3.0 (3.7) events/hr. RDI had decreased by 22% or 1.5 events/hour (95%CI: 0.6, 1.9) with each year of age (P = 0.005). Subjects with more severe respiratory disease had 38% more central events (P = 0.02). Infants exposed to secondhand smoke had 2.4% lower (P = 0.04) oxygen saturation nadirs and a pattern for more desaturation events. Non-white subjects were found to have 33% higher OAHI (P = 0.05), while white subjects had a 61% higher rate of central events (P < 0.001).

CONCLUSIONS

RDI was elevated in a selected BPD population compared to norms for non-preterm children. BPD severity, smoke exposure, and race may augment the severity of SDB. RDI improved with age but was still elevated by age 4, suggesting that this population is at risk for the sequelae of SDB.

Apnea in the Otherwise Healthy, Term Newborn: National Prevalence and Utilization during the Birth Hospitalization

OBJECTIVES

To describe the prevalence of apnea in otherwise healthy term newborns, identify attributable length of stay (LOS) and healthcare utilization (cost) of apnea, and measure hospital variation in attributable LOS and cost of apnea in this population.

STUDY DESIGN

We conducted a secondary analysis of a national administrative dataset, the 2012 Kids' Inpatient Database, which included 3.4 million newborn discharges in the US. The birth hospitalizations of approximately 2.6 million otherwise healthy, full-term newborns were included for analysis. Attributable LOS and cost of apnea were calculated using multivariate analyses.

RESULTS

Apnea was diagnosed in 1 in 1000 healthy full-term newborns. Multivariate analyses showed that newborns with apnea had 0.6 days longer LOS (P < .001) and $483 greater costs (P < .001) compared with healthy term newborns, per birth hospitalization. Newborns diagnosed with apnea plus hypoxia and/or bradycardia had 1.4 days longer LOS (P < .001) and $653 greater costs (P < .001). The attributable LOS and cost attributable to apnea varied between individual hospitals and differed by hospital region.

CONCLUSIONS

Apnea is associated with higher LOS and cost in the newborn hospitalization, with variation in hospital practice. This suggests the need for better comprehension of the underlying physiology and standardization of practice in its management in the term newborn.

Polysomnography for the diagnosis of sleep disordered breathing in children under 2 years of age

OBJECTIVES

To describe clinical polysomnography (PSG) results, sleep physicians' diagnosis, and treatment of sleep disorder breathing in children less than 2 years of age.

STUDY DESIGN

Retrospective clinical chart review at a pediatric tertiary care center, pediatric sleep laboratory.

SUBJECT SELECTION

Children less than 2 years of age who underwent clinical PSG over a 3-year period.

METHODOLOGY

PSG results and physician interpretations were identified for inclusions. Children were excluded if either PSG results or physician interpretations were unavailable for review. Infants were classified in three age groups for comparison: <6 months, 6-12 months, and >12 months.

RESULTS

Matched records were available for 233 PSGs undertaken at a mean age 11.1 ± 7.0 months; 31% were <6 months, 23% were 6-12 months, and 46% were 12-24 months of age. Infants <6 months showed significant differences on sleep parameters and respiratory indicators compared to other groups. Compared to physician sleep disordered breathing (SDB) classification, current pediatric apnea-hypopnea index (AHI)-based SDB severity classification overestimated SDB severity. Age and obstructive-mixed AHI (OMAHI) were most closely associated with physician identification of SDB.

CONCLUSION

Children <6 months of age appear to represent a distinct group with respect to PSG. Experienced sleep physicians appear to incorporate age and respiratory event frequently when determining the presence of SDB. Further information about clinical significance of apnea in infancy is required, assisted by identification of factors that sleep physicians use to identify SDB in children <6 months of age.

Developmental changes in sleep and breathing across infancy and childhood

Sleep and breathing are physiological processes that begin in utero and undergo progressive change. While the major period of change for both sleep and breathing occurs during the months after birth, considered a period of vulnerability, more subtle changes continue to occur throughout childhood. The systems that control sleep and breathing develop separately, but sleep represents an activity state during which breathing and breathing control is significantly altered. Infants and young children may spend up to 12 hours a day sleeping; therefore, the effects of sleep on breathing are fundamental to understanding both processes in childhood. This review summarizes the current literature relevant to understanding the normal development of sleep and breathing across infancy and childhood.

Obstructive sleep apnea in infancy: a 7-year experience at a pediatric sleep center

PURPOSE

To investigate the common indications for polysomnogram (PSG) associated co-morbid conditions, evaluation strategies, treatment options, and outcomes in a series of infants diagnosed with obstructive sleep apnea (OSA) by a PSG.

METHODS

Retrospective chart review of infants who underwent PSG over a 7-year period was done. Infants with PSG diagnosed OSA were included in this study.

RESULTS

A total of 97 infants (59 males, mean age 4.6 months, standard deviation 3.3 months) were diagnosed with OSA (AHI ≥ 1/hr) based on PSG. The most common indication for PSG in infants were excessive snoring (53%) followed by nocturnal desaturations (24%). Associated co-morbid conditions included gastro-esophageal reflux (30%), laryngomalacia (24%), and craniofacial abnormalities (16%). Genetic abnormalities were found in 53%, of which trisomy 21 was the most common. Surgical treatments were employed in 36% and oxygen therapy in 15%. Thirty-eight patients were followed up with a repeat sleep study after a median interval of 8 months (range 1-24 months), of whom 26/38 had resolution of symptoms. Twenty-seven patients (28%) were followed clinically after a mean interval of 5 months of intervention (range, 1-34.5 months), in whom the symptoms resolved in 23/27 patients. Seven patients were deceased at review. Causes of death included status epilepticus, respiratory failure, hepatic failure, kidney failure, or unknown causes.

CONCLUSION

The etiologies of OSA in infants are different when compared to older children. PSG is feasible and a valuable tool in the diagnosis of OSA in infants and may help determine timely and appropriate evaluation and interventions. Clinical improvement in symptoms and resolution of PSG parameters were noted following medical and/or surgical interventions. Prospective studies need to be done to ascertain the long-term outcome of infants diagnosed with OSA to assess the benefits of early intervention on their neurocognitive development.

Resuscitation and auto resuscitation by airway reflexes in animals

Various diseases often result in decompensation requiring resuscitation. In infants moderate hypoxia evokes a compensatory augmented breath - sigh and more severe hypoxia results in a solitary gasp. Progressive asphyxia provokes gasping respiration saving the healthy infant - autoresuscitation by gasping. A neonate with sudden infant death syndrome, however, usually will not survive. Our systematic research in animals indicated that airway reflexes have similar resuscitation potential as gasping respiration. Nasopharyngeal stimulation in cats and most mammals evokes the aspiration reflex, characterized by spasmodic inspiration followed by passive expiration. On the contrary, expiration reflex from the larynx, or cough reflex from the pharynx and lower airways manifest by a forced expiration, which in cough is preceded by deep inspiration. These reflexes of distinct character activate the brainstem rhythm generators for inspiration and expiration strongly, but differently. They secondarily modulate the control mechanisms of various vital functions of the organism. During severe asphyxia the progressive respiratory insufficiency may induce a life-threatening cardio-respiratory failure. The sniff- and gasp-like aspiration reflex and similar spasmodic inspirations, accompanied by strong sympatho-adrenergic activation, can interrupt a severe asphyxia and reverse the developing dangerous cardiovascular and vasomotor dysfunctions, threatening with imminent loss of consciousness and death. During progressive asphyxia the reversal of gradually developing bradycardia and excessive hypotension by airway reflexes starts with reflex tachycardia and vasoconstriction, resulting in prompt hypertensive reaction, followed by renewal of cortical activity and gradual normalization of breathing. A combination of the aspiration reflex supporting venous return and the expiration or cough reflex increasing the cerebral perfusion by strong expirations, provides a powerful resuscitation and autoresuscitation potential, proved in animal experiments. They represent a simple but unique model tested in animal experiments.

Assessing ventilatory control in infants at high risk of sleep disordered breathing: a study of infants with cleft lip and/or palate

Neonatal exposure to intermittent hypoxia results in altered ventilatory response to subsequent hypoxia in animal models. The effect of similar exposure in human infants is unknown. Our objective was to determine the impact of sleep disordered breathing (SDB) in early infancy on ventilatory response in infants. We recruited consecutive infants with cleft lip and/or palate (CL/P) to undergo ventilatory response testing using exposure to a hypoxic (15% O(2) ) gas mixture during sleep. This population is at high risk of SDB because of smaller airway caliber and abnormal palatal muscle attachments predisposing them to airway obstruction of ranging severity from birth. Ventilatory responses were compared between infants with a low apnea-hypopnea index (AHI; AHI < 15 events/hr) and a high AHI (AHI ≥ 15 events/hr). Testing was successfully completed in 22 of 23 infants who underwent testing at 4.4 ± 4.8 months. Infants with high AHI had lower weight z-scores, higher number of oxygen desaturation events during sleep, but similar oxygen saturation (S(p) O(2) ) nadir compared to infants with low AHI. The pattern of ventilatory response to hypoxia differed between the two groups; infants with high AHI had an earlier ventilatory decline and a blunted maximal ventilatory response to hypoxia. Infants with a high AHI use a different strategy to augment ventilation in response to hypoxia; while infants with a low AHI initially increased respiratory rate, tidal volume was the first parameter to increase in infants with high AHI. These results demonstrate that SDB in infancy is associated with altered ventilatory response to hypoxia.

Polysomnographic features in infants with early diagnosis of congenital hypothyroidism

Thyroid hormones play a major role in the maturation process of the brain. Currently, congenital hypothyroidism is detected by mass screening. The impact of this early hormonal deficiency on the organization of the sleep pattern is not known. In this study, the polysomnographic features in children diagnosed with congenital hypothyroidism were analyzed. Children were detected by mass population screening and the hormonal replacement therapy starts immediately. Children's age ranged between 1.5 and 18 months of age. The duration of hormonal treatment before sleep recordings varied between 8 days and 17 months. Children were polysomnographically recorded in the morning, for at least 2h, obtaining more than one sleep cycle. Results showed a high prevalence of females (5/1) in the group studied. A high proportion of infants (43%) displayed central apnea in different degrees (mild, moderate and severe) as well as hypopnea (83%), mainly in subjects around 4 and 8 months of age. The proportion of infants displaying central apnea decreases as age increases. In addition, indeterminate (light) sleep increase and quiet (slow wave) sleep decrease significantly regardless of age and treatment. The percentage of REM sleep correlated positively with the age of the child at the beginning of the treatment, and negatively with their age at the time of the study. These data indicate that congenital hypothyroidism facilitates the presence of central sleep apnea. The decrease of these respiratory alterations correlates with the increase of the hormonal replacement therapy. It seems that sleep respiratory alterations in congenital hypothyroidism are linked to brain maturation processes in which thyroid hormones play a major role.

[Epidemiological characteristics and risk factors for apparent life-threatening events]

INTRODUCTION

To report our experience with a guideline approach for the assessment of apparent life-threatening events (ALTE) in our pediatric emergency departments (PED), to know their incidence, epidemiological characteristics and the yield of laboratory investigations (LI).

PATIENTS AND METHODS

Prospective, case-control study of a guideline approach for infants under age 12 months who suffered an ALTE between 01/06/06 and 31/05/07 and were attended at our PEDs. We ordered LI as a function of the clinical history. All the cases were admitted for a minimum of 12h. We conducted a telephone interview at 12 months.

RESULTS

Fifty ALTE were included, corresponding to an incidence of 5 per thousand live births. The median age was 8.46+/-8.7 weeks. Compared to controls they had significantly more primogenits and previous behavioral abnormalities. Only 13 presented significant abnormalities at examination, and 6 had recurrent ALTE at the PED. LI were abnormal in 41 (82%), but only in 8 cases did they contribute to a secondary diagnosis. There were 29 idiopathic ALTE (58%). Twenty one (42%) had associated conditions, who had smoked significantly more during pregnancy, age older than 12 weeks and abnormalities at examination. Four had recurrence of the episodes: one suffered a sudden infant death syndrome (SIDS). At 12 months the cases had a significantly higher incidence of recurrent vomiting, breath holding spells and weight-psychomotor retardation.

CONCLUSIONS

The ALTE incidence was 5 per thousand live births. Primogenits and/or behavioral abnormalities were most frequent during the first weeks after birth and/or thereafter at 12 months of age. A total of 42% had a related diagnosis: associated with age older than 12 weeks, maternal smoking habits and abnormalities at examination. There was one case of SIDS. Laboratory investigations had a low yield.

Osteopathy may decrease obstructive apnea in infants: a pilot study

Background

Obstructive apnea is a sleep disorder characterized by pauses in breathing during sleep: breathing is interrupted by a physical block to airflow despite effort. The purpose of this study was to test if osteopathy could influence the incidence of obstructive apnea during sleep in infants.

Methods

Thirty-four healthy infants (age: 1.5–4.0 months) were recruited and randomized in two groups; six infants dropped out. The osteopathy treatment group (n = 15 infants) received 2 osteopathic treatments in a period of 2 weeks and a control group (n = 13 infants) received 2 non-specific treatments in the same period of time. The main outcome measure was the change in the number of obstructive apneas measured during an 8-hour polysomnographic recording before and after the two treatment sessions.

Results

The results of the second polysomnographic recordings showed a significant decrease in the number of obstructive apneas in the osteopathy group (p = 0.01, Wilcoxon test), in comparison to the control group showing only a trend suggesting a gradual physiologic decrease of obstructive apneas. However, the difference in the decline of obstructive apneas between the groups after treatment was not significant (p = 0.43).

Conclusion

Osteopathy may have a positive influence on the incidence of obstructive apneas during sleep in infants with a previous history of obstructive apneas as measured by polysomnography. Additional research in this area appears warranted.

Respiratory-swallowing interactions during sleep in premature infants at term

Non-nutritive swallowing occurs frequently during sleep in infants and is vital for fluid clearance and airway protection. Swallowing has also been shown to be associated with prolonged apnea in some clinical populations. What is not known is whether swallowing contributes to apnea or may instead help resolve these clinically significant events. We studied the temporal relationships between swallowing, respiratory pauses and arousal in six preterm infants at term using multi-channel polysomnography and a pharyngeal pressure transducer. Results revealed that swallows occurred more frequently during respiratory pauses and arousal than during control periods. They did not trigger the respiratory pause, however, as most swallows (66%) occurred after respiratory pause onset and were often tightly linked to arousal from sleep. Swallows not associated with respiratory pauses (other than the respiratory inhibition to accommodate swallowing) and arousal occurred consistently during the expiratory phase of the breathing cycle. Results suggest that swallowing and associated arousal serve an airway protective role during sleep and medically stable preterm infants exhibit the mature pattern of respiratory-swallowing coordination by the time they reach term.