Normal values for respiratory sleep polygraphy in children aged 4 to 9 years at 2,560 m above sea level

Prevalence of pulmonary hypertension in children with obstructive sleep apnea living at high altitude

Introduction

The prevalence of obstructive sleep apnea (OSA) is 1-4 %. Some reports describe its association with pulmonary hypertension (PH), but its prevalence is unknown. No studies at high altitude have determined the relationship between OSA and PH. The aim of this study was to establish the prevalence of PH in children diagnosed with OSA living in a high-altitude city at 2640 m above sea level.

Methods

Children between 2 and 16 years of age referred to the Sleep Laboratory of the Fundación Neumológica Colombiana in Bogotá with a positive polysomnogram for OSA were included, and a two-dimensional transthoracic echocardiogram (TTE) was performed to evaluate PH. Statistical analysis was performed using median, interquartile range, chi-squared test, and Kruskall-Wallis test.

Results

Of the 55 patients (n: 55), 63.6 % were male, with a median age of 6 years, 14 children (25.5 %) were overweight; 12 children (21.8 %) had mild OSA, 12 (21.8 %) had moderate OSA and 31 (56.4 %) severe OSA. In patients with severe OSA, the minimum saturation during events was 78 % with a desaturation index (DI) of 33.8/hour (p < 0.01). T90 and T85 increased proportionally with OSA severity (p < 0.05). Of the 55 patients with OSA, none had PH according to echocardiography; 4 patients (7.2 %) had pulmonary artery systolic pressure (PASP) at the upper limit of normal (ULN), and it was not related to a higher body mass index (BMI).

Conclusions

We found no association between OSA and PH in children with OSA at high altitude.

The Brain at High Altitude: From Molecular Signaling to Cognitive Performance

The brain requires over one-fifth of the total body oxygen demand for normal functioning. At high altitude (HA), the lower atmospheric oxygen pressure inevitably challenges the brain, affecting voluntary spatial attention, cognitive processing, and attention speed after short-term, long-term, or lifespan exposure. Molecular responses to HA are controlled mainly by hypoxia-inducible factors. This review aims to summarize the cellular, metabolic, and functional alterations in the brain at HA with a focus on the role of hypoxia-inducible factors in controlling the hypoxic ventilatory response, neuronal survival, metabolism, neurogenesis, synaptogenesis, and plasticity.

Sleep problems in low income, urban pediatric populations living at different altitudes in Colombia

OBJECTIVE

To determine the frequency of sleep problems in low-income, urban pediatric populations in cities at different altitudes in Colombia.

METHODS

A descriptive, cross-sectional population-based observational study was conducted in children aged between 2 and 12 years in the low income, urban areas of three cities in Colombia (Santa Marta, Bucaramanga, and Bogotá) located at 15, 959, and 2640 m above sea level, respectively. Sociodemographic data were collected, and the Spanish version of the Pediatric Sleep Questionnaire was used.

RESULTS

1989 children were surveyed, distributed as follows: Santa Marta (32.0%), Bucaramanga (33.4%), and Bogotá (34.6%). The overall prevalence of sleep problems was 39.0%. Children from Santa Marta had the highest frequency of parasomnias (58.0%); those from Bucaramanga had the highest frequency of attention deficit symptoms (4.0%) and apneic pauses witnessed by parents or caregivers (5.7%). Finally, Bogotá, the only high-altitude location, had the highest frequency of sleep disordered breathing (17.2%).

CONCLUSIONS

The study found a high frequency of sleep problems in the pediatric population, especially at higher altitudes when compared to lower altitude settings. Sleep disorders warrant early detection and timely therapeutic intervention.

Recent advances in paediatric sleep disordered breathing

This article reviews the latest evidence pertaining to childhood sleep disordered breathing (SDB), which is associated with negative neurobehavioural, cardiovascular and growth outcomes. Polysomnography is the accepted gold standard for diagnosing SDB but is expensive and limited to specialist centres. Simpler tests such as cardiorespiratory polygraphy and pulse oximetry are probably sufficient for diagnosing obstructive sleep apnoea (OSA) in typically developing children, and new data-processing techniques may improve their accuracy. Adenotonsillectomy is the first-line treatment for OSA, with recent evidence showing that intracapsular tonsillectomy results in lower rates of adverse events than traditional techniques. Anti-inflammatory medication and positive airway pressure respiratory support are not always suitable or successful, although weight loss and hypoglossal nerve stimulation may help in select comorbid conditions.

Educational aims

To understand the clinical impact of childhood sleep disordered breathing (SDB).To understand that, while sleep laboratory polysomnography has been the gold standard for diagnosis of SDB, other diagnostic techniques exist with their own benefits and limitations.To recognise that adenotonsillectomy and positive pressure respiratory support are the mainstays of treating childhood SDB, but different approaches may be indicated in certain patient groups.

Breathing Patterns and Oxygenation Saturation During Sleep in Children Habitually Living at High Altitude in the Andes: A Systematic Review

BACKGROUND

Human respiratory physiology changes significantly in high altitude settings and these changes are particularly marked during sleep. It is estimated that 170 million people live above 2,500 m in environments where normal sleep parameters differ from those established at sea level or low altitude.

METHODS

We conducted a systematic review of publications reporting sleep studies in healthy children living at high altitude. For this purpose, data from PubMed, EMBASE, SciELO and Epistemomikos bases were retrieved up to August 2021.

RESULTS

Six articles met specified inclusion criteria; all reporting data were from South America involving 245 children (404 sleep studies) in children aged 0.6 months to 18 years, at altitudes between 2,560 to 3,775 m. The main results were: (1) Central apnea index decreased as the age increased. (2) The obstructive apnea/hypopnea index showed a bimodal profile with an increase in young infants up to age of 4 months, decreasing to 15 months of age, and then a second peak in children aged 4 to 9 years of age, dropping in older schoolchildren and adolescents. (3) Periodic breathing in the first months of life is more marked with increasing altitude and decreases with age.

CONCLUSIONS

There are few studies of sleep physiology in children living at high altitude. The international parameters defining normal apnea indices currently used at low altitude cannot be applied to high altitude settings. The interpretation of sleep studies in children living at high altitude is complex because there are important developmental changes across childhood and a wide range of altitude locations. More normative data are required to determine thresholds for respiratory pathology at a variety of high altitude settings.