Abstract

ALDUNCIN, José et al. Problemas respiratorios durante el sueño en lactantes nativos del altiplano argentino. Arch. argent. pediatr. [online]. 2005, vol.103, n.1, pp.14-22. ISSN 0325-0075.

Introduction. During medical visits to San Antonio de los Cobres, Salta, we noticed an increased rate of sudden unexpected postneonatal infant deaths, an average rate of 13 cases per thousand per annum between 1996 and 2001, with no postmortem studies. Taking into account that altitude is a risk factor for sudden infant death syndrome, and that at least 20% of sudden unexpected death of infants may be attributed to this syndrome, we considered describing the respiratory events during sleep of healthy infants from 1 to 6 months of age, who were native residents at this altitude, in relation to chronic exposure to hypobaric hypoxia. Population, materials and methods. Study design: cross sectional, descriptive and observational study including 12 infants recruited from the local urban population, studied with polysomnographic and pulse oximetry recordings at an altitude of 3,775 m above sea level. Inclusion criteria: children between the ages of 1 and 6 months, native and stable residents in the area. Exclusion criteria: gestational age below 36 weeks, clinically evident malnutrition, fever, recent history of upper or low respiratory tract infections, neurological disease, craniofacial malformations and congenital cardiopathies. Statistical analysis: anthropometric data were expressed as medians and ranges, and events occurring during sleep, as means ± SD and ranges. Results. There were occasional significant decreases in SaO2 during sleep, as well as associated to central or obstructive apneas and periodic breathing in all infants, with a minimum average of 67%. We found no changes in cardiac frequency in polysomnographic records during maximal hypoxemic events. Conclusion. All the studies differed from normal standards for children at sea level. There was an increased number of arousals compared to normal values, but not in the magnitude that might be expected in subjects with chronic hypobaric hypoxia when compared with normal sea level values. We found poor variability in the cardiac autonomic response to the marked hypoxemic events during sleep.

Keywords : High altitude; Hypobaric hypoxia; Cardiorrespiratory events during sleep; Arousals; Sudden unexpected death of infants; Sudden infant death syndrome; Hypoxic ventilatory response.

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