Sleep
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To compare the effectiveness of auto-titrating continuous positive airway pressure (APAP) versus conventional continuous positive airway pressure (CPAP) in reducing the apnea-hypopnea index (AHI), reducing the mean airway pressure, improving subjective sleepiness, and improving treatment adherence in patients with obstructive sleep apnea (OSA). ⋯ Compared to standard CPAP, APAP is associated with a reduction in mean pressure. However, APAP and standard CPAP were similar in adherence and their ability to eliminate respiratory events and to improve subjective sleepiness. Given that APAP is more costly than standard CPAP, APAP should not be considered first-line chronic therapy in all patients with OSA. However, APAP may be useful in other situations (eg, home titrations, detection of mouth leak) or in certain subgroups of patients with OSA. Identifying circumstances in which APAP is a definite improvement over CPAP in terms of costs or effects should be the focus of future studies.
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Excessive daytime sleepiness (EDS), as measured by objective criteria, is infrequent in snoring children despite a high prevalence of EDS-related behavioral manifestations. We hypothesized that sleep architecture and arousal indexes may be altered relative to the severity of sleep-disordered breathing (SDB). ⋯ Sleep architecture is not preserved in children with SDB. An algorithm allowing for calculation of sleep propensity and disturbed sleep homeostasis in children who snore is proposed and may be of practical value in the assessment of sleepiness.
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Expiratory changes in pressure: flow ratio during sleep in patients with sleep-disordered breathing.
The size of the upper airway is smallest during sleep, at the end of expiration. This may favor upper-airway collapse in patients with obstructive sleep apnea. In the respiratory cycles preceding obstructive events during sleep, our hypothesis is that upper-airway resistance (UAR) increased earlier during expiration prior to changes occurring during inspiration. ⋯ Increases in the expiratory UAR occurred earlier than during inspiration in the cycles preceding upper-airway collapse in patients with sleep apnea. This finding suggested an important role of the expiratory phase in promoting upper-airway collapse and is in accordance with the inspiratory pharyngeal instability occurring when lowering the expiratory pressure in patients with obstructive sleep apnea.
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To define the clinical and polysomnographic features of a distinct variant of obstructive sleep-disordered breathing that is remarkably mild during rapid eye movement (REM) sleep. ⋯ This variant of sleep apnea may reflect a dominant component of respiratory instability and periodic breathing coupled with upper-airway obstruction. Its existence questions the conventional practice of calculating global respiratory indexes. Besides positive airway pressure, measures to treat periodic breathing may be required.