Aging is associated with increased propensity for central apnea during NREM sleep

Abstract

The reason for increased sleep-disordered breathing with predominance of central apneas in the elderly is unknown. We hypothesized that the propensity to central apneas is increased in older adults, manifested by a reduced carbon-dioxide (CO) reserve in older compared with young adults during non-rapid eye movement sleep. Ten elderly and 15 young healthy adults underwent multiple brief trials of nasal noninvasive positive pressure ventilation during stable NREM sleep. Cessation of mechanical ventilation (MV) resulted in hypocapnic central apnea or hypopnea. The CO reserve was defined as the difference in end-tidal CO ([Formula: see text]) between eupnea and the apneic threshold, where the apneic threshold was [Formula: see text] that demarcated the central apnea closest to the eupneic [Formula: see text]. For each MV trial, the hypocapnic ventilatory response (controller gain) was measured as the change in minute ventilation (V̇e) during the MV trial for a corresponding change in [Formula: see text]. The eupneic [Formula: see text] was significantly lower in elderly vs. young adults. Compared with young adults, the elderly had a significantly reduced CO reserve (-2.6 ± 0.4 vs. -4.1 ± 0.4 mmHg, P = 0.01) and a higher controller gain (2.3 ± 0.2 vs. 1.4 ± 0.2 l·min·mmHg, P = 0.007), indicating increased chemoresponsiveness in the elderly. Thus elderly adults are more prone to hypocapnic central apneas owing to increased hypocapnic chemoresponsiveness during NREM sleep. NEW & NOTEWORTHY The study describes an original finding where healthy older adults compared with healthy young adults demonstrated increased breathing instability during non-rapid eye movement sleep, as suggested by a smaller carbon dioxide reserve and a higher controller gain. The findings may explain the increased propensity for central apneas in elderly adults during sleep and potentially guide the development of pathophysiology-defined personalized therapies for sleep apnea in the elderly.

Natural History of REM-OSA in Children and Its Associations with Adverse Blood Pressure Outcomes: A Longitudinal Follow-Up Study

“…The arousal indexes were also generally higher at 10-year follow-up than baseline in all OSA subtypes, which was consistent with previous findings of decreasing arousal threshold with increasing age. 42 Similarly, the changes in ventilatory control during sleep with aging have not been fully elucidated. As there is an increasing prevalence of SDB and central apneas in the elderly, it is postulated that the stability in ventilatory control decreases with aging.…”

“…The arousal indexes were also generally higher at 10-year follow-up than baseline in all OSA subtypes, which was consistent with previous findings of decreasing arousal threshold with increasing age. 42 Similarly, the changes in ventilatory control during sleep with aging have not been However, studies have demonstrated contrasting results in this aspect that some reported an increase in loop gain in the elderly 42 while others did not. 43 Further studies are needed to evaluate how the ontogenetic variations in the endotypes, including airway collapsibility, arousal threshold, and ventilatory control, influence the patterns of occurrence of disordered breathing in different sleep stages across age groups.…”

Obstructive Sleep Apnea in Elderly

“…Predominantly central apneas are common in the elderly due to increased breathing instability during non-REM sleep, as suggested by a lower carbon dioxide reserve and a higher controller gain (6). Despite the pharyngeal muscle function and the size of the airway lumen being reduced in elderly people, an increase in arousal frequency due to aging causes hyperventilation and hypocapnia, which promote respiratory instability (7). These two studies of Chowduri et al were both contrary to our study while in our study oxygen saturation values of the elderly were not significantly different from the younger OSA patients.…”

Treatment-Emergent Central Apnea

“…For example, increased controller gain may explain increased propensity to central apnea in men vs premenopausal women, 14 and in older adults compared with young and middle-aged adults. 15 Likewise, patients with OSA also exhibit a higher propensity to induced central apnea, and higher loop gain, compared with healthy matched adults. 13 Interestingly, PAP therapy for 4 weeks is associated with decreased controller gain and widening of the CO 2 reserve.…”