Role of nocturnal rostral fluid shift in the pathogenesis of obstructive and central sleep apnoea

Abstract

Obstructive sleep apnoea (OSA) is common in the general population and increases the risk of motor vehicle accidents due to hypersomnolence from sleep disruption, and risk of cardiovascular diseases owing to repetitive hypoxia, sympathetic nervous system activation, and systemic inflammation. In contrast, central sleep apnoea (CSA) is rare in the general population. Although their pathogenesis is multifactorial, the prevalence of both OSA and CSA is increased in patients with fluid retaining states, especially heart failure, where they are associated with increased mortality risk. This observation suggests that fluid retention may contribute to the pathogenesis of both OSA and CSA. According to this hypothesis, during the day fluid accumulates in the intravascular and interstitial spaces of the legs due to gravity, and upon lying down at night redistributes rostrally, again owing to gravity. Some of this fluid may accumulate in the neck, increasing tissue pressure and causing the upper airway to narrow, thereby increasing its collapsibility and predisposing to OSA. In heart failure patients, with increased rostral fluid shift, fluid may additionally accumulate in the lungs, provoking hyperventilation and hypocapnia, driving P CO 2 below the apnoea threshold, leading to CSA. This review article will explore mechanisms by which overnight rostral fluid shift, and its prevention, can contribute to the pathogenesis and therapy of sleep apnoea.

Risk of obstructive sleep apnea and hemodialysis efficacy

“…Volume overload and night time rostral fluid shift have been suggested as the pathogenic mechanisms for the high prevalence of OSA in HD patients (17). Our study reproduced the results of other studies in terms of high prevalence of OSA risk in HD patients (3,(18)(19)(20).…”

Elevated Body Position Early after Delivery Increased Airway Size during Wakefulness, and Decreased Apnea Hypopnea Index in a Woman with Pregnancy Related Sleep Apnea

“…1,9 We here present a noninvasive, low-technology treatment alternative for pregnancy-related OSA during the early post-partum period: elevated body position. The underlying mechanism may include beneficial effects on pharyngeal tissue edema and rostral fluid shift similar to those observed in patients with heart failure 10 and an increase in functional residual capacity and endexpiratory lung volume. 9 Thus elevated body posture may be an effective, inexpensive, and easy treatment for pregnancyrelated OSA and should be the subject of further investigation.…”

Night-to-night Variability in Obstructive Sleep Apnea Severity: Relationship to Overnight Rostral Fluid Shift

“…6 In non-obese men, men with heart failure and in hypertensive patients, there are strong relationships between the AHI and the amount of fl uid moving out from the legs overnight and with the overnight increase in neck circumference. [7][8][9] Diuretics have been shown to reduce the AHI in hypertensive patients with OSA in proportion to the reduction in the amount of fl uid shifting out of the legs overnight.…”

“…4 During the daytime, fl uid accumulates in the interstitial and intravascular spaces of the legs due to gravity, and on lying down at night, fl uid shifts rostrally towards the neck, where it may narrow the upper airway, predisposing to upper airway collapse and OSA. 6 In non-obese men, men with heart failure and in hypertensive patients, there are strong relationships between the AHI and the amount of fl uid moving out from the legs overnight and with the overnight increase in neck circumference. [7][8][9] Diuretics have been shown to reduce the AHI in hypertensive patients with OSA in proportion to the reduction in the amount of fl uid shifting out of the legs overnight.…”