Obstructive Sleep Apnea Severity and Overnight Body Fluid Shift before and after Hemodialysis

Abstract

Background and objectives Obstructive sleep apnea is associated with significantly increased cardiovascular morbidity and mortality. Fluid overload may promote obstructive sleep apnea in patients with ESRD through an overnight fluid shift from the legs to the neck soft tissues. Body fluid shift and severity of obstructive sleep apnea before and after hemodialysis were compared in patients with ESRD.Design, setting, participants, & measurements Seventeen patients with hemodialysis and moderate to severe obstructive sleep apnea were included. Polysomnographies were performed the night before and after hemodialysis to assess obstructive sleep apnea, and bioimpedance was used to measure fluid overload and leg fluid volume.Results The mean overnight rostral fluid shift was 1.2760.41 L prehemodialysis; it correlated positively with fluid overload volume (r=0.39; P=0.02) and was significantly lower posthemodialysis (0.7860.38 L; P,0.001). There was no significant difference in the mean obstructive apnea-hypopnea index before and after hemodialysis (46.8622.0 versus 42.1618.6 per hour; P=0.21), but obstructive apnea-hypopnea index was significantly lower posthemodialysis (210.1610.8 per hour) in the group of 12 patients, with a concomitant reduction of fluid overload compared with participants without change in fluid overload (obstructive apnea-hypopnea index +8.2616.1 per hour; P,0.01). A lower fluid overload after hemodialysis was significantly correlated (r=0.49; P=0.04) with a lower obstructive apnea-hypopnea index. Fluid overload-assessed by bioimpedance-was the best predictor of the change in obstructive apnea-hypopnea index observed after hemodialysis (standardized r=20.68; P=0.01) in multivariate regression analysis.Conclusions Fluid overload influences overnight rostral fluid shift and obstructive sleep apnea severity in patients with ESRD undergoing intermittent hemodialysis. Although no benefit of hemodialysis on obstructive sleep apnea severity was observed in the whole group, the change in obstructive apnea-hypopnea index was significantly correlated with the change in fluid overload after hemodialysis. Moreover, the subgroup with lower fluid overload posthemodialysis showed a significantly lower obstructive sleep apnea severity, which provides a strong incentive to further study whether optimizing fluid status in patients with obstructive sleep apnea and ESRD will improve the obstructive apnea-hypopnea index.

Sleep disturbance and sleep‐disordered breathing in hemodialysis patients

“…using ODI of 15 as a cutoff point. Ogna et al . further demonstrated that gender was a weak predictor of SDB in the HD population (OR: 0.72; CI: 0.12‐4.20, P >.2) and should not be used to screen for SDB in this population.…”

“…For example, insomnia is more female predominant due to changes in hormones (menstrual cycle or menopause), and SDB is more often found in males due to larger pharyngeal length . In the HD population, gender difference does not correlate to poor sleep quality nor to the presence of SDB . Tada et al .…”

“…In HD patients, the value of BMI is further affected by fluid overload and protein‐energy wasting, whereby excess catabolism of muscle and fat occurs as kidney disease progresses . For this reason, neck circumference (>40 cm) is increasingly recognized as a more predictive factor of SDB in the HD population . In HD patients, an increased neck circumference is positively associated with fluid overload and severity of SDB .…”

“…For this reason, neck circumference (>40 cm) is increasingly recognized as a more predictive factor of SDB in the HD population . In HD patients, an increased neck circumference is positively associated with fluid overload and severity of SDB . Ogna et al .…”

Cardiovascular Disease in Dialysis Patients

“…Lins et al showed that atrial natriuretic peptide concentrations decrease post dialysis in those patients whose BP responded to ultrafiltration [29]. Other reported mechanisms include increased arterial stiffness [30], renin-angiotensin-aldosterone system activation [31], sympathetic hyperactivity [32,33], endothelial dysfunction [34,35], sleep apnoea [36] and use of erythropoiesis-stimulating agents (ESAs) [37,38].…”