Alleviation of Sleep Apnea in Patients with Chronic Renal Failure by Nocturnal Cycler–Assisted Peritoneal Dialysis Compared with Conventional Continuous Ambulatory Peritoneal Dialysis

Abstract

Nocturnal hemodialysis has been shown to improve sleep apnea in patients who receive conventional hemodialysis. It was hypothesized that nocturnal peritoneal dialysis (NPD) also is effective in correcting sleep apnea in patients who receive continuous ambulatory PD (CAPD). Overnight polysomnography (PSG) was performed in 46 stable NPD and CAPD patients who were matched for demographic and clinical attributes. The prevalence of sleep apnea, defined as an apnea-hypopnea index (AHI; or frequency of apnea and hypopnea per hour of sleep) >15, was 52% for NPD patients and 91% for CAPD patients (P ‫؍‬ 0.007). The mean (؎SD) AHI in NPD and CAPD patients was 31.6 ؎ 25.6 and 50.9 ؎ 26.4 (P ‫؍‬ 0.025), respectively. For validation of the efficacy of NPD in alleviating sleep apnea, a fixed sequence intervention study was performed in which 24 incident PD patients underwent one PSG study during mandatory cycler-assisted NPD while awaiting their turn for CAPD training and a second PSG recording shortly after they were established on stable CAPD. The prevalence of sleep apnea was 4.2% during NPD and 33.3% during CAPD (P ‫؍‬ 0.016). AHI increased from 3.4 ؎ 1.34 during NPD to 14.0 ؎ 3.46 during CAPD (P < 0.001). With the use of bioelectrical impedance analysis, total body water content was significantly lower during stable NPD than CAPD (32.8 ؎ 7.37 versus 35.1 ؎ 7.35 L; P ‫؍‬ 0.004). NPD delivered greater reductions in total body water (؊2.81 ؎ 0.45 versus ؊1.34 ؎ 0.3 L; P ‫؍‬ 0.015) and hydration fraction (؊3.63 ؎ 0.64 versus ؊0.71 ؎ 0.52%; P ‫؍‬ 0.005) during sleep. Pulmonary function tests remained unchanged before and after conversion from NPD to CAPD. These findings suggest that NPD may have a therapeutic edge over CAPD in sleep apnea that is associated with renal failure as a result of better fluid clearance during sleep.

Improvement in Sleep Apnea during Nocturnal Peritoneal Dialysis Is Associated with Reduced Airway Congestion and Better Uremic Clearance

“…The PSG data in 24 incident PD subjects and body water composition data in 15 of these 24 subjects during NPD and CAPD were reported previously (12). Here, we extended these data by recruiting another 22 incident patients to undergo PSG and magnetic resonance imaging (MRI) of the upper airway during NPD and CAPD.…”

“…Nevertheless, time-averaged intraperitoneal pressure may be higher during CAPD than during NPD because of the permanent load of peritoneal dialysate during the night in CAPD. Theoretically, this may have two effects: (1) changes in respiratory mechanics, such as reduction in vital capacity (27), although recent studies showed that sleep apnea is unrelated to pulmonary function measurements [12,28] and that flow-volume curve indices have no value in predicting sleep apnea (29); (2) more pressure effect on the diaphragm. To maintain the same tidal volume, a more negative intrathoracic pressure has to be generated, which may cause arousal and airway collapsibility, which could in turn lead to sleep apnea.…”

“…All measurements were made with the patient in the euvolemic state, i.e., after the patients' condition had become stabilized while they were undergoing a particular mode of PD. Formulas for deriving body water compositions were described in our recent report (12).…”

“…Recently, we also reported improvement of sleep apnea by nocturnal cycler-assisted peritoneal dialysis (NPD) compared with conventional continuous ambulatory peritoneal dialysis (CAPD) (12) through better fluid clearance during sleep. However, a direct proof of whether a reduction in total body water (TBW) content would alleviate airway occlusion is still lacking.…”

Sleep Apnea and Cardiovascular Disease

“…309 Recent data support the concept that nocturnal peritoneal dialysis is superior to chronic ambulatory peritoneal dialysis in attenuating sleep apnea as a result of better fluid clearance during sleep. 311 …”