Last updated on July 2016

A Study of Sleep Patterns in Patients Performing Nocturnal Home Dialysis Utilising the VIVIA System

Brief description of study

Sleep disorders are common in patients who have chronic kidney disease (CKD). Insomnia is reported in up to 50% of patients treated with hemodialysis compared to 12% of a control population. Restless leg syndrome (RLS) and periodic limb movement disorder (PLM) have been described in 30 to 70% of patients with end stage kidney disease (ESKD). Patients with CKD have also been reported to have a very high prevalence of sleep apnoea disorder. Conventional hemodialysis and peritoneal dialysis do not appear to improve sleep disorders in patients with CKD. Nocturnal hemodialysis (NHD) has recently been developed to dramatically improve biochemical control of uremia in patients with ESKD. There is now convincing clinical and epidemiological evidence that NHD provides superior clinical and survival outcomes when compared to conventional dialysis. Many centers now offer NHD to patients as the premier treatment of kidney failure when live or deceased kidney transplantation is not available. Regimens for NHD vary between centers - in the investigators' programme NHD patients are encouraged to perform eight hours of HD (utilizing the VIVIA system) on 2 of every 3 nights. By so doing, patients receive an average of five nights of dialysis per week and receive forty hours of dialysis treatment. Initial anecdotal experience in the first programme participants suggests that, despite the need for caution when the patient is asleep, patients sleep much better overall while getting NHD then they do while on conventional HD. Furthermore, a dramatic improvement in restless leg syndrome in patients who undertake NHD has been noted. The investigators propose a prospective study in which twenty patients commencing NHD will undergo a formal polysomnogram study in their home prior to switching to NHD. This will be followed by two overnight polysomnogram studies within one month of NHD initiation and will be on two consecutive nights - one during which they perform NHD and one on a dialysis-free night. A further two overnight polysomnogram studies (under similar conditions) will take place six months after commencing NHD. Participants will also complete a number of surveys of perceived sleep quality. In this study the investigators will identify the impact of NHD on sleep quality.

Detailed Study Description

Baseline data will include details of the following: - Cardiovascular disease is defined as an affirmative response to a history of physician diagnosed heart failure, myocardial infarction/heart attack or previous coronary artery bypass/angioplasty. - Lung disease is based on an affirmative answer to diagnosed bronchitis, asthma, or emphysema. - Diabetes will be defined as concurrent use of insulin or oral hypoglycemic agents. - Smoking will be classified as greater than 20 pack lifetime exposure. - Alcohol will be measured by the total number of beer, wine or spirit beverages consume in an average week. - Caffeine exposure will be defined using the number of cups of caffeinated coffee, tea and soft drinks consumed per day. The investigators will look at a variety of objective and subjective measures of sleep quality and daytime function at five different timepoints as described later. Sleep studies will be performed utilising the Weinmann Somnolab 2 system. The investigators have entered into a collaboration with Respiratory Care Ireland who will arrange to meet the participant in their home to install the equipment needed to record and analyse the data. Sleep studies will be performed between 20.00 and 08.00. The tests which the investigators will perform on each patient at 5 different time-points will be overnight polysomography, expired carbon monoxide, inductance plethysmography, pulse oximetery and tibialis anterior electromyography. All variables will be recorded continuously on a computerised data acquisition system and stored for later analysis. The overnight polysomnography will be recorded by 2-channel electroencephalography, electro- oculogram, and submental electromyogram using surface electrodes. Airflow will be detected by monitoring expired carbon monoxide at the nose and mouth through nasal cannulae connected to a carbon dioxide detector. Respiratory effort will be monitored by inductance plethysmography and transducers placed around the chest and abdomen. Arterial oxygen saturation will be monitored by pulse oximetery. Leg movements will be monitored by recording tibialis anterior electromyography from both legs using surface electrodes. Means between the five studies will be compared using Students T test and means between the studies will be compared by one way analysis of variance (ANOVA) with a Bonferroni test to determine significant differences. Correlation between variables will be determined by univariate regression analysis. Data analysis and scoring will be carried out by an experienced sleep scientist blinded to the clinical characteristics and timing of studies. Sleep studies will be scored according to the guidelines developed by Rectschaffen and Kales. Arousals will be identified according to the American Sleep Disorders criteria. All polysomograms will be scored manually according to established criteria by an experienced sleep scientist. An arousal will be defined as an awakening from sleep for 3 to 15 seconds, as evidenced by simmultaneous alpha activity on electroencephalogram, electromyogram activation , and eye movements, Apnea will be defined as absence of airflow for more than 10 seconds. Hypopnea will be defined as a reduction in amplitude of respiratory effort to between 10% to 50% of the sleeping baseline level for more than 10 seconds with or without an associated fall in oxygen saturation. Apneas and hypopneas will be classified as central if the chest wall and abdomen move synchronously, as obstructive if they move paradoxically, and mixed if a central event was terminated by 2 or 3 obstructed breaths. The Apnea-hyponea index will be defined as the number of apneas and hypopneas per hour of sleep. Mean oxygen saturation during sleep will be calculated by averaging the high and low values for each 30-second epoch. Periodic leg movements (PLM) will be defined as 4 or more consecutive, involuntary leg movements during sleep, lasting 0.5 to 5.0 seconds with an intermovement interval of 5 to 90 seconds. Each participant will be asked to keep a detailed diary of their sleep schedule for two weeks before each sleep study. This will include a record of when they retired to bed, fell asleep, got out of bed, number of awakenings and their estimated total sleep time. In addition, the diary will record the consumption of alcohol and caffeinated beverages. Sleep symptoms will be assessed using the sleep habits questionnaire on a 5 point likert scale to the items, such as: "Having trouble falling asleep", "Wake up during the night and have difficulty getting back to sleep", "Wake up too early in the morning and unable to get back to sleep" and "take sleeping pills or other medication to help sleep". Daytime symptoms will be "Unrested during the day" "Overly sleepy", and "Not enough sleep" response options being Never, Rarely (1/month or less), Sometimes (2-4/month), Often (5 -15/month) and Almost Always (16-30/month).

Clinical Study Identifier: NCT02583347


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Claire Kennedy, MB BCh BAO

Beaumont Hospital
Dublin, Ireland
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