**14. Excessive day time sleepiness**

Excessive day time sleepiness (EDS) has been described in dialysis patients. Seventy-seven percent of patients on CAPD reported taking day time naps and 51% reported falling asleep unintentionally (46). The **Multiple Sleep Latency Test** (MSLT) is a sleep disorder diagnostic tool. It is used to measure the time elapsed from the start of a daytime nap period to the first signs of sleep, called **sleep latency**. The test is based on the idea that the sleepier people are, the faster they will fall asleep. The test consists of four or five 20-minute nap opportunities that are scheduled about two hours apart. The test is often performed after an overnight sleep study. During the test, data such as the patient's, EEG, muscle activity, and eye movements are monitored and recorded. The entire test normally takes about 7 hours.In one study, 44 HD patients were studied. Potential subjects with other major chronic conditions or those with medications known to have CNS effects were excluded from the study. In addition, to exclude those with obvious causes of EDS, subjects with a history suggestive of SAS, RLS and PLMD were also excluded. All subjects underwent polysomnography along with MSLT. One third of patients of the subjects had MSLT scores consistent with abnormal sleepiness (mean sleep latency <8min). High AHI was significantly associated with lower MSLT score, but explained only 10% of the variance in MSLT score, suggesting that

Sleep Disorders Associated with Chronic Kidney Disease 395

Day time sleepiness is common in patients with ESRD and patients with CKD not on

Sleep disorders have negative impacts on overall quality of life in patients with kidney

**Blood Urea Nitrogen** (BUN) is the blood test used to measure nitrogen in the form of Urea, which is the by product from protein metabolism produced in liver and removed by kidney **Dialysate**-the fluid used in dialysis, typically with a lower solute concentration than the

**Hemodialysis**(HD)-a process of removal of fluid and solutes through a semi-permeable membrane into dialysate by passing the blood through an artificial kidney. Hemodialysis is most commonly delivered to patients three times a week for three to four hours (Conventional Hemodialysis-CHD), but may also be given more slowly across the day or

**Nocturnal Hemodialysis** (NHD). Nocturnal hemodialysis or nightly hemodialysis is a form of hemodialysis which is done at home by the patient or a family member when the patient is sleeping at night. Most patients dialyze five to seven nights a week, anywhere from six

**Peritoneal Dialysis** (PD)-the process of removal of fluid and wastes from the body using the

**Continuous Ambulatory Peritoneal Dialysis** (CAPD)-continuous dialysis process that involves infusion of fluid into peritoneum, a prolonged dwell period for dialysis and

**Kt/V** is a way of measuring dialysis adequacy. Kt/V is defined as the dialyzer clearance of urea (**K**, obtained from the manufacturer in mL/min, and periodically measured and verified by the dialysis team) multiplied by the duration of the dialysis treatment (**t**, in minutes) divided by the volume of distribution of urea in the body (**V**, in mL), which is

[1] Walker S, Fine A, Kryger MH. Sleep complaints are common in a dialysis unit. Am J

[2] Pressman MR, Benz RL. High incidence of sleep disorders in end stage renal disease.

[3] Jung, HH, Han, H & Lee, JH: sleep apnea, Coronary artery disease, and antioxidant

[4] Zoccali, C, Mallamci, F, Tripepi, G & Benedetto, FA: Autonomic neuropathy is linked to

nocturnal hypoxemia and to concentric hypertrophy and remodelling in dialysis

status in hemodialysis patients, Am J kidney Dis, 45:875-82, 2005

patients, Nephrol Dial Transplant, 16:70-7, 200

semi-permeable membrane of the peritoneum for the diffusion and osmosis,

drainage. The procedure typically involves four exchanges of fluid daily.

diseases and may affect rehabilitative potential of treatment.

blood, into which metabolic waste and excess electrolytes diffuse.

**16. Glossary of dialysis-related terms** 

night (Nocturnal Hemodialysis-NHD).

to12 hours, on average for eight hours.

approximately equal to the total body water.

Kidney Dis 1995; 26(5): 751±756

Sleep Research 1995; 24: 417.

**17. References** 

dialysis.

additional factors play an important role in the expression of day time sleepiness in this group (65).

Benz etal reported the effects of hematocrit normalization with recombinant erythropoietin on the sleep of 10 HD patients (44). All subjects underwent an initial nocturnal polysomnogram, with seven completing a 40 minutes MWT the next day. Tests were repeated after normalization of hematocrit. Treatment resulted in a significant reduction of nocturnal periodic limb movements and improvement on the MWT.

SAS, RLS and PLMD are prevalent in patients with advanced kidney disease and could explain EDS, but some studies suggested that other factors related to renal disease or its treatment may contribute to EDS (52, 53).

Mild elevations of BUN and creatinine in renal failure patients have been associated with increased slow wave activity in the waking EEG and abnormalities in cognitive function, which may explain the susceptibility of patients with advanced renal disease to sleepiness (54). Elevation of parathyroid hormone has been associated with increased waking EEG slow wave activity in uremic animals and stable dialysis patient (55). The metabolites of creatinine may inhibit GABA responses (in mouse neurons) and may interfere with neurotransmissions necessary for sleep to occur. These changes may destabilize the wakeful state by increasing day time sleepiness propensity and decreasing nocturnal sleep (56).

Treatment with dialysis may also predispose patients to sleepiness. Abnormal production of interleukin-1, TNF-alpha, factor S can increase somnolence (57, 58). Rapid removal of these sleep inducing substances has also been postulated as the cause for fragmented nocturnal sleep and resulting day time sleepiness and fatigue in one study on patients on CAPD (59). Dialysis also results in rapid change in electrolytes, acid base balance and serum osmolarity which may decrease arousal and alertness (60). Treatment with dialysis may also disrupt the circadian pattern sleepiness due to inappropriately timed elevation of serum melatonin in response to the hemoconcentration (61) or from change in rhythm of body temperature (62). Medications such as antihypertensive and antidepressants may also contribute to the EDS in CKD patients.
