Central sleep apnea more common in dialysis patients

There is another form of sleep apnea that is more common in dialysis patients than in healthy people. It is called central sleep apnea and is caused by the center in the brain stem that controls breathing. For unknown reasons this center does not give enough signals for breathing during the sleep of somebody who suffers from this form of sleep apnea. With either form of sleep apnea, the sleep is interrupted so often during the night that a restful sleep is impossible, causing fatigue and weariness during the day. Sleep apnea also increases the blood pressure, which might be one of the reasons why people who suffer from sleep apnea have a high risk for developing cardiovascular problems and for dying from heart attacks and strokes.

Some scientists believe that dialysis patients have an increased risk for developing both central and obstructive sleep apnea because they have higher blood levels of urea than healthy people. Urea is a waste product of the protein metabolism that is cleared by the kidney in healthy people and by dialysis in patients with end stage kidney disease. In the light of the recent study that showed a significantly increased risk of dialysis patients to die from a heart attack, if they experienced chronic fatigue and weariness, sleeping problems, in particular sleep apnea should not be taken lightly. Appropriate dialysis to reduce urea levels in the blood and treatment of obstructive sleep with devices that keep the airway open might therefore do more for the patients than improving quality of life by decreasing weariness and fatigue and increasing cognitive functioning. These treatments might actually save the life of the patient.

Another sleeping problem commonly found in dialysis patients

Another sleeping problem commonly found in dialysis patients that is also associated with increased cardiovascular risk is restless leg syndrome. Restless leg syndrome is a condition in which the patient feels pin pricks, or sensations like having fire ants in the legs that force the patient to constantly move the legs. A restful night of sleep is impossible. Again elevated blood urea levels might be a factor in the development of this condition, and its frequent association with sleep apnea might be the reason why this condition is also a sign of an increased risk of heart attacks.

Anemia can be another reason why there is a relation between fatigue, weariness and heart attack in dialysis patients, as anemia can not only severely impact the quality of life, but also the capacity to exercise. Anemia is common in dialysis patient as the diseased kidney is not able to produce enough erythropoietin, a hormone that enables the body to build red blood cells and hemoglobin, the protein that makes our blood red and transports oxygen from the lungs to the tissues. Different studies have shown that treatment of dialysis patients with erythropoietin shots can have a positive impact on the patient’s quality of life, capacity to exercise, and, together with regular exercise, improve overall and cardiovascular health. However, if too much erythropoietin is given, it can increase the patient’s risk for strokes. Scientists, however, disagree about how much erythropoietin is too much. Healthy people have about 12-14g of hemoglobin in every deciliter of blood. Dialysis patients who have not received erythropoietin shots often have hemoglobin values in the range of 6-7 g/dl. It has been shown that increasing hemoglobin level in dialysis patient to about 10g/dl significantly improves the overall health of the patient as well as the quality of life and the patients self assessment. However, whether further increasing the hemoglobin level from 10g/dl to normal levels between 12 and 14 g/dl further improves exercise capacity and quality of life and whether this improvement outweighs the increased risk for strokes, is highly controversial.