Introduction: Currently, chronic kidney disease (CKD) is one of the most serious public health problems, becoming a global epidemic. It is also known that the amount of displacement of overnight rostral fluid, from the lower limbs, is related to increased neck circumference and severity of obstructive sleep apnea (OSA) in patients with end-stage renal disease. Method / Design: A clinical trial study aiming to assess the degree of collapsibility of the upper airway in patients with CKD undergoing hemodialysis has been proposed. The test of the negative expiratory pressure and nocturnal polysomnography will be performed before and after the hemodialysis session. Discussion: The incidence of CKD has increased, due to the increased number of cases of diabetes mellitus and hypertension. Our hypothesis is that the weight gain due to volume overload, observed in the interdialytic period, will exert a negative influence on the degree of collapsibility of the upper airways predispose to OSA in CKD patients.

Inclusion Criteria:

• male or female patients aged 18 to 80 years;
• chronic kidney failure;
• candidate for kidney transplant with indication for dialysis;
• cognitive level sufficient for understanding the procedures and following the instructions;
• absence of dementia or treatment-refractory psychiatric diseases leading to an inability to provide informed consent.
• and agreement to participate by signing a statement of informed consent.

Exclusion Criteria:

• craniofacial abnormalities;
• undergoing active treatment of sleep apnea;
• active malignancy;
• active alcohol and/or drug abuse;