Effect of Hemodialysis on Upper Airways Collapsibility in Patients With Chronic Kidney Disease

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.

Chronic kidney disease patients undergoing hemodialysis will be recruited consecutively and screened for eligibility using a standardised protocol.

Daytime haemodialysis was standardised. It was performed 3 times per week, with a 4-h session duration, 250-mL/min blood flow, and 500-mL/min dialysate flow, using bicarbonate buffered dialysate with 1.25 mmol/L ionised calcium concentration, dialysate temperature of 36.5°C. The ultrafiltration amount for each haemodialysis session was decided by individual dry weight, which was fixed during the trial. In addition, the patients were not permitted to change their medication or start new drugs, especially antiplatelet agents, angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, calcium-channel blockers, and β-blockers. The patients who required a change in medication for medical reasons were subsequently excluded from the study.

Degree of upper airway collapsibility through the negative expiratory pressure test in patients with chronic kidney disease on hemodialysis.

To assess the effects of dialysis on sleep parameters and determine the prevalence and severity of sleep disorders.

Lung function tests will be performed during the day, with the patient seated in a comfortable position. For such, the KoKo PFT Spirometer System version 4.11 (nSpire Health, Inc, Louisville, CO, USA) will be used in accordance with the guidelines for the execution of lung function tests established by the Brazilian Society of Pneumology and European Respiratory Society.

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;