This study examines the effects of intradialytic parenteral nutrition (IDPN) on muscle growth and blood pressure in patients undergoing chronic hemodialysis.

Rationale: Malnutrition and a negative protein balance are highly prevalent in hemodialysis (HD) patients. In these patients, nutritional status and body composition are closely linked to morbidity, mortality, and quality of life. Muscle wasting in HD patients is the result of poor intake, anabolic resistance and the intradialytic loss of amino acids, leading to a negative protein balance. Intradialytic parenteral nutrition (IDPN) has been shown to reverse this anabolic state in the short term (a single dialysis session) in studies using primed constant infusion of isotope-labeled amino acids. However, such studies were carried out in fasted state, which may significantly overestimate the effect. Moreover, they provide no insight in muscle synthesis over longer periods of time, including the interdialytic interval and across multiple dialysis sessions. The use of deuterated water (2H2O) enables longer-term assessment of muscle protein synthesis in an outpatient setting. The administration of IDPN, due to its volume, may have intradialytic hemodynamic effects, which have not been characterized in previous studies.

Objective: To study the effect of IDPN on muscle protein synthesis in chronic hemodialysis patients and to characterize the hemodynamic effects of IDPN.

Study design: Investigator-initiated intervention study with crossover design.

Study population: Chronic hemodialysis patients aged over 18 years (dialysis vintage over 3 months).

Intervention: IDPN (Olimel N12, Baxter, 1L/session) or regular care without IDPN.

Main study parameters/endpoints: Difference in myofibrillar fractional synthetic rate during a one-week treatment with IDPN versus one control week consisting of regular care.

Data collection: The study includes a maximum of 9 study visits, which will take place during regular hemodialysis sessions. These may include non-invasive measurements such as bioimpedance spectroscopy, measurements of cardiac output, blood sampling (for which venepuncture), three percutaneous muscle biopsies (vastus lateralis), food intake registration, collection of dialysate, handgrip strength and activity levels.

Inclusion Criteria:

• Age above 18 years
• Receiving HD treatment over 3 months
• Receiving HD treatment 3 times per week for at least 4 hours per session
• 24-hour urine production < 100 mL
• Adequate dialysis dose (eKt/V over 1.2)
• AV fistula with blood flow (measured invasively or by Doppler ultrasound) over 750 mL/min

Exclusion Criteria:

• Occurrence of intradialytic hypotension in the last month, defined by systolic blood pressure < 90 mm Hg combined with a nursing intervention
• Hospitalization < 3 months before inclusion
• Active infection or inflammation at randomization
• Use of oral or intravenous corticosteroids
• Incapacitation
• Patients who are not expected to be able to complete the study protocol (e.g., due to a planned kidney transplantation within the planned study time frame)
• Pregnancy
• Use of oral anticoagulants or antiplatelet agents that cannot be safely stopped during the study
• Diabetes mellitus
• AV fistula with recirculation