Online measurement of hemodialysis adequacy using effective ionic dialysance of sodium-A review of its principles, applications, benefits, and risks
Dialysis dose is an important determinant of clinical outcomes in patients with end stage renal disease on maintenance dialysis. In clinical practice dialysis dose is monitored at least monthly by urea clearance based on Urea Kinetic Modeling. Online clearance monitoring using effective ionic dialysance (EID) of sodium (Na+) is available on some hemodialysis machines. This paper reviews the background, methodology, additional applications, and potential risks associated with EID. Effective ionic dialysance provides a reliable, real-time, noninvasive, and inexpensive measurement of dialysis dose during an ongoing hemodialysis (HD) session to allow interventions and assess the impact of these changes on clearance. Surveillance of vascular access flow rates can be used to screen for access dysfunction and refer for interventions. There is a concern that EID measurements may cause Na+ loading because of high dialysate Na+ used during these measurements, however, mathematical models, in vitro experiments, and clinical studies in patients on maintenance HD do not show any evidence of Na+ loading during EID measurements. We cannot rule out the possibility of nonosmotic Na+ accumulation in the skin because no published literature exists on this topic as it pertains to clearance measurements based on EID of Na+.