title: Urea Rebound Assessment Based on UV Absorbance in Spent Dialysate.
abstract: The aim of the study was to examine the possibility of postdialysis urea rebound assessment using UV-absorbance measurements in spent dialysate. Twenty-six patients on chronic three-times-a-week hemodialysis (HD) were studied in two separate studies. Double-beam spectrophotometer was used for the determination of UV absorbance in the collected spent dialysate samples. Also, on-line UV absorbance was monitored. The equilibrium concentration (C(eq)) of urea at the end of the rebound phase was calculated based on urea concentration in blood and dialysate and UV absorbance in spent dialysate. Based on C(eq), urea rebound was expressed relative to urea concentration at the end of HD (R1) and relative to the decrease in urea concentration during HD (R2). Estimates based on UV-absorbance values in spent dialysate (R(1_a), R(2_a)) slightly over assess postdialysis rebound compared with results based on the blood sample drawn 30 min after HD (R(1_30post), R(2_30post)), but R(1_a) and R(2_a) presented greater consistency and accuracy compared with the estimates based on the intradialytic blood sample (R(1_b), R(2_b)). In summary, the results show that it is possible to assess postdialysis urea rebound in blood based on UV-absorbance measurements in spent dialysate.
authors.affiliation: From the *Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia; and †Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University, and Department of Nephrology UHL, County Council of Östergötland, Linköping, Sweden.
authors.forename: Ruth
authors.initials: R
authors.lastname: Tomson
authors.forename: Fredrik
authors.initials: F
authors.lastname: Uhlin
authors.forename: Ivo
authors.initials: I
authors.lastname: Fridolin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015314:Dialysis Solutions / Q000032:analysis / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014508:Urea / Q000097:blood*; D055815:Young Adult
chemical_list: D015314:Dialysis Solutions; D014508:Urea