title: Urea removal during continuous hemodiafiltration.
abstract: OBJECTIVE
  To compare urea nitrogen removal by continuous hemodiafiltration vs. functional native kidneys in critically ill, septic patients receiving > 2 g of amino acids/kg body weight per day.
  
  
  METHODS
  Prospective, comparative, unblinded study.
  
  
  METHODS
  Trauma critical care units of a Level I adult trauma hospital.
  
  
  METHODS
  Fifteen septic patients with multiple organ failure including renal failure who were receiving continuous hemodiafiltration; 11 septic patients with multiple organ failure without renal failure (control group). Ages of patients ranged from 18 to 60 yrs.
  
  
  METHODS
  Collection of effluent (dialysate + ultrafiltrate) from hemodiafilters. Collection of urine from control patients.
  
  
  METHODS
  Urea nitrogen and creatinine concentrations in blood, urine, and the hemodiafiltration effluent, measured every 24 hrs for 6 days. Effluent and urine volumes were measured.
  
  
  RESULTS
  Hemodiafilters were operational for 21.8 +/- 3.0 hrs/day. Mean urea nitrogen removal in the renal failure group was 28 +/- 10 g/day. Blood urea nitrogen was stable over the 6-day study period. In control subjects, urea nitrogen removal was 27 +/- 9 g/day, which was not significantly different from the continuous hemodiafiltration group. Blood urea nitrogen concentrations in control patients increased over the 6-day study period (p < .05). Urea nitrogen removal correlated moderately well with amino acid intake in the control group (r2 = .30), but not in the continuous hemodiafiltration group (r2 = .0004). In patients receiving continuous hemodiafiltration, effluent volume was most significantly correlated with urea nitrogen removal (r2 = .69).
  
  
  CONCLUSIONS
  The technique of continuous hemodiafiltration can remove substantial amounts of urea nitrogen, similar to that of normal native kidneys. In addition, at amino acid intake rates of > 2 g/kg body weight/day, urea nitrogen removal during continuous hemodiafiltration remains a function of effluent volume, so there is no need to restrict amino acid intake in acute renal failure patients supported with continuous hemodiafiltration.
authors.affiliation: Department of Nutrition, RA Cowley Shock Trauma Center, Baltimore, MD 21201.
authors.forename: D C
authors.initials: DC
authors.lastname: Frankenfield
authors.forename: H N
authors.initials: HN
authors.lastname: Reynolds
authors.forename: C E
authors.initials: CE
authors.lastname: Wiles
authors.forename: M M
authors.initials: MM
authors.lastname: Badellino
authors.forename: J H
authors.initials: JH
authors.lastname: Siegel
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000382:microbiology / Q000628:therapy; D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage; D000704:Analysis of Variance; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D005260:Female; D017583:Hemodiafiltration; D006801:Humans; D007239:Infections / Q000150:complications; D008297:Male; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000097:blood; D011446:Prospective Studies; D012044:Regression Analysis
chemical_list: D000596:Amino Acids; D003404:Creatinine