Urea removal during continuous hemodiafiltration.
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.
Frankenfield
D C
DC
Department of Nutrition, RA Cowley Shock Trauma Center, Baltimore, MD 21201.
Reynolds
H N
HN
Wiles
C E
CE
Badellino
M M
MM
Siegel
J H
JH
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
D000596:Amino Acids; D003404:Creatinine