Significance of nitrogen removal mass in uremic patients on different modalities of dialysis therapy.
OBJECTIVE
While most nephrologists use Kt/V values for dialysis prescriptions, some researchers are beginning to view the role of solute removal mass as an indicator of adequate dialysis. This study, using nitrogen as a surrogate for solute removal, probed whether solute removal mass can be used as the target of adequate dialysis. Mathematical formulas for easy bedside calculation of nitrogen removal mass were used to avoid the problems associated with direct measurement.


METHODS
The weekly removal mass of urea nitrogen (M) and the urea generation rate (G) of 32 conventional hemodialysis (HD) and 21 continuous ambulatory peritoneal dialysis (CAPD) patients were calculated. All the patients were anuric, clinically stable, and under adequate dialysis pursuant to either the criterion of the urea index, Kt/V, or clinical requirements.


RESULTS
The difference in MHD (MHD = 41.9 +/- 9.5 g/week, MCAPD = 38.8 +/- 11.9 g/week) and G (GHD = 3.90 +/- 1.02 mg/min, GCAPD = 3.85 +/- 1.21 mg/min) between the two groups was statistically insignificant (p = 0.119 and p = 0.868, respectively). When protein nitrogen leaking through the peritoneal membrane was considered and added to MCAPD, nitrogen removal in CAPD patients (M'CAPD = 42.3 +/- 13.0 g/week) approached that in HD patients (p = 0.886). There was no correlation between dialysis dosage and urea removal mass in either the CAPD or HD groups.


CONCLUSIONS
Urea nitrogen removal mass is similar to the protein catabolic rate (PCR) in stable patients. It is meaningful in dialysis evaluation only when it is used simultaneously with blood urea nitrogen measurement. However, because M changes at the inception of dialysis, it more significant than PCR in the evaluation of unstable patients.
Chen
T W
TW
Department of Medicine, Taipei Veterans General Hospital, Taiwan.
Huang
T P
TP
Wang
M L
ML
D000328:Adult; D000368:Aged; D001806:Blood Urea Nitrogen; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000378:metabolism*; D010531:Peritoneal Dialysis, Continuous Ambulatory; D006435:Renal Dialysis; D014508:Urea / Q000378:metabolism*; D014511:Uremia / Q000378:metabolism* / Q000628:therapy
D014508:Urea; D009584:Nitrogen