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. 2016 Aug 23;4(1):75-78.
doi: 10.1002/ams2.219. eCollection 2017 Jan.

Relationship between nitrogen loss and blood urea nitrogen concentrations in patients requiring continuous renal replacement therapy

Takeaki Sato  1 , Shigeki Kushimoto  2
Affiliations

Relationship between nitrogen loss and blood urea nitrogen concentrations in patients requiring continuous renal replacement therapy

Takeaki Sato et al. Acute Med Surg. .

Abstract

Aim: It is well known that continuous renal replacement therapy (CRRT) produces some amount of nitrogen loss, but there are few tools that are easily applied to measure it. This study aimed to evaluate nitrogen loss using blood urea nitrogen (BUN) measurement in patients receiving CRRT.

Methods: The subjects were 28 patients who received CRRT (except for liver failure) between 2010 and 2012. Nutrition data and nitrogen excretion in dialysate and urine were measured.

Results: The median age of the patients was 61 years, with an Acute Physiology and Chronic Health Evaluation score of 27 points and a Sequential Organ Failure Assessment score of 12 points. All-cause hospital mortality was 50%. Median protein intake was 40 g/day. The daily urinary volume was 245 mL and volume of dialysate was 26,000 mL/day. The median amount of nitrogen loss was 10.58 g/day, with BUN showing a strong correlation (r = 0.804, P < 0.0001). There was a poor relation between protein intake (g/kg body weight) and nitrogen balance (r = 0.322, P = 0.002).

Conclusions: In patients receiving CRRT, the nitrogen loss showed a positive correlation with BUN but not with protein intake. According to the guidelines, recommended protein intake was 1.5-2.0 g/kg/day, but we should be careful to avoid elevating BUN at the same time. The results showed that BUN might be a useful marker to check nitrogen balance in the nutritional management of patients receiving CRRT.

Keywords: Continuous renal replacement therapy; nitrogen balance; nitrogen loss.

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Figures

Figure 1
Figure 1
Correlation between nitrogen excreted and blood urea nitrogen (BUN) in patients receiving continuous renal replacement therapy. There was a strong relationship between nitrogen loss and BUN. Pearson's correlation, r = 0.794 (P < 0.001). An approximate line was plotted: nitrogen loss (g/day) = 0.275 × BUN (mg/dL)−0.31.
Figure 2
Figure 2
Protein intake and nitrogen balance in patients receiving continuous renal replacement therapy. There was poor relation between protein intake (g/kg body weight [BW]) and nitrogen balance (g/day).
See this image and copyright information in PMC

References

    1. Cano NJ, Aparicio M, Brunori G et al ESPEN Guidelines on Parenteral Nutrition: adult renal failure. Clin. Nutr. 2009; 28: 401–14. - PubMed
    1. Bellomo R. How to feed patients with renal dysfunction. Blood Purif. 2002; 20: 296–303. - PubMed
    1. Schaefer RM, Shaefer L, Horl WH. Mechanisms for protein catabolism in acute renal failure. Nephrol. Dial. Transplant. 1994; 9: 44–7. - PubMed
    1. Wilmore DW. Catabolic illness: strategies for enhancing recovery. N. Engl. J. Med. 1991; 325: 695–702. - PubMed
    1. Martinez JL, Sanchez‐Izquierdo RJA, Jimenez Jimenez FJ. Guidelines for specialized nutritional and metabolic support in the critically‐ill patient. Update. Consensus SEMICYUC‐SENPE: acute renal failure. Nutr. Hosp. 2011; 26: 21–6. - PubMed

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