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| Year : 2009 | Volume
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| Issue : 4 | Page : 639-642 |
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| The effect of increasing blood flow rate on dialysis adequacy in hemodialysis patients |
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SR Borzou1, M Gholyaf2, M Zandiha1, R Amini1, MT Goodarzi3, B Torkaman4
1 Department of Nursing, Hamadan University of Medical Sciences, Hamadan, Iran
2 Department of Nephrology, Hamadan University of Medical Sciences, Hamadan, Iran
3 Department of Biochemistry, Hamadan University of Medical Sciences, Hamadan, Iran
4 Ateyh Hospital, Hamadan, Iran
Click here for correspondence address and email
| Date of Web Publication | 8-Jul-2009 |
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 Abstract | | |
Inadequacy of dialysis is one of the determinants of morbidity and mortality in patients undergoing dialysis. The aim of this study was to assess the effect of increasing blood flow rate during hemodialysis (HD) on the adequacy of dialysis. In this study, 42 patients on maintenance HD were assessed. Body weight and blood urea nitrogen (BUN) levels before and after HD sessions were recorded on all the study patients. Volume of ultrafiltration, the duration of dialysis, percentage of filter clearance and flow rate of the dialysate were collected and documented in a checklist. Both Kt/V and urea reduction ratio (URR) were determined at two different blood pump speeds, i.e. 200 and 250 mL/min. During HD, hemodynamic status and vital signs of patients were monitored and controlled. After collecting the necessary data, efficiency of dialysis was calculated using the standard formula. Descriptive and analytical statistics was carried out to analyze the data. Using blood flow rate of 200 mL/min, 16.7% of patients had Kt/V higher than 1.3 and URR higher than 65. On the other hand, with flow rate of 250 mL/min, 26.2% of patients had Kt/V higher than 1.3 and 35.7% of subjects had URR higher than 65. Paired t-test with 95% confidence showed a significant difference in dialysis efficiency between two groups. Our data further confirm that increasing the blood flow rate by 25% is effective in increasing dialysis adequacy in HD patients. Keywords: Blood flow rates, Adequacy, Hemodialysis
How to cite this article:
Borzou S R, Gholyaf M, Zandiha M, Amini R, Goodarzi M T, Torkaman B. The effect of increasing blood flow rate on dialysis adequacy in hemodialysis patients. Saudi J Kidney Dis Transpl 2009;20:639-42 |
How to cite this URL:
Borzou S R, Gholyaf M, Zandiha M, Amini R, Goodarzi M T, Torkaman B. The effect of increasing blood flow rate on dialysis adequacy in hemodialysis patients. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2022 Sep 25];20:639-42. Available from: https://www.sjkdt.org/text.asp?2009/20/4/639/53255 |
| Introduction | |  |
Patients with end stage renal disease are unable to sustain life without dialysis support. [1] Dialysis delivery should be adequate to not only improve quality of life and also to prolong survival. [2] The aims of dialysis are thus, to decrease morbidity, increase quality of life and prolong life span. [3] To achieve these aims, dialysis must be performed effectively. Effective hemodialysis (HD) is one of the important factors that plays a role in decreasing morbidity and mortality of patients, [4] and ineffective dialysis is one of the factors causing mortality of these patients. [5] There are many surveys that indicate the relationship between dose of dialysis and mortality and morbidity of patients. [6],[7],[8],[9],[10],[11],[12] Sehgal, [13] and colleagues assessed the morbidity and the cost of inadequate HD. They concluded that inadequate dose of dialysis increases duration of hospitalization and the overall cost of care. Therefore, effective dialysis can decrease morbidity rate as well as the cost of care. [13] The National Cooperative Dialysis Study established that greater the efficiency of dialysis, lesser is the mortality and complications of uremia. [5]
One method of assessing dialysis dose is calculation of Kt/V. This index reflects the efficiency of dialysis and correlates with mortality and morbidity rate of patients. [14],[15],[16] Dialysis dose can also be assessed measuring the urea reduction ratio (URR). [17] The URR can be assessed by measuring blood urea levels before and after dialysis.
The results of many surveys show that achieving a Kt/V of 1.2 or more and URR of 65% or more is effective in improving prognosis of patients on dialysis. [18] Therefore, achieving this goal remains one the aims of dialysis. Many factors can increase Kt/V and URR including use of high level dialyzers, increasing blood flow rate (BFR), increasing flow of dialysate and dialysis time; some of these methods cannot be used routinely due to economic constrains. [19] ,[20]
Increasing duration of dialysis is a useful method for increasing Kt/V, but it is not always possible because of economic factors and intolerance of patient. Also, increasing the flow rate of the dialysate leads to increased diffusion of urea from blood to the dialysate, but the effect cannot be prolonged. Also, using high quality filter is not economical.[21],[22] We conducted this study to assess the effectiveness of increasing BFR, on efficiency of dialysis in HD patients.
| Materials and Methods | | |
This was a quasi experimental clinical trial study. In this survey, the efficiency of HD was assessed using two different BFRs. A total of 42 patients on maintenance HD at the Ekbatan Hospital (Hamadan, Iran) participated in this study. The inclusion factors for this study included: having arterio-venous fistula, receiving three sessions of dialysis per week each session lasting four hours, being on HD for at least one year, having good tolerance to dialysis, willing to participate in the study and not having any associated cardiovascular disease. Informed consent was obtained from the patients and their immediate family members. Detailed demographic data were obtained for all patients. The dialysis machines were checked for accurate function. During the study period, each patient was hemodialyzed using the same dialysis machine and dialysate and a specific BFR. The BFR was regulated at 200 and 250 mL/min in the first and second sessions, respectively. The study was conducted over a period of two months during which time, a total of 24 sessions of HD were performed on each patient. The study was divided into two phases, each phase comprising of one HD session per patient. In the first phase, the BFR was kept at 200 mL/min and in the second phase, it was increased to 250 mL/min. The patients' body weight was recorded and blood samples collected before and after each dialysis session. During HD, the clinical signs and homodynamic status of the patients were monitored and controlled appropriately. For assessing the efficacy of dialysis, Daugirdas II formula and urea reduction ratio (URR) were used.
The validity of collected data tools was assessed by content validity and the reliability of the tools was checked using pilot study in a small sample. For data description and assessing absolute and partial frequency, descriptive statistics and for analyzing effectiveness of increasing BFR on dialysis efficiency, the student-t test was used. The data were analyzed using SPSS.
| Results | | |
Data analysis showed that 66.7% of patients were men, majority of patients were between 40-49 years of age and 28.6% were 60 years and above; 54.8% had primary education and 61.9% of subjects had a history of diabetes.
About dialysis efficiency, 16.7% of patients with BFR of 200 mL/min had URR of 65% or more, 21.4% of patients had URR of 55-64% and 61.9% of patients had URR less than 54%. The Kt/V was 1.3-1.7 or more in 16.6% of patients and 0.9-1.2 in 45.2%.
The results of the effect of change of BFR on efficiency of dialysis showed that 45.2% of patients with BFR of 200 mL/min had Kt/V of 0.9-1.2. This percentage changed to 50% using BFR of 250 mL/min (P= < 0.05) [Table 1]. With BFR of 200 mL/min, 40.5% of patients had URR of 45-54% and with BFR of 250 mL/min, 38.1% of patients had URR of 55-64% [Table 2]. Paired T-test showed a significant statistical difference in URR between the two groups.
| Discussion | | |
Our study showed that only 16.7% of patients with BFR of 200 mL/min had Kt/V more than 1.3 and URR of 65-75%. Comparing these data with similar studies [23],[24],[25],[26] it was clear that dialysis efficiency in this center was not in the standard range but by increasing the BFR, dialysis efficiency was increased. The study of Kim and his colleagues showed that by increasing the BFR by 15-20% in patients with low efficiency dialysis (Kt/V less than of 1.2), efficiency of dialysis would increase. [21]
Gutzwiller and her colleagues assessed the effectiveness of increasing BFR on clearance of potassium and phosphate with dialysis and showed that increasing the BFR was effective in increasing clearance of potassium but was not effective in phosphorus clearance. [27] According to the United States Renal Data System (USRDS), increasing Kt/V by 0.1 can result in reducing partial risk of cardiovascular and infectious diseases [28] and each 0.1 reduction of Kt/V can increase the mortality rate by 5-7% in dialysis patients. [19] Available literature suggests that usage of more efficient dialyzers, increasing the BFR, increasing dialysate flow rate and increasing dialysis duration can all increase delivery of HD. However, the advantages and disadvan tages of each method should be examined. [19] ,[20] ,[22]
Results of this study showed that increasing the BFR can increase the dialysis efficiency. Nevertheless, attention should be given to factors such as patients' tolerance, hemodynamic status, using suitable filter according to patients' weight, and suitable BFR. It should be remembered that increase of the BFR need not always lead to higher clearance of blood urea. Thus, increasing BFR by 100% from 200 mL/min to 400 mL/min can increase blood urea clearance by 33%. [22]
In conclusion, our study further reinforces the observation that higher BFR increases the efficacy of HD, which in turn will reduce the morbidity and mortality of patients on maintenance HD.
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Correspondence Address:
S R Borzou
Department of Nursing, Hamadan University of Medical Sciences, Shariaty St. Hamadan
Iran
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 19587507 
[Table 1], [Table 2] |
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| This article has been cited by | | 1 |
Dialysis adequacy and kidney disease outcomes quality initiative goals achievement in an iranian hemodialysis population |
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| Malekmakan, L. and Haghpanah, S. and Pakfetrat, M. and Malekmakan, A. and Alimanesh, M. and Haghpanah, A. and Khajehdehi, P. | | Iranian Journal of Kidney Diseases. 2010; 4(1): 39-43 | | [Pubmed] | |
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