The effect of exercise on solute removal during haemodialysis in end-stage renal disease

Abstract

Exercise assessment, counseling and training are not widely offered to patients with chronic kidney disease. Haemodialysis patient’s participation in exercise and an adequate assessment of exercise effects on haemodialysis outcome are needed so that more interventions can be developed to improve the well being of those patients with chronic kidney disease. Exercise is not routinely advocated in patients with end-stage renal disease receiving maintenance haemodialysis. Lack of widespread awareness of exercise in haemodialysis literature may be contributing to these shortcomings in clinical practice.

Purpose of the study

This study was aimed to establish the effect of exercise during haemodialysis on pedal oedema and solute removal. This is the first time that such a study was undertaken in dialysis units in South Africa.

Methodolgy

In a quasi-experimental design, thirty-four end-stage renal failure patients on three times weekly haemodialysis program from Bloemfontein and Newcastle MediClinic Renal Units participation in the study. Ethical approval for the study was obtained from Durban University of Technology Ethics Committee. Seventeen patients were in the intervention group (aged between 25 and 60) and seventeen in the control group (aged between 18 and 60). The intervention group did not exercise for the first three months of the study in order to establish a baseline period. Thereafter, exercising took place from the fourth to the ninth month. Patients pedaled on an exercise cushion for fifteen minutes every hour to achieve a total of sixty minutes of exercise over a four-hour dialysis session. Patients in the control group did not pedal on the exercise cushion during the nine-month study period. Pre and post haemodialysis measurements of creatinine, urea and potassium using the Alkaline Picrate, Urease and Ion Selective Electrode methods respectively were done for each patient monthly over the nine month period. Oedema of the lower limb was evaluated by measuring the right and left ankle circumference, in centimeters before and after dialysis. Urea Kt/V was also measured before and after haemodialysis for each patient over the study period.

Results

Statistical analysis of results showed a significant 30% reduction in urea levels and a 46% reduction in creatinine levels in the intervention group at the end of the nine month period, a 12% reduction in the potassium levels in the intervention group which was 4% more than the control group. The urea Kt/V in the intervention group showed a 9% greater reduction than the control group. There was a significant improvement in oedema of 45% of the right ankle for the first three months of exercise and thereafter there was a an increase in ankle size in the last three months which was a 13% reduction in oedema compared to baseline. There was a significant improvement in oedema of 60% of the left ankle for the first five months of exercise and thereafter there was an increase in ankle size in the last month which showed a 25% reduction compared to baseline. The reason for the increase in ankle size in both ankles in the last three months in inconclusive and future investigation is recommended.

Conclusion

The results of this study demonstrated benefits of exercise during haemodialysis on solute removal and oedema perhaps due to the acute increases in blood flow and therefore increasing perfusion of skeletal muscles.