Metabolic and volume status evaluation of hemodialysis patients with and without residual renal function in the long interdialytic interval

Abstract

Introduction: It is unclear whether residual renal function (RRF) in dialysis patients can attenuate the metabolic impact of the long 68-hour interdialytic interval, in which water, acid, and electrolyte accumulation occurs. Objective: to evaluate serum electrolyte levels, water balance, and acid-base status in dialytic patients with and without RRF over the long interdialytic interval (LII). Methodology: this was a single-center, cross-sectional, and analytical study that compared patients with and without RRF, defined by diuresis above 200 mL in 24 hours. Patients were weighed and serum samples were collected for biochemical and gasometric analysis at the beginning and at the end of the LII. Results: 27 and 24 patients with and without RRF were evaluated, respectively. Patients without RRF had a higher increase in serum potassium during the LII (2.67 x 1.14 mEq/L, p < 0.001), reaching higher values at the end of the study (6.8 x 5.72 mEq/L, p < 0.001) and lower pH value at the beginning of the interval (7.40 x 7.43, p = 0.018). More patients with serum bicarbonate < 18 mEq/L (50 x 14.8%, p = 0.007) and mixed acid-base disorder (57.7 x 29.2%, p = 0.042), as well as greater interdialytic weight gain (14.67 x 8.87 mL/kg/h, p < 0.001) and lower natremia (137 x 139 mEq/L, p = 0.02) at the end of the interval. Calcemia and phosphatemia were not different between the groups. Conclusion: Patients with RRF had better control of serum potassium, sodium, acid-base status, and volemia throughout the LII.

Factors associated with nursing diagnoses in chronic kidney patients: a cross-sectional study

“…A study carried out in the North East of Brazil, showed that patients with decreased RRF had an average of two years of haemodialysis, and those who did not have it were on treatment for an average of 7.2 years. Also, in this study, whereby patients with and without RRF were compared, it was found that patients without RRF had a greater intradialytic weight gain 25 .…”

Should serum potassium levels be routinely checked after the last dialysis of the week and before the first dialysis of the week?

“…This is lower than the postdialysis means of 3.7 mEq/L and 4.1 mEq/L reported previously after the last dialysis of the week. 5,6 However, postdialysis hypokalemia by itself is not associated with higher mortality when statistical adjustments are made for the older age and greater morbidity characterizing this group. 4 This might be explained by the rapid rebound of serum potassium levels due to movement of potassium from cells to the extracellular fluid, which corrects postdialysis hypokalemia to or close to normal within 5 hours.…”