Abstract
Hyperkalemia is a life-threatening complication in hemodialysis patients. Potassium intake is usually strictly restricted in all hemodialysis patients. In order to adjust K restriction to the most appropriate level for each individual patient according to their underlying conditions, we investigated factors other than diet contributing to the serum K concentration.
Serum K concentrations, serially measured at the beginning of hemodialysis every week during a period of one year from July, 1991, were analyzed in 59 patients. Dietary records were kept by 17 patients, and arterial pH, body mass index (BMI) and residual urine volume were measured in all subjects. 20.5% of the serially measured serum K levels during the one-year period were over 6.0mEq/l. The frequency of hyperkalemia (over 5.0mEq/l) was significantly higher in those with a residual urine volume of under 400ml/day than in those with a residual urine volume of over 400ml/day (p<0.05). Serum K and arterial pH showed a significant inverse relationship except for oliguric diabetic patients. In anuric hemodialysis patients, BMI was 20.4±2.4kg/m2 in the group with hyperkalemia (over 30% of serial serum K levels<6.0mEq/l) and 22.4±2.4kg/m2 in the group with near normokalemia (over 30% of serum K levels<5.0mEq/l). This difference was statistically significant (p<0.05). There was no significant correlation between K intake and serum K in a cross-sectional study of the 17 patients who were asked to record their diet. In a long-term chronological study, however, there were two types of patients, those whose changes in serum K levels were associated with K ingestion, and those in whom no such relationship was observed.
It was considered that serum K was influenced by arterial pH, BMI and residual urine volume, in addition to diet. We concluded that uniform strict restriction of K intake could be avoided and individualized adequate safe levels of K intake should be established for each patient based on that patient's own characteristics.
