Potassium Balance and Acid-Base Changes in Patients Undergoing Regular Haemodialysis Therapy

Publisher Website
Google Scholar
Abstract
Serial measurements of total body potassium in 21 patients with chronic renal failure being treated with three 10-hour periods of dialysis per week, against a dialysate fluid containing 1·5 mEq of potassium per litre, showed no evidence of potassium depletion. Mild hyperkalaemia was found in some patients before dialysis, correlated with the pre-dialysis hydrogen ion concentration. Hypokalaemia occurred during dialysis in almost half of the studies made; the plasma potassium concentration, however, rose to normal levels within two to four hours of stopping dialysis. A delay in the movement of potassium from the cells into the extracellular fluid is suggested as a cause for the observed hypokalaemia. In all but one patient the pre-dialysis blood pH was normal, but rose to alkalaemic levels during dialysis. A pronounced degree of hypocapnia was noted before dialysis, and this was not altered by a rising blood pH during dialysis. It is suggested that a stimulus to respiration other than the hydrogen ion gradient between the brain cells and cerebral spinal fluid may produce the observed hypocapnia.