DIALYSATE POTASSIUM LOSS CONTRIBUTES TO HYPOKALEMIA IN PD PATIENTS
Dr Surjit Tarafdar1,2,3, Associate Professor LUKAS KAIRAITIS1,2, Dr JOHN LEE1,2, Dr KATRINA CHAU1,2, Dr MIRNA VUCAK-DZUMHUR1,2,4,5,7, Dr RONALD CASTELINO1,6, Dr CUN PHANG1
1Blacktown Hospital, Sydney, Australia, 2Blacktown Clinical School, School of Medicine, Western Sydney University, Blacktown, Australia, 3Department of Nephrology, Kasturba Medical College, Manipal, India, 4Auburn Hospital, Auburn, Australia, 5University Notre Dame, Sydney, Australia, 6University of Sydney, Sydney, Australia, 7Westmead Hospital, Sydney, Australia
Aim: To investigate the role of dialytic removal of potassium (K+) as a major cause of hypokalemia in patients on peritoneal dialysis (PD).
Background: Hypokalemia is a well-recognized complication of PD with a prevalence of 10 to 35 %. We postulated that dialytic removal of K+ contributes significantly to hypokalemia in PD.
Methods: Data about 135 patients undergoing PD at Blacktown Hospital Dialysis Centre between November 2023 and February 2024 was collected retrospectively. Patients whose serum K+ decreased by over 2.2 mmol/L or developed hypokalaemia (<3.5 mmol/L) after initiation of PD were selected for measurement of K+ in the drained PD fluid.
Results: 19 of 135 patients (14.07%) met our selection criteria for hypokalaemia, of whom 10 were on CAPD and 9 were on APD.
The drained PD fluid K+ in these patients averaged 2.51 mmol/L. The total 24 hours PD fluid drained out ranged from 5.792 to 12 L with an average of 8.8 L while the total K+ drained out in PD fluid over 24 hours ranged from 12.27 mmols to 36.22 mmols with an average of 23.12 mmols.
Conclusions: 98% of body K+ is held tightly intracellularly. A 72kg male would have approximately 15 L of extracellular water (3 L plasma and 12 L interstitial fluid) and an average serum K+ of 4 mmol/L would translate into 60 mmol of total extracellular K+. A daily loss of 23.12 mmols of K+ in the PD fluid (38 % of total extracellular K+) will predispose to hypokalaemia. There was an inverse co-relation between the amount of PD fluid drained out over 24 hours and serum K+, supporting the role of PD loss of K+.
Biography:
After working for seven years as a rural GP in India, Dr. Tarafdar did his postgraduate training in UK and Australia. He edited ‘Nephrology: A Comprehensive Guide to Renal Medicine’ published by Wiley-Blackwell in Feb 2020. Dr. Tarafdar conceptualised and started “Revise Nephrology” in 2015; annual weekend nephrology program for the BPTs. Since its inception has been attended by 1200 doctors. He established the annual Australia and New Zealand General Medicine Update:www.anzgmu.com.au, a platform for General Medicine consultants and ATs to update their knowledge. Started in 2019, the 2024 event was attended by 125 doctors including 70 consultants