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Acute haemodialysis (HD) in patients with hyponatraemia with or without hyperkalaemia are challenging because of needing to minimize changes in serum sodium level while trying to achieve adequate potassium, urea or toxin removal.
A mathematical model was derived to safeguard the treatment, which was then incorporated into software: https://drive.google.com/drive/folders/1O3DD81gwO_PVQF3moPw6zk-qZXUtds20. Software spreadsheets could be freely downloaded by clinicians for use of critical patients. Calculated concurrent intravenous (IV) dextrose 5% (D5%) was given to minimize serum [Na] changes.
There were 28 cases of hyponatraemia ([Na] <=130 mmol/L) being enrolled and among them, 11 cases were with concurrent hyperkalaemia ([K] >= 6 mmol/L).
Table 1 showed the dialysis regime with the help of mathematical model while figure 1 showed QR code for software.
In hyponatraemia cases, changes of Na with dialysis was 6 ± 4 with mathematical model help, versus 14 ± 1 mmol/L without it (p=0.010).
There were 25 out of 26 cases survived without neurological complication with mathematical model being applied pre-dialysis versus none out of 2 cases without model (96% versus 0%, p=0.008). Without mathematical model, one patient suffered from osmotic demyelination syndrome (ODS) as proven by MRI of brain, but fortunately recovering the neurological function fully a month after dialysis.
Survival of cases with concurrent dysnatraemia and hyperkalaemia was 10 out of 10 cases (100%) with mathematical model being applied for [Na] and [K] pre-dialysis: long HD duration and/or high dialysate flow versus 0 out of 1 case (0%) for patients without prior mathematical model (p=0.091), related to better achievement of serum [K] post-dialysis with mathematical model (4.1 ± 0.6 versus 5.1 mmol/L, p=0.142) and thus lesser risk of rebound hyperkalaemia.
Utilization of mathematical model and calculated concurrent intravenous fluid and dialysate flow rate help achieve desirable serum [Na] and [K] in HD, while preventing neurological complication. During HD, concurrent IV dextrose minimizes the sodium increment in hyponatraemia patients, while allowing high dialysate flow rate to remove potassium, urea and other toxin. As the saying of The Lord, “You are the salt of the earth”, and “Have salt among yourselves, and be at peace with each other” (Matthew 5:13, Mark 9:50), clinicians must be gentle and wise in treating hyponatraemia patients: aiming near iso-natraemic HD while remove excessive [K], urea and other toxin during dialysis.