119 CORRECTION OF EXTREME HYPERNATREMIA IN ACUTE KIDNEY INJURY WITH CONTINUOUS RENAL REPLACEMENT THERAPY: A CASE REPORT

Abstract

Category: RRT Technique Characteristics Presenter: Dr SU HOOI TEO Keywords: Acute Kidney Injury, Hypernatremia Management of extreme hypernatremia in patients with acute kidney injury (AKI) with hemodialysis poses a therapeutic challenge with risk of inadvertent over-rapid hypernatremia correction. An 84 year-old 49kg man with history of hypertension and cerebrovascular accident presented with a three-day history of reduced oral intake and cough. On examination, he was severely dehydrated and confused, with blood pressure of 115/67 mmHg and heart rate of 107/min. Initial laboratory investigations showed serum sodium of 173 mmol/L, serum creatinine of 291 umol/L and urea of 56.3 mmol/L. His baseline creatinine was 120 umol/L. He was diagnosed to have AKI secondary to severe dehydration and pneumonia, and started on intravenous hydration with estimated total water deficit of 4.7 L. He however did not respond and decision was made to initiate continuous venovenous hemodiafiltration (CVVHDF) with Qb (blood flow rate) of 150ml/min, Qd (dialysate flow rate) of 0.5L/hour, Qr (replacement flow rate) of 1L/hour. Customization of dialysate and replacement fluid by modifying sodium concentration was performed with addition of calculated amount of 3% Hypertonic Sodium Chloride solution. The mean achieved sodium correction was a reduction of 6 mmol/L every 24 hours from 168 mmol/L to 150 mmol/L over 72 hours, followed by 2 sessions of intermittent hemodialysis with sodium modeling with subsequent complete normalization of serum sodium level. Hypernatremia is an important risk factor for mortality in critically ill patient. Continuous renal replacement therapy (CRRT) may be useful in extreme hypernatremia to allow gradual, stepwise and controlled correction of hypernatremia with the aim of preventing cerebral oedema and related neurological complications. Current recommendation suggests that a daily maximal reduction in serum concentration of 8 to 10 mmol/L is considered safe especially in setting of chronic hypernatremia.