RFT – Potassium

HYPOKALEMIA

Key Symptoms and Vitals

  • Palpitations
  • Hypotension
  • Muscle cramps or weakness
  • GI symptoms (e.g., nausea, ileus)

ECG Changes

  • T wave flattening
  • ST depression
  • U waves (in severe hypokalemia)

Always correct hypomagnesemia before or alongside potassium replacement

MANAGEMENT

Potassium Level Management
3.0–3.5 mmol/L Oral Slow-K 1–2 tablets TDS. Repeat RFT the next day. Stop if K⁺ > 4.5 mmol/L.
2.5–3.0 mmol/L IV KCl 20 mmol in 200 mL NS over 2 hours. Recheck labs after correction.
<2.5 mmol/L or symptomatic IV KCl 40 mmol in 400 mL NS over 4 hours. Add oral K⁺ if tolerated. Requires cardiac monitoring.

Formulations Available (MOH)

  • IV Potassium
    • Potassium chloride 15% – 10 mL = 20 mmol
    • Potassium phosphate – 15 mL = 66 mEq K ≈ 45 mmol phosphate
  • Oral Potassium
    • Slow-K tablet: 600 mg ≈ 8–9 mmol K
    • Potassium chloride 6.6% syrup: ≈ 1.3 mmol K per 1.5 mL
    • Potassium citrate 14.4% syrup: ≈ 6.6 mEq K per 5 mL

HYPERKALEMIA

Key Symptoms and Vitals

  • Palpitations
  • Hypotension
  • Muscle weakness
  • GI upset

ECG Changes

  • Tall, peaked T waves
  • Prolonged PR or QRS
  • Sine wave pattern (in severe hyperkalemia)

MANAGEMENT

Potassium Level / ECG Treatment Notes
K⁺ 5.4–6.0 mmol/L or ECG changes D50W 50 mL + Actrapid 10 units IV,
Calcium gluconate 10 mL of 10% over 10 min,
Repeat RFT after correction		 Stabilizes myocardium and shifts K⁺ intracellularly;
monitor ECG closely
K⁺ > 6.0 mmol/L All of the above
+ oral binders: Calcium Resonium® 15 g TDS + Lactulose 15 mL TDS,
escalate to senior/nephrology		 Initiate full protocol and escalate early;
avoid delay in severe cases

Potassium Binders

Drug Type Onset Indication Notes
Calcium Resonium Non-selective resin 2–12 hrs Mild–moderate hyperkalemia GI side effects; use with lactulose
Lokelma® Selective potassium binder ~1 hour Acute or subacute hyperkalemia Fast-acting, low GI risk
Veltassa® Polymer binder 4–7 hours Chronic hyperkalemia Not for emergencies; risk of hypomagnesemia

Measures Available in MOH

  • Calcium polystyrene sulfonate (Calcium Resonium®) – oral/rectal
  • Sodium polystyrene sulfonate (Resonium A®) – oral/rectal
  • Sodium zirconium cyclosilicate (Lokelma®) – oral
  • Patiromer (Veltassa®) – oral
    Lactulose – oral or rectal

Clinical Notes

  • Review meds that may worsen potassium balance (e.g., ACEi, ARBs, spironolactone)
  • Repeat test if the sample was hemolyzed before acting

ECG Reference

MOC