Acute Kidney Injury Part 1:
Life Threatening Hyperkalaemia
1. IMMEDIATE ACTION: STABILISATION
- Assess ABCDE and treat accordingly:
- Correct hypoxaemia.
- IV access.
- Continuous ECG monitoring is mandatory.
- Monitor oxygen saturation and aim for >96%.
- Specific treatment depends on ECG changes and potassium concentration.
- If ECG shows peaked T waves or more severe changes titrate IV calcium gluconate 10% or calcium chloride 10% in 1 ml aliquots watching the ECG. The trace will normalise as the calcium takes effect. If too much IV calcium is given it can result in cardiac arrest in asystole. The required amount varies from 2 or 3 mls to 20mls. This simply stabilises the myocardium giving time to institute therapy to reduce the potassium. This may need to be repeated.
- In cardiac arrest follow ALS algorithm and give 10mls 10% calcium chloride IV. VF will be resistant to defibrillation if calcium not given.
2. REDUCING THE POTASSIUM
- Bolus IV dextrose 50ml 50% solution with 5-10iu Actrapid (or equivalent e.g. Humulin S). Takes 20-30 mins to work. Increases cell wall sodium-potassium ATP-ase activity pushing K+ into cells.
- This can be followed with a slow infusion of 10% or 20% dextrose running at between 10ml/hr and 50ml/hr. Monitor blood sugar regularly and add insulin as required.
- Nebulised salbutamol 5mg and repeated.
- Sodium bicarbonate 1.26% IV infusion. Start at 100ml/hr and titrate to HCO3 and K+ levels. Not for routine use. May help: discuss with senior clinician.
3. ELIMINATING THE POTASSIUM
- The best way of removing potassium is to restore urine output and recover renal function.
- Failing this potassium removal by haemodialysis (HD) or haemofiltration (HF) may be required. During HF/HD stop dextrose and insulin infusions to allow potassium to move out of cells down concentration gradient.
- In potassium poisoning with normal renal function give IV fluids and furosemide to secure renal potassium loss.
- Ion exchange resins are difficult to administer orally or pr in the ill patient and take several hours to work. They are most useful in chronic situations or if the patient needs to be transferred a long distance. Calcium resonium 15g stat oral, then 15g 2 to 3 times daily. An oral laxative should be prescribed at the same time.