Potassium by IV infusion should only be used for the treatment of severe hypokalaemia as it cannot be rapidly corrected via the oral route. It is prescribed by, and administered under the supervision of, a doctor physically present.
– Adult: 40 mmol (= three 10 ml ampoules of 10% KCl, containing 13.4 mmol/ampoule) in one litre of RL over 4 hours. Do not exceed 10 mmol/hour.
– Child over 1 month: 0.2 mmol/kg/hour over 3 hours. Each mmol of KCl is diluted in 25 ml of RL.
Example for a child weighing 10 kg: 0.2 (mmol) x 10 (kg) = 2 mmol/hour x 3 (hours) = 6 mmol
6 mmol (= 4.5 ml of 10% KCl solution) in 150 ml of RL (6 x 25 ml of RL) administered over 3 hours.
8.3 Prescription and monitoring
– For the prescription, the doctor must write clearly on the patient’s file the dose of potassium in mmol and in ml and the number of ml in which to dilute the potassium as well as the length of infusion.
Example for a child weighing 10 kg: 6 mmol (= 4.5 ml of 10% KCl) in 150 ml of RL to be administered over 3 hours
– During the infusion, monitor the radial pulse every 15 minutes. In the event of bradycardia or tachycardia, call the doctor immediately and measure the blood pressure. If the potassium causes pain at the infusion site, check that the catheter is functional and slow down the infusion rate (risk of necrosis if the fluid infiltrates outside the vein).
– In parallel, start ORS if the patient is still exclusively receiving RL.
– After the infusion of potassium has been completed, re-evaluate the patient for signs of hypokalaemia. Check the patient is drinking sufficient ORS. The same dose can be repeated once during the same day if necessary, by medical prescription, under medical supervision and only after a clinical examination.
IV potassium must NEVER be given by direct IV injection. It must always be diluted in infusion fluid (RL or 0.9% sodium chloride). It must never be administered subcutaneously or intramuscularly.
MSF provides ampoules of 10 ml of 10% potassium chloride. Each ampoule contains 13.4 mmol of K+. The nurse preparing the infusion must always check the concentration in each ampoule.
Always use a separate bag of IV fluid and infusion line from those used for RL rehydration. Never add potassium to the bottle being used for rapid bolus infusions as the perfusion rate is far too fast.
Be careful to dilute the potassium after it has been added to IV fluid by inverting the bag or paediatric burette several times to achieve full mixing.
Respect the prescribed infusion rate. Use a paediatric burette and infusion set in children. Frequently check that the infusion rate is not too rapid so as to avoid the risk of cardiac arrest.