Management of Fluid and Electrolyte problems in Children

The safest route of administration is orally.

Intravenous therapy is indicated if:

• GI problems limit absorption or intake
• there is severe hypokalaemia with either respiratory muscle weakness or cardiac arrhythmias
• therapy is likely to cause a shift of potassium into cells e.g. treatment of DKA

Rate of administration
The concentration of potassium in fluids given through a peripheral intravenous cannula should not exceed 60 mmol/l because of local irritation to veins.

The rate of infusion should not normally exceed 0.2 mmol/kg/hr although rates up to 0.5 mmol/kg/hr may sometimes be justified. This does not apply to acute episodes which may require larger doses to be administered via a central line.

Preparations

KCl
This is the commonest form of potassium given.
Important to replace chloride in cases of hypokalaemia associated with ECF volume contraction.
Available in various forms.

KHCO₃
Use if the patient also needs bicarbonate e.g. certain diarrhoeal states.
Note that bicarbonaturia may promote the renal excretion of potassium.

Potassium phosphate
If the potasium loss is accompanied by loss of intracellular anions (phosphate), the potassium deficit will only be corrected when phosphate is given. Examples:

• Anabolism associated with total parenteral nutrition
  
• Recovery from diabetic ketoacidosis

Dietary potassium
This is the ideal way to replace potassium.
Foods rich in potassium include meats and fresh fruit.

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