Sodium bicarbonate in hyperkalaemia

Use to correct acidosis (if serum HCO3- is less than 20mmol/l)

Use only if fluid overload is not a danger.

Dose: IV infusion of 50-100mls of 4.2% sodium bicarbonate or 200-300 mls of 1.26% sodium bicarbonate. Titrate against PH or serum bicarbonate.

Sodium bicarbonate encourages movement of extracellular potassium into cells. Traditionally its actions has been attributed to its effect on blood pH, but it may affect serum potassium without increasing blood pH. The sodium ion itself may play an important role in stimulating the uptake of potassium. Effects are observed within 30-60 minutes. This is a temporary measure. Doses may repeated as needed, especially if the patient is acidotic.

Note that there are risks associated with the use of sodium bicarbonate. These are:

• risk to patient with circulating volume overload, congestive heart failure or pulmonary oedema.
• rapid alkalinisation of the blood may precipitate tetany by lowering serum ionised calcium concentration.
• excessive administration may lead to alkalosis.