HDCN Article Review/Hyperlink

Allon M, Shanklin N

Effect of bicarbonate administration on plasma potassium in dialysis patients: interactions with insulin and albuterol

Am J Kidney Dis (Oct) 28:508-514 1996

Sodium bicarbonate (NaBi) has long enjoyed substantial, and perhaps undeserved, cache as a first line treatment for hyperkalemia, the reasoning being that an increase in pH will drive K+ into the intracellular space. While acute respiratory alkalosis does indeed achieve this affect, it has been observed at least since the 1950s that metabolic alkalosis produces a minimal K+ shift. Over the decades several studies have shown no decrease, indeed some even an increase, in the serum K+ following NaBi administration. In contrast there seems little doubt that both insulin and the beta-2 agonist albuterol produce an intracellular flow of K+, effectively lowering the serum concentration.

The study by Allon et al. examined the possibility that NaBi may work synergistically with either albuterol or insulin perhaps increasing the hypokalemic affect of these agents. Six different infusions were given to patients with end-stage renal failure: saline or isotonic NaBi, either alone or with albuterol or insulin. Neither saline nor NaBi alone significantly changed the serum K+. Both albuterol and insulin significantly decreased K+, but in each case there was no difference if these were given with saline or NaBi. They concluded that there was no evidence that the addition of NaBi produced a synergistic effect on the K+ lowering properties of insulin or albuterol.

Comment: This study clearly weighs in against a direct potassium lowering affect of NaBi. This does not necessarily obviate any role for NaBi in hyperkalemia. For example, in hyperkalemia an infusion of calcium does not lower the serum K+ but does have a "membrane stabilizing" effect through its ability to raise the myocardial action potential threshold. It has been suggested that raising the serum Na+ with hypertonic saline or NaBi has a similar "membrane stabilizing" effect. In the setting of clinical hyperkalemia a bolus injection of hypertonic NaBi is often administered which may have a salutory effect through this later mechanism. (Greg Cowell, M.D., University of Illinois at Chicago)