Medscape
Patients who have mild or moderate hypokalemia (potassium level of
2.5-3.5 mEq/L) are usually asymptomatic; if these patients have only
minor symptoms, they may need only oral potassium replacement
therapy. If cardiac arrhythmias or significant symptoms are present,
then more aggressive therapy is warranted. This treatment is similar
to the treatment of severe hypokalemia.
If the potassium level is less than 2.5 mEq/L, intravenous
potassium should be given. Maintain close follow-up care, provide
continuous ECG monitoring, and check serial potassium levels.
Intravenous potassium, which is less
well tolerated because it can be highly irritating to veins, can be
given only in relatively small doses, generally 10 mEq/h.
Under
close cardiac supervision in emergent circumstances, as much as 40
mEq/h can be administered through a central line. Oral and parenteral
potassium can safely be used simultaneously.
Monitor for toxicity of hypokalemia,
which generally is cardiac in nature.
Uptodate
For patients with severe hypokalemia due to gastrointestinal or
renal losses, the recommended maximum rate of potassium
administration is 10 to 20 meq/hour in most patients. However,
initial rates as high as 40 meq/hour have been used for
life-threatening hypokalemia [
2,46-48].
Rates above 20 meq/hour are highly irritating to peripheral veins.
Such high rates should be infused into a large central vein or into
multiple peripheral veins.
Potassium can be given intravenously via a peripheral or a large
central vein. To decrease the risk of inadvertent administration of a
large absolute amount of potassium, we suggest the following maximum
amounts of potassium that should be added to each particular sized
infusion container [
47,49]:
●In any 1000 mL sized container of appropriate non-dextrose
fluid, we suggest a maximum of 60 meq of potassium.
●In a small volume mini-bag of 100 to 200 mL of water that is to
be infused into a peripheral vein, we suggest 10 meq of potassium.
●In a small volume mini-bag of 100 mL of water that is to be
infused into a large central vein, we suggest a maximum of 40 meq of
potassium.
Intravenous potassium is most often infused in a peripheral vein
at concentrations of 20 to 60 meq/L in a non-dextrose-containing
saline solution. Use of an infusion pump is preferred to prevent
overly rapid potassium administration in any intravenous container
with more than 40 meq of potassium or if the desired rate of
potassium administration is more than 10 meq/h. For patients with
severe hypokalemia, administration in a large central vein is
preferred if this access is available
he necessity for aggressive intravenous potassium replacement most
commonly occurs in patients with diabetic ketoacidosis or hyperosmolar
hyperglycemic state (nonketotic hyperglycemia). These patients typically
have a substantial reduction in potassium stores due to urinary losses,
but usually present with normal or even high serum potassium levels due
to transcellular potassium shifts. Patients who present with
hypokalemia have an even larger potassium deficit [
46].
Furthermore, treatment with insulin and intravenous fluids will
exacerbate the hypokalemia and minimize the efficacy of potassium
repletion. Thus, insulin therapy should be
delayed until the serum potassium is above 3.3
meq/L to avoid possible complications of hypokalemia
Although isotonic saline is often the initial replacement fluid used in
treating diabetic ketoacidosis or nonketotic hyperglycemia, the addition
of potassium will make this a hypertonic fluid (since potassium is as
osmotically active as sodium), thereby delaying reversal of the
hyperosmolality. Thus, 40 to 60 meq of potassium per liter in one-half
isotonic saline is preferred.
Potassium repletion is most easily accomplished orally but can be given
intravenously. The serum potassium concentration can transiently rise by
as much as 1 to 1.5
meq/L after an oral dose of 40 to 60 meq, and by as much as 2.5 to 3.5
meq/L after 135 to 160 meq [
42,43].
The serum potassium concentration will then fall back toward baseline
over a few hours, as most of the exogenous potassium is taken up by the
cells
Potassium must be given more rapidly to patients with hypokalemia that is severe (serum potassium less than 2.5 to 3.0
meq/L) or symptomatic (arrhythmias, marked muscle weakness, or rhabdomyolysis).
Patients with gastrointestinal losses are treated with
potassium chloride if they have metabolic alkalosis (as usually seen with vomiting) or a normal serum bicarbonate concentration, and with
potassium bicarbonate
(or potassium citrate or acetate) in the presence of metabolic acidosis
(as seen with diarrhea or renal tubular acidosis). Treatment is usually
started with 10 to 20 meq of potassium given two to four times per day
(20 to 80
meq/day), depending upon the severity of the hypokalemia.
Potklor solution provides 20 mEq K and Cl per 15 ml
syrup potassium chloride in the dose of 1–2 mEq/kg/ day (15 mL of syrup potklor provide 20 mEq K).
