Potassium (K+)
Posted: Tuesday, August 31st, 2021 | Updated: Monday, February 7th, 2022
Posted: Tuesday, August 31st, 2021 | Updated: Monday, February 7th, 2022
Canine Normal Values:
3.9-5.2 mEq/L
Feline Normal Values:
3.3-5.7 mEq/L
Significance:
Used in the assessment of a variety of diseases
Increases in Values:
May help support the diagnosis of mineralocorticoid deficiency as seen with Addison’s Disease or hypoadrenocorticism. Serum sodium levels must be interpreted along with potassium levels to support this assessment. An ACTH stimulation test could also help determine if Addison’s Disease is truly present. Elevations may also be seen in patients with urinary tract obstructions. Potassium levels greater than 7.5 mEq/L are known to cause weakness, collapse, cardiac arrhythmias, bradycardia, and cardiac arrest. Bradycardia often results from hyperkalemia by it's effect on lowering the resting cell membrane potential. Severe hyperkalemia usually results in the loss of P waves, widening of the QRS complex, and tented T waves. Levels above 6 mEq/L should be corrected
Mild increase: 5.5-6.5 mEq/L
Moderate increase: 6.5-9.0 mEq/L
Severe increase: >9.0 mEq/L
In cases of moderate to severe hyperkalemia, initial treatment can be accomplished with:
Calcium Gluconate 10%
Beneficial for temporarily protecting the heart against the cardiotoxic effects of hyperkalemia by altering the cell membrane threshold potential
Insulin and Dextrose
Insulin helps to shift potassium back into the cells, but because insulin may also result in hypoglycemia, dextrose is typically given concurrently
Sodium Bicarbonate
Sodium Bicarbonate therapy may be useful in metabolic acidosis situations with severe hyperkalemia because it helps draw out hydrogen ions from the cells in exchange for potassium. The result is a shift of potassium back into the cells
Crystalloids
Results in dilution of serum potassium while correcting the volume deficits
Decreases in Values:
Decreased values may occur through renal or gastrointestinal losses and diuresis. Potassium levels less than 2.5 mEq/L are known to cause profound weakness. Levels below 3.0 mEq/L should have supplementation. When correcting for hypokalemia, potassium rates should not exceed 0.5 mEq/kg/hr. Potassium chloride and/or potassium phosphate is usually chosen for intravenous supplementation. In general, hypokalemia elevates the cell membrane potential and is less likely to cause arrhythmias when compared to hyperkalemia
Mild decrease: 3.0-3.5 mEq/L
Moderate decrease: 2.5-3.0 mEq/L
Severe decrease: <2.5 mEq/L
Note:
Potassium and Sodium are inversely related. Potassium is primarily found in the intracellular fluid compartment where serum levels are regulated by the sodium potassium pump. Potassium plays a huge role in maintaining the resting cell membrane potential of neurons and cardiac myocytes. Potassium and magnesium have a similar relationship
3.9-5.2 mEq/L
Feline Normal Values:
3.3-5.7 mEq/L
Significance:
Used in the assessment of a variety of diseases
Increases in Values:
May help support the diagnosis of mineralocorticoid deficiency as seen with Addison’s Disease or hypoadrenocorticism. Serum sodium levels must be interpreted along with potassium levels to support this assessment. An ACTH stimulation test could also help determine if Addison’s Disease is truly present. Elevations may also be seen in patients with urinary tract obstructions. Potassium levels greater than 7.5 mEq/L are known to cause weakness, collapse, cardiac arrhythmias, bradycardia, and cardiac arrest. Bradycardia often results from hyperkalemia by it's effect on lowering the resting cell membrane potential. Severe hyperkalemia usually results in the loss of P waves, widening of the QRS complex, and tented T waves. Levels above 6 mEq/L should be corrected
Mild increase: 5.5-6.5 mEq/L
Moderate increase: 6.5-9.0 mEq/L
Severe increase: >9.0 mEq/L
In cases of moderate to severe hyperkalemia, initial treatment can be accomplished with:
Calcium Gluconate 10%
Beneficial for temporarily protecting the heart against the cardiotoxic effects of hyperkalemia by altering the cell membrane threshold potential
Insulin and Dextrose
Insulin helps to shift potassium back into the cells, but because insulin may also result in hypoglycemia, dextrose is typically given concurrently
Sodium Bicarbonate
Sodium Bicarbonate therapy may be useful in metabolic acidosis situations with severe hyperkalemia because it helps draw out hydrogen ions from the cells in exchange for potassium. The result is a shift of potassium back into the cells
Crystalloids
Results in dilution of serum potassium while correcting the volume deficits
Decreases in Values:
Decreased values may occur through renal or gastrointestinal losses and diuresis. Potassium levels less than 2.5 mEq/L are known to cause profound weakness. Levels below 3.0 mEq/L should have supplementation. When correcting for hypokalemia, potassium rates should not exceed 0.5 mEq/kg/hr. Potassium chloride and/or potassium phosphate is usually chosen for intravenous supplementation. In general, hypokalemia elevates the cell membrane potential and is less likely to cause arrhythmias when compared to hyperkalemia
Mild decrease: 3.0-3.5 mEq/L
Moderate decrease: 2.5-3.0 mEq/L
Severe decrease: <2.5 mEq/L
Note:
Potassium and Sodium are inversely related. Potassium is primarily found in the intracellular fluid compartment where serum levels are regulated by the sodium potassium pump. Potassium plays a huge role in maintaining the resting cell membrane potential of neurons and cardiac myocytes. Potassium and magnesium have a similar relationship
Sources:
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.
Poli, Gerardo. MiniVet Guide: Companion Animal Medicine. InHouse Publishing, 2016.
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.
Poli, Gerardo. MiniVet Guide: Companion Animal Medicine. InHouse Publishing, 2016.