Hypokalemia =========== þ K+ Replacement - Rough equivalents: 0.3 mmol/L = 100 mmol replacement - IV K+: + 20 mEq over an hour > ^ K+ 0.5 mmol/L þ Admitting: - Standard practice is that a K+ of 2.5 or less gets admitted to a monitor. þ Normal K+ Metabolism þ Hypokalemia and Vomiting - Hypokalemia in patients with severe vomiting is generally due to the intracellular shifts caused by the metabolic alkalosis which develops from vomiting acidic gastric contents. The hypokalemia is not usually due to loss of potassium present in the regurgitated stomach contents. A "contraction alkalosis" caused by dehydration also contributes to the hypokalemia. Ref: Tintinalli 3rd ed. p 71 þ Hypokalemic Metabolic Acidosis - Severe diarrhea often causes a loss of both bicarbonate and potassium in the stool, which can lead to this condition. - Some forms of renal tubular acidosis can cause this condition. - Also, during treatment of diabetic ketoacidosis with insulin, the intracellular potassium shifts that occur with insulin administration can cause a hypokalemia. As the pH rises, this hypokalemia will worsen even further. - Refs: Tintinalli 3rd ed. p 71, Rosen 3rd ed. p 2150 þ Role of Mg++ in maintaining hypokalemia - If a hypokalemic patient with a normal pH is given a large amount of potassium but the hypokalemia persists, concurrent hypomagnesemia can make correction of the hypokalemia difficult. Correction of the hypomagnesemia facilitates therapy of the hypokalemia. Ref: Rosen 3rd ed. p 2152