endocrine and metabolic disorders
Hypokalemia
Treatment of Hypokalemia
Oral potassium supplements IV potassium supplements for severe hypokalemia or ongoing potassium losses Many oral potassium supplements are available. Because high single doses can cause GI irritation and occasional bleeding, deficits are usually replaced in divided doses. Liquidpotassium chloridegiven orally elevates concentrations within 1 to 2 hours but has a bitter taste and is tolerated particularly poorly in doses>25 to 50 mEq (> 25 to 50 mmol). Wax-impregnatedpotassium chloridepreparations are better tolerated. GI bleeding may be even less common with microencapsulatedpotassium chloridepreparations. Several of these preparations contain 8 or 10 mEq/capsule. Because a decrease in serum potassium of 1 mEq/L (1 mmol/L) correlates with about a 200- to 400-mEq (200 to 400 mmol) deficit in total body potassium stores, total deficit can be estimated and replaced over a number of days at 20 to 80 mEq (20 to 80 mmol)/day. When hypokalemia is severe (eg, with ECG changes or severe symptoms), is unresponsive to oral therapy, or occurs in hospitalized patients who are takingdigoxinor who have significant heart disease or ongoing losses, potassium must be replaced IV. Because potassium solutions can irritate peripheral veins, the concentration should not exceed 40 mEq/L (40 mmol/L). The rate of correction of hypokalemia is limited because of the lag in potassium movement from the extracellular space into cells.Routine infusion rates should not exceed 10 mEq (10 mmol)/hour. In hypokalemia-induced arrhythmia, IVpotassium chloridemust be given more rapidly, usually through a central vein or using multiple peripheral veins simultaneously. Infusion of 40 mEq (40 mmol)potassium chloride/hour can be undertaken but only with continuous cardiac monitoring and hourly serum potassium determinations.Dextroseor glucose solutions used for dilution are avoided because elevation in the seruminsulinconcentrations could result in transient worsening of hypokalemia. 100 to 120 mEq (> 100 to 120 mmol) of potassium in a 24-hour period unless potassium loss is ongoing. In potassium deficit with high serum potassium concentration, as in diabetic ketoacidosis, IV potassium is deferred until the serum potassium starts to fall. When hypokalemia occurs with Treatment , both the potassium and magnesium deficiencies must be corrected to stop ongoing renal potassium wasting. 