Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support

Serum Potassium

(mEq/L)

Potassium Chloride Dosage

(mEq)a,b

Laboratory Tests

3.5–3.6

40 to 60 mEq

Obtain BMP, magnesium next AM

3–3.4

80 mEq

Obtain BMP, magnesium next AM; may obtain

potassium 1–2 hours after repletion is completed,

especially if losses are thought to be high; reassess

2–2.9

120 mEq

Obtain repeat serum potassium 1–2 hours after

repletion is completed and reassess; may need one

or two additional boluses; repeat; check serum

magnesium next AM; reassess

aPotassium phosphate may be considered in lieu of potassium chloride if concurrent hypokalemia and hypophosphatemia (very common in critically ill patients receiving

EN/PN). Thirty millimoles of potassium phosphate is equivalent to 44 mEq of potassium.

bLower doses may be required for patients with renal dysfunction to avoid overcorrection.

AM = morning; BMP = basic metabolic panel.

vii.

The historical assumption of “a 0.5 to 0.6 mEq/L increase in serum potassium will occur for

every 40 mEq of intravenous potassium administered” (J Clin Pharmacol 1994;34:1077-82;

Arch Intern Med 1990;150:613-7) is potentially inaccurate for many critically ill subpopulations

such as emaciated patients or patients with obesity, those with renal dysfunction, exaggerated

requirements such as trauma or thermally injured patients (J Parenter Enteral Nutr 2017;41:796-

804), those with volume overload, or those receiving diuretic therapy.

viii.

Serum potassium concentrations are equilibrated within 1–2 hours after completion of the

1991;19:694-9), and repeated assessments are recommended for patients with severe and/or

complicated cases of hypokalemia.

Hyperkalemia

Definition: Serum potassium greater than 5.2 mEq/L, although usually not a significant problem

until serum potassium approaches 6 mEq/L

Signs and symptoms: ECG changes (peaked and tented T waves) and arrhythmias (bradyarrhythmias,

ventricular fibrillation, asystole), symptoms similar to those of hypokalemia (weakness, paralysis)

Etiologies:

Drugs – Potassium-sparing diuretics (spironolactone, amiloride, triamterene), angiotensin-

converting enzyme inhibitors, angiotensin receptor blockers, nonsteroidal anti-inflammatory

drugs, heparin, trimethoprim, octreotide, succinylcholine, digoxin

ii.

Excessive intake (usually in combination with compromised renal function) – Be sure to

examine all intravenous fluids, EN and PN regimens, penicillin G (1.7 mEq of potassium per

million units), packed red blood cells.

iii.

Renal dysfunction (chronic kidney disease [CKD], AKI)

iv.

Hyporeninemic hypoaldosteronism

Tissue catabolism (chemotherapy, rhabdomyolysis, tumor lysis syndrome, crush injury)

vi.

Severe acidemia

vii.

Older adult patients are also at risk because of decreased renal function, reduced renal

functional reserve, and loss of body cell mass.

viii.

Laboratory errors (sample hemolysis or improper sample collection)