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

Signs and symptoms: Weakness, paresthesias; severe depletion can lead to congestive

cardiomyopathy, cardiac arrest, seizures, coma, respiratory arrest due to weakness of the

diaphragm, rhabdomyolysis

Etiologies:

Alcoholism

ii.

Malnutrition/refeeding syndrome

iii.

Critical illness (especially trauma, TBI, thermal injury)

iv.

Diabetic ketoacidosis

Hepatic resection

vi.

Drugs – Insulin, catecholamines, antacids, sucralfate, calcium, ferric carboxymaltose

injection, diuretics

vii.

Alkalemia

viii.

Malabsorption – Chronic diarrhea

ix.

Hyperparathyroidism

Cancer (phosphatonins [e.g., fibroblast growth factor-23])

xi.

Renal replacement therapies

xii.

Hungry bone syndrome following parathyroidectomy or thyroidectomy

Target serum phosphorus concentration when patient is in the ICU and ventilator dependent:

ii.

Intravenous dosing guidelines

Serum Phosphorus

(mg/dL)

General Medical-Surgical Population

Dosage (mmol/kg)

High Requirementsc Population

Dosage (mmol/kg)

(JPEN J Parenter Enteral Nutr

2006;30:209-14)

2.3–3

0.16

0.32

1.6–2.2

0.32

0.64

< 1.6

0.64

aThe drug should be mixed in 100–250 mL of normal saline or 5% dextrose in water and given at a rate no faster than 7.5 mmol/hour. Phosphorus should always be

ordered in millimoles for ease of use and preparation. For ease of use and preparation in the pharmacy, phosphorus should be ordered in units divisible by 3 mmol (e.g.,

15, 30, 45, 60) whenever possible.

bPotassium phosphate salt can be used for patients with a serum potassium less than 4 mEq/L, but ensure potassium content does not exceed estimated potassium

repletion needs (for most products, 3 mmol of phosphorus = 4.4 mEq of potassium; for one commercially-available product, 3 mmol of phosphorus = 4.7 mEq of

potassium). Sodium phosphate salt should be used for patients with a serum potassium of 4 mEq/L or greater or if the potassium content of potassium phosphate dose

would exceed potassium repletion needs (3 mmol of phosphorus = 4 mEq of sodium).

cPatients with thermal injury (JPEN J Parenter Enteral Nutr 2001;25:152-9), those with trauma (especially those with a traumatic brain injury) (Nutrition 2010;26:784-

90; JPEN J Parenter Enteral Nutr 2006;30:209-14), those malnourished with evidence of significant complications from refeeding syndrome, or those with hepatic

resections.

iii.

Repletion using oral phosphorus formulations

because of the need to rapidly correct the phosphorous concentration and the potential

for adverse effects (eg, diarrhea) with higher oral doses. A recent study evaluated the

usefulness of oral phosphorous replacement in critically ill patients with mild to moderate

hypophosphatemia and found no difference in efficacy with a reduction in waste and cost

phosphorous, potassium, and sodium each product contains.