Fosfato en UCI: Puntos clave


Phosphate in Critical Care- Key Points

  1. Phosphate is the most abundant intracellular anion

  2. Phosphate is involved in virtually every intracellular reaction, it is the body’s source of chemical energy

  3. Hypophosphatemia is caused by inadequate intake (malnutrition or intestinal binding), excessive loss (diuretics) or redistribution within the body (catecholamines/refeeding).

  4. Hypophosphatemia causes muscle weakness, failure to wean from mechanical ventilation, myopathy, myocardial dysfunction and impaired oxygen dynamics.

  5. Hyperphosphatemia is caused by increased absorption, decreased loss (renal failure) or increased production (cell destruction).

  6. Hyperphosphatemia causes hypocalcemia and ectopic calcification

  7. The treatment is phosphate binding agents

  8. Refeeding syndrome occurs when previously malnourished patients are fed with high carbohydrate loads, the result is a rapid fall in phosphate, magnesium and potassium, along with an increasing ECF volume, leading to a variety of complications.

  9. Phosphate replacement can be given enterally or parenterally. If the patient is severely hypophosphatemic, a drip is started and 6mg/kg/hour replenished, up to 2mg/dl, then oral replacements are given.

Hyposphatemia Treatment

There are a variety of different formulations of phosphate available, both in enteral and parenteral form. The route of administration depends on the speed and availability of that route. Of the parenteral formulations, both sodium and potassium phosphate are available. I usually use the potassium preparation, as most ICU patients are deficient in both potassium and phosphate. In addition, I almost always add KPO4 to the dialysis fluid in CVVHDF. If the patient is severely hypophosphatemic, then intravenous replenishment at 6mg/kg/hour is administered until the PO4 level is above 2mg/dl.

Preparations available for Phosphate repletion


Phosphate Content



Oral preparation

  Skim cow's milk

1 g/L

28 meq/L

38 meq/L


250 mg/packet

7.1 meq/packet

7.1 meq/packet


150 mg/mL

4.8 meq/mL


  Neutra-Phos K

250 mg/capsule


14.25 meq/capsule

  K-Phos Original

150 mg/capsule


3.65 meq/capsule

  K-Phos Neutral

250 mg/tablet

13 meq/tablet

1.1 meq/tablet

Intravenous preparations

  Neutral sodium potassium PO4

1.1 mmol/mL

0.2 meq/mL

0.02 meq/mL

  Neutral sodium PO4

0.09 mmol/mL

0.2 meq/mL


  Sodium PO4

3.0 mmol/mL

4.0 meq/mL


  Potassium PO4

3.0 mmol/mL


4.4 meq/mL

Fosfato Monopotasico (10 ml=1'3 gr de fosfato) 1 mmol/mL   1 mmol/mL