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.

Further Reading and Source Material

N. C. Bugg and J. A. Jones. Hypophosphataemia. Pathophysiology, effects and management on the intensive care unit. Anaesthesia 53 (9):895-902, 1998.

W. J. Fawcett, E. J. Haxby, and D. A. Male. Magnesium: physiology and pharmacology. Br.J.Anaesth. 83 (2):302-320, 1999.

R. Subramanian and R. Khardori. Severe hypophosphatemia. Pathophysiologic implications, clinical presentations, and treatment. Medicine (Baltimore) 79 (1):1-8, 2000.

J. R. Weisinger and E. Bellorin-Font. Magnesium and phosphorus. Lancet 352 (9125):391-396, 1998.

          
                   
       

         
     

       
       

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