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Management of fluids, electrolytes, and acid-base disorders in the emergency department (ED) involves immediate correction of life-threatening abnormalities, identification and treatment of the underlying disorder, and eventual restoration of normal tissue homeostasis.


Crystalloid fluids for human administration have three general components: water, electrolytes, and glucose (Table 4-1).

Table 4–1

Electrolyte Concentrations of Fluids (mEq/L)

Because the osmolarity of normal saline (NS) and Lactated Ringer's solution matches that of serum, they are excellent fluids for volume replacement. Dextrose solutions are hypotonic and should never be used to replace volume but may be given as maintenance fluids with or without potassium.

Hypovolemia and Hypervolemia

Hypovolemia or hypervolemia can be determined entirely from the history and physical examination. History of bleeding, vomiting, diarrhea, fever, and/or findings of dry mucous membranes with features of poor perfusion, for example, decreased capillary refill, reduced urine output, and altered level of consciousness are suggestive of hypovolemia. Lethargy and coma are more ominous signs and may indicate a significant comorbid condition. Risk factors for hypervolemia include renal, cardiovascular, and liver diseases. Edema (central or peripheral), respiratory distress (pulmonary edema), and jugular venous distention (in congestive heart failure) are clinical features of hypervolemia.

Blood pressure and heart rate do not necessarily correlate with volume status alone and laboratory values are not reliable indicators of fluid status. Bedside ultrasound can be used to assess the volume status as an adjunct to, not a replacement for, the physical exam. Measurements of the IVC and following changes in size and respiratory dynamics over time with fluid challenges effectively determine the vascular volume status.


Management of electrolyte disorders is guided by two variables: severity of symptoms and rate of onset. If the clinical picture and the laboratory data conflict, repeat the lab test prior to initiating therapy. Abnormalities should be corrected at the same rate they develop; however, slower correction is usually safer unless in life-threatening situations which warrant rapid or early intervention.

Hyponatremia ([Na+] <138 mEq/L)

Hyponatremia is a ...

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