Fluid And Electrolyte Problems

Michael Lodner Christine M. Carr Gabor D. Kelen



Solutes Homeostasis

ClinicalAssessment of Volume. Status

Volume.Lo.ss Volume,, Overload


Hyponatremia Hypernatremia


Hypokalemia Hyperkalemia

Hypocalcemia Hypercalcemia iM,agn.esiu.m,,,,(..M.g2+,)

Hypomagnesemia Hypermagnesemia ch.lpri.d,e,„(.C.l"),




Hypophosphatemia Hyperphosphatemia

Chapter, References

Fluid and electrolyte disturbances encompass a broad spectrum of acute and chronic disease. The body deals with abnormalities under a specific stratification. Its first concern is oxygenation and ventilation, the second is circulation, and then equilibrium of acid-base status. Although derangements in any of these are often interrelated, abnormalities in any of these often lead to fluid and electrolyte derangement that may correct once the underlying abnormality itself is addressed. There are some general principles to follow in the initial evaluation of patients with fluid and electrolyte disturbances:

1. Treat the patient, not the laboratory value, particularly if the abnormality was unexpected. An aberrant laboratory value may simply be spurious. Errors occur obtaining, labeling, performing, and reporting laboratory tests. The patient's history and physical examination should be reviewed to determine whether the abnormality is congruous with the patient's presentation. When results remain seemingly inexplicable, the test should be repeated.

2. Often the rate of change defines the severity of an ailment, not the absolute value. In the same light, the rate of correction should generally mirror the rate of derangement. The rapid correction of disorders that developed slowly may lead to worse iatrogenic outcome or possible overcorrection. The body often can help itself once the underlying disorder is corrected. Full deficit correction of electrolytes is rarely appropriate during the initial period. As a rule of thumb, approximately half the deficit is replaced during the initial period (8 to 12 h), and the situation is then further addressed.

3. When fluids and electrolytes are altered, they should be corrected in the following orderly fashion:

1. Volume

3. Potassium, calcium, and magnesium

4. Sodium and chloride

Equilibrium of fluid, electrolytes, and pH depends on adequate tissue perfusion and often corrects spontaneously with resolution of the underperfused state.

4. Lastly, fluids, electrolytes, and pH status are all intertwined. Correction of any one facet must be undertaken with deference to the overall effect. For example, correction of the pH will have a significant effect on the serum potassium, ionized calcium, and ionized magnesium. Rapid replacement of volume may result in a dilutional non-anion-gap acidosis that, in turn, will decrease serum potassium.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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