Fluid and Electrolyte Balance: Nursing Study Guide

Fluid and electrolyte balance influences cardiovascular function, nerve conduction, muscle activity, kidney function, and acid-base status. Students should focus on patterns and clinical assessment rather than memorizing numbers without context.

Body Fluid Compartments

Body water is distributed mainly between intracellular and extracellular compartments. The extracellular compartment includes interstitial fluid and plasma.

Sodium

Sodium is the major extracellular cation and strongly influences extracellular fluid balance. Abnormal sodium may affect neurological status, thirst, volume status, and muscle function.

Potassium

Potassium is the major intracellular cation and is important for cardiac and neuromuscular function. Significant potassium abnormalities can contribute to dangerous cardiac rhythm changes.

Calcium and Magnesium

Calcium supports bone health, muscle contraction, nerve transmission, and coagulation. Magnesium participates in many enzyme reactions and neuromuscular functions.

Assessment of Fluid Status

Consider intake and output, daily weight, blood pressure, pulse, edema, mucous membranes, urine concentration, lung findings, mental status, and laboratory trends.

Common Imbalance Patterns

Fluid deficit may occur with vomiting, diarrhea, bleeding, fever, inadequate intake, or diuretic use. Fluid excess may occur with cardiac, renal, or hepatic dysfunction or excessive fluid administration.

Nursing Priorities

Monitor trends, administer prescribed fluids and electrolytes accurately, watch for signs of deterioration, assess IV sites, review relevant laboratory results, and escalate significant abnormalities promptly.