Summary NSG 3113 Fluid and Electrolytes Imbalance Review

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Chapter 7 Fluid and Electrolyte Imbalance
 Basic Concepts of Fluid and Electrolyte Balance
o Human body is ~60% water
o Intracellular fluid (ICF)
 Fluid in cells
 ~40% of body weight
o Extracellular fluid (ECF)
 Outside cells
 Most found in intravascular spaces
 ~20% of body weight
o Interstitial fluid (ISF)
 Filtrate of blood located between cells or between cells and capillaries
 Normally lacks proteins
 Fluid Compartments




 Overview of Key Terms
o Hydrostatic pressure
 Force of fluid pressure in bloodstream
o Osmotic pressure
 Pressure by solutes in solution
o Oncotic pressure
 “Colloid pressure”
 Pressure due to albumin in blood
o Osmolality
 Concentration of solutes/kg solution
o Osmolarity
 Number of osmoles of solute per liter of solution

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 Hydrostatic and Osmotic Pressures




 Oncotic Pressure




 Tonicity
o Amount of solutes in solution compared with the bloodstream
o Isotonic
 Same tonicity as blood
 Does not cause fluid shifts or changes in cell size
 Standard isotonic solution: 0.9% NaCl
o Ringer’s lactate
 Similar physiological constituents as those found in blood
o Hypotonic
 Fewer particles (more water) than blood
 IV infusion causes shift from ECF into ICF
 0.45% NaCl as treatment for dehydration
o Hypertonic
 More particles (less water) than blood
 IV infusion pulls water from ICF into ECF; 3% NaCl
 Mannitol infusion used in cerebral edema
 Starling Law of Capillaries
o Explains the movement of fluid that occurs at capillary beds
o Outcome of 2 major opposing forces:
 Hydrostatic pressure
 Osmotic pressure