Fluid Imbalances
Learning Objectives
Learning Objectives
Understand the role of kidneys, lungs, and endocrine glands in fluid, electrolyte, and acid-base imbalances.
Identify common conditions related to fluid imbalances:
Edema
Third Spacing
Hypovolemia
Hypervolemia
Fluid Compartments
Extracellular Fluid (ECF): Outside cells (intravascular, interstitial, transcellular).
Intracellular Fluid (ICF): Inside cells.
Total Body Fluid: Varies by age; adult (), older adult (), infant ().
Fluid Movement
Movement between compartments is essential for:
Temperature regulation
Transportation of nutrients and waste
Lubrication and chemical reactions
Hydration and shock absorption.
Forces Moving Fluid
Osmolality: Concentration of solutes influences water movement.
Osmotic Forces: Draw water across membranes.
Starling Forces: Balance of hydrostatic and oncotic pressures influencing filtration and reabsorption.
Fluid Imbalances
Hypovolemia: Low fluid in intravascular space.
Causes: Hemorrhage, dehydration.
Leads to reduced blood pressure and cardiac output.
Hypervolemia: Excess fluid in intravascular space.
Causes: Renal failure, heart failure.
Leads to edema and possible organ dysfunction.
Edema: Excess fluid in interstitial space.
Etiology: Increased capillary hydrostatic pressure, decreased oncotic pressure.
Third Spacing: Accumulation of fluid in non-functional spaces such as ascites and pleural effusion.
Fluid Volume Changes
Isotonic: Equal loss of water and sodium.
Hypertonic: Loss of more water than sodium (dehydration).
Hypotonic: Loss of more sodium than water (cellular swelling).
Renal & IV Management
Fluid replacement based on type of deficit/excess:
Isotonic for isotonic losses, hypotonic for hypertonic, hypertonic for hypotonic losses.
Common IV fluids include NS for isotonic, D5W for hypotonic.
Nursing Considerations
Monitor fluids in older adults and infants closely due to variations in total body fluid and communication abilities.
Recognize early signs of fluid imbalances, particularly in vulnerable populations.
Identify common conditions related to fluid imbalances:
Edema
Third Spacing
Hypovolemia
Hypervolemia
Fluid Compartments
Extracellular Fluid (ECF): Outside cells (intravascular, interstitial, transcellular).
Intracellular Fluid (ICF): Inside cells.
Total Body Fluid: Varies by age; adult (60%), older adult (55%), infant (80%).
Fluid Movement
Movement between compartments is essential for:
Temperature regulation
Transportation of nutrients and waste
Lubrication and chemical reactions
Hydration and shock absorption.
Forces Moving Fluid
Osmolality: Concentration of solutes influences water movement.
Osmotic Forces: Draw water across membranes.
Starling Forces: Balance of hydrostatic and oncotic pressures influencing filtration and reabsorption.
Fluid Imbalances
Hypovolemia: Low fluid in intravascular space.
Causes: Hemorrhage, dehydration.
Leads to reduced blood pressure and cardiac output.
Hypervolemia: Excess fluid in intravascular space.
Causes: Renal failure, heart failure.
Leads to edema and possible organ dysfunction.
Edema: Excess fluid in interstitial space.
Etiology: Increased capillary hydrostatic pressure, decreased oncotic pressure.
Third Spacing: Accumulation of fluid in non-functional spaces such as ascites and pleural effusion.
Fluid Volume Changes
Isotonic: Equal loss of water and sodium.
Hypertonic: Loss of more water than sodium (dehydration).
Hypotonic: Loss of more sodium than water (cellular swelling).
Renal & IV Management
Fluid replacement based on type of deficit/excess:
Isotonic for isotonic losses, hypotonic for hypertonic, hypertonic for hypotonic losses.
Common IV fluids include 0.9% NS for isotonic, D5W for hypotonic.
Nursing Considerations
Monitor fluids in older adults and infants closely due to variations in total body fluid and communication abilities.
Recognize early signs of fluid imbalances, particularly in vulnerable populations.