Fluid and Electrolyte Balance Quiz

Adult Health: Fluid & Electrolytes Module A

• Learning Objectives: Define fluid and electrolyte homeostasis, explain fluid and electrolyte physiology & homeostasis regulation, identify causes and manifestations of imbalances, and evaluate treatment outcomes.

What is Homeostasis?

• Body fluid characteristics are balanced in terms of volume, concentration (osmolarity), composition (electrolytes), and acidity (pH).
• Balance is achieved by fluid and electrolyte movement between intracellular and extracellular compartments.
• Imbalances can be dangerous.

Two Types of Fluid in the Body

• Intracellular Fluid (ICF): 40% of body weight, fluid inside cells.
• Extracellular Fluid (ECF): 20% of body weight, fluid outside cells, including blood plasma and interstitial fluid.

Cellular Homeostasis

• Diffusion: Movement of particles from high concentration to low concentration across a permeable membrane. Essential for electrolyte transport.
• Osmosis: Movement of solvent (water) across a selectively permeable membrane to equalise solute concentration.

Fluid Balance

• Fluid intake and output are balanced.
• Daily fluid intake averages 2300 mL, mainly from food and liquids.
• Fluid loss occurs through various routes, but most significantly through urine (minimum 400-600 mL/day to remove waste).
• Insensible water loss (skin, lungs, stool) is also significant (500-1000 mL/day.)

Hormonal Regulation of Fluid Balance

• Aldosterone: Secreted when sodium levels are low in the extracellular fluid; promotes sodium and water reabsorption by the kidneys.
• ADH (Antidiuretic Hormone): Released when blood osmolarity increases; promotes water reabsorption in the kidneys.
• Natriuretic Peptides: Secreted by the heart when blood volume and pressure increase; promotes sodium and water excretion.
• Renin-Angiotensin II Pathway: A critical system for maintaining blood pressure and volume.

Electrolyte Balance & Imbalances

• Electrolyte levels must remain within normal, narrow ranges for proper body function.
• Changes, even small ones, can cause significant problems.
• Older adults, those with kidney disease, or those generally unwell are at higher risk for imbalances.
• Lab tests, such as BMP and CMP, are essential to assess electrolyte levels.

Dehydration

• Fluid intake is insufficient, or fluid loss exceeds intake, resulting in hypovolemia.
• Causes include vomiting, diarrhoea, excessive sweating, and certain medications.
• Symptoms include decreased urine output, weight loss, and changes in skin turgor.
• Assessment, vital signs, and weight monitoring are critical.

Fluid Overload

• Fluid intake or retention exceeds the body's needs, causing hypervolemia.
• Causes include kidney failure, heart failure, and prolonged steroid use.
• Symptoms include increased weight, edema, increased blood pressure, and changes in respiratory rate.
• Monitoring weight, vital signs, and urine output is essential.

Interventions & Patient Safety

• Monitoring vital signs (heart rate and blood pressure) and neurological status (alertness, orientation) is crucial.
• Assess risk of falls due to postural hypotension, and muscle strength, gait stability, and level of alertness.
• Replace fluids as needed to maintain balance or via intravenous (IV) fluids.
• Monitor fluid intake and output.
• Continuous observation for fluid overload or dehydration is essential.