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Fluid Imbalances and Regulation - Lecture Notes Review

HYPOVOLEMIA

  • Definition: Loss of water + electrolytes
  • Causes: bleeding, GI loss, burns, trauma, diuretics
  • Signs/Symptoms (S/S): thirst, dry mucosa, poor turgor, hypotension, tachycardia, hypovolemic shock
  • Treatment (Tx):
    • Oral fluids when able
    • IV normal saline (NS) or lactated Ringer's (LR)
    • Blood products if needed

DEHYDRATION

  • Definition: Loss of water only; typically associated with hypernatremia and ↑ osmolality
  • Causes: vomiting, diarrhea, fever, sweating, DKA
  • S/S: thirst, lethargy, dry mucosa, oliguria, hypotension, tachycardia
  • Treatment (Tx):
    • Oral rehydration if able
    • IV fluids; D5W suggested for severe cases
    • Note: management depends on ability to take fluids and severity

HYPERVOLEMIA

  • Definition: Excess water & sodium in the extracellular space
  • Causes: heart failure (HF), kidney failure, cirrhosis, certain meds
  • S/S: JVD (jugular venous distension), edema, bounding pulse, dyspnea, hypertension
  • Treatment (Tx):
    • Diuretics
    • Sodium/fluid restriction
    • Daily weights
    • Dialysis when indicated

REHYDRATION

  • Oral rehydration options: water, sports drink
  • Pediatric dosing (example):
    • 50-100 \, \mathrm{mL/kg} \, \text{over } 4 \text{ hours}
  • Additional considerations: rehydration approach may vary by severity; IV options (e.g., D5W) for severe dehydration as noted in dehydration management

FLUID IMBALANCES

  • Overview: Disturbances in fluid balance across compartments due to shifts in water and electrolytes
  • Major categories addressed: dehydration, hypovolemia, hypervolemia, and hypernatremia/hyponatremia dynamics when discussed within regulation mechanisms

REGULATION MECHANISMS

  • Thirst
    • Primary mechanism driving fluid intake in response to osmolality changes and volume status
  • ADH (vasopressin)
    • Role: promotes water reabsorption in the kidneys to conserve body water
  • Osmosis
    • Movement of water between fluid compartments driven by solute (osmotic) gradients

FLUID COMPARTMENTS

  • Intracellular: ext{approximately } 67\% of total body water
  • Interstitial: ext{approximately } 25\%
  • Intravascular (plasma): ext{approximately } 8\%
  • Notes: movement between compartments is regulated by osmosis; fluid shifts can alter compartment volumes

HYPERMAGNESIUM

  • Definition: Elevated magnesium levels in the body
  • Treatment (MILD to SEVERE):
    • IV calcium gluconate or calcium chloride to stabilize cardiac membranes
    • Diuretics to promote excretion
    • Specific management depends on severity

IV FLUIDS

  • IV fluids - crystalloids
    • Examples: NS (normal saline), LR (lactated Ringer's)
  • IV fluids - colloids
    • Used to expand intravascular volume by increasing oncotic pressure

HYPERMAGNESIUM (RECAP)

  • Common context: electrolyte disturbances related to magnesium excess; treatment focuses on membrane stabilization and facilitating magnesium removal

MISCELLANEOUS TOPICS PROMINENT IN THE SLIDES

  • Magnesium supplements
    • Role in overall fluid and electrolyte balance; often considered in the context of hypomagnesemia management (noted in the slides)
  • Foods high in magnesium
    • Dietary sources relevant to magnesium homeostasis (mentioned as a topic in the slides)

ADDITIONAL NOTES FROM SLIDES

  • Rehydration strategies depend on clinical status (mild vs severe dehydration)
  • Daily weights provide an objective measure of fluid balance in hypervolemia management
  • When dehydration is severe or complicated (e.g., with DKA or inability to tolerate oral intake), IV fluids with appropriate composition (e.g., D5W in severe cases) may be employed
  • The content emphasizes a structured approach: assess fluid status, categorize as dehydration/hypovolemia/hypervolemia, select appropriate oral vs IV therapy, and monitor with vitals and weights