Fluid & Electrolyte Imbalances Flashcards
Second spacing
Edema, fluid shifting from primary intravascular space to interstitial space
Water content of an average adult
50-60%
Water content of an average older adult
45-55%
ICF (Intracellular)
2/3 of all fluid is inside the cell
inside the cell, makes up 42% of body weight
- 2/3 of fluid is inside cells
- High in K+ and PO43- (phosphate)
- low in Na+
ECF (extracellular)
1/3 of all fluid is outside the cell
- primarily interstitial spaces and lymph between cells (2/3), intravascular space/plasma fluid (1/3)
- high in Na+ and Cl-
- low in K
Lymph or transcellular fluid
1L of body fluid including CSF, joint fluid, pleural, peritoneal, synovial
Can become a “third space”
What kind of transport is a Na-K pump?
Active transport - molecules move against [ ] gradient, ATP required
What kind of transport is glucose moving into cells?
Facilitated diffusion
What does high osmolality mean?
Highly concentrated (lots of solute)
What is osmotic pressure?
Amount of pressure required to stop osmotic flow of water determined by concentration of solutes in solution.
What is hydrostatic pressure?
Force within a fluid compartment (ex. BP generated by contraction of heart) Major force that pushes water out of vascular system at capillary level. Gradually decreases as blood moves through artery.
What is oncotic pressure?
Osmotic pressure exerted by colloids (proteins) in solution (colloidal osmotic pressure). Measure albumin.
role of albumin in the body
Keeps fluid from leaking out of your blood vessels into other tissues (pulls water back at the venous end) Carries hormones, vitamins, and enzymes throughout your body. Without enough albumin, fluid can leak out of your blood and build up in your lungs, abdomen (belly), or other parts of your body
Decreased plasma albumin may result in
ECF excess, edema, colloid osmotic pressure inside capillary has decreased
Two pressures causing movement into capillaries
Interstitial hydrostatic pressure and Plasma oncotic pressure
Two pressures causing movement out of capillaries
Interstitial hydrostatic pressure, plasma oncotic pressure
Push pressure
hydrostatic
Pull pressure
oncotic
Forces at the arterial end of the capillary
Capillary: hydrostatic 40 mm Hg, (plasma) oncotic 25 mm Hg
Interstitial: hydrostatic 1 mm Hg and oncotic 1 mm Hg
Forces at the venous end of the capillary
Capillary: hydrostatic 10 mm Hg, (plasma) oncotic 25 mm Hg
Interstitial: hydrostatic 1 mm Hg and oncotic 1 mm Hg
What causes edema
elevated capillary hydrostatic pressure
decreased plasma oncotic pressure
elevated interstitial oncotic pressure
What pressure do compression stockings increase?
interstitial hydrostatic pressure
Third Spacing puts the vascular system at risk of
Deficient Fluid Volume/Fluid Volume Deficit/FVD/hypovolemia
- state or condition where the fluid output exceeds the fluid intake
In Phase II of Third spacing when the fluid moves back, it puts the vascular system at risk of
Fluid Volume Excess, could lead to HF
Regulation of Water Balance
Hypothalamic, pituitary, adrenal, renal, cardiac, GI, insensible water loss
Hypothalamic regulation
osmoreceptors sense fluid change and stimulate thirst and ADH from pituitary regulation
Adrenal Cortical Regulation
releases hormones to regulate water and electrolytes
- glucocorticoids (ex. cortisol, anti-inflam)
- mineralocorticoids (ex. aldosterone, ↑ Na+ retention, ↑ K+ excretion)
Insensible Water Loss
Invisible vaporization from lungs and skin to regulate body temperature
- ~900 mL/day is lost
- no electrolytes are lost
