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ICF
-intracellular fluid
-2/3 of total body water
-inside the cells
ECF
-extracellular fluid
-1/3 of total body water
-outside the cells
-compartmentalized into interstitial fluid and plasma
-water moves between interstitial fluid and plasma based on hydrostatic pressure and oncotic pressure
-blood is ECF: not totality of ECF but blood samples are
TRUE/FALSE
Water moves between ICF and ECF based on concentration gradients
TRUE
how much of the ECF is made up if interstitial fluid
80%
how much of the ECF is made up of plasma?
20%
TRUE/FALSE
Both interstitial fluid and plasma have hydrostatic pressure and oncotic pressure
TRUE
Plasma Hydrostatic Pressure
-hydrostatic pressure: trying to push water from bloodstream to IS fluid (like a soaker hose for plants)
-blood volume has a direct correlation to plasma hydrostatic pressure: high BV= high pressure
-if you donate plasma: low BV
Plasma Oncotic Pressure
-oncotic pressure: trying to keep water in the vessel
-based on plasma albumin levels
Albumin (plasma oncotic pressure)
-has an attractive force for H2O
-most abundant plasma protein
-liver produces albumin
-Hespan (given IV) acts like albumin
-holds onto water which increases oncotic pressure
Water Movement within ECF
-if the hydrostatic pressure is the same as the oncotic pressure there is no net movement
-high hydrostatic pressure and low oncotic pressure= water out
-low hydrostatic pressure and high oncotic pressure= water in
-on arterial side of vessel: filtration
-on venous side of vessel: reabsorption
Edema
-accumulation of fluid in the IS fluid space
-example: 85% ECF to 15% ICF or 90% ECF to 10% ICF
-can occur anywhere: pulmonary edema (lungs); ankle edema
-it is a distribution problem
-there are different levels of edema: mild, moderate, severe
What are the 4 factors that favor edema?
1. Increase in Plasma Hydrostatic Pressure
2. Decrease in Plasma Oncotic Pressure
3. Increase in Capillary Permeability
4. Lymphatic Obstruction
Increase Plasma Hydrostatic Pressure
-Increasing in BV: by increase of water intake, by decrease of output (UO), heart failure
-CHF (congestive heart failure): can develop pulmonary edema, decrease in force of contractions, decrease in blood flow, leads to renal profusion by less blood flow to kidneys so less glomerular filtration, retention of fluid by releasing aldosterone, release HDH, conserve water, decrease UO
Decrease Plasma Oncotic Pressure
-decreased levels of albumin
-low liver function or liver failure
-potential fix: Hespan (IV fluid that acts like albumin)
-increase protein loss in urine
Increase Capillary Permeability
-anything that makes the capillaries more "leaky"
-trauma can cause this (either localized or widespread)
-trauma can cause the breaking of vessel which causes swelling= edema
-inflammation: fluid goes into the interstitial space
Lymphatic Obstruction
-when obstructed: can't provide drainage of IS fluid which leads to accumulation
-common causes
-a woman has a mastectomy and resect axillary lymph nodes will result in upper extremity edema because the IS fluid can't be drained/ circulated
-actual blockage of the vessel by a tumor or other cause that prevents the circulation of IS fluid
What are lymphatic vessels responsible for?
-IS fluid has to be circulated to be regulated meaning some travels back into venous circulation to maintain equilibrium
-draining any IS fluid from a particular region or helping circulate
Water Movement between ECF and ICF
-water moves based on concentration gradients (differences)
-normal concentration for ECF and ICF: 280-300 mOsm/Kg (normal amounts of H2O and solute)
-H2O v. Solute
-compare amounts
-lower number= dilute= more H2O
-higher number= concentrated= more solute
-both relative amounts result in total concentration
Water movement:
ICF=290
ECF=290
-no net movement
Water movement:
ICF=290
ECF=190
-H2O travels to ICF
-this can be caused by drinking a lot of water= a more concentrated gradient
-ECF: relatively more dilute= more H2O
-ICF: relatively more concentrated= less H2O
-cells could expand (must consider the region; swelling of cells in brain is not good)
Water movement:
ICF: 290
ECF: 390
-this can be caused by eating a lot of salt
-H2O travels to ECF
-ECF: relatively more concentrated
-ICF: relatively more dilute
-cells shrink (still consider region)
Isotonic
-normal concentration (280-300)
-H2O=solute
Hypertonic
-more concentrated (>300)
-low H2O
-high solute
Hypotonic
-less concentrated (<280)
-high H2O
-low solute
What are the adverse effects when water starts to move (ECF/ICF)?
-hemolysis
-brain cells swelling and pressure builds in the skull
-any CNS injury: the healing process is slow (months to years)
The 2 hormones that help regulate tonicity of ECF and ICF and target organ
-ADH
-directly regulates water
-primary target: kidneys
-Aldosterone
-influence on sodium regulation
-primary target: kidneys
-Kidneys
-help to regulate secretion and retention of water and sodium which influences how much is in the blood
-diet has an influence on concentration of blood
Hypernatremia
-Na+ >145
- high sodium, low water
-cells shrink which can result in neurological problems
-Causes: hypertonic ECF; gaining net sodium; water deficit problem (loss or intake)
-symptoms are nonspecific: nausea, vomiting, mental changes
-common in elderly home bound patients and hospital patients with dietary restrictions
-majority of the time= less water in blood
-Treatment: replenish water slowly, too quickly can cause problems; treat water loss first, then address other problems such as increased UO
What is the normal range for sodium levels?
135-145 mEq/L
Hyponatremia
-Na+ <135
-low sodium, high water
-causes: less net sodium, by sodium loss/intake/increase excretion; diluting the blood with water; diuretics by enhancing urinary sodium excretion and prevent absorption of sodium in the kidneys; heart failure
-mild: 130-134
-moderate: 125-129
-severe: <125
-Treatment: give sodium SLOWLY
TRUE/FALSE
Basic for ALL electrolytes: more acute changes have more problems than with more chronic changes.
TRUE
What is the normal range for K+?
3.5-5.0 mEq/L
How do we normally regulate K+?
-renal function plays an important role
-aldosterone enhances K+ excretion by lowering blood K+ levels and increase UO K+ level
-insulin decreases blood K+ levels and increases K+ shift into ICF from ECF
What does K+ affect?
-neuromuscular excitability if the K+ levels are not within normal range: includes skeletal muscle, smooth muscle, and cardiac muscle
Hypokalemia
-