Topic 5 Fluid Compartements & Fluid Shifts Flashcards
Distribution between plasma and interstitial compartments is controlled by what? (4)
forces moving fluid into and out of the capillaries -Capillary hydrostatic pressure -Interstitial hydrostatic pressure -Capillary colloid oncotic pressure -Interstitial colloid oncotic pressure
Distribution between intracellular and extracellular compartments is controlled by what mainly?
osmotic effect of sodium & chloride (mainly) across cell membranes
Cell membranes: permeability?
- high permeability to water
- low permeability to solute
Water moves quickly into or out of the cell to keep ICF isotonic with ECF
Osmole -
means of measuring total concentration of particles in solution
1 osmole = 1 mole of particles (6.02 x 1023)
Each mOsm of solute that cannot cross the membrane will generate an osmotic pressure of what?
of 19.3 mmHg
osmotic gradient across the cell membrane: how do you calculate?
Intracellular osmolarity x 19.3mmHg (Pressure each mOsm of solute that cant cross membrane generates) = osmotic gradient across cell
EX: Exposing RBC with intracellular osmolarity of 300 mmHg to pure water would result in an osmotic gradient across the cell membrane of 5790 mmHg
Interstitial/ intracelluar and plasma mOsm/L are all about what?
300 mOsm/L
Small changes in the concentration of impermeable solute will create large shifts of what? creating Lrg changes in what as well?
water creating large changes in compartment volumes
0.9% Sodium Chloride (0.9 grams of NaCl /100 mls solution–9 grams / L) is what kind of solution?
Isotonic Solution
Hypo-osmotic Solutions?
Solutions with lower osmolarity than intracellular fluid even if some solute is
permeable
Hyperosmotic Solutions?
Solutions with higher osmolarity than intracellular fluid even if some solute is permeable
Causes of imbalance (4)
Water ingestion
Dehydration
Fluid loss from gastrointestinal tract
Abnormal fluid loss by sweating or kidneys
If you add Normal Saline to a solution and the Osmolarity of solution is the same as ECF.
- what happens to ECF osmolarity?
- what happens ECF volume?
Think of graph
No change in ECF osmolarity
Expand volume of ECF by volume of solution
(the liter starts in the plasma of the CBV within 15 minutes 75% will move to the Interstitial fluid–25% will remain in the CBV)
If you add Hypertonic Solution to a solution?
- what happens to ECF osmolarity/volume?
- what happens to ICF osmolarity/volume?
Think of graph
ECF Osmolarity & VOL INCREASE
ICF VOL Decreases & Osmolarity Increases
- Osmolarity of solution higher than osmolarity of ECF so ECF osmolarity will increase
- Osmolarity of ECF > than osmolarity of ICF so water moves from ICF to ECF
- Overall increase in osmolarity
- ECF volume increases (more than the volume added)
- Most of the sodium and chloride remains in the ECF
If you add Hyportonic Solution to a solution?
- what happens to ECF osmolarity/volume?
- what happens to ICF osmolarity/volume?
Think of graph
ECF Osmolarity Decrease & Vol Increase
ICF Osmalarity Decrease & Vol Increse
- Osmolarity of solution lower than osmolarity of ECF so ECF osmolarity will decrease
- Osmolarity of ECF < than osmolarity of ICF so water moves from ECF to ICF
- Overall decrease in osmolarity
Most common Nutrient solution given?
Glucose
Given IV
Nearly Isotonic (If not, given slowly so does not upset balance)
When a Nutrient Solution that was give is metabolized what is the patient often left with?
As nutrient metabolized patient often left with surplus of water
Usually removed via kidneys
What is a good measure for plasma osmolarity?
Plasma Sodium Concentration
Sodium and chloride account for 90% of solute in ECF
Sodium and chloride are what % of solute in ECF?
90% of solute in ECF
What is higher than normal Na osmolarity concentration called?
Hypernatremia
What is lower than normal Na osmolarity concentration called?
Hyponatremia
Hyponatremia caused by what?
[hyponatremia-dehydration]
Loss of Na [NaCl] from ECF, which decreases ECFV and increases ICFV
Hyponatremia causes/side affects? (4)
[hyponatremia-dehydration]
- Diarrhea & vomiting
- Diuretic overuse (inhibit ability to conserve sodium)
- Renal disease that “wastes” sodium
- Addison’s disease results from decrease secretion of aldosterone
Hyponatremia :Caused by addition of excess water to ECF; Effects to fluid compartments? (3)
Decrease in plasma [Na+]
Increased ECFV
Increased ICFV
Hyponatremia :Caused by addition of excess water to ECF; Causes what? (2)
Excess water retention
Excessive secretion of antidiuretic hormone
Most common electrolyte disorder encountered in clinical practice? % of pt’s
Hyponatremia
15-25% hospitalized patients
Addisons Disease?
decreased decreation of Aldosterone, impairs ability of kidneys to reabsorb Na and cause modest hyponatremia
Consequences of Hyponatermia? symptoms
Cell swelling - can have big effects on tissue and organ function esp in brain (bc edema in brain)
Symptoms: headache; nausea; lethargy;
disorientation
With Hyponatermia, major brain damage can occure if Na concentration falls below what?
what are some symptoms?
120 to 115mE/L range
Significant brain swelling Seizures Coma Permanent brain damage (if brain volume increases by more than 10%) Death
How does the brain attempts to compensate hyponatremia ?
Brain attempts to compensate by moving sodium, chloride, potassium, organic solutes from cells out to ECF
When administering treatment for hyponatremia what is a concern?
DO not to correct too quickly [10 to 12 mmol/L over 24 hours]
Hypernatremia - Caused by water loss from the ECF; effects the fluid volumes in the body how?
[aka hypernatremia-dehydration]
Increased plasma [Na+]
Decreased ECFV
Decreased ICFV
Hypernatermia different causes? (2)
Caused by water loss from the ECF
Caused by addition of excess sodium to
ECF
Hypernatremia - Caused by addition of excess sodium to ECF; causes secretion of what?
[hypernatremia-overhydration]
Excessive secretion of aldosterone (causes reabsorbtion of water and sodium)
Hypernatremia - Caused by water loss from the ECF; causes inability to what?
[aka hypernatremia-dehydration]
-Inability to secrete antidiuretic hormone (needed for urine concentration)
– produce large amounts of dilute urine (diabetes insipidus)
-Excessive sweating so output greater than intake
Hypernatremia - Caused by addition of excess sodium to ECF; effects the fluid volumes in the body how?
[hypernatremia-overhydration]
Increased plasma [Na+]
Increased ECFV
Decreased ICFV
Hypernatremia - cells do what? and how do you treat?
- Tissue cells shrink
- Not as common as hyponatremia and requires very high sodium concentration (158 to 160 mEq/L) since high sodium concentrations result in intense thirst
- Patient’s with hypothalamic disease have an impaired thirst reflex
- Slow correction best
Why is Hypernatremia - Caused by addition of excess sodium to ECF called hypernatremia-overhydration?
by it results from some degree of water retention due to the excess secretion of Aldosterone(which causes Na retention thus H2O reabsorption)
Major causes of Intracellular Edema? (4)
- Hyponatremia
- Depression of metabolic systems within cells
- Sodium-potassium pump–shift of sodium into the cell - Lack of adequate nutrition delivery to cells
- Inflammation
- Increased cellular permeability–shift of sodium into cell
During Intracellular edema: why is there is depression of metabolic systems within cells and how does that cause the edema?
BC: decreased BF = lack of nutrition = ionic pumps become depressed so….Na ions leak into interior of cell and cant be pumped out by Na/K pump and Intracellular Na [ ] increases so water moves into cell. This is a preclude to death of tissue.
Why would inflammation cause intracellular edema?
bc inflammation increases cell membrane permeability so ions go in and water follows
Extracellular Edema causes?
- Abnormal leakage of fluid from plasma to interstitial space across capillary
- Most common form created by increased capillary filtration
- Failure of lymphatics to return fluid from interstitial space to vascular system
Extracellular edema most common cause?
Most common form created by increased capillary filtration
Lymphedema
Failure of lymphatics to return fluid from interstitial space to vascular system(blood)
can cause extracellular edema
Lymphedema can be caused by?
blockage or loss of lymph vessels so plasma proteins that leak into interstitium have no way to be removed. So this rise in protein concentration increases colloid osmotic pressure of the interstitial fluid thus drawing fluid out of the capillaries
Most common cause of Edema is?
Heart Failure