Phys. of Body Compartments Flashcards
60-40-20 Rule
Total Body water = 60% of weight
ICF = 40 % of body weight
ECF = 20% of body weight
Components of ECF
25% Plasma
75% Interstitial
Third Spacing
Fluid enters non-functional spaces
seen in edma or ascites
Indicator-Dilution Method
Use of radioactive albumin to determine the volume of a specific compartment of the body
What happens to plasma concentration and hematocrit with a ECF loss?
Increase plasma concentration
Increase Hematocrit concentration
What happens to plasma and hematocrit with an ECF gain?
Decrease plasma concentration (increase dilution)
Decrease hematocrit concentration
What happens to plasma and hematocrit with an ICF loss?
RBCs shrink, decrease hematocrit
What happens with an ICF gain?
increased hematocrit (RBCs are swelling)
What forces will promote filtration? (out of capillary)
Hydrostatic capillary pressure, interstitial oncotic pressure
What 2 physiologic things lead to edema?
- Altered capillary hemodynamics (increased filtration)
2. Renal retention of Na / Increase ECF volume
What are crystalloids?
Salts that stay in ECF, decrease across capillary walls
What are colloids?
Molecules that don’t cross a membrane- stay in the intravascular space and draw fluids in.
When do you use normal saline IV? (.9%)
Hemorrhage, Shock, Blood Transfusions, Resuscitations, Fluid Challenges
When do you use D5W (5% Dextrose)?
Fluid Loss, Dehydration, Hypernatremia
When do you use Lactated Ringers?
Burns, Dehydrations, Fluid loss, GI fluid loss
What IV is best for intracellular fluid replacement?
D5W
What IV is best for acute blood loss?
0.9% Saline
What IV is best for plasma volume replacement?
Colloid IV
What 2 IVs are best to replace interstitial and lympthatic fluid?
Saline 0.9%, and balanced crystalloids
What causes Hypernatremia?
Greater water loss than Na loss
Results in water moving into ECF
What labs indicate Hypernatremia?
High serum osmolarity
High serum Na+
What causes Hyponatremia?
Greater Na+ loss than water loss
Results in fluid moving into ICF
What labs indicate Hyponatremia?
Low serum osmolarity
Low serum Na+
3 conditions associated with Hyperosmotic Contraction
Diabetes
Alcohol
Dehydration
3 conditions associated with Isosmotic Contraction?
Acute Hemorrhage
Diarrhea
Vomiting
2 conditions associated with Hypo-osmotic Expansion?
Excess water intake
SIADH
What causes Isosmotic expansion?
Saline IV
What changes in any graph iso-osmotic?
ONLY ECF!
