Fluid Management Flashcards
What % of body weight is total body water?
60% average.
55% Man
45% Woman
80% Infant
What percent of total body water is intracellular volume?
Extracellular volume?
Intracellular 40%.
Extracellular 20%.
The extracellular volume (ECV) is broken into two fluid compartments, what are they are how are they distributed?
Interstitial fluid volume 75% of ECV.
Plasma Volume 25% of ECV.
What separates the two extracellular fluid compartments?
Vascular endothelium.
Do obese individuals have more or Total Body Water (TBW) than non-obese individuals?
Less TBW
What separates the intracellular space from the extracellular space?
Cell membrane
Which three electrolytes does the intracellular fluid compartment contain in high concentration?
Potassium.
Phosphate.
Magnesium.
What is responsible for maintaining the high concentration of K+ in ICF?
Na+K+ATPase.
Sodium potassium pump.
What two electrolytes are in high concentration in the EFC?
Sodium and Chloride.
Is there a larger concentration of proteins (particularly Albumin) in the blood vessels or in the interstitial space?
Inside the capillary.
What is the formula for serum osmolality?
2 (Na+) + (BUN/2.8) + (Glucose/18)= Serum osmolality.
What is a normal serum osmolality?
285-295
Fluid movement across a fluid compartment is affected by what two things?
- Properties of membranes separating compartments.
2. Concentration of osmotically active substances within a compartment.
Hydrostatic pressure in capillary (Pc). Pushing/pulling/where?
Pushing pressure out.
Hydrostatic pressure in the interstitium (Pi). Pushing/pulling/where?
Low pressure, typically negative d/t lymphatics
Oncotic pressure in the capillary (pc).
Pushing/pulling/where
Pulling into the capillary.
Oncotic pressure in the interstitium (pi).
Pushing/pulling/where?
Pulling out of the capillary.
A net driving force that is positive moves fluid into the capillary- T/F?
False.
How a solution affects cell volume is a measurement of its _____?
Tonicity:
i.e. hypotonic, hypertonic, isotonic.
What does a hypotonic solution do to a sell?
Causes cell engorgement, it fills with fluid.
What does a hypertonic solution do to a cell?
Causes cell shrinkage, it pulls fluid out of the cell.
Difference between hypovolemia and dehydration?
Hypovolemia is loss of extracellular fluid/reduced circulating volume.
Dehydration is a concentration disorder/osmolality issue/insufficient water present in relation to sodium levels (can be caused by too much Na+ or too little water).
What is the most abundant electrolyte in the ECF?
Na+
Which two electrolytes are responsible for normal osmotic activity of the ECF?
Na+ and Cl-
Unlike the rest of the body/organs, the blood-brain barrier lacks premeability and instead of protein being the major determinant of water movement, what is?
Sodium
What is a normal ECV Sodium?
ICV?
ECV 140
ICV 25
Hyponatremia can be caused by what?
Vomiting. Diarrhea. Diuretics. Adrenal insufficiency. SIADH. Renal failure. Water intoxication. CHF. Liver failure. Nephrotic Syndrome.
Major clinical manifestations of hyponatremia:
Cerebral edema is most significant factor for us.
Coma. Confusion. Headache.
Malaise. Agitation. Anorexia. N/V. Cramps. Weakness.
What three methods of treatment can be used for hyponatremia?
- Fluid restriction.
- Hypertonic saline.
- Osmotic/loop diuretic.
What is important to consider when correcting hyponatremia?
Needs to be corrected slowly.
No more than 1-2mEq/hr and no more than 10-15mEg change in 24 hrs.
What problem can be caused by too fast of a sodium increase?
Myelinolysis=demylenation.
What is the most common cause of hypernatremia?
Water deficiency d/t:
- Excessive loss.
- Inadequate intake.
What are some other causes of hypernatremia?
Exogenous Na+ load.
Primary hyperaldosteronism.
Diabetes Insipidus.
Renal dysfunction.
Clinical manifestations of hypernatremia?
Weakness, seizure, hallucinations, irritability, disorientation, coma, intracranial bleed, hypervolemia, polyuria or oliguria, renal insufficiency.
How is hypernatremia treated?
Estimate water deficit and correct hypernatremia by replacing the water deficit.
Correction should take place over 24hr period.
What electrolyte is in highest concentration within ICV?
Potassium
What is intracellular K+?
Extracellular K+?
Intracellular= 150-160mEq/L. Extracellular= 3.5-5.0mEq/L