1. Fluid Balance

2. Body Fluid Spaces ECF: Interstitial fluid ICF ECF 2/3 of body fluid
Vascular Space

3. Osmosis
Water moves through a semipermeable membrane from an area of lower concentration to an area of higher concentration until concentrations are equalized on both sides of the membrane.

4. Osmosis

5. Osmolality
Osmolality is the concentration of solute Which side has the higher osmolality?
A B

6. Osmolality
Osmolality is the concentration of solute The higher the osmolality of a solution, the greater its pulling power.
A B

7. Osmolality Na and protein are major solutes in plasma
Urea and glucose are both large particles that increase the serum osmolality, when present in excess amounts in the blood
A B

8. Isotonic, Hypotonic, and Hypertonic Solutions

9. Isotonic Isotonic IV fluids have the same osmolality as normal plasma
Isotonic IV fluids include
Normal saline (NS, 0.9% NaCl)
Ringer’s solution: contains Na, K, and Ca
Lactated Ringer’s solution (LR): contains Na, Cl, K, Ca and lactate
Isotonic IV fluids provide no free water

10. Hypotonic
Hypotonic IV fluids have a lower osmolality than normal plasma
Water is pulled out of vessels into the cells, resulting in decreased vascular volume and increased cell water
Hypotonic IV fluids are used to prevent and treat cellular dehydration by providing free water to the cells

11. Hypotonic
Hypotonic IV fluids are contraindicated in acute brain injuries because cerebral cells are very sensitive to free water, absorbing it rapidly and leading to cellular edema
Hypotonic IV fluids include:
5% dextrose in water (D5W): 2/3 enters cells and 1/3 remains in the ECF
.45% saline (1/2 NS) and saline (1/4NS); ½ moves into cells and ½ remains in the ECF

12. Maintenance Fluids Saline mixed with dextrose and water
5% dextrose in 0.45 saline (D5 1/2NS) and 5% dextrose in 0.225% saline (D5 1/4 NS)
Have a degree of hypotonic effect
Provides some water to cells
Provides calories
5% dextrose in 0.9% saline (D5 NS)
Provides some free water to cells
Provides less free water and more EC water

13. Hypertonic
Hypertonic IV fluids have a higher osmolality than normal plasma
Water is pulled from the cells into the vessels, resulting in increased vascular volume and decreased cell water
Hypertonic solutions are used to treat very specific problems and are administered in carefully controlled, limited doses in order to avoid vascular volume overload and cell dehydration

14. Hypertonic Hypertonic fluids include
Saline solutions greater than 0.9% (3% saline & 5% saline)
Clinical indications for hypertonic saline use is when the serum Na is dangerously low (≤ 115mg/dL)
Hypertonic saline is used with great caution and the limited doses need to be on an IV infusion pump

15. Hypertonic
What assessments need to be monitored when a client is receiving a hypertonic saline solution?
H2O

16. Hypertonic
Clients receiving hypertonic saline solutions require frequent monitoring of:
Vital signs
Neurological status
Lung sounds
Urine output
Serum Na

17. Hypertonic
Dextrose solutions (10% dextrose & 50% dextrose) are considered hypertonic solutions
Used on a limited basis to treat client with hypoglycemia

18. Colloid Volume Expanders
A colloid is a large solute particle, such as protein that pulls fluid from tissue into the vessels by osmosis, increasing vascular volume

19. Fluid Balance Fluid output Normally via skin, lungs, GI tract, kidneys
Abnormally via vomiting, wound drainage, hemorrhage
Influenced by
Antidiuretic hormone (ADH)
Renin-angiotensin-aldosterone system (RAAS)
Atrial natriuretic peptides (ANPs)