1. Fluid Balance

2. Body Fluid Spaces ECF: Interstitial fluid ICF 2/3 of body fluid ECF 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 (D 5 W): 2/3 enters cells and 1/3 remains in the ECF –.45% saline (1/2 NS) and 0.225 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 (D 5 1/2NS) and 5% dextrose in 0.225% saline (D 5 1/4 NS) Have a degree of hypotonic effect Provides some water to cells Provides calories – 5% dextrose in 0.9% saline (D 5 NS) Provides some free water to cells Provides calories 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? H2OH2O

16. Hypertonic Clients receiving hypertonic saline solutions require frequent monitoring of:

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)