Fluid and electrolytes

Fundamentals exam 2 Fluid and electrolytes Fluid Facts  Water- primary body fluid and most critical element; the fundamental solvent for all biochemical processes in the body  Total body water or fluid comprises about 50-40% avg. adult weight  Loss of 5-10% body fluid=SERIOUS  Loss of 15-20% body fluid=may be FATAL  Fluid gained each day should=fluid lost each day (2-3L/day average) Fluid Compartments  Intracellular Fluid: o =Fluid within cells o -2/3 (70%) of total body water  Extracellular Fluid (ECF)=Fluid outside of cells o -1/3 (30%) of total body water o 3 divisions:  Interstitial (fluid that surrounds tissue cells including lymph)  Intravascular/plasma (liquid part of the blood)  Transcellular (minor compartment) Variations in Fluid Content  Fat has a tiny amount of water; lean tissue (muscle) has lots of water  Females have less body fluid than males  Age variations exist in regards to water content of fluid compartments o Older adults (after the age of 60) have less percentage (45%) of body fluid o Infants have more total body fluid and ECF than adults=605 of H2O is founf in ECF, 40% of H2O is found in ICF  What might this mean in regards to fluid loss for an infant?  What age groups at higher risk for alterations in balance? Fluid Balance Example  How to calculate net fluid intake and net fluid output? o A client drinks 1000 mL (I) of water, eats food containing 500 mL of water (I), and the client vomits 250 ml (O) emesis over 24 hours. The 24-hour net gastric fluid intake is: 1000(I) + 500(I) -250(O)=1250 mL o Another client has a NG tube in place. The NG irrigation fluid is 200 mL (I), the NG drainage output is 1300 mL(O), and the emesis is 300 mL (O) over 24 hours. The 24-hour net gastric fluid output is 1300(O) + 300(O) -200(I)= 1400 mL Electrolytes  Works with fluid to keep the body healthy and in balance  They are solutes that are found in various concentrations and measures in terms of milliequivalents (mEq) unit  Can be negatively charged (anions) or positively charged (cations)  For homeostasis body needs: Total body anions (e.g. chloride, bicarbonate, phosphate) =Total body cations (e.g. sodium, potassium, calcium, hydrogen, magnesium)  Major electrolytes in the ECF include sodium, chloride, calcium, bicarbonate  Major electrolytes in the ICF include potassium, phosphorus, magnesium Regulation and Homeostatic Mechanism of Fluid and Electrolyte Balance  Osmosis o Major method of transporting body fluid o Movement of water (or other solute) from an area of lesser to one of greater concentration  Diffusion o Passive movement of electrolytes or other particles down the concentration gradient (from higher to lower concentration)  Active transport o Movement of ions against osmotic pressure to an area of higher pressure; requires energy  Capillary filtration o Movement across a membrane, under pressure, from higher to lower pressure Osmosis, Diffusion and Active Transport Filtration and Osmosis Osmolarity and IV Fluid  Normal serum (blood0 osmolality=275-295 mOsm/L  Isotonic solution: A solution that has osmolarity equal to serum (blood)  Hypotonic solution: A solution that has LOW osmolarity is one that is serum osmolarity  Hypertonic solution: A solution that has HIGH osmolarity is one that is ?serum osmolarity IV Fluid-Isotonic  Total osmolality close to that of the ECF; replace ECF  0.9% Sodium Chloride (NS- normal saline)  Lactated Ringer’s Solution o Has the same osmolality as blood solutions on both sides of the semipermeable membrane are equal in concentration. Expand the blood volume without causing a shift from one compartment to another o Expands ECF and ICF volume o Used to treat fluid volume deficit from hemorrhage, severe vomiting and diarrhea, heavy drainage from GI suction, fistulas and wounds; 1st line resuscitation fluid IV Fluid-Hypotonic  Hypotonic to plasma; replace ICF  0.45% NS(1/2-strength normal saline)  0.33% NS(1/3-strength normal saline) o A solution of lower osmotic pressure moves fluid into the cells, causing them to expand. Shift ECF to ICF with decrease in ECF o Used to “dilute” plasma particularly in hypernatremia o Treats cellular dehydration (as in diabetic ketoacidosis) and hypernatremia (high serum Na+) o Do not use for patients with increased intracranial pressure risk or third spacing risk increased fluid to brain cells and third space o Can worsen existing hypovolemia and hypotension-fluid pulled out of IVC