Fluids and Electrolytes
|Fluids (Water)|| Provides an extracellular transportation route to deliver nutrients to the cells and carry waste products from the cells.|
Acts as lubricant for tissues
Aids in maintenance of acid base balance
|Intracellular fluid|| 66% of body's fluid|
Contains the fluid inside the billions of cells within the body
|Extracellular fluid|| Contains any fluid outside the cell|
Divided into interstitial and intravascular compartments.
|Interstitial fluid|| Between cells or in the tissue|
Accounts for approx. 27% of fluid in the body
Ex: Lymph, cerebrospinal fluid, gastrointestinal secretions.
|Intravascular fluid|| Plasma within the vessels|
Make up 7% of fluid volume.
|Fluid leaves body through the...|| Kidneys|
|Minimum hourly amount of waste excreted from kidneys||30 ml/hr|
|1 liter of fluid equals....||1 kg (2.2 lbs) a weight change of 1 kg will reflect a loss or gain of 1 L of body fluid.|
|Sensible fluid losses||Fluids that we are aware of and are measurable|
|Insensible fluid losses|| May occur without the person's awareness. Minimal loss in an adult is about 800 ml/daily|
Occur through the skin and lungs
|Passive transport||No cellular energy is required to move substance from a high concentration to a low concentration.|
|Active transport||Cellular energy is required to move substance from a low concentration to a high concentration through the use of ATP|
|Diffusion|| The movement of particle in all directions through a solution or gas.|
Solutes move from an area of higher concentration to an area of lower concentration, which eventually results in an equal distribution of solutes within the 2 areas.
|Osmosis|| Diffusion of water from and area of lower concentration to an area of higher concentration.|
Equalizes the concentration of ions or molecules on both sides of the membrane.
Flow of water will continue until the number of ions or molecules on both sides are equal.
|Hypertonic solutions|| A solution of higher osmotic pressure|
Pulls fluid from the cells
|Isotonic solutions|| A solution of same osmotic pressure|
Expands the body's fluid volume without causing a fluid shift.
|Hypotonic solutions|| A solution of lower osmotic pressure.|
Moves into the cell, causing them to enlarge.
|Filtration||Transfer of water and dissolved substances from an area of higher pressure to an area of lower pressure.|
|Risk factors for Fluid Volume Excess/Hypervolemia|| Heart failure|
Cirrhosis of the liver
|Manifestations of Fluid Volume Excess/Hypervolemia|| Edema, Jugular vein distention|
Abnormal lung sounds, tachycardia
Increased BP, Pulse pressure
Rapid pulse, Increased weight
Cough, Ascites (Fluid build up in abdomen)
|Medical management for Fluid Excess Volume/Hypervolemia|| Directed at the cause|
Restriction of fluids and sodium
|Fluid volume deficit/Hypovolemia||An abnormal decrease in volume of blood|
|Electrolytes||Develop tiny electrical charges when they dissolve in water and break up into particles known as ions.|
|Cations|| Have a positive charge|
|Anions|| Have a negative charge|
Hydrogen Phosphate (HPO4-)
|Sodium|| Most abundant electrolyte in body|
Kidneys are primary excretion route
Regulates water balance
Controls extracellular fluid volume
|Normal sodium level||134-142 mEq/L|
|Hyponatremia|| Less than normal concentration of sodium in the blood.|
Sodium level less than 134 mEq/L
Occurs because water is being retained, or water excess.
Restrict fluid intake and replace loss with fluids containing sodium, not plain water.
|Hypernatremia|| Greater than normal concentration of sodium in the blood.|
Sodium level greater than 145 mEq/L
Can occur when there is a sodium excess or water loss.
Decrease sodium intake in diet.
|Potassium|| Dominant intracellular cation|
Approximately 65 mEq required daily
Excretion through kidneys, feces, and perspiration.
Regulation of water and electrolyte content within the cell.
|Normal potassium level||3.5 to 5 mEq/L|
|Hypokalemia|| Decrease in body's potassium to a level below 3.5 mEq/L|
Major cause of loss is renal excretion
Can affect skeletal and cardiac function
Cause muscle weakness, can cause life threatening cardiac conduction abnormalities.
|Hyperkalemia|| Increase in the body's serum potassium level about 5 mEq/L|
Major cause is renal disease
Can lead to overstimulation of the cardiac muslce which can lead to cardiac arrest.
|Chloride|| An extracellular anion|
The chief anion in interstitial and intravascular fluid.
Main route of excretion is kidneys
Needed for the formation of HCL in gastric juice and assists in regulation of acid-base balance.
|Normal Chloride level||96-105 mEq/L|
|Hypochloremia|| Usually occurs when sodium is lost.|
Most common causes are vomiting and prologed nasogastric or fistula drainage.
|Hyperchloremia||Rarely occurs but may be seen when bicarbonate levels fall.|
|Calcium|| A positively charged ion|
Needed for normal blood clotting and formation, and maintenance of strong bones and teeth
Regulates muscle contraction and relaxation and acts as an enzyme activator for chemical reactions in body.
|Normal Calcium level||8.5-10.5 mg/dL|
|Hypocalcemia|| S/S develop when the serum level is below 4.5 mg/dL|
Deficiency may be caused by infusion of excess amounts of citrated blood, excessive loss through diarrhea, inadequate dietary intake.
|Tetany||excessive muscle cramps, laryngeal spasm, stridor, contraction of facial muscles (Chvostek's sign) and carpal spasms (Trousseau's sign)|
|Hypercalcemia|| Occurs when levels exceed 10.5 mg/dL|
Neuromuscular activity is depressed and renal calculi may develop.
|Phosphorus||Chiefly and intracellular anion and present as hydrogen phosphate (HOP4-)|
|Normal phosphorus level||4 mEq/L|
|Hypophosphatemia|| Can occur from a dietary insufficiency, impaired kidney function, or maldistribution of phosphate.|
Muscle weakness, especially affecting the respiratory muscles occurs.
|Hyperphosphatemia|| Most commonly occurs as a result of renal insufficiency. Also can occur with increased intake of phosphate or vitamin D.|
S/S: Tetany, numbness and tingling around the mouth, and muscle spasms.
|Magnesium||The second most abundant cation in the intracellular fluid.|
Important in maintaining normal body function.
Dietary intake usually 200-400 mg per day
Major route of excretion is the kidneys
Promotes regulation of Ca+, Ph-, and K+, is essential for the integrity of nervous tissue, skeletal muscle function, and cardiac functioning.
|Hypomagnesemia||Develops when blood levels fall below 1.5 mEq/L|
A decreased level often parallels decreased potassium.
S/S: Increased neuromuscular irritability, mental status changes, paresthesias, seizures, and cramps.
Major cause are increased excretion by the kidneys, impaired absorption from the GI tract, and prolonged malnutrition.
|Normal magnesium levels||1.5-2.5 mEq/L|
|Hypermagnesemia||Develops when blood levels exceed 2.5 mEq/L|
Rarely occurs when kidney function is normal
Major causes are impaired renal functions, excess magnesium administration, and diabetic ketoacidosis when there is severe water loss.
S/S: Hypotension, vasodilation, thirst, loss of deep tendon reflexes, and respiratory depression
May lead to coma or cardiac arrest
|Bicarbonate|| A main anion of the extracellular fluid|
An alkaline electrolyte whose major function is the regulation of the acid base balance.
|Normal Bicarbonate levels||22-24 mEq/L|
|Acid base balance means...||Homeostasis of the hydrogen ion concentration in the body fluids.|
|Blood buffers||Circulate throughout the body in pairs, neutralizing excess acids or bases by contributing or accepting hydrogen ions.|
|Lungs||Can increase or decrease the amount of carbon dioxide in the blood|
|Kidneys||Excrete varying amounts of acid or base|
|Bicarbonate imbalance causes...||Metabolic acidosis/alkalosis|
|Carbonic acid imbalance causes...||Respiratory acidosis/alkalosis|
|Respiratory acidosis||Cause by any condition that impairs normal ventilation.|
A retention of carbon dioxide occurs with a resultant increase of carbonic acid in the blood
As pH falls, the Pco2 level increases
Shallow respirations result because of retained carbon dioxide and depression of the central nervous activity.
Kidneys will retain increased amounts of HCO3 to increase pH
Primary treatment is aimed at improving ventilation.
|Respiratory Alkalosis|| Caused by hyperventilation|
pH rises because of decrease in carbonic acid being blown of with each exhalation.
Kidneys will excrete increased amounts of HCO3 to lower pH
Treatment is sedation, breathing into paper bag.
|Metabolic Acidosis||Can result from a gain of hydrogen ions or a loss of bicarbonate. Retaining too many acids, or losing too many bases.|
Without sufficient bases, the pH of the blood falls below normal; the bicarbonate level will also drop
The effect is hyperventilation, as lungs attempt to compensate by blowing off carbon dioxide to low the Pco2 Level.
Lungs "blow off" CO2 to raise pH
Treatment is administration of sodium bicarbonate.
|Metabolic Alkalosis||Lungs retains CO2 to lower pH|
|Arterial Blood Gases normal values|| pH: 7.35-7.45|
Paco2: 35-45 mm Hg
Pao2: 80-100 mm Hg
HCO3: 22-24 mEq/L