Fluid and Electrolytes
*Liquid output includes what?
-Liquid output includes all fluids leaving the body, including those lost through perspiration and expiration. EX: Urine, diarrhea, vomitus, nasogastric suction, and chest tube drainage are examples of *measurable output.* *Drainage from surgical wounds and drainage collected in surgical receptacles such as the Jackson-Pratt, Davol, or Hemovac systems are also considered liquid output.
Although the electrolytes move freely among the fluid compartments, each has a primary ______.
-Location. *The location and the function of each electrolyte become important in understanding dx processes. The healthy body maintains homeostasis by correcting any excesses or deficiencies of the electrolytes.
As water moves through all parts of the body, it is constantly being ____. (Hows does fluid leave the body? / 4 ways)
-Lost. -Fluid leaves the body through the kidneys, the lungs, the skin, and the GI tract. *To maintain homeostasis, the normal daily lost must be met by the normal daily intake.
____ has not been a widley recognized electrolyte until recently. (It is now linked as what?)
-Magnesium. -It is now linked as a cofactor in the activation of many enzymes. It also promotes regulation of serum calcium, phosphate, and potassium levels and is essential for integrity of nervous tissue, skeletal muscle, and cardiac functioninfg.
Acid-Base Imbalance
-Means homeostasis of the hydrogen ion concentration. -A steady acid-base balance is normally maintained in the body. An upset in acid-base balance results in either acidosis (when the blood pH is less than 7.35), or alkalosis (When the bloo pH is greater than 7.45).
As water moves through the compartments of the body, it contains substances that are sometimes called _____ or ____ but which are technically known as ________.
-Minerals and salts. -Electrolytes
*Whereas it took seconds for the buffer systems to work, its takes ____ for the lungs to begin to adjust to the pH.
-Minutes. *Even though the respiratory system is slower then the buffers, however, the lungs are able to eliminate large amounts of acid (in the form of carbon dioxide) from the body. Just enough carbon dioxide is retained in the blood to maintain a normal pH level.
TABLE: 22-5: Acid-Base imbalances and Compensatory Mechanisms: *Respiratory Alkalosis*
-Mode of compensation: *Kidney will excrete increased amounts of HCO3- to lower pH.
TABLE: 22-5: Acid-Base imbalances and Compensatory Mechanisms: *Respiratory Acidosis*
-Mode of compensation: *Kidneys will retain increased amounts of HCO3- to increase pH.
TABLE: 22-5: Acid-Base imbalances and Compensatory Mechanisms: *Metabolic Acidosis*
-Mode of compensation: *Lungs "blow off" CO2 to raise pH.
TABLE: 22-5: Acid-Base imbalances and Compensatory Mechanisms: *Metabolic Alkalosis*
-Mode of compensation: *Lungs retain CO2 to lower pH.
Normal urine is ____ because why?
-Normal urine is acidic. -Because the body produces excess acids in the metabolic processes that occur continuously in the body.
NURSING PROCESS: Assessment of fluid, electrolyte, and acid-base balances includes what?
-Nursing hx; physical examination; measuring and recordign I & O; lab studies; and consideration of factors influencing fluid, electrolyte, and acid-base balances.
*How man grams of calcium are in the body? of that, 99% is concentrated where? What about that 1%?
-Of the 1200g of calcium in the body, 99% is concentrated in the bones and the teeth, where it is physiologically inactive. -The remaining 1% is found in the soft tissue and the extracellular fluid. *Calcium is deposited in the bones and mobilized as needed to keep the blood level constant during any period of insufficient intake.
Two general types of disturbances can cause a pH imbalance:
-One imbalance arises from an increase or a decrease in the base substance- bicarbonate. The other imbalance results from adding or subtracting the acid substance- carbonic acid.
A sample of _____ is taken to measure the electrolytes.
-Plasma -The measurement is expressed in milliequivalents (mEq). Rather than electrolytes being measured by their wieghts, they are measured by their electrical activity.
*Because the major route of excretion of potassium is the kidneys, any condition that causes a decrease in urine output also causes what?
-Potassium retention. *Serum potassium levels increase in kidney failure. -A rise in potassium nessecitates continuous monitoring. An important consideration in homeostasis is that kidney function will determine the potassium level in the body.
*Excess intake of foods high in ____, especially with decreased urine output, may cause an increased serum _____ level.
-Potassium/Potassium -
Prevention of osteoporosis focuses on adequate _____ intake (How much? (In both per- and post-menopausal women?)
-Prevention of osteoporosis focuses on adequate calcium intake (1000 mg/day in premenopausal women and postmenopausal women taking estrogen and 1500 mg/ day in postmenopausal women who are not recieving supplemental estrogen.)
Active transport
-Requires energy. -It is a force that move molecules into cell w/o regard regard for their positive or negative charge and against concentration factors that will prevent entry into the cell via diffusion. *Active transport moves fluid and electrolytes from an area of lower concentration to an area of higher concentration.
*There are 4 primary types of acid-base imbalances:
-Respiratory acidosis -Respiratory alkalosis -Metabolic acidosis -Metabolic alkalosis
The 4 primary types of acid-base imbalance are what?
-Respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis.
Calcium (DEFINED): *What is normal blood level?
-Silvery-yellow metal; the most abundant mineral in the body; a positively charge ion, known as a cation. -The normal blood level of calcium (Ca++), a positively charged ion, is approximately 4.5 mEq/L.
The following are examples of cations:
-Sodium (Na+) -Potassium (K+) -Calcium (Ca++) -Magnesium (Mg++)
Substances actively transported through the cell membrane include what?
-Sodium, potassium, calcium, iron, hydrogen, and amino acids. -The movement of glucose into the cells occurs through the process of active transport. *Insulin provides the transport for glucose to leave the intravascular compartment and move into the cells, where the glucose can then be used for energy.
*Calcium is required for the formation and maintenance of what?
-Strong bones and teeth. *It is also necessary for normal blood clotting. *Calcium has a depressing or sedative effect on neuromuscular irritability and thus promotes normal transmission of nerve impulses; it also helps regulate normal muscle contraction and relaxation. *It helps hold body cells together by establishing the thickness and strength of cell membranes. One of the most important functions is to act as an enzyme activator for chemical rxns in the body.
What are the 3 major causes of hypermagnesemia?
-The 3 major causes are impaired renal function, excess magnesium administration, and diabetic ketoacidosis when there is severe water loss. *An excess of magnesium severely restricts nerve and muscle activity.*
The nephrons filter blood at a rate of what per min? And what is this called?
-The Nephrons filter blood at a rate of 125 mL/min, or about 180 L/day. -This is called the glomerular filtration rate and leads to an output of 1 to 2 L (1000 mL-2000mL) of urine per day. *The nephrons reabsorb the remaining 178 L or more of fluid.
Another important influence on the amount of water in the body is what?
-The amount of fat in the individual. *There is a correlation between water content and fat content; fat contains relatively little water. *A woman has proportionately more body fat than a man, which means the woman has less body fluid than the man. *The more obese the individual, the smaller the percentage of body water.
What is the average daily intake of calcium? (What about for infants and females between the age of 15 to 18?)
-The average daily intake is 200 to 2500 mg. *The dietary reference intakes (DRIs) vary from 360 mg for infants to 1200 mg for females 15 to 18 years of age. *During pregnancy and lactation, 1300 mg are required.
The body has three systems that work to keep the pH in the narrow range of normal:
-The blood buffers. -The respiratory system. -The kidneys. *These systems are the three lines of defense that are constantly working to maintain a normal pH.*
How many major buffer systems does the body have? Which is the most important? why?
-The body has 4 major buffer systems. -The bicarbonate-carbonic acid system is the most important. It is responsible mainly for buffering blood and interstitial fluid. *Decreasing the strength of potentially damaging acids and bases reduces the danger these chemicals pose to pH balance.*
What is the body's third line of defense?
-The body's third line of defense is the kidneys.
What is the common txment for respiratory alkalosis?
-The common txment for respiratory alkalosis is sedation and reassurence. *If the cause is anxiety, it helps to make the pt aware of the abnormal breathing pattern. Instruct the pt to breath slowly to retain and accumulate carbon dioxide in the body. -Another effective txment is for the pt to breath into a paper bag, which will cause rebreathing of the exhaled carbon dioxide.
The pH Scale
-A pH of 7 is considered neutral. -Values toward the top (less than 7) are acidic (The lower the # the more acidic). Values towards the bottom (greater than 7) are basic (The higher the number the more basic). (EX: gastric fluid pH: 0-4 (Acid) versus milk of magnesia pH 10.5 (Base))
What is an acid pH #? alkaline?
-A pH of less then 7.35 is acid. -A pH greater than 7.45 is alkaline. -The normal pH of arterial blood is approximately 7.45, whereas the normal pH of venous blood and interstitial fluid is approximately 7.35. *Between 7.35 and 7.45 is considered normal blood pH.*
A serum potassium level of what or greater risks serious cardiac dysrhythmias?
-A serum potassium level of 7 mEq/L or greater risks serious cardiac dysrhythmias.
Hypertonic
-A solution of higher osmotic pressure. -These solutions pull fluid from the cells.
Hypotonic
-A solution of lower osmotic pressure. -These solutions move into the cells, causing them to enlarge. *EACH of these 3 actions occurs through the mechanism of osmosis*
Isotonic
-A solution of same osmotic pressure. -These solutions expand the body's fluid volume w/o causing a fluid shift from one compartment to another.
*A urine specific gravity of more than what indicates concentrated urine? (Seen in conditions of hydration) A urine specific gravity of less than what indicates dilute urine?
-A urine specific gravity of more than 1.030 indicates concentrated urine (Seen in conditins of dehydration), whereas a measurement of less than 1.010 indicates dilute urine (seen in conditios of hydration).
Many dxs create a potential for ____-____ imbalances as well as fluid and electrolyte problems. *DXs that pose a risk for these imbalances include what?
-Acid-base. *They include diabetes mellitus, end-stage renal dx, COPD, as well as severe vomiting and diarrhea.
The body's repiratory system affect the ___ side of the balance- So what does this cause?
-Acid. -So a carbonic acid imbalance causes respiratory acidosis or alkalosis.
As implied by their name, _____ transport processes necessitate the expenditure of energy by the cell, and ____ transport process do not.
-Active/ Passive.
Adequate intake of what, is necessary for the absorption of both calcium and phosphorus?
-Adequate intake of vitamin D. *Because a generous amount of phosphorus is present in many foods, a deficiency seldom occurs.
What is the usual txment for acidosis? (EX: Administration of what?)
-Administration of sodium bicarbonate is the usual txment for acidosis.
First, ____ affects the amount of water in the body. *A new borns body weight is comprised of how much water?
-Age -A newborn's body weight is compromised of 70 - 80% water. That percentage increases in a premature infant to as high as 90%. The infant begins to lose body fluid most rapidly in the first 6 months, and by 12 years the proportion approachs that of an adult.
*Intake includes what?
-All fluids entering the body. *Fluids are either liquids taken orally or those consumed in food, including foods that assume a liquid consistency at room temperature. *Additional intake includes tube feedings and parenteral intake such as IV fluids, blood components, and TPN.
Where is magnesium found in the body?
-Although only small amounts of magnesium are in the blood, it is important in maintaining normal body function. -The majority (60%) is found in the bone, 39% in the muscle and soft tissue, and 1 % in the intracellular fluid, most of which is in the cerebrospinal fluid.
Chloride is necessary for the formation of what in the gastric juices?
-Chloride is necessary for the formation of hydrochloric acid in gatsric juice. *It is also a valuable electrolyte in regulating the osmotic pressure between the compartments and assisting in the regulation of acid-base balance.
What is the chief anion in interstitial and intravascular fluid?
-Chloride.
*OLDER ADULTS: Dehydration*: *Older adults are at increased risk of dehydration because of the following factors: EX: Dehydration, s/s of dehydration, dehydration increases the risk for what?
-Dehydration will sometimes first manifest as mild disorientation. -S/s of dehydration = include thirst, dry mucous membranes, increased heart rate, decreased BP, poor skin turgor, and falt neck veins. -Dehydration increases the risk of othrostatic hypotension.
TABLE: 22-1: Body Fluid Distribution: *Interstitial*
-Description: Fluid in tissues (Between cells or in body spaces) -Fluid: EXs: Interstitial fluid, lymph, cerebrospinal fluid, intraoccular fluid, gastrointestinal (GI) secretions, urine, perspiration, exudates.
TABLE: 22-1: Body Fluid Distribution: *Extracellular*
-Description: Fluid outside cells -Fluid: Extracellular fluid (ECF)
TABLE: 22-1: Body Fluid Distribution: *Intravascular*
-Description: Fluid w/in blooe vessels -Fluid: Plasma
TABLE: 22-1: Body Fluid Distribution: *Intracellular*
-Description: Fluid w/in cells -Fluid: Intracellulart fluid (ICF)
Filtration
-Description: Movement of water and small solute particles, through a filtration membrane; movement occurs from an area of high pressure to area of low pressure. -Examples: In the kidney, water and small solutes move from blood vessels but blood proteins and blood cells do not, this beginning the formation of urine.
Examples of metabolic acidosis include:
-Diabetic ketoacidosis from ketone accumulation, lactic acid elevation (seen in shock), and acidosis from loss of too many bases (As seen in severe diarrhea or renal failure).
The major source of sodium comes from the ____.
-Diet. *That is true about all electrolytes. However, unlike the other electrolytes, sodium is a substance that is frequently necessary to limit in the diet rather than encourage.
What is the usual dietary intake of magnesium? What is the minimum daily requirement?
-Dietary intake is usually 200 to 400 mg daily. -The minimum daily requirment is 250 mg for the average adult, 150 mg for an infant, and 400 mg for a female during pregnancy and lactation.
*Diets low in magnesium may create a risk for what?
-Diets low in magnesium may create a risk for hypertension, cardiac dysrhythmias, ischemic heart dx, and sudden cardiac death. *Decreased intracellular magnesium levels may contribute to the hypertension, abnormal glucose tolerance, and insulin resistance common in diabetics.
The primary passive transport process that move substances through the cell membranes include the following:
-Diffusion -Osmosis -Filtration
During respiratory acidosis, how long does it take for the kidneys to respond?
-During respiratory acidosis, it takes 24-hours for the kidneys to respond in a compensatory mechanism by retaining bicarbonate.
ion
-Electronically charged particle resulting from the break-down of an electrolyte; negatively or positively charged. *Ions develop either a positive or negative electrical charge.
Extracellular versus Intracellular
-Extracellular: Outside of the cells -Intracellular: Inside the cells. *Extracellular fluid is lost from the body more rapidly than intracellular fluid.
*Where sodium is, water will what?*
-FOLLOW!
W/O the sufficient bases, the pH of the blood ____ _____ the normal 7.35-7.45.
-Falls below. -With the loss of base substances, the bicarbonate level will also drop.
*OLDER ADULTS: Dehydration*: *Older adults are at increased risk of dehydration because of the following factors: EX: Fat, kidney function, and mobility/thirst
-Fat replaces lean muscle as aging progresses, leading to a decrease in total body fluid. -The aging kidney is less able to concentrate urine, so more fluid is lost. -Decrease in mobility and diminished sense of thirst often result in decreased fluid intake.
*Because the normal amounts of potassium are so small, fluctuations have the potential to what?
-Fluctuations have the potential to develop into serious problems. *Hypokalemia has the capacity to affect skeletal and cardiac function. The resulting *muscle weakness* causes life-threatening cardiac conduction abnormalities.
The three systems work closely together to maintain a normal _____ ___ concentation.
-Hydrogen ion. *The buffers are immediate and continuous in contributing or accepting hydrogen ions. The respiratory system has the capacity to come into play w/in minutes, regulating the CO2 levels in the blood and thus controlling the carbonic acid.
Hypercalcemia (When does this occur?)
-Hypercalcemia occurs when levels exsceed 5.8 mEq/L. -It may occur when calcium stored in the bones enters in the circulation, for example, in pts who are immobilized. *An increase intake of calcium and vitamin D also causes hypercalcemia. *Neuromuscular activity is depressed, and renal calculi may develop because of the excretion of high levels of calcium by the kidneys*
Hyperchloremia
-Hyperchloremia rarely occurs but is possible when bicarbonate levels fall. The increase in chloride ions represents an attempt to compensate and maintain equal numbers w/the cations in the body fluid. -Because chloride imabalances rarely occur independently of other electrolytes, there are no specific s/s to identify a chloride imbalance.
Hypernatremia causes what? (In terms of fluid in the cells?)
-Hypernatremia causes fluid to shift from the cells to the interstitial spaces, resulting in cellular dehydration and an interruption in cellular processes. *Again a potassium imbalance frequently occurs. In sodium retention, potassium is excreted.
Hyperphosphatemia
-Hyperphosphatemia most commonly occurs as a result of renal insufficiency. Another cause is increased intake of phosphate or vitamin D. *S/s of tetany, numbness and tingling around the mouth, and muscle spasms develop.
Solutions are classified in the body as what?
-Hypertonic, isotonic, or hypotonic according to the electrolyte concentration. *The concentration of the solution will cause the cells of the body to react the same way the red blood cell does.
The effect of metabolic acidosis is what? Why?
-Hyperventilation. -Occuring as the lungs attempt to compensate by blowing off carbon dioxide to lower the PCO2 level.
Hypocalcemia (When does it develope?)
-Hypocalcemia develops when the serum level is less than 4.5 mEq/L.
Hypochloremia (When does this usually occur? and why?) (What are the most common causes?)
-Hypochloremia usually occurs when sodium is lost, because sodium and chloride are frequently paired. -The most common causes of hypochloremia are vomiting and prolonged nasogastric or fistula drainage.
Which is more common hypo- or hyperkalemia?
-Hypokalemia. *Hyperkalmeia is not as common as hypokalemia as long as renal function is normal.
Hypomagnesemia (When does it develop?) *A decrease in magnesium often parallels a decrease in potassium, why?
-Hypomagnesemia develops when blood levels fall to less than 1.5 mEq/L. - A decrease in magnesium often parallels decreased potassium, because if the magnesium level is low, the kidneys tend to excrete more potassium.
Why does hyponatremia occur?
-Hyponatremia occurs because water is being retained in the body, which has a diluting effect on all of the blood components. *The s/s of hyponatremia depend on the cause and how rapid and severe the sodium loss is. *As sodium levels decrease in the extracellular fluid, water is pulled into the cells, causing them to become edematous, and as the fluid moves into the cells, potassium is shifted out; therefore the pt is likely to have a potassium imbalance.*
Hypophosphatemia
-Hypophosphatemia is possible as a result of a dietary insufficiency, impaired kidney function, or maldistribution of phosphate. *Muscle weakness, especially affecting the respiratory muscles, sometimes occurs.
The red blood cells offer an example of osmotic process in the body... how?
-If extracellular fluid is more concentrated than intracellular fluid, the fluid from inside the cells moves out to the extracellular fluid, causing the red blood cell to shrink. -If the fluid among the compartments is in equilibrium, fluid will enter and leave the cell at the same rate and the cell size will not change. *Another example is is when extracellular fluid is less concentrated than the fluid in the RBCs. Fluid moves into the cell, causing it to enlarge. The process will sometimes continue until the cell ruptures.
*The daily requirements for Chloride is equal to that of what? And how much is it? (and what is the main route of excretion?)
-It is equal to that of sodium. -(3.65 to 10.85 g/day) *Foods containing sodium also contain chloride. -The main route of excretion is through the kidneys.
It is necessary for the kidneys to excrete a minimum of how many mL an hour to eliminate waste products from the body?
-It is necessary for the kidneys to excrete a minimum of 30 mL/hr of urine (720 mL/24hr) to eliminate waste products from the body. *The kidneys react to fluid excesses be excreting a more dilute urine; this rids the body of excess fluid and conserves electrolytes.
*Although hyperkalemia is less common then hypokalemia, it is often more what? why?
-It is often more dangerous, because of cardiac arrest, which is caused by overstimulation of the cardiac muscle.
Dietary intake of phosphorus is usually what? What is the minimum daily requirement?
-It is usually 800 to 1500 mg/day. -The minimum daily requirement is 800 mg/day *Higher intake during pregnancy and lactation is needed*
Acid-Base balance (Dedined)
-It means homeostasis of the hydrogen ion (H+) concentraion in the body fluids. -The hydrogen ion concentration is determined by the ratio of carbonic acid (H2CO3) to bicarbonate (HCO3-) in the extracellular fluid.
Water has many functions....
-It provides an extracellur transportation route to deliver nutrients to the cells and carry waste products from the cell. *Once inside the cells, it provides a medium in which chemical rxns, or metabolism, is able occur. -Water also acts as a lubricant for tissues.
Arterial blood gases will reveal whether the blood is what?
-It will reveal whether the blood is acid, neutral, or alkaline. *The more hydrogen ions in a solution, the more acid the solution .The fewer hydrogen ions in a solution, the more alkaline the solution.
The ____ play an extremely important role in fluid balance.
-Kidneys. -If the kidneys are not functioning properly, the body has great difficulty w/regulating fluid balance. The nephrons are the functioing units of the kidney.
*A pt with diabetic ketoacidosis will often develop _____ ______.
-Kussmaul's Respirations. *A pt with diabetic ketoacidosis will often develop Kussmaul's respirations. (deep, rapid breathing), which serve to blow off carbon dioxide in an attempt to reverse the condition of metabolic acidosis.
The details of active and passive transport of substances across cell membranes is much easier to understand if you keep in mind the following two key factors:
1. In passive transport processes, no cellular energy is required to move substances from a high concentration to a low concentration; and... 2. In active transport processes, cellular energy is required to move substances from a low concentration to a high concentration.
Potassium * (What is it? and what is its normal range?) *What is the "intracellular level" of potassium?
-The dominant intracelluar cation . - Normal range: 3.5-5 mEq/L. -The level of potassium in the extracellular fluid is low because potassium is an intracellular electrolyte. -The intracellular level of potassium is (Usually not measured) is much higher at 150 mEq/L. *Of the bodies potassium, 98% is in the cells and 2% is in the extracellular fluid.
The functions of sodium include what?
-The functions of sodium include regulation of water balance. Sodium controls the extracellular fluid volume mainly through osmotic pressure, because water follows the sodium in the body (Where sodium is, water will follow). It also increases cell membrane permeability. Sodium stimulates conduction of nerve impulses and helps maintain neuromuscular irritability. It is important in controlling contractility of muscles, especially the heart.
Which of the two compartments are the largest and what is the percentage?
-The intracellular fluid compartment is the larger of the two compartments, compromising 66% of the body's fluid. It contains the fluid inside the billions of cells w/in the body.
The routes of potassium excretion are what?
-The kidneys (80 % to 90%) and in the feces and perspiration (10% to 20%). *The kidneys controll the excretion of potassium.
What system is the slowest in the line of defense? AND how long does this system's response take?
-The kidneys are the slowest of the systems, but they are efficient enough to return the pH to exactly normal. -Their response takes hours to days.
How do the kidneys assist the bicarbonate buffer system? How about the lungs?
-The kidneys assist the bicarbonate buffer system in regulating production of bicarbonate. -The lungs assist by regulating the production of carbonic acid, which results from combining caron dioxide and water. *The other systems (Of the 4 major buffer systems) are the phosphate, protein, and hemoglobin buffer systems.
If the body loses even 1% to 2% of its fluid, the kidneys conserve fluid by what?
-The kidneys conserve fluid by reabsorbing more water from the renal filtrate, which results in a more concentrated urine.
Sodium and potassium seem to pair off against each other, and the kidneys prefer to conserve which one? why?
-The kidneys prefer to conserve sodium, even when both electrolyets are depleted. *In both normal and abnormal situations, sodium will be reabsorbed and potassium will be excreted.
What is the primary excretion route of sodium?
-The kidneys. *It is important to know that many electrolytes, such as sodium, not only pass into and out of the body, but also move back and forth between a number of body fluids during each 24-hour period.
The major route of magnesium excretion is what?
-The kidneys. *There is a correlation between the amount of magnesium and the amount of potassium excreted. The kidneys do not conserve potassium, but they do conserve magnesium; therefor if a magnesium deficiency develops, the body will conserve magnesium at the expense of excreting potassium.
The Fluid compartments are as follows: *(2 compartments)
1. Intracellular 2. Extracellular (Further divided into:) a. Interstitial b. Intravascular
The ____ are the third line of defense, and although they work more slowly than the other two systems, they are able to what?
-The kidneys. -They are able to eliminate either hydrogen ions or bicarbonate ions, which means they can either increase or decrease pH.
What two major organs are responsible for regulation of the acid and base substances in the body?
-The lungs and the Kidneys. *When imbalances occur, they represent an imbalance in the function of the lungs, the kidneys, or both.
The main function of potassium is what?
-The main function of potassium is regulation of water and electrolyte content w/in the cell. *With sodium and calcium it promotes transmission of nerve impulses and also skeletal muscle function. Potassium assists in the cellular metabolism of carbohydrates and proteins.
What is the major cause of potassium excess?
-The major cause of potassium excess is renal dx, in which potassium is not excreted adequately. *When severe tissue damage occurs, potassium is released from the cells. Shock often accompanies this damage, resulting in reduced kidney output. The result is an elevated potassium level.*
The major cause of potassium loss is what?
-The major cause of potassium loss is renal excretion. The kidneys do not conserve potassium and they excrete it even when the body needs the potassium.
*Boiling a hot dog is an example of osmosis... how?
-What happens when you boil a hotdog in water is an example of osmosis. The water passes through the hot dog skin, which is a semipermeable membrane, in attempt to equalize the # of molecules on both sides of the membrane. Finally, when the hot dog is able to hold no more water, the skin, or semipermeable membrane, ruptures.
Hyponatremia occurs when the sodium drops to less than what?
-When the sodium drops to less then 134 mEq/L.
A # of processes allow this mass movement of substances into and out of cells. These transport proccesses are classified under two general headings:
1. Passive transport process 2. Active transport process
With calcium, _____ contributes to the support and maintenance of ____ and ____.
1. Phosphorus / 2.Bones / 3. Teeth *It is important in many chemical rxns and it acts as a buffer to regulate the bodie's acid-base balance. *It promotes the effectiveness of many of the B vitamins, assists in normal nerve and muscle activity, and participates in carbohydrate metabolism.*
*If the pH drops suddenly from the normal range of 7.35 to 7.45 to 7, the respiratory system is able to return the pH to about 7.2 to 7.3 within how long?
-Within 1 minute. *Chemoreceptors in the medulla of the brainstem provide stimulus to increase respirations; however, as the hydrogen ion concentration approaches normal, the stimulus is lost. The buffers will accomplish the remaining adjustments needed to return the level to normal.
The determination of ____ _____ of fluid loss and fluid ______ is not possible as part of nursing interventions, so you will use approximations.
-exact amounts -replacment *Because it is possible to measure fluid I & O, the importance of accurate record keeping cannot be overemphasized when determining a pt's fluid needs.
The symbol used to indicate hydrogen ion balance is what?
-pH. *When pH is measured, it is actually the hydrogen ion concentration in the pt's body that is measured. A sample of extracellular fluid, specifically arterial blood, is used to determine the body's pH.
hydrostatic pressure
-which is the force of fluid pressing outward on a vessel wall.
*Sodium-containing internal secretions produced every day: 1. Saliva 2. Gastric 3. Intestinal 4. Bile 5. Pancreatic
1. 1300 mL 2. 2000 mL 3. 3000 mL 4. 700 mL 5. 1200 mL
The percentage water makes up in the body declines from that highest precentage at birth to ___% to ___% in adults and ___% to ___% in the older adult.
1. 50-60% 2. 45-55%
Two other important functions of water is to aid in the maintenance of ____ -_____ _____ and to assist in _____ regulation by evaporation.
1. Acid-base balance 2. Heat
Three considerations are important in the blood calcium level:
1. Deposition and resorption of bone. 2. Absorption of calcium from the GI tract. 3. Excretion of calcium in urine and feces.
Table: 22-3: Normal Fluid I & O in an adult Eating 2500 calories per day (Approximate figures): ROUTE: -1.Water in Food -2.Water from oxidation -3.Water as liquid -4.Total*
1. Gain: 1000mL / Route: Skin / Amount of loss: 500mL 2. Gain: 300 mL / Route: Lungs / Amount of loss: 350 mL 3. Gain: 1200 mL / Route: Feces/Kidney / Amount of loss: Feces: 150 mL / Kidney: 1500 mL 4. TOTAL: Gain: 2500 mL / Route: Total / Amount of loss: 2500 mL.
The extracellular compartment contains any fluid outside the ____.
*Cells. -This compartment contains any fluid outside the cells. This compartment is further divided into the interstitial and the intravascular fluid compartments.
The locations of fluids in the body are identified by cateforizing them into ______.
*Compartments. -However, compartment is an abstract term because rather than being contained in a compartment in a specific area, the fluids are in a *constant motion* throughout the body to carry out their functions.
A balance exists among the _____.
*Electrolytes. -The principle electrolytes must be present in proper quantities for normal metabolism and function in the body. For this balance to occur, there must be a negatively charged anion for each positively charged cation.
Substances entering the body begin their journey in the ______ fluid.
*Extracellular -However, to carry out their functions, they have to cross the semipermeable membrane surrounding each body cell and enter the cell. -The fat and protein molecules that make up the membrane are arranged so that some substances can enter the cells and others cannot. Several methods are used to move fluids, electrolytes and other solutes, or dissolved substances from one compartment to another.
What foods can you find magnesium in?
*Magnesium is another electrolyte commonly distributed in foods. -EX: Whole grains, fruits, vegtables, meat, fish, legumes, and dairy products are dietary sources.
*In the ____, more than half of the total body fluid is extracellular.
*Newborn. -As the child grows, proportions gradually reach adult levels.
Table: 22-2: Body Fluid Distribution: *Intracellular fluid*
*Percent of total body fluid: 66 *Fluid Volume: 42
Table: 22-2: Body Fluid Distribution: *Intravascular fluid* (Plasms)
*Percent of total body fluid: 7 *Fluid Volume: 2.8
Table: 22-2: Body Fluid Distribution: *Extracellular fluid/Interstitial Fluid* -Percent of total body fluid -Fluid Volume (L)
*Percent of total/interstitial fluid: 27 *Fluid Volume: 11.2
What is the result (In terms of the pt) with Respiratory Acidosis?
*Shallow respirations result because of the retained carbon dioxide. The pt will also experience a depression of the CNS activity. Because the lungs are responsible for the respiratory parameters of the acid-base balance, the kidneys, which are responsible for the metabolic parameters, will attempt to compensate by ratining the base substance bicarbonate.
A pH lower then what? and higher then what? is considered fatal?
-A pH lower then 6.8 or higher then 7.8 is usually fatal.
Phosphorus
-Chiefly, an intracellular anion in fluid of the body. -The normal blood level of phosphorus, chiefly present as hydorgen phosphate (HPO4-), an intracelluar anion, is approximately 4 mEq/L.
The following are examples of anions:
-Chloride (Cl-) -Bicarbonate (HCO3) -Sulfate (SO4) -Hydrogen Phosphate (HPO4-)
What organ is responsible for the excretion of phosphorus? and how is the remainder excreted?
*The kidneys are responsible for approximately 90% of the excretion of phosphorus. The remainder is excreted in the feces.
Where in the body is phosphorus found? (%)
*The majority (70% to 80%) of phosphorus is found combined with calcium in an individual's bones and teeth, 10% is in an individual's muscle, and the remaining 10% is in the nerve tissue of the body.
______ is critically important to the body.
*Water. -Water constitutes the largest percentage of body weight. *This percentage depends on several factors and varies with each individual.
Daily intake and output is approximately what?
- 2500 mL
Sodium
-(Na+) -A cation and the most abundant electrolyte in the body. -Normal Value: 134 to 142 mEq/L. -It is the major extracellular electrolyte, and because the plasma sample used to measure electrolyte levels comes from the extracellular fluid, the level is high.
Tests for Hypocalcemia include what?
-*Chvostek's sign*: Is a contraction of the facial muscles in response to a light tap over the facial nerve in fron of the ear. -*Trousseau's sign*: Is a carpal (wrist) spasm induced by inflating a blood pressure cuff above the systolic pressure for a few minutes.
ACID-BASE BALANCE
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ACID-BASE IMBALANCE
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ACTIVE TRANSPORT
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Bicarbonate
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Calcium
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Chloride
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Electrolytes
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FLUID COMPARTMENTS
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INTAKE AND OUTPUT
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MOVEMENTS OF FLUID AND ELECTROLYTES
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Magnesium
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Metabolic Alkalosis
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Metabolic acidosis
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PASSIVE TRANSPORT
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Phosphorus
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Potassium
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Respiratory Acidosis
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Respiratory Alkalosis
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In contrast, the intracellular level of sodium is approximately ___ mEq.
-10 mEq.
A normal pH is maintained by a ratio of __ part(s) carbonic acid to ___ part(s) bicarbonate.
-1:20
The Average daily intake of potassium is what?
-60 to 100 mEq.
During a 24-hour period, more than ____ of fluid containing _____ to _____ mEq of sodium are poured into the digestive system.
-8L of fluid containing 1000 to 1300 mEq of sodium. *This sodium, along with that contained in the diet, is almost completely reabsorbed.
Hyponatremia
-A less-than-normal concentration of sodium in the blood. -This is possible when there is a sodium loss or a water excess.
A loss of what % of water is serious in adults? what is fatal? What about in infants?
-A loss of 10% of body fluid is serious in an adult, and a 20% loss is fatal. -In an infant those figures are even more significant. A loss of 5% is serious, 10% is very serious, and 15% is fatal.
Bicarbonate (What is the normal level?) (What is its major function?)
-A main anion of the extracellular fluid. -The normal level of bicarbonate (HCO3-), one of the main ions in extracellular fluid, is 22-24 mEq/L. -It is an *alkaline* electrolyte whose major function is the regulation of the acid-balance, also called acid-alkaline balance.
An example of filtration occurs at the capillary level of the circulation...for EX?
-An example of filtration occurs at the capillary level of the circulation. A force behind filtration is called *hydrostatic pressure*, which is the force of fluid pressing outward on a vessel wall. The pumping action of the heart is responsible for the amount of force, the hydrostatic pressure, that causes water and elactrolytes to move from the capillaries to the interstitial fluid.
Hyperkalemia
-An increase in the bodie's serum potassium level greater than 5 mEq/L. -Because the normal range for serum potassium level is narrow (3.5-5 mEq/L), a slight increase poses the risk of serious consequences. *Potassium is gained through intake and lost by excretion.
*Another function of potassium is to control the hydrogen ion concentration. How?
-Another function of potassium is to control the hydrogen ion concentration. When potassium moves out of the cell, sodium and hydrogen ions move in. The result is the regulation of acid-base balance.
Respiratory Acidosis
-Any conition that impairs normal ventilation causes respiratory acidosis. Retention of carbon dioxide occurs with a resultant increase of carbonic acid in the blood. As pH falls and the normal 20:1 bicarbonate to carbonic acid ratio is upset, the PCO2 (Partial carbon dioxide) level increases.
Electrolytes
-Are substances that when in solution, seperate (or dissociate) into electrically charged particles. *Electrolytes develop tiny electrical charges when they dissolve in water and break up into particles known as ions.
An inverse relationship exists between hydrogen ion concentration and and the pH level: (What is it?)
-As the #s of hydrogen ions increase, the acidity of the solution increases and the pH decreases. -The opposite happens w/alkalinity- The number of hydrogen ions decrease and the pH increases.
The bodies metabolism affects the ___ side of balance- so what does this cause?
-Base -So a bicarbonate imbalance causes metabolic acidosis or alkalosis.
The terms ____ and alkaline are interchangable.
-Base. -A base IS an alkaline substance.
How many Liters of Fluid is equal to the amount of pounds lost?
-Because 1 Liter of fluid equals 2.2 pounds (1 kg), a weight change of 2.2 pounds will reflect a loss or gain of 1 L of body fluid.
*OLDER ADULTS: Dehydration*: *Older adults are at increased risk of dehydration because of the following factors: EX: WHy is giving IV cautioned? Monitor the complete blood count carefully to detect what?
-Because the aging kidney is less efficient at excretion, giving intravenous (IV) infusions or supplements containing sodium or potassium increases the risk of electrolyte imbalance. -Monitor the complete blood count carefully to detect changes in the hematocrit as it relates to hemoglobin. Decreased plasma volume elevates the hematocrit, whereas the hemoglbin level remains constant.
Bicarbonate acts as a what?
-Bicarbonate acts as a buffer to neutralize acids in the body and maintain the *20:1* bicarbonate to carbonic acid ratio needed to keep the body in homeostasis. *The kidneys selectively regulate the amount of bicarbonate retained or excreted.
Both ____ and ____ ____ are at risk for complications of illness from dehydration or fluid shifts because why?
-Bothe obese and older adults. *Because they have less fluid reserve in their bodies.
*When a deficiency results from sodium loss, the body attempts to compensate by what?
-By decreasing water excretion.
Water is able to move freely from one compartment to another by what?
-By diffusion.
A simple and accurate method of determining water balance is what?
-By weighing the pt under exact conditions, for example, same time of day, same amount of bed clothing, same type of gown, and same attached equipment, such as electrodes. *Empty all drainage bags before weighing the pt*
*How is calcium removed from the body?
-Calcium is removed from the body via urine and feces.
Phosphorus and _____ have an inverse realtionship in the body: Ex?
-Calcium. -For ex: An increase in one causes a decrease in the other. *As blood calcium levels increase, a decrease in phosphorus levels is necessary, and vice versa.
The energy required for active transport processes is obtained from an important chemical substance called what? Where is this substance produced?
-Called adenosine triphosphate (ATP). *ATP is produced in the mitochondria from nutrients and is capable of releasing enery that in turn enables the cell to work. -For active transport process to occur, the breakdown of ATP and the use of the related enery are required.
*Some major dietary sources of sodium are what?
-Cheese, table salt, seafood, processed meat, canned vegtables, canned soups, ketchup, and snack foods, such as pretzels and potato chips. *Precise regulation and control of sodium levels is required for survival.
*OLDER ADULTS: Dehydration*: *Older adults are at increased risk of dehydration because of the following factors: EX: Incontinence, tastes, physiologic changes
-Incontinent older individuals sometimes restrict fluid intake to reduce the frequency of urination. -To compensate for changes in taste, older adults often over salt their foods, resulting in electrolyte and fluid imbalances. -Physiologic changes in the skin and mucous membranes make them less reiable indicators of dehydration.
____ are also at risk for dehydration.
-Infants. *More than half of an infant's fluid is extracellular.
*Possible deficiencies in calcium arise from a variety of problems:
-Infusion of excess amounts of citrated blood (citrates bind to the calcium) -Excessive loss through diarrhea. -Inadequate dietary intake of calcium or vitamin D. -Surgical removal of parathyroid glands. -Decreased parathyroid function. -Pancreatic dx -Small bowel dx.
Interstitial Fluid (Defined) (What % is this) *What are examples of interstitial fluids?
-Interstitial fluid is between the cells, or in the tissues. It accounts for approximately 27% of the fluid in the pt's body. -EX: lymph, cerebrospinal fluid, and gastrointestinal (GI) secretions.
*____ _____ contain large amounts of potassium.
-Intestinal Fluids. *In excessive GI losses from gastric suctioning or prolonged vomiting, potassium tends to become depleted. *Severe diarrhea, fistulas, ileostomy, villous adenoma (tumor of the intestine that produces potassium-containing mucus), and excessive diaphoresis will also somtimes result in potassium loss.
The body has 2 primary fluid compartments: *(What are they?)
-Intracellular and extracellular. *Even though each is specific in its location and functions, there is constant interaction between compartments.
With each inhalation by the pt, oxygen enters the lungs and moves into the ______ compartment and into the cells by diffusion.
-Intravascular compartment. * Gases, including oxygen, nitrogen, and carbon dioxide, leave the capillaries and diffuse into the cell membrane and become distributed throughout the body.
Anions
-Ions with a negative charge.
Cations
-Ions with a positive charge.
Tetany
-Is a condition characterized by excessive muscle cramps, laryngeal spasms, stridor, carpal spasms (Trousseau's sign), pedal spasms, and contraction of facial muscles. *(Hypocalcemia)*
Milliequivalent (mEq)
-Is a measure of the chemical activity or chemical combining power of an ion. -The chemical activity of an electrolyte is compared with the chemical activity of hydrogen. One milliequivelant of any electrolyte has the same chemical combining power as 1 mEq of hydrogen. *In each fluid compartment of the body, the cations and anions balance each other w/their chemical combining power to maintain electrical neutrality, which again keeps the body in homeostasis.*
Homeostasis
-Is a relative constancy in the internal environment of the body, naturally maintained by adaptive responses that promote healthy survival. *To maintain homeostasis, it is necessary that bodily fluids and electrolytes remain w/in the exact limits of normal.
Diffusion (defined) (EX)
-Is the movement of particles in all directions through a solution or gas. *In diffusion, solutes move from an area of higher concentration to an area of lower concentration, which eventually results in an equal distribution of solutes w/in the two areas.* EX: Diffusion occurs, for exmple, when ink is dropped into a glass of water. The ink will disperse in all directions until it is evenly distributed throughout the fluid. When diffusion occurs in the body, the molecules have the same action as the ink spreading through the water.
Osmosis
-Is the movement of water from an area of lower concentration to an area of to an area of higher concentration. *Osmosis equalizes the concentration of ions or molecules on each side of the membrane. The flow of water will continue until the # of ions or molecules on both sides of the membrane is equal.
Intravascular Fluid
-Is the plasma w/in the vessels. *The cells of the blood are considered solid particles. -After the cells are removed, the liquid that remains is the plasma. It makes up the remaining 7% of the fluid volume.
Filtration
-Is the transfer of water and dissolved substances from an area of higher pressure to an area of lower pressure.
Hypomagnesemia causes s/s of what? And what are the major causes of low magnesium?
-It causes s/s of increased neuromuscular irritability similar to those observed with with hypocalcemia. -The major causes of low magnesium are increased excretion by the kidneys, impaired absorption from the GI tract, and prolonged malnutrition.
Metabolic alkalosis depresses the what?
-It depresses the Central Nervous System. -The respiratory rate is decreased, thus decreasing the amount of carbon dioxide exhaled and raising the level of plasma CO2. *Again, as with other acid-base imbalances, txment is aimed at the cause.*
Hypokalemia
-It is a decrease in the body's potassium to a level less than 3.5 mEq/L. *Because the normal range for a serum potassium level is narrow (3.5-5 mEq/L), a slight decrease has profound consequences.
Txment for respiratory acidosis is aimed at what? (What is the primary goal?)
-It is aimed at imporoving ventilation. -The primary goal is to support the pt's respirations. *Intermittent positive-pressure breathing (IPPB) to promote exhalation of carbon dioxide, antibiotic administration for any respiratory infection, adequate hydration (2 to 3L/day) to keep the mucous membranes moist and aid in removal of secretions, and use of bronchodilators to help reduce bronchial spasms will be possible elements of the txment regimen. *Therapy is also directed at correcting the primary condition responsible for the imbalance.*
Respiratory Alkalosis (What is it caused by?)
-It is caused by hyperventilation. -Respirations that increase the rate, depth, or both have the potential to result in the loss of excessive amounts of carbon dioxide with a resultant lowering of the carbonic acid level in the blood. *The pH rises because of the decrease in carbonic acid, which is blown off with each exhalation.
Chloride (What is it and what is the normal blood level?)
-The normal blood level of chloride (Cl-), an extracellular anion, is 96 to 105 mEq/L. -DEFINED: Negatively charged extracellular anion; a salt hydrochloric acid. *It is the chief anion in interstitial and intravascular fluid.
What is the ratio needed for homeostasis?
-The ratio needed for homeostasis is 1 part carbonic acid to 20 parts bicarbonate.
What are the s/s of hypocalcemia?
-The s/s of hypocalcemia are neuromuscular irritation and increased excitability. *As neuromuscular s/s increase, *tetany* is possible.
Magnesium (Defined): What is the normal level?
-The second most abundant cation in the intracellular fluid of the body. -The normal level of magnesium (Mg++), the second most abundant cation in the intracellular fluid, is 1.5 to 2.4 mEq/L.
*The use of what kinds of medications promotes hypokalemia?
-The use of diuretics, such as thiazides or furosemide (Lasix), promotes hypokalemia. ALSO: *Conditions that cause injury to the cells in turn cause the release of potassium from the cells to the interstitial spaces and ultimately to the kidneys. If the renal function is normal than the potassium will be excreted.
For every 1 million hydrogen ions that enter the body, the buffer systems are able to neatralize all but how many? What happens when the buffer system becomes exhausted?
-They are able to neutralize all but 5. *Once the buffer systems are exhausted, the body calls on the second line of defense: The lungs. By speeding up or slowing down respirations, the lungs have th capacity to increase or decrease the amount of carbon dioxide in the blood. Removing carbon dioxide from the blood lowers the carbonic acid level; this is the mechanism by which the respiratory system regulates pH.
*The best food sources of calcium are what?
-They are milk and cheese. -Other sources include beans, nuts, cauliflower, lettuce, and egg yolks.
The intracellular and extracellular compartments are seperated by what? (What does this do?)
-They are seperated by a semipermeable membrane. *This membrane allows for a constant back-and-forth flow as nutrients are taken into the cell and waste products are carried out.
Foods especially high in phosphorus include what?
-They include beef, pork, fish, poultry, milk products, and legumes.
Hypermagnesemia (When does this develop?)
-This develops when blood levels exceed 2.5 mEq/L. -It rarely occurs when kidney function is normal.
Hypernatremia *What is this? and what are the #s?
-This is a greater-than-normal concentration of sodium. -The sodium level exceeds 145 mEq/L. -It is caused by an excess of sodium or a decrease in body water. *The body attempts to correct the imbalance by conserving water through renal reabsorption.
Metabolic Acidosis
-This is possible as a result of either a gain of hydrogen ions or a loss of bicarbonate- in other words, retaining too many acids (H+ ions) or losing too many bases (HCO3-)
Metabolic Alkalosis (When does this result?)(What are the most common causes?)
-This results when a significant amount of acid is lost from the body or an increase in the bicarbonate level occurs. -The most common causes are vomiting gastric content (usually high in acid) and gastric suction. -Metabolic alkalosis is also possible in pts who ingest excess amounts of alkaline agents, such as bicarbonate-containing antacids (ex: Alka-Seltzer, soda bicarbonate).
Too much or too little potassium affects which muscle (the most)?
-Too much or too little potassium affects the heart muscle and has potential to result in a life-threatening disturbance in cardiac rhythm (dysrhythmia).
Blood buffers (What do they do?)
-Try thinking of blood buffers as chemical sponges. -They circulate throughout the body in pairs, neutralizing excess acids or bases by contributing or accepting hydrogen ions. *One buffer will dominate if the solution is too acidic; the other will dominate if the solution is alakline.*They work w/in a fraction of a second to prevent an excessive change in the hydrogen ion concentration.
*Who are at high risk for developing a deficeint fluid volume?
-Very young, very old, and obese pts are at a higher risk for developing a deficient fluid volume.
What 3 components are necessary for the absorption and utilization of calcium?
-Vitamin D, calcitonin, and parathyroid hormone (parathormone)are necessary for the absorption and utilization of calcium.
The action of the lungs in coping with an imbalance is simple: (What is it?): How do the kidneys cope?
-We breath more slowly or more quickly. -The kidneys have much more selective control. They are able to excrete varying amounts of acid or base into the urine. If the acidity of the blood rises above normal, the kidneys will selectively eliminate more acids so the hydrogen ion concentration increases in the blood. If the blood becomes too alkaline, the kidneys will selectively eliminate more bases, especially bicarbonate.
*A ___-____ diet usually provides adequate potassium. (How much is required each day?)
-Well-balanced diet. * Approximately 65 mEq of potassium is required each day. -Potassium is widely distributed in natural foods; fruits, such as oranges, bananas, apricots and cantaloupe; legumes; leafy vegtables; potatoes; mushrooms; tomatoes; carrots; and meat are sources of potassium.
*Even though chloride accounts for more than _____ of the anions in the body, it is usually not considered ____.
1. two-thirds / 2. alone. *Chloride has the ability to diffuse quickly between the intracellular and extracellular compartments and combines easily with sodium to form sodium chloride or with potassium to form potassium chloride. *It is more often linked with sodium*
Other causes of hyperkalemia include what?
1.Excessive use of salt substitutes (Most of which use potassium as a substitute for sodium); 2. Potassium supplements (oral or IV); 3. Infusion of a large volume of blood nearing its expiration date (Serum concentration increases the longer donated blood is stored); 4. Drugs such as beta-blockers, which inhibit potassium shifts into cells.; 5. Potassium-sparing diuretics such as spironolactone.;6. Chemotherapy, which causes cell death or lysis with release of high levels of intracellular potassium into the blood; 7. Angiotension converted enzymes ACE inhibitors); 8. NSAIDS; 9. Aminoglycosides.
Osmosis
Description: Diffusion of water through a selectively permeable membrane in the presence of at least one impermeable solute. Examples: Diffusion of water molecules into and out of cells to correct imbalances in water concentration.
Diffusion
Description: Movement of particles through a membrane from an area of high concentration to an area of low concentration- that is, down the concentration gradient. Examples: Movement of carbon dioxide out of all cells; movement of sodium ions into nerve cells as they conduct an impulse.
Water loss is replenished in two ways:
First, By ingestion of liquids and food, and second, by metabolism, both of food and and in body tissues.