Chapter 29 Fluids, Electrolytes, and Introduction to Acid-Base Balance

Older adult body weight

50% to 55%.

Solvent

A solvent is generally a liquid in which solutes, or solids, are dissolved to make a solution

NAFVE

Check dependent body sites for edema. Dependent sites are those that are hanging down or where blood can pool. When the patient is sitting in a chair, the lower legs, feet and ankles are in a dependent position. When the patient is lying on his or her back in bed, the sacral area is in a dependent position.

fluid volume deficit notes

Fluid volume deficit is caused by prolonged insufficient fluid intake or by loss of fluid. Patients with fluid loss may not always experience thirst, especially the elderly and patients with brain injuries. Safety: Young children should be offered fluids often. They can develop a fluid volume deficit if they are without fluids for a prolonged time.

intracellular fluid

In healthy patients, approximately two-thirds of body fluids reside inside individual cells. Fluid within the cells is called intracellular fluid (ICF).

NAFVE

Monitor urine output every 2 to 3 hours, or even every hour if inadequate urine excretion is suspected.

Calcium (Ca2+)Cation

Normal Blood Range: Total Ca2+: 8.2-10.2 mg/dL Ionized Ca2+: 4.64-5.28mg/dL Function: Strengthen skeletal bones and teeth Ionized Ca2+: stimulates conduction of electrical impulses via nerves, which controls muscle contraction and relaxation, includes heart muscle Initiates enzyme action Cellular membrane permeability Source for Intake: Dairy products, green vegetables, shellfish, salmon, dried beans

Nursing Actions for People with hypernatremia

Nursing actions for patients with hypernatremia include the following: Monitoring for elevated blood pressure and bounding pulse. Teaching patients to monitor their dietary sodium intake in an effort to prevent future problems. (See Table 29.3 for a list of foods high in sodium.)

More Notes

Once the water has entered the bloodstream, it becomes part of the plasma and is circulated throughout the blood vessels until it reaches the capillary beds. This is where semipermeable capillary walls allow fluid, nutrients, and oxygen to move into the interstitial spaces

Nursing Actions for Fluid Volume Deficit

Replace fluids orally and by IV as ordered by the health-care provider

Hormonal Regulation

Several hormones help to maintain fluid levels in the body and to produce an appropriate volume of urine output. Antidiuretic hormone (ADH) and aldosterone both work on the kidneys to decrease urine production and increase body fluid level. Atrial natriuretic factor (ANF) causes the kidneys to excrete more urine to decrease the body fluid level

Sodium

Sodium is the primary electrolyte involved in determining extracellular fluid volumes and controls fluid distribution throughout the body because water follows sodium. Sodium stimulates conduction of electrical impulses needed for skeletal and heart muscles to contract and relax.

Respiratory Alkalosis

When a patient is breathing rapidly and deeply, he or she will "blow off" more carbon dioxide than normal. Some mental states and illnesses that might cause this include fear and anxiety, fever, and overdose of aspirin. All of these cause hyperventilation. Remember that carbon dioxide combined with water makes carbonic acid, so when hyperventilation occurs, more carbonic acid is lost than with normal breathing. When acid is lost, the blood pH moves towards alkalosis. Because the lungs are unable to regulate pH normally, this is referred to as respiratory alkalosis

Nursing Actions for Chloride Imbalances

When you care for patients with chloride imbalances, it will be important for you to follow these nursing actions: Encouraging foods high in sodium chloride for hypochloremia. These are listed in Table 29.3. Monitoring I&O carefully. If the patient routinely drinks water without electrolytes or drinks bottled water, the health-care provider may restrict the patient from drinking it. Measuring fluids lost through vomiting or diarrhea for appropriate replacement. Watching for signs of respiratory or neurological depression; high and low levels of chloride can change the acid-base balance of the body and cause serious neurological and respiratory changes. Monitoring the patient's I&O and laboratory results because hyperchloremia may be associated with metabolic acidosis.

infants and premature infants

highest percentage of water in their body weight, with water making up 65% to 80% of their total weight.

Osmosis

when water moves through a semipermeable membrane to equalize concentration of solutes on each side of the membrane. Real life: A raisin contains concentrated sugars and other solutes. When you soak it in a tablespoon of water, the raisin eventually plumps up as water crosses its skin (semi-permeable membrane) to equalize fluid in each side. Body: If a patient is given an IV solution that is more concentrated than plasma, some of the water in the red blood cells will leave the cells and cross the cell membrane to equalize the concentration in the fluid on the outside of the cell. This causes the red blood cell to shrivel, which is called crenation.

Blood is composed of ?

80% to 83% water. Safety: Fluid loss interferes with homeostasis and impairs body functions so much that a person can only survive a few days without water intake. The volume of fluid in the body is directly affected by the amount of water ingested and absorbed from the gastrointestinal (GI) tract.

Osteoporosis and Calcium Levels

A disease known as osteoporosis causes a higher level of calcium resorption than the level being deposited in the bones. Resorption is the process of removing calcium from the bones and absorbing it back into the bloodstream. The higher level of resorption leaves the bone structure weakened, with tiny holes or gaps within the bone, giving it a honeycomb appearance. Because of their weakened structure, the affected bones are easily fractured, sometimes without a trauma or fall. For example, a patient may present for treatment reporting that he or she fell. Upon examination, a femur fracture is identified. Your first thought may be that the fall caused the fracture, which is normally the case. However, a patient with severe osteoporosis may experience a fracture without trauma, which then causes the individual to fall because the broken bone is no longer able to bear the person's weight. It is important to remember that even though a patient has a healthy serum calcium level, he or she may have a severe deficit of calcium in the bones. Bone density tests help detect this situation early.

Hypermagnesemia

A high level of magnesium, known as hypermagnesemia, will slow the nervous system responses, including the respiratory rate, and generally depress neuromuscular junctions. (See Table 29.4 for information about magnesium imbalances.)

fluid volume deficit

A true fluid volume deficit (hypovolemia) results when the patient loses both fluid and the electrolytes contained in that fluid. The most common cause for this is the loss of a large amount of blood through hemorrhage

INTRODUCTION TO ACID-BASE BALANCE

Acid-base balance refers to the balance of the acids and alkaline bases of body fluids. A prolonged or extreme imbalance between the two will lead to death. Safety: An individual's blood pH must stay within a very narrow range that is slightly alkaline to ensure survival—between 7.35 and 7.45. Other body fluids each have a different pH (Fig. 29.4). Box 29.7 briefly explains the pH scale.

NAFVD

Administer IV fluids at the rate ordered. Safety: Even though a patient who has fluid volume deficit needs fluids, rapid infusion of IV fluids may cause fluid volume excess, or overload.

NAFVD

Administer antiemetic medications ordered for nausea or vomiting, or antidiarrheal medication for loose stools.

NAFVE

Administer diuretics as ordered by the health-care provider. Safety: Some diuretics such as furosemide, a loop diuretic, are known to deplete the serum level of potassium, so check those levels often.

NAFVE

Administer ordered diuretics and monitor for effectiveness.

Nursing Actions for Calcium Imbalances

Administering oral calcium tablets or IV calcium along with vitamin D as ordered by the health-care provider for hypocalcemia. Safety: IV infusion of calcium can cause bradycardia and death if administered too rapidly. Use an infusion pump and assess the IV site and rate of infusion every 30 to 60 minutes. Monitoring the patient with hypocalcemia for muscle twitching, tetany (severe muscle spasms), and ECG changes. Assessing for spasms of the facial muscles and the arms and legs, as well as tingling around the mouth or tips of the fingers. The patient may become disoriented and confused. Being aware that patients suffering from hypocalcemia may also present with Trousseau's sign (Fig. 29.2) and Chvostek's sign (Fig. 29.3). Nursing actions for hypercalcemia include the following: Encouraging fluids and monitoring IV infusions, as ordered, to help lower the calcium levels. Monitoring the patient for bradycardia, digestive complaints, and visual disturbances if also on digitalis (Lanoxin) because high calcium can cause digitalis toxicity.

Acid-Base Imbalance

An uncorrected acid-base imbalance will lead to either acidosis or alkalosis. Acidosis is an increase of acids in the blood and moves the pH to below 7.35. Alkalosis is an increase in blood alkalinity and moves the pH to above 7.45. Normally, there are minimal shifts back and forth in the blood pH between slightly acidotic and slightly alkalotic as conditions change. The buffer, respiratory, and renal systems are able to accommodate these shifts and bring the blood back to a normal pH, between 7.35 and 7.45. The respiratory system responds quickly to minute changes in pH and works very rapidly, continuously adjusting as needed to help balance the pH. However, it is only capable of making small adjustments in the pH. When a larger pH adjustment is required, especially for a longer period of time, the kidneys will take action to return the pH to normal ranges.

More Notes

Approximately 80% of the volume of water entering the first section of the large intestine, the cecum, is absorbed there. The water molecules must cross through the intestinal wall and capillary wall to enter the bloodstream.

NAFVE

Assess daily weights at the same time of the day, preferably before breakfast, using the same scales and with the patient wearing the same type of garment.

NAFVD

Assess each patient to be sure that he or she has voided at least every 8 hours and notify the health-care provider if this does not occur.

Signs and Symptoms of Fluid Volume Deficit

Be alert for signs and symptoms that may indicate the presence of or risk for developing fluid volume deficit. Be especially vigilant when monitoring infants, children, and older adults, who are at increased risk for fluid imbalances. Patient report of little or no fluid intake or urine output Patient report of frequent vomiting or diarrhea Flushed, pale, hot, dry skin with nonelastic turgor (nonelastic turgor is a very late sign) Complaints of thirst or nausea Dry, cracked tongue and lips Elevated heart rate Weak pulse Fever Low blood pressure In newborns, sunken or depressed fontanels Decreased level of consciousness (severe fluid volume deficit) Confusion (severe fluid volume deficit) Assess the patient's oral mucous membranes for dryness and provide mouth care as needed.

Bicarbonate Buffer System

Bicarbonate (HC03") occurs naturally in the body as the main anion in the extracellular fluid. The normal range for bicarbonate is 22 to 26 mEq/L. It is an alkaline substance that helps decrease the acidity of the blood. Carbonic acid is formed when carbon dioxide combines with water. It is a weak acid that helps decrease the alkalinity of the blood. A buffer is a substance that can bind with a strong acid or base to prevent major changes in the pH of body fluids. The bicarbonate buffer system consists of the following two chemicals: Sodium bicarbonate (NaHCO3): a weak base Carbonic acid (H2CO3): a weak acid To maintain acid-base balance, the following ratio must be met: 1 part carbonic acid to 20 parts sodium bicarbonate. When sodium bicarbonate, which is a weak base, combines with a strong acid, such as hydrochloric acid, it forms two different substances: sodium chloride (salt), which is a base, and carbonic acid, which is a weak acid. When this occurs, the pH moves back into the normal range. The kidneys help control the pH of the blood by releasing or reabsorbing sodium bicarbonate as needed. If carbonic acid, which is a weak acid, combines with a strong base, it helps decrease the strength of the base and move the pH back towards normal. The levels of carbonic acid are regulated by the lungs.

Phosphorus (PO43-) Anion

Blood Range: 2.5-4.5 mg/Dl May be higher in children Function: Vital for all tissues; muscle and red blood cell functions; metabolism of fat, protein, carbohydrates; manufacturing ATP energy source Source of Intake: Meats, fish, egg yolks, dairy products, nuts, beans, legumes, whole grains, soft drinks

Distribution of Body Fluids

Body fluids are found in one of two water compartments: the intracellular space or the extracellular space.

Calcium

Calcium (Ca2+) is the most common mineral in our bodies; 99% of it is combined with phosphorus and located in the bones and teeth, with the remaining 1% located outside the skeletal system in the blood. This 1%, known as the total serum calcium level, easily and rapidly exchanges back and forth between the blood and bone. Ionized calcium, which is available for the body's use, stimulates the transmission of electrical impulses along nerve pathways, including the electrical conduction pathways of the heart that control contraction and relaxation of the heart. (See Table 29.3 for more information about calcium.) Vitamin D is required for absorption of calcium from the GI tract. They are often combined in supplements for better absorption. Hypocalcemia is defined as having lower-than-normal serum calcium. It is common with diseases that cause poor digestive absorption, such as anorexia or inflammatory bowel disease. Chronic low calcium levels can cause loss of bone and high blood pressure. (See Box 29.6 for information about osteoporosis, which is due to calcium moving from the bone to the blood.) Hypercalcemia is the term for too much calcium in the blood, which can cause a variety of conditions. (See Table 29.4 for more information about calcium imbalances.)

More Notes

Carbon dioxide and other waste products are diffused from the interstitial fluid across the capillary wall into the bloodstream to be carried away and removed from the body. Waste products from the cells travel via the interstitial fluid into the bloodstream and on to the kidneys, where the waste products are filtered out into the urine.

Nursing Actions for Fluid Volume Excess/When you care for patients with fluid volume excess, whether due to too much sodium, heart failure, or kidney failure, you will perform these nursing actions:

Carefully monitor I&O for fluid volume excess (intake greater than output).

Chloride

Chloride (Cl-) accounts for approximately two-thirds of the body's anions and is commonly bound with sodium or potassium ions. Chloride is found in interstitial fluid, lymph fluid, sweat, and gastric and pancreatic digestive juices, with lesser amounts in the blood. Chloride combines with hydrogen to form hydrochloric acid in the gastric juices of the stomach, which is used to break down foods. (See Table 29.3 for more information about chloride.) Chloride is nearly always chemically bonded to another electrolyte in the body. As a result, chloride imbalances are most commonly seen in combination with other electrolyte imbalances. A below-normal serum level of chloride is known as hypochloremia. When the chloride level is above normal levels it is called hyperchloremia. (See Table 29.4 for more information about chloride imbalance.) Nursing Actions for Chloride Imbalances

ELECTROLYTES

Electrolytes are chemical substances that, when dissolved in water, release either their positive or their negative electrically charged particles, called ions. These ions are capable of conducting electrical current. An anion is a negatively charged ion such as chloride (Cl-). A cation is a positively charged ion such as sodium (Na+) or potassium (K+). Electrolytes play various roles, including helping to transmit electrical impulses through nerve and muscle fibers and assisting to maintain balance between the ICF and ECF compartments. Table 29.3 provides the normal blood ranges, functions, and nutritional sources of the various electrolytes.

fluid deficit S&S

Extreme nausea, even though there is no vomiting, may prevent someone from drinking fluids for several days. Another cause of fluid deficit is abnormal fluid losses. Losses can be due to bleeding, prolonged tachypnea, excessive sweating, fever, diarrhea, vomiting, or excessive urination due to diuresis. Severe depletion of fluid volume also occurs in hot climates or with extreme amounts of exertion or exercise. Fluid volume deficit can occur in varying degrees of seriousness, ranging from mild to life-threatening.

Body Composition

Fatty tissue contains less water than muscular tissue, so body composition and size influence the volume of water in the body. Men, who typically are more muscular than women, tend to have a higher percentage of body weight due to water. Obese individuals and the elderly have a lower percentage of body fluid due to lack of muscle mass.

Loss

Fluid Source: Gastrointestinal Tract Volume: 100-200mL vomiting can cause loss 6,000mL

Loss

Fluid Source: Insensible Perspiration Volume: 400-600mL If enviromental temperatures are high enough, can cause loss up to 1,000 mL/hr

Loss

Fluid Source: Insensible respirations Volume: 200-300mL

Gain

Fluid Source: Oral Liquids Volume: 1,000-2,000mL

Gain

Fluid Source: Water in food Volume: 800-900mL

Gain

Fluid Source: Water production through metabolism of ingested food 100-300mL

Loss

Fluid source: Urine Volume: 1,200-2100 mL Diuretics can cause loss up to 6,000mL

Fluid Volume Imbalances

Fluid volume imbalances involve not just gaining or losing fluid, but also losing electrolytes or having them become more concentrated. As a nurse, you will need to be very aware of your patients' fluid volume and electrolyte status throughout their care.

Fluid Notes

Fluid volumes are very closely related to the concentration of sodium chloride, also known as table salt. If individuals take in or retain too much sodium chloride, they will also retain excess water. Water will travel back and forth between ICF spaces and ECF spaces, depending on where there is more sodium chloride. One way to think of it is where sodium goes, water follows. That is why, after eating a large bag of buttered, salted popcorn, you find yourself thirsty and drinking lots of liquids.

Movement of Body Fluids

Fluids are continually moving across membranes to other compartments in an effort to maintain equilibrium between the compartments. This movement of fluid is controlled by several processes, including osmosis, diffusion, and filtration.

Metabolic Acidosis

If a patient has a condition that causes an increase in hydrogen ions or a very low level of bicarbonate ions, it will result in metabolic acidosis. Conditions that can cause this include prolonged diarrhea, intestinal disorders, and surgical removal of the colon. Because the intestinal tract contains large amounts of bicarbonate ions, damage to this area leads to loss of bicarbonate, causing the pH to lower. Two other conditions that also cause this situation are lactic acidosis, often the result of shock, and ketoacidosis, the result of uncontrolled diabetes mellitus. Both of these are types of metabolic acidosis. When patients are in kidney failure, their kidneys cannot respond to changes in pH, hydrogen ions are retained, and the pH falls below 7.35.

Metabolic Alkalosis

If a patient has a condition that causes either a marked loss of hydrogen ions or a marked increase of sodium bicarbonate, it will lead to metabolic alkalosis. Some conditions that cause this are severe vomiting and nasogastric suction. Both of these situations cause the patient to lose large amounts of hydrochloric acid from the stomach. Other possible causes of metabolic alkalosis include taking diuretic medications and overuse of antacids or taking sodium bicarbonate for heartburn. Diuretics can cause a loss of potassium in the urine, which stimulates the kidneys to excrete hydrogen ions to save potassium ions, leading to the pH increasing above 7.45. Antacids and sodium bicarbonate are alkaline, and excess amounts lead to alkalosis.

NAFVE

If the patient is on a fluid restriction, determine the volume of fluid allowed on each shift and monitor it closely. Post the volume of fluids allowed for each shift above the patient's bed or on a marker board to serve as a reminder for patient, family, and staff. Collaborate with the dietary service to limit fluids sent on meal trays. Provide patient and family teaching to ensure their understanding and cooperation.

Role of the Respiratory System

In relation to acid-base balance, the lungs are responsible for one of two functions: either retaining more carbon dioxide (CO2) to increase the acidity of the blood or removing excess carbon dioxide from the blood to decrease the acidity of the blood. To retain CO2, the lungs slow the rate of respiration, allowing the formation of carbonic acid to help increase acidity. To remove excess CO2, the lungs increase the rate of respiration so that they can exhale more CO2 from the body into the atmosphere. The decrease in carbonic acid in the blood decreases the acidity. This relatively simple respiratory mechanism helps to maintain the pH within the normal range between 7.35 and 7.45. This action taken by the lungs can change the blood pH quickly, but the change does not last a long time.

Sodium Notes

In the blood, sodium is measured in milliequivalents; in food, it is measured in milligrams. Safety: The American Heart Association recommends that healthy adults consume no more than 2,300 mg per day. This is about 1 teaspoon of table salt. Safety: For people with hypertension, those over the age of 40, and African Americans, it is recommended that they consume no more than 1,500 mg per day because of their risk factors for cardiovascular disease.

interstitial space

Interstitial space—the areas surrounding and between the cells. This fluid is also called tissue fluid or interstitial fluid.

Magnesium

Like calcium, magnesium (Mg2+) is also part of the bone structure. About 50% to 60% of the body's magnesium is located within bone cells. It also assists with the work of the heart, muscles, and nerve cells. Magnesium also helps to lower blood pressure by dilating the peripheral blood vessels. Research shows that magnesium can help protect the heart and support the immune system. Magnesium is sometimes used by patients who experience twitching and uncontrolled movements of their legs while trying to sleep. The magnesium works at the neuromuscular junctions, producing somewhat of a sedative effect, reducing the twitching of the muscles. (See Table 29.3 for more information about magnesium.)

Functions of Water in the Body

Maintaining temperature: Water helps to maintain body temperature, whether warm or cold. Because it takes longer for the temperature of liquid to change than it does for solid matter, the body's water protects from extreme changes. For example, when you step out of a warm house into a blizzard, your body fluids help to preserve heat. When the body is overheating, evaporation of fluid from sweat and from breathing will keep the body cool. However, water can only help the body to preserve heat for a certain length of time. When the body becomes dehydrated after large amounts of sweat are lost and not replenished, water is no longer available to decrease the body's temperature. Safety: When patients are dehydrated, they can lose the ability to regulate body temperature.

Diuretics and Potassium Levels

Many patients are prescribed diuretics to assist with elimination of excess fluids. Patients often call these drugs their "water pills." Some types of diuretics, such as loop diuretics, cause the patient to lose potassium and sodium. Furosemide (Lasix), a common loop diuretic, can also cause magnesium and calcium losses. Thiazide diuretics, such as hydrochlorothiazide, also cause potassium loss. Because hypokalemia is common with these types of diuretics, the health-care provider may also prescribe extra dietary potassium or potassium supplements. According to the Institute of Medicine, adequate intake of potassium for adults is 4,700 mg per day. Most patients will be prescribed a supplement dose of 20 milliequivalents (mEq), which equals about 1,500 mg per day. The patient must then obtain the rest of their potassium intake through their diet. Teach your patients taking diuretics to follow up for their blood work as ordered. It is very important that electrolyte levels be checked regularly. Encourage patients to eat foods high in potassium, such as bananas, which provide about 500 mg of potassium each. Other foods high in potassium include yellow and orange fruits such as oranges and apricots, avocados, and sweet potatoes; other good sources include baked potatoes, yogurt, white beans, and halibut. It is also very important to know if your patient is on a potassium-sparing diuretic, such as spironolactone. These types of diuretics do not cause potassium loss in the kidneys. Therefore, these patients should avoid excessive potassium in their diets and supplements containing potassium because of the risk of hyperkalemia

NAFVD

Measure and monitor intake and output (I&O) for balance. Normally, the output total should be equal to or within 300 to 500 mL of the total intake. If a patient has a fluid volume deficit, urinary output initially will be less than the intake but should gradually increase as the patient becomes more hydrated. Safety: Persistent urinary output below 30 mL per hour may indicate renal failure.

Nursing Actions for Fluid Volume Deficit

Monitor electrolyte levels closely.

NAFVE

Monitor meal trays to ensure there are no extra salt packets or high-sodium foods because the patient will likely be on a low-sodium diet.

NAFVE

Monitor vital signs for elevated blood pressure, increased pulse rate, bounding pulse, elevated temperature, and pulse oximetry every 4 hours.

NAFVD

Monitor vital signs for low blood pressure, elevated pulse rate, and elevated temperature.

Fluid Volume Excess

Most fluid volume excess (hypervolemia) is caused by retention of sodium and water in extracellular fluid. Causes of this include increased intake of dietary sodium; administration of IV fluids containing sodium; or retention of sodium or fluid as a result of medication or kidney, heart, or liver disease. Fluid volume excess causes decreased urinary output and excess fluid in the intravascular and interstitial spaces. Infants, small children, frail elders, and patients with heart failure or renal failure are more susceptible to fluid overload than average adult patients. Even when fluids are ordered orally or intravenously, it can place the patient in fluid overload. (See Box 29.4 for the signs and symptoms of fluid overload.)

Sodium Notes

Most individuals think of sodium intake as "only that salt they have sprinkled on their food." However, a significant amount of sodium can be found in canned and processed foods. Even some prescription and over-the-counter medications contain sodium in the form of sodium bicarbonate Too much sodium or too little sodium can cause a variety of problems. symptoms of both hyponatremia (too little sodium in the blood) and hypernatremia (too much sodium in the blood.)

Magnesium (Mg2+)Cation

Normal Blood Range: 1.6-2.2 mg/dL Funtion: Assists neuromuscular function; dilation of arteries and arterioles; enzyme function; carbohydrate and protein metabolism Source for Intake: Leafy green vegetables, whole grains, beans, fish (halibut), almonds, soybeans

Sodium (Na+)Cation

Normal Blood Range: 135-145 mEq/L Changes in direct proportion to Cl- Functions: Controls fluid osmolality and volume of bloodStimulates conduction of electrical impulses along nervesWorks with calcium to regulate muscle contraction Source for Intake: Salt: Most individuals obtain 90%-94% from packaged, processed foods, including bacon, ham, canned vegetables, soy sauce, steak sauces, other sauces, salad dressings, processed cheeses, sandwich meats, salty snacks such as chips, jerky, pretzels, canned soups, brothsAdding table salt to prepared foods

Potassium (K+)Cation

Normal Blood Range: 3.5-5.3 mEq/L Function: 98% in ICF helps regulate fluid balance 2% in ECF is important for neuromuscular functions, especially for the heart's contractility and rhythm Source for Intake: Dried fruits, tomatoes, potatoes, spinach and other leafy greens, oranges, bananas, cantaloupe, red meat, chicken, fish, nuts, soy products

Chloride (Cl-)Anion

Normal Blood Range: 97-107 mEq/L Changes in direct proportion to sodium Has inverse relationship with bicarbonate Functions: Assists sodium in regulating fluid osmolality and volumeImportant for acid-base balance Production of gastric HCl Source for Intake: High-sodium-content foods listed aboveLettuce, tomatoes, celery, olives, seaweed

Nursing Actions for Sodium Imbalance

Nursing actions for patients with hyponatremia include the following: Administering additional sodium, either orally, via nasogastric tube, or intravenously as ordered by the health-care provider. Examples of IV fluids are 0.9% sodium chloride (normal saline) and lactated Ringer's solution. Assessing vital signs for hypotension, increased pulse rate, or decreasing pulse volume. Monitoring I&O and evaluating balance. If hyponatremia is severe, assessing the patient for signs and symptoms of increased intracranial pressure. Decreases in LOC may be very subtle, such as decreased attentiveness or mild drowsiness, or obvious, such as profound unresponsiveness. Changes in LOC are also exhibited as excitement, ranging from subtle signs of increasing nervousness, anxiety, or agitation to strong unexplained anger or outbursts and erratic body movements. †When seen together, these three signs are known as Cushing's triad.

Phosphorus

Phosphates are ions of the element phosphorus, but the two names are generally used interchangeably. Phosphate (PO43-) is the primary intracellular anion and is essential to all body tissues, especially red blood cells and muscle cells. Phosphorus is used in energy exchange by cells. It also serves as part of the acid-base buffering system. Similar to magnesium, most of the body's phosphorus is stored in the bones and teeth. Small amounts are found in nerve tissue and muscle cells. (See Table 29.3 for information about phosphorus.) When there is a low magnesium level or a high calcium level, you will want to check for a low phosphorus level, known as hypophosphatemia. Phosphorus is abundant in the Western diet. Hyperphosphatemia is the name for excessively high blood levels of phosphorus; few signs or symptoms accompany the elevation. (See Table 29.4 for information about phosphorus imbalances.)

Potassium

Potassium (K+) is represented by the letter "K" because of its ancient name, Kalium. It is the most abundant cation in the intracellular fluid. Although 3.5 to 5.3 mEq/L is considered to be the normal serum range for potassium, some health-care providers prefer to keep the serum potassium above 4.0 mEq/L in patients with heart problems to reduce risk of arrhythmias. The Institute of Medicine recommends a dietary intake of 4.7 g of potassium per day to help decrease long-term health problems (see Table 29.3). Hypokalemia is a potassium level that is below the normal range, and hyperkalemia is an elevated level. Safety: Both too low and too high levels of potassium levels can affect the heart rhythm and cause life-threatening arrhythmias. (See Table 29.4 for further information regarding potassium imbalances.)

The Dangers of Potassium Chloride

Potassium chloride is a dangerous drug—so dangerous, in fact, that in some states it is given by injection to prisoners sentenced to die—which is why it is so very important to be careful when administering it to a patient. The following story illustrates just how careful you should be: A student nurse on a medical-surgical clinical was administering medications. One of the patients was scheduled to receive a daily dose of potassium chloride (KCl) via the IV route. After the student read the order, she interpreted the order to mean IV push, which means to inject the drug directly into the IV line over a couple of minutes, rather than to dilute the KCl in a 1,000-mL bag of IV solution and infuse it over several hours. The student administered the KCl via direct IV push. The concentrated dose of KCl interrupted the electrical conduction in the patient's heart. The patient arrested and died. This tragic but true event could have been prevented by using basic safety measures. Always make certain you are familiar with any medication you are going to administer no matter what it is—over-the-counter or prescription, narcotic or vitamin supplement, or electrolyte. If you are not familiar with the specific medication, always look it up in your drug reference book. Safety: When administering an electrolyte in less than 1,000 mL of fluid via the IV route, a second nurse should be asked to double-check and confirm the prepared medication, route, and rate before administration.

Fluid Intake in Elders

Seniors, whether they live independently, with caregivers at home, or in a long-term care facility, are at high risk for dehydration. Many seniors experience a declining sense of thirst due to changes in the brain. When this occurs, either the senior or the caregiver will need to ensure that the senior is drinking water even when he or she does not feel thirsty. The recommended amount of fluid intake per day is about 1,800 mL, or 2 quarts. Alcohol and dietary supplements are less hydrating than water. Some liquids such as coffee and tea can also have a diuretic effect. Elderly patients with cardiac or kidney disease, however, may be placed on a fluid restriction. These seniors will need to monitor how much fluid their physician or nurse practitioner has prescribed for them to take daily, monitor their daily weight, and watch for increased or decreased amounts of urine production.

Signs and Symptoms of Fluid Volume Excess

Signs and symptoms of fluid volume excess may appear suddenly. Assess the potential of each patient receiving IV fluids for risk of fluid volume excess. Increased respiratory rate, shortness of breath with exertion, or labored respirations Sudden onset of coughing Jugular vein distention Increased blood pressure or pulse pressure Full, bounding pulse Edema of extremities or dependent areas, such as feet, ankles, lower legs, and sacrum while in bed Auscultation of crackles or wheezes in the lungs and muffled or distant heart sounds Weight gain Increased urine production Pink or frothy sputum Decreased oxygen saturation level Anxiety or fear that is unexplainable by the patient

Fluid Notes

The concentration of certain elements inside of cells is much higher than that outside of cells.

Signs and Symptoms of Increased Intracranial Pressure

The earlier the signs and symptoms are detected, the better the patient's chance of escaping brain damage and permanent neurological deficits. Observe for even subtle changes in level of consciousness (LOC). Early Sign Changes in LOC* Late Signs Rising systolic blood pressure to hypertensive levels† Widening pulse pressure† Decreasing pulse rate to bradycardia† Pupillary changes Impaired body temperature control by the hypothalamus

Fluid Notes

The electrolyte potassium and protein molecules are found in much higher concentrations inside of cells than outside of cells

More Notes

The goal of all the fluid movement back and forth between water compartments is to maintain constant relative proportions of fluid and solutes.

Role of the Kidneys

The kidneys have the ability to perform four basic functions as needed to maintain the proper blood pH: Retain hydrogen (H+) Excrete H+ Retain sodium bicarbonate (NaHCO3) Excrete NaHCO3 When the blood becomes too acidic, the kidneys remove hydrogen ions from the blood and excrete them into the urine. Also, the kidneys reabsorb more bicarbonate back into the blood. Together these two actions will make the blood more alkaline, helping to return the pH back to normal. When the kidneys sense that the blood is too alkaline, they will retain more hydrogen ions in the blood and also will excrete more bicarbonate into the urine. Both of these actions make the blood more acidic, once again helping to return the pH back to normal. This action of the kidneys works more slowly than the lungs, changing the pH balance over a period of days rather than hours. Once the pH changes are made, however, they are longer lasting than those made by the bicarbonate-carbonic acid buffer system or the respiratory system. Therefore, the kidneys could be described as the most effective of the three systems for balancing blood pH.

Regulation of Body Fluids

The most important factor determining water intake is thirst. The hypothalamus in the brain receives information from osmoreceptors, which detect when there is an elevated concentration of solutes in the blood. Increased concentration of the plasma (osmolality) results in low fluid levels in the blood. This stimulates thirst. However, if there is too much fluid or if there is a problem with the osmoreceptors, the hypothalamus in the brain does not cause you to be thirsty.

Normal Fluid Losses

The most obvious ways in which the body loses fluid is through elimination of urine and feces. Fluid lost through urine is controlled by ADH, aldosterone, and insensible fluid loss. Insensible fluid loss is that which cannot be directly measured, such as fluid lost during respiration and

extracellular fluid

The other one-third of the body's fluid is located outside the cells and is known as extracellular fluid

What is pH?

The pH scale is used to measure the acidity or alkalinity of a substance. The number on the pH scale corresponds to the "parts of hydrogen" (pH) in the substances. The scale ranges from 0 to 14. The number 7 on the scale is neutral, neither acidic nor alkaline. Pure water has a pH of 7. Substances with a higher concentration of hydrogen ions (H+) have a lower number on the pH scale and are more acid. Substances with a higher concentration of hydroxyl ions (OH-) have a higher number on the pH scale and are more alkaline (see Fig. 29.4).

semipermeable

The tissues that form the blood vessel walls and the cellular membranes

Semipermable cont..

This means that they allow passage of some substances, but not all substances, through the cell membrane or blood vessel walls.

Regulation of Acid-Base Balance

Three systems work together in the body to regulate and maintain acid-base balance. Each system does its part to compensate for impairment in the other systems and correct any changes in pH. The following are the three systems: Bicarbonate/carbonic acid buffer system Respiratory system—the lungs control retention and elimination of carbon dioxide (CO2), an acid Renal system—the kidneys control retention and elimination of hydrogen (H), an acid, and sodium bicarbonate (NaHCO3), a base Note: Sodium bicarbonate (NaHCO3) is commonly used interchangeably with bicarbonate (HCO3-) when discussing blood gases, as you will notice in this chapter.

Functions of Water in the Body/Transporting electrolytes, minerals, vitamins, and waste products

Transporting electrolytes, minerals, vitamins, and waste products: Water transports electrolytes such as sodium and potassium; an electrolyte is a salt that transmits electrical impulses when it is dissolved in water. Water also transports minerals such as zinc and copper and vitamins such as vitamin C and the B-complex vitamins to all the individual cells throughout the body. Water also transports waste products from the cells to the blood so that they can be eliminated in the urine.

Distribution of body fluids notes

Very small amounts of additional fluids are found in certain body spaces, such as the cerebrospinal fluid around the brain and spinal cord. the fluids within the chambers of the eye, and synovial fluid in joints. These are not significant amounts, however, so they are not considered a part of fluid and electrolyte balance.

Lubricating the joints and digestive tract:/Functions of Water in the Body

Water helps to lubricate joints such as the knees and elbows, reducing friction and allowing for smoother movement. It also provides for the smooth passage of food through the digestive tract, from the mouth through the large intestine.

Water

Water normally accounts for 50% to 70% of the body's total weight and serves as the liquid in which the body's solid components are dissolved. Age affects the percentage of water that comprises total body weight.

Protecting the brain and spinal cord:/ Functions of Water in the Body

Water, as a component of spinal fluid, acts as a cushion for organs such as the brain and spinal cord, protecting these organs from damage from outside forces.

Notes

When a difference in concentration exists in the fluid on two sides of a semipermeable membrane, the body attempts to balance those differences.

Respiratory Acidosis

When a patient does not breathe as deeply and frequently as normal, he or she will retain more carbon dioxide than normal. Some conditions that could cause this include opioid pain medications, certain other types of medications, pneumonia, and chronic respiratory diseases such as emphysema and chronic bronchitis. All of these cause hypoventilation, which traps carbon dioxide in the lungs where it converts to carbonic acid. When acid is trapped, the blood pH moves towards acidosis. Because the lungs are unable to regulate pH normally, this is referred to as respiratory acidosis.

Dehydration

When a patient loses only fluids, the remaining electrolytes become more concentrated. This is called dehydration. Hemorrhage and dehydration require different treatments.

Nursing Actions for Magnesium Imbalances

When caring for patients with magnesium imbalances, it is important to remember that both deficient and excessive levels of magnesium are closely linked to potassium and calcium imbalance. Nursing actions for hypomagnesemia include the following: Assessing for imbalance in potassium and calcium as well as magnesium; restoring the magnesium level will also require restoring the balance of potassium and calcium Administering oral magnesium tablets as ordered for mildly low magnesium Monitoring I&O and assessing for fluid imbalances Teaching patients which foods are good sources of magnesium, such as nuts (cashews and almonds), seeds (sunflower, pumpkin, and flax), bananas, milk, oatmeal, and broccoli Nursing actions for hypermagnesemia include the following: Monitoring IV calcium, if ordered Administering diuretic medications as ordered Assisting with scheduling the patient for dialysis if required to lower the magnesium level Asking about the patient's use of over-the-counter antacids and laxatives containing magnesium, which could contribute to elevated magnesium levels

Nursing Actions for Phosphorus Imbalances

When caring for patients with phosphorus imbalance, take the following nursing actions: Ask the patient about a history of malnutrition and laxative use. Administer oral medications, as ordered, that will bind phosphorus. Patients with chronic kidney disease may have high phosphorus levels. Encourage a low-phosphorus diet if ordered by the healthcare provider. If the patient has hypophosphatemia, encourage dietary changes and administer supplements as ordered. If IV phosphorus is ordered, it must be infused no faster than 10 mEq per hour.

Nursing Actions for Potassium Imbalances

When caring for patients with real or potential potassium imbalances, it is critical for you to monitor them closely. When you care for patients with a potassium imbalance, you must be careful to prevent correcting the situation too much one way or the other. Nursing actions for patients with hypokalemia include the following: Administering supplemental potassium chloride (KCl) as ordered in oral tablets, liquids, powders, or IV formulations. If the patient routinely takes certain diuretics, be certain to administer potassium as ordered by the healthcare provider to prevent hypokalemia (see the Patient Teaching Connection feature). Safety: If the patient has less than 30 mL per hour of urinary output, hold all oral potassium supplements and check IV fluids for added potassium. Notify the health-care provider before administering potassium since doing so when urine output is very low could lead to kidney damage. Monitoring the serum lab reports of all your patients, being especially mindful of the serum potassium levels if the patient Is vomiting or having diarrhea, Has a nasogastric tube to suction, or Is taking loop diuretics. Safety: KCl is never administered by IV push or intramuscularly. Because of a high potential for death associated with IV potassium, most institutions require that it be mixed into a diluted IV solution by the pharmacy and then be double-checked by the nurse before it is administered to the patient. Administering IVs containing KCL over several hours at the preferred rate of 10 to 20 mEq per hour. The infusion rate should never exceed 40 to 60 mEq per hour. Safety: When KCl is added to a 1,000-mL bag of solution, the KCl will concentrate at the bottom of the bag of IV solution. Agitate the solution well before infusing. Nursing actions for hyperkalemia include the following: Administering emergency medications for severe hyperkalemia, which may include sodium polystyrene sulfonate (Kayexelate) given via enema to bind with potassium, or the administration of IV insulin to push potassium back into the cells and lower serum levels. Restricting dietary intake of potassium-rich foods (see Table 29.3 for foods high in potassium). Monitoring the serum lab reports of all your patients, being especially mindful of the serum potassium levels if the patient is suffering from malnutrition or dehydration or has renal disease.

Hormones That Regulate Fluids and Electrolytes/Antidiuretic Hormone (Vasopressin)

When the blood becomes more concentrated, with less water than usual, the hypothalamus in the brain stimulates the release of antidiuretic hormone. This hormone acts on the kidneys, causing them to increase water reabsorption, which makes the urine more concentrated.

Hormones That Regulate Fluids and Electrolytes/Aldosterone

When the blood volume becomes low, blood pressure falls. This is detected by the baroreceptors located in various blood vessels and the heart. These receptors send a message that causes the kidneys to release renin. Through a number of interactions (Fig. 29.1), aldosterone is then produced by the adrenal cortex. Aldoseterone regulates fluids and electrolytes by telling the kidneys to reabsorb more sodium and excrete more potassium. This causes more water to be reabsorbed by the kidneys and circulate in the blood. The principle of water follows sodium is at work here. When more water is reabsorbed, the blood volume increases and the blood pressure goes up.

Hormones That Regulate Fluids and Electrolytes/Atrial Natriuretic Factor

When there is excessive blood volume, it causes the blood pressure to go up. The hormone atrial natriuretic factor is then produced. It causes the production of renin to be suppressed, which interferes with the production of aldosterone. Now the kidneys will excrete more sodium and therefore more water. This increases the urinary output and lowers blood pressure. perspiration. Normal fluid loss for healthy patients varies from about 1 to 3 L per day, depending on fluid intake.

Nursing Actions for Acid-Base Imbalances

When you care for patients with acid-base imbalances, it is important to be aware of how both the lungs and the kidneys are functioning. In addition, take the following nursing actions: Monitor vital signs for tachypnea and bradypnea, tachycardia, and fever. Assess the patient's respirations for depth and pattern, dyspnea, length of inspiration versus expiration, and use of accessory respiratory muscles. Assess skin, mucous membranes, and nailbeds for cyanosis. Assess O2 saturation and need for supplemental O2. Monitor laboratory results of arterial blood gases (ABGs). Seriously ill patients may require endotracheal intubation and mechanical ventilation. In Chapter 28, you were introduced to the laboratory diagnostic test called ABGs. (See Table 28.2 to review the normal ranges for ABGs and the significance of abnormal levels.)

Movement of Absorbed Water From the Gastrointestinal Tract

When you drink a glass of water, the water you swallow passes through the esophagus and into the stomach. The bloodstream absorbs some of the water from the stomach and small intestine, but most of the water is not absorbed until it reaches the large intestine

Adult male body weight

an adult male's body weight is made up of 60% to 65% water

Intravasular Space

includes the blood vessels and heart, which hold blood; the liquid portion of the blood which surrounds and holds the blood cells is called plasma.

Hypomagnesemia

refers to a blood level of magnesium that is below the normal range. Decreased levels of magnesium can increase nervous system irritability and muscular contractility. Patients with alcoholism frequently develop hypomagnesemia along with other nutritional deficiencies. A high level of magnesium, known as hypermagnesemia, will slow the nervous system responses, including the respiratory rate, and generally depress neuromuscular junctions. (See Table 29.4 for information about magnesium imbalances.)

Fluid Notes

sodium, chloride, and bicarbonate normally occur in higher concentrations outside.

Water Intake

the average adult needs to consume somewhere between 1,440 and 1,920 mL of water per day, roughly between 1.5 to 2 liters each day. Some individuals may need more water intake, such as pregnant or nursing women, those individuals who work or exert in extremely hot environments, and athletes.

the number of solutes present in the solvents determines what ?

the fluids osmolatity or concentration

Diffusion

when molecules move from an area of higher concentration to an area of lower concentration to equalize the amount throughout the area or space. Real life: If you spray air freshener in one corner of a room, the molecules will diffuse from that area (higher concentration) to the rest of the room (lower concentration) until equalized; then it can be smelled throughout the room. Body: In the lungs, the blood in the capillaries around the air sacs contains higher levels of carbon dioxide and lower levels of oxygen than room air. When you inhale, room air that is higher in oxygen and lower in carbon dioxide is drawn into the air sacs. Oxygen molecules move into the capillaries (higher to lower concentration), and carbon dioxide molecules move out of the capillaries into the air sacs to be exhaled (higher to lower concentration).

Filteration

when solids are separated from liquids or gases by a barrier that only the liquids and very fine solutes can pass through. Real life: A coffee filter holds ground-up coffee beans. Hot water passes through the beans and the filter. Tiny particles of the beans stay in the water, giving it flavor and color and turning it into coffee, but the grounds are separated out by the paper filter. Body: The liver filters blood to remove dissolved substances such as medications, over-the-counter drugs, alcohol, caffeine, and toxins from the blood.