Fluid/Electrolytes & Acid Base

Define intracellular fluid

(ICF) fluid contained within the cells

identify the major functions of Magnesium

(Magnesium) - Involved in protein and carbohydrate metabolism - Necessary for protein and DNA synthesis within the cell - Maintains normal intracellular levels of potassium - Involved in electrical activity in nerve, cardiac, and muscle membranes

Define anion

An anion is an electrolyte that carries a negative charge. Examples are chloride (Cl−), bicarbonate (HCO3−), phosphate (HPO42−), and sulfate (SO42−).

Define electrolyte

An electrolyte is a substance that develops an electrical charge when dissolved in water.

Identify at least five potassium-rich foods.

Bananas Oranges Apricots Figs Dates Carrots Tomatoes Spinach Dairy products Meats

Define deficient fluid volume

Deficient fluid volume occurs when there is a proportional loss of water and electrolytes from the ECF. It may occur as a result of insufficient intake of isotonic fluid; bleeding; excessive loss through urine, skin, insensible losses, or the gastrointestinal tract; or loss of fluid into a third space.

Molecules move across a membrane to equalize concentration.

Diffusion

Define excess fluid volume

Excess fluid volume involves excessive retention of sodium and water in the ECF. A synonym is hypervolemia. Fluid volume excess occurs as a result of excessive salt intake, disease affecting kidney or liver function, or poor pumping action of the heart.

Identify the eight potential blood types.

The eight potential blood types are A+, A−, B+, B−, AB+, AB−, O+, and O−.

What are the preferred locations for peripheral IV lines?

The most distal veins in the hands and arms are the preferred locations for peripheral IV lines.

Define cation

an electrolyte that carries a positive charge. They include sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+).

What factors should be considered when selecting an insertion site for a peripheral IV line?

● Age ● Body size ● Clinical status ● Skin condition ● Impairments ● Type of fluid ● Duration expectation of IV therapy

Identify and describe types of transfusion reactions.

● Allergic—allergy to blood being transfused ● Bacterial—contamination of the blood ● Febrile—temperature elevation due to sensitivity to WBCs, plasma proteins, or platelets ● Hemolytic—an incompatibility between donor and receiver blood ● Circulatory overload—administering too great a volume or too rapidly

what is the major function of Bicarbonate

(Bicarbonate) -Maintains acid-base balance by functioning as the primary buffer in the body

Identify the major functions of calcium

(Calcium) - Promotes transmission of nerve impulses - Regulates muscle contractions - Maintains cardiac automaticity - Serves as an essential factor in the formation of blood clots - Catalyzes many cellular activities - The major component of bones and teeth

identify the major functions of Chloride

(Chloride) - Works with sodium to maintain osmotic pressure of blood - Essential for production of hydrochloric acid (HCl) for gastric secretions - Functions as a buffer for the gas exchange (oxygen and carbon dioxide) in RBCs - Assists with acid-base balance

Define extracellular fluid

(ECF) fluid outside the cells. ECF consists of three types of fluid: interstitial, intravascular, and transcellular fluid.

identify the major functions of Phosphate

(Phosphate) (Phosphorous) - Serves as a catalyst for many intracellular activities - Promotes muscle and nerve action - Bound with calcium, as calcium phosphate, in bones and teeth - Assists with acid-base balance - Important for cell division and transmission of hereditary traits

Identify the major functions of potassium

(Potassium) - Maintains osmolality of intracellular fluid - Regulates conduction of cardiac rhythm - Transmits electrical impulses in multiple body systems -Assists with acid-base balance

What are major concerns associated with potassium intake

(Potassium) cardiac dysrhythmias (bradycardia, heart block, asystole) potential for acid-base imbalance (metabolic acidosis)

Identify the major functions of sodium

(Sodium) - Regulates fluid volume - Helps maintain blood volume - Interacts with calcium to maintain muscle contraction -Stimulates conduction of nerve impulses

What are the major concerns associated with sodium and potassium intake?

(Sodium) weight gain (edema) hypertension (high blood pressure)

Rank order the acid-base balance mechanisms from most rapidly acting to the most slowly acting.

- Buffers act the most rapidly. -Respiratory mechanisms are intermediate. -Renal mechanisms act the slowest.

Interpret the following ABG results. 1. pH = 7.53 PCO2 = 26 mm Hg HCO3− = 22 mEq/L 2. pH = 7.40 PCO2 = 39 mm Hg HCO3− = 25 mEq/L 3. pH = 7.25 PCO2 = 70 mm Hg HCO3− = 30 mEq/L 4. pH = 7.48 PCO2 = 46 mm Hg HCO3− = 30 mEq/L

1. Respiratory alkalosis uncompensated 2. Normal ABG results 3. Respiratory acidosis, partially compensated 4. Metabolic alkalosis, partially compensated

Define solute

A solute is a solid substance dissolved in body fluids.

Molecules move against a concentration gradient.

Active transport

Molecules move to equalize pressure.

Filtration

identify major electrolytes in ECF

In extracellular fluid (ECF), the major cation is sodium (Na+), and the major anions are chloride (Cl−) and bicarbonate (HCO3−).

Identify the major electrolytes in the ICF

In intracellular fluid (ICF), the major cations are potassium (K+) and magnesium (Mg2+), and the major anion is phosphate (HPO42−)

Fluid moves across a membrane to equalize concentration.

Osmosis

Briefly describe the three mechanisms used to maintain pH.

● Buffers. Buffer systems respond to electrolyte imbalances to prevent wide swings in pH. A buffer system consists of a weak acid and a weak base. These molecules react with strong acids or bases to keep them from altering the pH by either absorbing free hydrogen ions or releasing free hydrogen ions (H+). ● Respiratory. When the serum pH is too acidic (pH is low), the lungs remove carbon dioxide (CO2) through rapid, deep breathing. This reduces the amount of carbon dioxide available to make carbonic acid (H2CO3)in the body. If the serum pH is too alkaline (pH is high), the lungs try to conserve carbon dioxide through shallow respirations. ● Renal. The kidneys affect pH by regulating the amount of bicarbonate (a base, HCO3−) that is kept in the body. If the serum pH is too acidic, the kidneys reabsorb additional bicarbonate to neutralize the acid. If the serum pH is too alkaline, the kidneys excrete additional bicarbonate to lower the amount of base and thereby decrease the pH. The kidneys also buffer pH by forming acids and ammonium (a base).

Identify the signs and symptoms of deficient fluid volume and excess fluid volume

● Deficient fluid volume (hypovolemia): ● The first symptom of hypovolemia is thirst. If the patient is able to recognize and respond to this symptom by drinking liquid, no further treatment may be required. If fluid is not available or the patient is unable to consume the liquid, the syndrome progresses. As fluid volume decreases, the heart pumps the remaining blood faster but not as powerfully, resulting in a rapid, weak pulse and a low blood pressure, although, initially as fluid is lost and the heart beats faster, the blood pressure rises through vasoconstriction in an attempt to keep blood flow and oxygenation going. Eventually, compensatory mechanisms wear out and blood pressure falls. ● Water is pulled from the interstitial spaces and the intracellular fluid into the vascular system, resulting in dry skin and mucous membranes, decreased skin turgor, and decreased urine output. ● Patients complain of muscle weakness, fatigue, and feeling warm. Temperature increases because the body is less able to cool itself through perspiration. In an older adult, temperature will rise but may not be elevated above normal body temperature. ● Weight is a sensitive measure of fluid loss. A sudden 5% loss of body weight is considered clinically significant. When loss approaches 8%, fluid loss is severe. A loss of 15% of body weight due to fluid loss is usually fatal. ● The patient with fluid volume deficit usually has an elevated blood urea nitrogen (BUN) level and elevated hematocrit. Both values increase because there is less water in proportion to the solid substances being measured. Specific gravity of the urine increases. ● Excess fluid volume (hypervolemia): ● The blood pressure is elevated, pulse is bounding, and respirations are increased and shallow. ● The neck veins may become distended, and edema develops in dependent areas. ● The skin is pale and cool. ● Urine output becomes dilute, and volume increases. ● The patient rapidly gains weight. In severe fluid overload, the patient develops moist crackles in the lungs, dyspnea, and ascites (excess peritoneal fluid). ● Hemodilution causes BUN, hematocrit, and the specific gravity of urine to decrease.

Describe dehydration and hypervolemia

● Dehydration implies the loss of water only. ● Hypervolemia implies excess water. Neither involves changes in electrolyte levels.

What aspects should be evaluated in a nursing history focused on fluid, electrolyte, and acid-base balance?

● Demographic data ● Past medical history ● Current health concerns ● Food and fluid intakes ● Fluid elimination ● Medications ● Lifestyle

Give at least five strategies to prevent fluid and electrolyte imbalance.

● Drink at least eight to ten 8-ounce glasses of water per day. Educate the client about usual fluid needs and circumstances that increase fluid needs, such as high environmental temperature, fever, gastrointestinal fluid loss, or draining wounds. Base your teaching on the client's current intake and the changes required to meet fluid goals. ● Instruct clients to use thirst as guide. When the client is physically able to access liquid, this is a useful tool. ● Limit consumption of fluids high in salt, sugar, caffeine, or alcohol. ● Teach the client to contact a healthcare provider if he experiences prolonged vomiting, diarrhea, or inability to tolerate liquids or food. ● Encourage clients to drink water before, during, and after strenuous exercise. ● Identify medications or conditions that place the client at risk for imbalances. For example, if the client is receiving a potassium-wasting diuretic, she will need to increase her potassium intake, either by taking a supplement or by altering her diet. ● Caution clients to avoid routine use of laxatives, antacids, weight-loss products, or enemas. All of these products may cause imbalances. ● Instruct the client to weigh himself daily if fluid balance is critical or if the client is experiencing excessive loss. ● Instruct the client to contact a health professional if there is a sudden change of weight, decreased urine output, swelling in dependent areas, shortness of breath, or dizziness. ● Encourage clients to eat a well-balanced diet, including dairy products rich in calcium.

In general, how often are administration sets changed on peripheral IV lines? When TPN is infused?

● For peripheral IV lines, the administration set is changed every 72 to 96 hours. ● When TPN is infused, the administration set is changed every 24 hours.

Identify three ways to regulate the flow rate of IV fluid.

● Gravity ● Electronic infusion-control device ● Volume-control set (e.g., buretrol)

The order reads, "5% dextrose in water/0.45% saline (D5W-½ NS) with 20 mEq KCl infuse 1 liter in 5 hours." Calculate the hourly rate and the drip rate using (a) a macrodrip administration set with 15 drops/mL and (b) a microdrip set.

● Hourly rate = 200 mL/hr ● Macrodrip = 50 drops/min ● Microdrip = 200 drops/min

What equipment is needed when inserting an IV and starting an IV infusion?

● IV catheter. When selecting the access device, consider the type of fluid and the speed at which you are to infuse it. For most IV fluids, you can use a 20- to 24-gauge catheter. However, you will need a larger size for rapid infusions or to infuse viscous fluids (e.g., use an 18-gauge catheter to transfuse blood). Select the smallest gauge and the shortest length catheter that will accommodate the prescribed therapy (Intravenous Nursing Society, 2000, p. 44). ● Administration set (infusion kit). The administration set connects the fluid container to the catheter you insert in the patient. An administration set consists of a plastic insertion spike, a drip chamber, tubing with a regulating (roller) clamp, a rubber injection port, and a catheter adapter (hub). Protective caps at both ends of the infusion set (over the spike and the catheter adapter) are sterile. Remove them just before use. Insert the spike into the port of the IV solution container; the adapter (hub) at the other end of the tubing fits into the IV catheter in the patient's vein. The drip chamber is calibrated to allow a predictable amount of fluid to be delivered in each drop. A macrodrip delivers 10 to 20 drops per milliliter of solution; a microdrip delivers 60 drops per milliliter. The drop factor is indicated on the package and varies with the manufacturer. Select a micro- or a macrodrip administration set based on the client's fluid needs. For very slow infusion rates or for children, use a microdrip. A roller clamp on the tubing controls the rate of flow. ● Extension tubing and filters. The end of the IV tubing contains a needle adapter that attaches to the inserted sterile IV catheter. You may use extension tubing to lengthen the primary tubing or to provide additional Y-injection ports for administration of other IV solutions or medications. Occasionally, an IV filter will be used on the tubing. Some administration sets have built-in filters. Usually the filter is placed at the end of the tubing. Filters remove particulate matter from the solution. They are used for additives or medications that have a tendency to clump, and also to filter microorganisms. Filters come in a variety of sizes; the finer the filter, the greater the degree of solution filtration. Many facilities do not use IV filters because of cost, but studies have shown that IV filters reduce the rate of phlebitis and bacteremia by as much as 40% (Intravenous Nursing Society, 2006b). ● Injection port. Use the injection port to administer a secondary IV fluid or medication (see Chapter 23). ● Solutions. Inspect the IV solution to be certain it contains the desired fluid, the fluid is clear, the bag is intact, and the solution has not expired. IV solutions are available in glass or plastic containers. Glass containers were the first IV systems available, but today, about 90% of all IV fluids are packaged in plastic (Phillips, 2005). Fluids for continuous infusions are packed in 1-liter or 500-mL bags. Smaller solution bags (50-mL, 100-mL, and 250-mL) are used for intermittent infusions, such as antibiotics or other medications. Plastic containers collapse as fluid infuses, so you can use a nonvented administration set. Glass bottles do not collapse and therefore require a vented administration set. Set up the solution and administration set prior to performing the venipuncture. Inspect the IV solution to be certain it contains the desired fluid, the fluid is clear, the bag is intact, and the solution has not expired IV supplies are sterile, prepackaged, and disposable. They vary based on manufacturer, so familiarize yourself with what is available in your facility.

Describe the difference between infiltration and extravasation as a complication of IV therapy.

● Infiltration involves a nonvesicant solution. ● Extravasation involves a vesicant (solution that causes the formation of blisters and subsequent tissue sloughing and necrosis).

Describe the types and functions of three IV solutions.

● Isotonic fluids (examples are lactated Ringer's and 0.9% sodium chloride (normal saline). The osmolality of isotonic fluids is similar to that of blood serum. When infused, isotonic solutions remain inside the intravascular compartment. As a result, they are useful for clients with hypotension or hypovolemia. Monitor them carefully if the client is at risk for fluid volume excess due to congestive heart failure (CHF) or hypertension. ● Hypotonic solutions (examples are 5% dextrose [D5W] and 0.45% sodium chloride [D5½NS]). Hypotonic solution osmolality is less than serum. Infusion of these solutions pulls body water from the intravascular compartment into the interstitial fluid compartment. As the interstitial fluid is diluted, its osmolarity decreases, drawing water into the adjacent cells. Hypotonic fluid is used for hyperglycemic conditions, such as diabetic ketoacidosis, in which high serum glucose draws fluid out of the cells and into the vascular and interstitial compartments. Hypotonic fluids must be administered carefully to prevent a sudden fluid shift from the intravascular space to the cells. ● Hypertonic fluids (volume expanders, such as dextran and serum albumin). Hypertonic fluids have a higher osmolality than serum. When administered, they pull fluids and electrolytes from the intracellular and interstitial compartments into the intravascular compartment. Hypertonic fluids can help stabilize blood pressure, increase urine output, and reduce edema. Volume expanders are used to increase blood volume following severe loss of blood or plasma, such as in severe burns or hemorrhage.

Identify laboratory tests that monitor fluid, electrolyte, and acid-base balance.

● Serum electrolytes measures sodium, potassium, chloride, and bicarbonate levels. Test often includes blood urea nitrogen (BUN), creatinine, and glucose. ● Serum osmolality is a measure of the solute concentration of the blood. ● Urine osmolality is the solute concentration of urine. ● Hematocrit is a measure of the percent of RBCs in whole blood. ● Specific gravity measures the kidney's ability to concentrate or dilute urine in relation to the plasma. ● ABGs measure acid-base balance and oxygen status.

Identify ten physical assessment components that can be used to monitor fluid, electrolyte, and acid-base balance.

● Skin is evaluated for six components: color, temperature, moisture content, continuity, turgor, and edema. ● The status of the mucous membranes provides information about fluid and electrolyte balance. ● All of the vital signs reflect information about fluid, electrolyte, and acid-base balance. ● If you suspect fluid volume deficit, be sure to assess the patient for orthostatic hypotension. ● Capillary refill and venous filling also offer information about fluid status. ● Respiratory rate and pattern, as well as breath sounds, offer clues about fluid, electrolyte, and acid-base status. ● Assess orientation, level of consciousness, reflexes, and fatigue. ● Monitoring daily change in weight is an accurate method of assessing fluid status. ● Measure all fluids consumed or excreted in a 24-hour period.

What is the purpose of IV fluids?

● To expand intravascular volume ● To correct an underlying imbalance in fluids or electrolytes ● To compensate for an ongoing problem that is affecting either fluids or electrolytes

Under what conditions would a central venous access device be preferable to a peripheral device?

● When highly irritating or hyperosmolar solutions are administered ● When the client is severely fluid depleted and a peripheral line cannot be started ● When central venous pressure monitoring is prescribed ● For parenteral nutrition ● For long-term IV therapy

Describe the types of blood products that are available for transfusion.

● Whole blood contains red blood cells, white blood cells, and platelets suspended in plasma. ● Red blood cells (RBCs) are prepared from whole blood by removing the plasma. RBCs can raise the client's hematocrit and hemoglobin levels while minimizing an increase in volume. RBCs are available for transfusion as packed RBCs (PRBC). ● Plasma is the liquid portion of the blood. It is 90% water and constitutes about 55% of blood volume. Plasma may be transfused whole or separated into specific products, such as albumin, clotting factor concentrates, and immune globulins. ● Platelets help the clotting process by sticking to the lining of blood vessels. Units of platelets are prepared by using a centrifuge to separate the platelet-rich plasma from the donated unit of whole blood. The platelet-rich plasma is then centrifuged again to concentrate the platelets further. Platelets are used to treat clients who have a shortage of platelets or abnormal platelet function. ● White blood cells, specifically granulocytes, can be collected by centrifugation of whole blood. They are transfused within 24 hours of collection and are used for infections that are unresponsive to antibiotic therapy. The effectiveness of white blood cell transfusion is still being investigated. ● Plasma derivatives are concentrates of specific plasma proteins that are prepared from many units of plasma. Plasma derivatives include a variety of clotting factors, immune globulins, and albumin.