OBJECTIVES • Name four components of body fluid. • List five physiologic transport mechanisms for distributing fluid and its constituents. • Name 10 assessments that provide data about a client’s fluid status. • Describe three methods for maintaining or restoring fluid volume. • Describe four methods for reducing fluid volume. • List six reasons for administering intravenous (IV) fluids. • Differentiate between crystalloid and colloid solutions, and give examples of each. • Explain the terms isotonic, hypotonic, and hypertonic when used in reference to IV solutions. • List four factors that affect the choice of tubing used to administer IV solutions. • Name three techniques for infusing IV solutions. • Discuss at least five criteria for selecting a vein when administering IV fluid. • List seven complications associated with IV fluid administration. • Discuss two purposes for inserting an intermittent venous access device. • Identify three differences between administering blood and crystalloid solutions. • Name at least five types of transfusion reactions. • Explain the concept of parenteral nutrition.
Chapter 16: Fluid and Chemical Balance • Body fluid is a mixture of water, chemicals (called electrolytes and nonelectrolytes), and blood cells. • Water, the vehicle for transporting the chemicals, is the very essence of life. • Water is not stored in any great reserve, daily replacement is the key to maintaining survival.
Body Fluid • Body fluid is a mixture of: • Water: human body has 45% to 75% • Electrolytes: have electrical charge • Nonelectrolytes: do not have electrical charge • Blood cells: RBCs, Leukocytes, WBCs, Platelets
Electrolytes • Possess an electrical charge when dissolved, absorbed, & distributed (sodium & chloride) • Obtained from dietary sources • Essential for maintaining cellular, tissue, & organ functions (muscle contractions) • Ions (+ or -), cations (+), anions (-); distributions vary per fluid compartment • Loss may occur through altered state of health, or inability to eat
Nonelectrolytes • Remain bound together when dissolved • Do not possess an electrical charge • Chemical end products of carbohydrates, fats, & proteins (glucose, fatty acids, amino acids) • Provide a continuous supply of non-electrolytes • Stable amounts circulate in body fluid as long as a person consumes adequate nutrients
Intracellular / Extracellular Fluid • Intracellular fluid: Fluid inside cells (greatest portion of water in the body) • Extracellular fluid: Fluid outside cells ** Extracellular fluid is one of the following: • Interstitial fluid (fluid in tissues) • Intravascular fluid (the watery plasma, or serum, portion of blood)
Fluid Transport Mechanisms • Osmosis: regulate the distribution of water by controlling the movement of fluid from one location to another H2O moves through a semipermeable membrane like those surrounding body cells, capillary walls, body organs and cavities. From areas where the fluid is more dilute to another area where the fluid is more concentrated. Produces colloidal osmotic pressure
Fluid Transport Mechanisms • Filtration: regulates the movement of water and substances from a compartment with high pressure to one with lower pressure Governs how the kidneys excretes fluid & wastes & then selectively reabsorbs H2O & substances that need to be conserved AKA: hydrostatic pressure
Fluid Transport Mechanisms • Passive diffusion: High concentrationto lower concentration through semipermeable membrane Occurs without expenditure of energy.. An absorption process that occurs in the body when carbohydrates are more highly concentrated in the intestine than in the blood. Very much like osmosis. Ex: O2 enters all cells passively, CO2 leaves all cells passively. Electrochemical neutrality (identical balance of cationswith anions)
Fluid Transport Mechanisms • Facilitated diffusion: process where substances require the assistance of a carrier molecule to pass from one side of a semipermeable membrane to the other. Ex: Glucose requires Insulin as the carrier substance because it binds to receptor proteins which then transport it into cells.
Fluid Transport Mechanisms • Active transport: process of chemical distribution that requires energy source, adenosine triphosphate (ATP). Allows chemical distribution from low concentration to one that is higher (opposite of passive diffusion). Ex: sodium-potassium pump on cellular membranes => K+ into cells and Na+ out of cells
Osmosis • left: The concentration of sugar molecules is greater on the right side of the membrane than on the left. The water molecules are small enough to move across the membrane, but the larger sugar molecules cannot pass through. • right: The water molecules move across the membrane until the water and sugar molecules are of equal concentration on both sides. This lowers the water level on the left side and raises it on the right side.
Passive Diffusion Before diffusion • Left beaker: has less red molecules than the beaker on the on right side of the membrane. After diffusion • Right beaker: has equal amounts of red and black molecules, but the fluid level has not changed.
Assessing a Client’s Fluid Status • Intake and output (I&O) measurement: one tool to assess fluid status by keeping record over a 24hr period. • Intake: Sum of all fluid consumed/instilled • Output: Sum of liquid eliminated from the body
Assessing a Client’s Fluid Status: Intake • All liquids client drinks • IV solutions given • Liquid equivalent of melted ice chips, which is half of the frozen volume • Foods that liquidize when swallowed: gelatin, ice cream, thin cooked cereal • Fluid instillations: tube feeds or tube irrigations
Assessing a Client’s Fluid Status: Output Urine Emesis (vomitus) Blood loss Diarrhea Wound or tube drainage Aspirated irrigations
Assessing Fluid Status Fluid volumes are recorded in milliliters (mL). 1 oz = 30 mL 1 cup = 8 oz = 240 mL 1 tsp = 5 mL 1 tbsp = 15 mL Nursing homes & hospitals usually provide equivalency charts from dietary department. If one is not available the nurse uses a calibrated container to measure specific amounts; estimated volumes are considered inaccurate (see Box 16-2 p.309)
Assessing Fluid Status Calibrated containers used to measure liquid volumes.
Assessing a Client’s Fluid Status Clients Commonly Place on I&Os Automatically • Post surgery: until eating, drinking and voiding in sufficient qualities • Clients receiving IV fluids • Clients receiving tube feedings • Clients with wound drainage or suction equipment
Assessing a Client’s Fluid Status • Clients with urinary catheters until it can be determined the output is adequate or they are voiding well after removal of the catheter • Clients undergoing diuretic drug therapy
Common Fluid Imbalances • Hypovolemia: low volume in extracellular fluid compartments • Dehydration: fluid deficit in both extracellular & intracellular compartments. In addition to weight loss, it is evidenced by decreased skin turgor (usually checked over the sternum)
Common Fluid Imbalances Dehydration: (p. 311) • Mild: 3%-5% loss of body weight • Moderate: 6%-10% loss of body weight • Severe: more than 9%-15% of body weight
Common Fluid Imbalance Dehydration: Physical S&S: Acute wt loss, Oliguria, concentrated urine, sunken eyes, poor skin turgor, low BP, weak rapid pulse, dizziness. Lab values when suspecting dehydration: High Na+, Low K+ =>muscle cramps, High BUN & CR, thirst & confusion.
Common Fluid Imbalances • Hypervolemia: excess water in intravascular fluid compartment Edema: excess fluid distributed to the interstitial space Dependent edema: fluid accumulates in dependent areas of the body (influenced by gravity) Box 13-2 Criteria Estimating Pitting Edema (Ch. 13, p. 243)
Figure 16-6 Foot care is very important for the client with edema. The edema and reddened areas can easily break down.
Common Fluid Imbalances • Third-spacing: movement of intravascular fluid to nonvascular fluid compartment s, where it becomes trapped and useless Peritoneum common place for fluid build-up Hypoalbuminemia(deficit of albumin in the blood). Ex: liver disease, chronic kidney disease, burns and severe allergic reactions
Figure 16-7 Fluid accumulation within the peritoneal cavity. Dullness on percussion indicates fluid, whereas tympany indicates air. (p. 314)
Third Spacing Treatment: • Depletion of fluid in the intravascular space may lead to hypotension and shock => fluid therapy becomes critical. • Done through IV fluids, sometimes in large rapid amounts. Blood transfusions/Albumin by IV are also used to restore colloidal osmotic pressure and to pull the trapped fluid back into the intravascular space. • When this is done, clients who were previously hypovolemic can suddenly become hypervolemic. Requires close monitoring for circulatory overload (acute respiratory distress and CHF).
Conditions Predisposing to Fluid Imbalance Fluid Deficit: Starvation Potent diuretics Impaired swallowing Hemorrhage Vomiting/Diarrhea Major burns Gastric suction Draining wounds Fever & sweating Exercise & sweating Laxative abuse Heat & humidity
Conditions Predisposing to Fluid Imbalance Fluid Excess: Kidney Failure Heart Failure (CHF) Rapid admin of IV fluid Admin of albumin or blood Pregnancy Excessive Na+ intake Corticosteroid drug PMS therapy (premenstrual fluid retention)
Restoring Fluid Volume • Treating the cause of hypovolemia • Increasing oral intake • Administering IV fluid replacements • Controlling fluid losses • Using a combination of these measures
Restoring Fluid Volume IV Fluids: • Maintain/restore fluid balance when oral replacement is inadequate/impossible • Maintain/replace electrolytes • Administer water-soluble vitamins • Provide a source of calories • Administer drugs • Replace blood and blood products
Reducing Fluid Volume • Treating the disorder contributing to the increased fluid volume • Restricting or limiting oral fluids • Reducing salt consumption • Discontinuing IV fluid infusions or reducing the infusing volume • Administering drugs that promote urine elimination • Using a combination of the above interventions
Question • Is the following statement true or false? Reducing salt consumption helps restore fluid volume.
Answer False. Reducing salt consumption helps reduce fluid volume.
Administering Intravenous Fluids • Maintain or restore fluid balance when oral replacement is inadequate or impossible • Maintain or replace electrolytes • Administer water-soluble vitamins • Provide a source of calories • Administer drugs • Replace blood and blood products
Crystalloid Solutions Crystalloid solutions are classified as isotonic, hypotonic and hypertonic, depending on the concentration of dissolved substances in relation to plasma. • Crystalloid solutions: made of water and other uniformly dissolved crystals such as salt and sugar
Types of Intravenous Solutions • Isotonic:contains the same concentration of dissolved substances as normally found in plasma (yellowish liquid component of blood that normally holds the blood cells in whole blood in suspension). • Generally administered to maintain fluid balance in clients who may not be able to eat/drink for a short period • Ex: 0.9% saline, D5W, LR
Types of Intravenous Solutions • Hypotonic:contains fewer dissolved substances than normally found in plasma. Temporarily increases blood pressure as it expands the circulating volume. Given to clients with fluid losses greater than fluid intake, diarrhea/vomiting. Effective way to rehydrate clients who have fluid deficits. Ex: 0.45% sodium chloride, D5.45 NS
Types of Intravenous Solutions • Hypertonic:more concentrated than body fluid and draws cellular and interstitial water into the intravascular compartment Causes cells and tissues to shrink Used in extreme cases when it is necessary to reduce cerebral edema or expand circulatory volume rapidly. Ex: D10W, 3% saline, D20
IV Solutions A. Isotonic solutions B. Hypotonic solutions (cell swelling) C. Hypertonic solutions (cell shrinkage)
Colloid Solutions • Colloid solutions: made of water and molecules of suspended substances such as blood cells and blood products (such as albumin). • Used to replace circulating blood volume, will pull fluid from other compartments Ex: blood, blood products, solutions known as plasma expanders, blood substitutes
Plasma Expanders • Various non-blood solutions used to pull fluid into the vascular space • Used to increase blood volume and raise blood pressure • Colloidal solutions (formed when mixed with water) • Hespan • Dextran 40
Question • Is the following statement true or false? Blood is an example of crystalloid solution.
Answer False. Blood is an example of colloid solution.