Fluids and Electrolytes AY 24-25 PDF
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Zara Jane V. Dinglasan, RN, MAN
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These lecture notes cover the care of clients with problems in fluid and electrolyte balance. The competencies of the course discuss anatomy and physiology, age-related differences in body fluid content, and strategies for maintaining fluid and electrolyte balance.
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Care of Clients With Problems in Fluid and Electrolyte Balance ZARAH JANE V. DINGLASAN, RN, MAN GUEST LECTURER Competencies for: Fluid, Electrolyte, & Acid-Base Balance By the end of the unit, the student will: 1. Describe the anatomy and physiology related to body fluids, flu...
Care of Clients With Problems in Fluid and Electrolyte Balance ZARAH JANE V. DINGLASAN, RN, MAN GUEST LECTURER Competencies for: Fluid, Electrolyte, & Acid-Base Balance By the end of the unit, the student will: 1. Describe the anatomy and physiology related to body fluids, fluid & electrolyte, and acid-base balance 2. Describe age-related differences in body fluid content and effect on fluid balance status 3. Describe how to promote and maintain fluid & electrolyte, and acid-base balance Competencies for: Fluid, Electrolyte, & Acid-Base Balance (continued) By the end of the unit, the student will: 4. Describe specific variables that may influence fluid & electrolyte, and acid-base balance 5. Teach clients about specific conditions that can lead to fluid & electrolyte imbalance, and acid- base imbalance 6. Describe care for clients at risk for or with actual problems related to fluid & electrolyte, and acid-base balance FLUIDS AND ELECTROLYTE'S INTRODUCTION The human body maintains a delicate balance of fluids and electrolytes to help ensure proper functioning and homeostasis. When fluids or electrolytes become imbalanced, individuals are at risk for organ system dysfunction. Functions of Water in the Body 1. Transporting nutrients to cells and wastes from cells 2. Transporting hormones, enzymes, blood platelets, and red and white blood cells 3. Facilitating cellular metabolism and proper cellular chemical functioning 4. Acting as a solvent for electrolytes and nonelectrolytes 5. Helping maintain normal body temperature 6. Facilitating digestion and promoting elimination 7. Acting as a tissue lubricant BASIC FLUID AND ELECTROLYTE CONCEPTS The body is in a constant state of change as fluids and electrolytes are shifted in and out of cells within the body in an attempt to maintain a nearly perfect balance. A slight change in either direction can have significant consequences on various body systems. Body Fluids Examples of Body Fluids Amniotic fluid, aqueous humor, bile, blood plasma, breast milk, cerebrospinal fluid, cerumen, chyle, exudates, gastric juice, lymph, mucus, pericardial fluid, peritoneal fluid, pleural fluid, pus, saliva, sebum, serous fluid, semen, sputum, synovial fluid, sweat, tears, urine, vomitus Intracellular fluids (ICF) are found inside cells and are made up of protein, water, electrolytes, and solutes. Extracellular fluids (ECF) are fluids found outside of cells. Extracellular Body Fluid Types of Extracellular Fluid 1. Intravascular Fluid 2. Interstitial Fluid 3. Transcellular Fluid Intravascular Fluid The first type is known as intravascular fluid that is found in the vascular system that consists of arteries, veins, and capillary networks. Intravascular fluid is whole blood volume and also includes red blood cells, white blood cells, plasma, and platelets. Loss of intravascular fluids causes the nursing diagnosis Deficient Fluid Volume, also referred to as hypovolemia. Hypovolemia A second type of extracellular fluid is interstitial fluid that refers to fluid outside of blood vessels and between the cells. The remaining extracellular fluid, also called transcellular fluid, refers to fluid in areas such as cerebrospinal, synovial, intrapleural, and gastrointestinal system. Fluid Movement Fluid movement occurs inside the body due to osmotic pressure, hydrostatic pressure, and osmosis. Proper fluid movement depends on: 1. Intact and properly functioning vascular tissue lining 2. Normal levels of protein content within the blood 3. Adequate hydrostatic pressures inside the blood vessels. HYDROSTATIC PRESSURE Pressure that a contained fluid exerts on what is confining it. Filtration Occurs when hydrostatic pressure pushes fluids and solutes through a permeable membrane so they can be excreted. Osmosis Water movement through a semipermeable membrane, from an area of lesser solute concentration to an area of greater solute concentration, in an attempt to equalize the solute concentrations on either side of the membrane. Osmosis causes fluid movement between the intravascular, interstitial, and intracellular fluid compartments based on solute concentration. Solute Movement Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration to equalize the concentration of solutes throughout an area. Active Transport Involves moving solutes and ions across a cell membrane from an area of lower concentration to an area of higher concentration. Fluid and Electrolyte Regulation The body must carefully regulate intravascular fluid accumulation and excretion to prevent fluid volume excesses or deficits and maintain adequate blood pressure. Water balance is regulated by several mechanisms including ADH, thirst, and the Renin-Angiotensin-Aldosterone System (RAAS). The Renin-Angiotensin- Aldosterone System (RAAS) plays an important role in regulating fluid output and blood pressure. Water Balance Fluid Imbalance Two types of fluid imbalances are excessive fluid volume (also referred to as hypervolemia) and deficient fluid volume (also referred to as hypovolemia). Excessive Fluid Volume Patients at risk for developing excessive fluid volume are those with the following conditions: Heart Failure Kidney Failure Cirrhosis Pregnancy Deficient Fluid Volume Individuals who have a higher risk of dehydration include the following: Older adults Infants and children Patients with chronic diseases such as diabetes mellitus and kidney disease Patients taking diuretics and other medications that cause increased urine output Individuals who exercise or work outdoors in hot weather INTRAVENOUS SOLUTIONS There are three types of IV fluids: 1. Isotonic 2. Hypotonic 3. Hypertonic Isotonic Solutions Isotonic solutions are IV fluids that have a similar concentration of dissolved particles as blood. An example of an isotonic IV solution is 0.9% Normal Saline (0.9% NaCl). Hypotonic Solutions Hypotonic solutions have a lower concentration of dissolved solutes than blood. An example of a hypotonic IV solution is 0.45% Normal Saline (0.45% NaCl). Hypertonic Solutions Hypertonic solutions have a higher concentration of dissolved particles than blood. An example of hypertonic IV solution is 3% Normal Saline (3% NaCl). Comparison of Osmotic Effects of Hypertonic, Isotonic, and Hypotonic IV Fluids on Red Blood Cells Type IV Solution Uses Nursing Considerations Fluid resuscitation for hemorrhaging, severe vomiting, Monitor closely for hypervolemia, especially with heart failure Isotonic 0.9% Normal Saline (0.9% NaCl) diarrhea, GI suctioning losses, wound drainage, mild or renal failure. hyponatremia, or blood transfusions. Should not be used if serum pH is greater than 7.5 because it Fluid resuscitation, GI tract fluid losses, burns, traumas, or Isotonic Lactated Ringer’s Solution (LR) will worsen alkalosis. May elevate potassium levels if used with metabolic acidosis. Often used during surgery. renal failure. 5% Dextrose in Water (D5W) *starts Should not be used for fluid resuscitation because after as isotonic and then changes to Provides free water to help renal excretion of solutes, dextrose is metabolized, it becomes hypotonic and leaves the Isotonic hypotonic when dextrose is hypernatremia, and some dextrose supplementation. intravascular space, causing brain swelling. Used to dilute metabolized plasma electrolyte concentrations. Monitor closely for hypovolemia, hypotension, or confusion due to fluid shifting into the intracellular space, which can be life- Used to treat intracellular dehydration and hypernatremia Hypotonic 0.45% Sodium Chloride (0.45% NaCl) threatening. Avoid use in patients with liver disease, trauma, and to provide fluid for renal excretion of solutes. and burns to prevent hypovolemia from worsening. Monitor closely for cerebral edema. Monitor closely for hypovolemia, hypotension, or confusion due Provides free water to promote renal excretion of solutes to fluid shifting out of the intravascular space, which can be life- Hypotonic 5% Dextrose in Water (D5W) and treat hypernatremia, as well as some dextrose threatening. Avoid use in patients with liver disease, trauma, supplementation. and burns to prevent hypovolemia from worsening. Monitor closely for cerebral edema. Monitor closely for hypervolemia, hypernatremia, and associated respiratory distress. Do not use it with patients Hypertonic 3% Sodium Chloride (3% NaCl) Used to treat severe hyponatremia and cerebral edema. experiencing heart failure, renal failure, or conditions caused by cellular dehydration because it will worsen these conditions. Monitor closely for hypervolemia, hypernatremia, and 5% Dextrose and 0.45% Sodium associated respiratory distress. Do not use it with patients Hypertonic Used to treat severe hyponatremia and cerebral edema. Chloride (D50.45% NaCl) experiencing heart failure, renal failure, or conditions caused by cellular dehydration because it will worsen these conditions. Monitor closely for hypervolemia, hypernatremia, and 5% Dextrose and Lactated Ringer’s associated respiratory distress. Do not use it with patients Hypertonic (D5LR) Used to treat severe hyponatremia and cerebral edema. experiencing heart failure, renal failure, or conditions caused by D10 cellular dehydration because it will worsen these conditions. ELECTROLYTES SODIUM ✓Sodium levels in the blood typically range from 136-145 mEq/L ✓Sodium is the most abundant electrolyte in the extracellular fluid (ECF) and is maintained by the sodium-potassium pump. ✓Sodium plays an important role in maintaining adequate fluid balance in the intravascular and interstitial spaces. Hypernatremia ✓An elevated sodium level in the blood Typically, hypernatremia is caused by excess water loss due to lack of fluid intake, vomiting, or diarrhea. As you recall, elevated sodium levels in the blood cause the osmotic movement of water out of the cells to dilute the blood. Hyponatremia ✓A decreased sodium level in the blood Hyponatremia can be caused by excess water intake or excessive administration of hypotonic IV solutions. Role of Vasopressin Vasopressin (also called antidiuretic hormone) is a substance naturally produced in the body that helps regulate the amount of water in the body by controlling how much water is excreted by the kidneys. Vasopressin decreases water excretion by the kidneys, which retains more water in the body and dilutes the sodium. Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH) The syndrome of inappropriate secretion of antidiuretic hormone develops when too much antidiuretic hormone (vasopressin) is released by the pituitary gland under certain inappropriate conditions, causing the body to retain fluid and lower the blood sodium level by dilution. Antidiuretic hormone (ADH) mainly affects our kidneys’ ability to reabsorb water. Under normal circumstances, our body signals ADH release for a variety of reasons. In most people with SIADH, drinking water doesn’t adequately suppress ADH release, and their urine remains concentrated. This leads to water retention, which dilutes our blood. This then leads to low levels of sodium in our blood (hyponatremia). POTASSIUM ✓Potassium levels normally range from 3.5 to 5.1 mEq/L. ✓Potassium is the most abundant electrolyte in intracellular fluid and is maintained inside the cell by the sodium- potassium pump. ✓Potassium is necessary for normal cardiac function, neural function, and muscle contractility, including effective contractility of the cardiac muscles. Abnormal potassium levels can cause significantly abnormal heart rhythms and contractility. Hyperkalemia There is an increased potassium levels in the blood. Hyperkalemia can be caused by kidney failure, metabolic acidosis, and administration of potassium-sparing diuretics or oral/intravenous potassium supplements. Signs and symptoms of hyperkalemia are generally cardiac in nature and include irritability, cramping, diarrhea, and electrocardiogram (ECG) abnormalities. As hyperkalemia worsens, ECG abnormalities may progress to cardiac dysrhythmias and cardiac arrest. Treatment for hyperkalemia For mild symptoms: ✓Decreased potassium intake in the diet. ✓Adjustment to medications contributing to increased levels of potassium For severe symptoms: ✓Administration of sodium polystyrene sulfonate (Kayexalate) orally or rectally. ✓Insulin ✓IV calcium gluconate For severe symptomatic hyperkalemia: ✓Temporary hemodialysis may also be used to quickly decrease potassium levels. Hypokalemia Decreased potassium level in the blood. Hypokalemia can be caused by excessive vomiting, diarrhea, potassium-wasting diuretics, and insulin use, as well as lack of potassium in the diet. Treatment for hypokalemia ✓Increasing oral intake of potassium in the diet ✓Oral or IV potassium in fluids supplementation. CALCIUM Calcium levels normally range from 8.6-10.2 mg/dL Calcium excretion and reabsorption are regulated by the parathyroid hormone (PTH) that is secreted from the parathyroid glands near the thyroid. Hypercalcemia Increased calcium level It can be caused by: ✓Prolonged immobilization ✓Many types of cancers ✓Hyperparathyroidism and parathyroid tumors Signs and Symptoms ✓Nausea ✓Vomiting ✓Constipation ✓Increased thirst and/or urination ✓Skeletal muscle weakness. Treatments ✓Decreasing calcium intake in the diet ✓Phosphate supplementation ✓Hemodialysis ✓Surgical removal of the parathyroid gland ✓Weight-bearing exercises Hypocalcemia Decreased calcium level in the blood ✓Hypocalcemia can be caused by hypoparathyroidism. ✓Hypocalcemia is also caused by vitamin D deficiency and renal disease. Signs and Symptoms Signs and symptoms of hypocalcemia often impact the musculoskeletal and nervous systems. These include paresthesias (numbness and tingling) of the lips, tongue, hands and feet, muscle cramps, and tetany. Chvostek’s sign Trousseau’s sign Chvostek’s Sign and Trousseau’s Sign PHOSPHORUS Phosphorus levels typically range from 2.5-4.0 mg/dL Phosphorus is stored in the bones and is predominantly found in the ICF with small amounts in the ECF. Dietary phosphorus sources include dairy products, fruits, vegetables, meat, and cereal. Hyperphosphatemia Increased phosphorus level in the blood Can be caused by kidney disease, crush injuries, or overuse of phosphate-containing enemas. Hyperphosphatemia itself is usually asymptomatic, but signs of associated hypocalcemia may be present due to the inverse relationship between phosphorus and calcium. Treatment for hyperphosphatemia includes decreasing intake of phosphorus, administration of phosphate-binder medications to help with excretion, and hemodialysis. Hypophosphatemia Decreased phosphorus level in the blood Acute hypophosphatemia can be caused by acute alcohol abuse, burns, diuretic use, respiratory alkalosis, resolving diabetic ketoacidosis, and starvation. Chronic hypophosphatemia is caused by hyperparathyroidism, vitamin D deficiency, prolonged use of phosphate binders, and hypomagnesemia or hypokalemia. Hypophosphatemia is usually asymptomatic, but in severe cases, it can cause muscle weakness, anorexia, encephalopathy, seizures, and death. Treatment for hypophosphatemia includes treating what is causing the imbalance, oral or IV phosphorus replacement, and increased phosphate- containing foods in the diet. MAGNESIUM Magnesium levels typically range from 1.5-2.4 mEq/L Magnesium is essential for normal cardiac, nerve, muscle, and immune system functioning. Dietary sources of magnesium include green leafy vegetables, citrus, peanut butter, almonds, legumes, and chocolate. Hypermagnesemia Elevated magnesium level in the blood. It is usually the result of renal failure, excess magnesium replacement, or use of magnesium containing laxatives or antacids. Signs and symptoms of hypermagnesemia include bradycardia, weak and thready pulse, lethargy, tremors, hyporeflexia, muscle weakness, and cardiac arrest. Treatment for hypermagnesemia involves increasing fluid intake, discontinuing magnesium- containing medications, and in severe cases, hemodialysis or peritoneal dialysis. Additionally, administration of calcium gluconate can be helpful to reduce the cardiac effects of hypermagnesemia until the magnesium level can be lowered. Hypomagnesemia Decreased magnesium level in the blood. It typically results from inadequate magnesium in the diet, or from loop diuretics that excrete magnesium. Chronic proton pump inhibitor use can also cause hypomagnesemia Signs and symptoms of hypomagnesemia include nausea, vomiting, lethargy, weakness, leg cramps, tremor, dysrhythmias, and tetany. Treatment for hypomagnesemia consists of increasing dietary intake of magnesium containing foods and oral or IV magnesium supplementation. Elevated Level Decreased Level Hypernatremia Causes: Excessive salt intake Hyponatremia Sodium (Na+) Symptoms: Lethargy, irritability, seizures, and Causes: Excessive water intake and diuretics Normal range weakness Symptoms: Headache, confusion, coma 136-145 mEq/L Treatments: Rehydrate w/ D5W and increase Treatments: 3% NS and fluid restriction water intake Hyperkalemia Hypokalemia Causes: Kidney dysfunction, excessive potassium Causes: Loop and thiazide diuretics and IV Potassium (K+) intake, and ACE inhibitors administration of insulin Normal range Symptoms: Cardiac arrhythmias, cramping, Symptoms: Weakness, arrhythmias, lethargy, 3.5-5.1 mmol/L diarrhea, and irritability and thready pulse (WALT) Treatments: Limit potassium in diet, loop Treatments: PO/IV potassium and increase K+ in diuretic, insulin, dialysis, and kayexalate diet Hypercalcemia Hypocalcemia Causes: Overactive parathyroid glands and Causes: Diuretic use and removal of parathyroid Calcium (Ca++) cancer glands Normal range Symptoms: Nausea, vomiting, constipation, and Symptoms: Numbness, tingling, Chvotek’s sign, 8.6 -10.2 mg/dL thirst and tetany Treatments: Decrease calcium in diet, increase Treatments: Increase Ca++ in diet and IV/PO mobility, and administer phosphorous calcium Hypomagnesemia Hypermagnesemia Causes: Diuretics, undernutrition, and long-term Causes: Kidney disease and excessive alcohol use disorder Magnesium (Mg+) magnesium intake (i.e., laxatives and antacids) Symptoms: Nausea, vomiting, lethargy, Normal range Symptoms: Muscle weakness, bradycardia, weakness, tetany, leg cramps, tremors, and 1.5-2.4 mg/dL asystole, tremors, and slow reflexes arrhythmias Treatments: Dialysis, increased fluid intake, and Treatments: Increase Mg+ in diet and PO/IV stopping medications containing Mg+ magnesium Chloride The normal range for chloride in adults is roughly between 98 and 107 milliequivalents of chloride per liter of blood (mEq/L) Chloride carries an electric charge and therefore is classified as an electrolyte, along with sodium and potassium. It helps to regulate the amount of fluid and types of nutrients going in and out of the cells. Chloride is absorbed in the small intestine and remains in the body’s fluids and blood. Any excess amount is excreted in urine. Chloride is usually bound to sodium, and therefore the amount in blood tends to coincide with sodium levels. Chloride is involved in many of our bodily functions. Similar to sodium and potassium, chloride creates specific channels in the membranes of our cells which help to carry different vital tasks. This mineral is needed to help red blood cells exchange oxygen and carbon dioxide in both the lungs (taking up oxygen and releasing carbon dioxide) and other parts of the body (delivering oxygen and taking up carbon dioxide). Chloride also plays a role in the digestion of foods, by supporting the production and release of hydrochloric acid (HCl) in the stomach. Hyperchloremia (High Chloride Levels) Excess chloride levels in the blood. It can be caused by severe dehydration, diarrhea, or metabolic problems in which the blood becomes too acidic, such as with kidney disease. A high salt diet can lead to an excessive intake of sodium chloride, which is associated with elevated blood pressure. The symptoms that may indicate hyperchloremia are usually those linked to the underlying cause of the high chloride level. Often this is acidosis, in which the blood is overly acidic. These symptoms may include: ✓fatigue ✓muscle weakness ✓excessive thirst ✓dry mucous membranes ✓high blood pressure Hypochloremia Low level of chloride in the blood A loss of chloride in the body usually accompanies conditions that cause sodium losses. Diuretic medications that remove fluid through the kidneys can also cause decreased chloride levels. In cases of sudden, very high levels of blood glucose such as seen in people with diabetes, the kidneys will flush more sodium and water out of the body, leading to lower chloride levels. ACID-BASE BALANCE Arterial Blood Gases An arterial blood gases (ABG) test measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. ABGs measure the pH level of the blood, the partial pressure of arterial oxygen (PaO2), the partial pressure of arterial carbon dioxide (PaCO2), the bicarbonate level (HCO3), and the oxygen saturation level (SaO2). Prior to collecting blood gases, it is important to ensure the patient has appropriate arterial blood flow to the hand. This is done by performing the Allen test. When performing the Allen test, pressure is held on both the radial and ulnar artery below the wrist. Pressure is released from the ulnar artery to check if blood flow is adequate. If arterial blood flow is adequate, warmth and color should return to the hand. Modified Allen's Test pH A neutral pH is 7, which is the same pH as water. Normally, the blood has a pH between 7.35 and 7.45. A blood pH of less than 7.35 is considered acidic, and a blood pH of more than 7.45 is considered alkaline. The body has several mechanisms for maintaining blood pH. The lungs are essential for maintaining pH and the kidneys also play a role. PaCO2 PaCO2 is the partial pressure of arterial carbon dioxide in the blood. The normal PaCO2 level is 35-45 mmHg. CO2 forms an acid in the blood that is regulated by the lungs by changing the rate or depth of respirations. Generally, the lungs work quickly to regulate the PaCO2 levels and cause a quick change in the pH. Therefore, an acid-base problem caused by hypoventilation can be quickly corrected by increasing ventilation, and a problem caused by hyperventilation can be quickly corrected by decreasing ventilation. HCO3 HCO3 is the bicarbonate level of the blood, and the normal range is 22-26. HCO3 is a base managed by the kidneys and helps to make the blood more alkaline. The kidneys take longer than the lungs to adjust the acidity or alkalinity of the blood, and the response is not visible upon assessment. As the kidneys sense an alteration in pH, they begin to retain or excrete HCO3, depending on what is needed. PaO2 PaO2 is the partial pressure of arterial oxygen in the blood. It more accurately measures a patient’s oxygenation status than SaO2 (the measurement of hemoglobin saturation with oxygen). Therefore, ABG results are also used to manage patients in respiratory distress. Adult ABG Critical Description Normal Component Value Value Acidity (7.45) of blood. Measure of H+ ions (acids). 7.60 kidneys through bicarbonate retention. 80-100 PaO2 Pressure of oxygen in the blood.