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1 Fluid, electrolyte, and acid-base balance
chapter 42 Fluid, electrolyte, and acid-base balance Fluid surrounds every cell in the body and is also inside the cells. Body fluids contain electrolytes such as sodium and potassium; They also have some acidity. Fluid, electrolyte, and acid-base balances in the body maintain the health and function of all body systems. In this chapter, you will learn how the body normally maintains fluid, electrolyte, and acid-base balance. The properties of body fluids affect the functioning of body systems due to their effects on cell function. These properties include the amount of fluid (volume), concentration (osmolarity), composition (electrolyte concentration), and acidity (pH). All of these functions have regulatory mechanisms that keep them in balance for normal functioning. You will also learn how imbalances arise; how various fluid, electrolyte, and acid-base imbalances affect patients; and ways to help patients maintain or restore balance safely. Copyright © 2017, Elsevier Inc. All rights reserved.

2 fluid balance [Look at Figure 42-1, Body Fluid Compartments, with students.] [Figure 42-2 is shown: Effects of isotonic, hypotonic, and hypertonic solutions. (From Hall JE: Guyton and Hall Manual of Medical Physiology, Vol. 13, Philadelphia, 2016, Saunders.)] Copyright © 2017, Elsevier Inc. All rights reserved.

3 Fluid Balance (continued) Fluid balance is fluid intake
liquid distribution liquid delivery HAD Renin-Angiotensin-Aldosterone System Atrial Natriuretic Peptide Fluid homeostasis is the dynamic interaction of three processes: fluid intake and absorption, fluid distribution, and fluid elimination. To maintain fluid balance, fluid intake must equal fluid output. Because part of normal daily fluid production (eg, urine, sweat) is hypotonic saline, individuals should have a fluid intake equal to that of sodium-containing hypotonic fluids (or water plus sodium-containing food). some salt) to maintain fluid balance (same intake for delivery). ). Fluid intake occurs orally through drink, but also through food, since most foods contain some water. The metabolism of food creates additional water. The average fluid intake via these routes for healthy adults is approximately 8 ounces, although this amount can vary widely based on exercise habits, preferences, and environment. Other routes of fluid intake include intravenous (IV), rectal (eg, enemas), and flushing of body cavities capable of receiving fluids. [See Table 42-1, Normal Laboratory Values ​​for Adults, with Students.] [Review Table 42-2, Mean Fluid Intake and Excretion in Healthy Adults, with students.] The term fluid distribution means the movement of fluid between its various compartments. The distribution of fluids between the extracellular and intracellular compartments occurs by osmosis. The distribution of fluid between the vascular and interstitial portions of the extracellular fluid (ECF) occurs through filtration. [Figure 42-3 shown: Osmosis moves water across the semipermeable membrane. (From Patton KT, Thibodeau GA: Anatomy and Physiology, 9th Edition, St. Louis, 2016, Mosby.)] [Look at Figure 42-4 with students, capillary filtration moves fluid between the vascular and interstitial compartments.] Copyright © 2017, Elsevier Inc. All rights reserved.

4 Fluid balance (continued) Thirst
An important regulator of fluid intake when plasma osmolarity increases The thirst control mechanism is located in the hypothalamus in the brain. Thirst, the conscious desire for water, is an important regulator of fluid intake when plasma osmolality is increased (osmoreceptor-mediated thirst) or blood volume is decreased (baroreceptor-mediated thirst and angiotensin II and III-mediated thirst). The thirst control mechanism is located in the hypothalamus in the brain. The osmoreceptors continuously monitor the osmolality of the plasma; When it increases, they cause thirst by stimulating neurons in the hypothalamus. [Figure 42-5: Stimuli Affecting the Thirst Mechanism Shown.] Copyright © 2017, Elsevier Inc. All rights reserved.

5 case study Robert is a third year nursing student who is Mrs. Reynolds. She has seen other patients with GI problems, but never fluid and electrolyte problems. Robert plans his care based on instructions from Mrs. Reynolds and her doctor. [Ask students: What will Robert learn about the patient from her story? Discuss: The patient's medical history indicates that she is at risk for an electrolyte imbalance due to a gastrointestinal (GI) disorder and continued use of a diuretic.] Copyright © 2017, Elsevier Inc. All rights reserved.

6 Fluid Balance (continued) Fluid Output
Usually through the skin, lungs, gastrointestinal tract, kidneys Influenced by Hormona antidiuretische (ADH) Renin-Angiotensin-Aldosterone System (SRAA) Atrial natriuretic peptides (ANPs) Fluid output normally occurs through four organs: skin, lungs, gastrointestinal tract, and kidneys. The gastrointestinal tract plays an important role in fluid balance. Approximately 3 to 6 liters of fluid flow into the gastrointestinal tract and then back into the ECF each day. The average adult normally only excretes 100 ml of fluid per day in the feces. However, diarrhea causes a large leakage of fluid from the gastrointestinal tract. The kidneys are the main regulators of fluid production, as they respond to hormones that affect urine production. As healthy adults drink more water, they increase urine output to maintain fluid balance. When they drink less water, sweat a lot, or lose fluids through vomiting, the volume of urine decreases to maintain hydration levels. These adaptations are mainly caused by the action of antidiuretic hormone (ADH), the renin-angiotensin-aldosterone system (RAAS), and atrial natriuretic peptides (ANP). ADH regulates the osmolarity of body fluids by affecting the amount of water excreted in the urine. It is synthesized by neurons in the hypothalamus, which release it from the posterior pituitary gland. ADH circulates in the blood to the kidneys, where it works in the collecting ducts. Humans normally release some ADH to maintain fluid balance. The more concentrated bodily fluids become, the more ADH is released. Factors that increase ADH levels include severely reduced blood volume (eg, dehydration, bleeding), pain, stressors, and some medications. RAAS regulates ECF volume by affecting the amount of sodium and water excreted in the urine. It also helps regulate blood pressure. Aldosterone circulates to the kidneys where it causes the reabsorption of sodium and water in an isotonic ratio in the distal renal tubules. The removal of sodium and water from the renal tubules and their return to the blood increases the volume of the ECF. To maintain fluid balance, some RAAS action usually takes place. ANP also regulates CVD by affecting the amount of sodium and water excreted in the urine. Cells in the atria of the heart release ANP when stretched (eg, by increased ECV). ANP is a weak hormone that inhibits ADH by increasing urinary sodium and water loss (see Fig. 42-6, C). ANP thus counteracts the effects of aldosterone. [Figure 42-6 shown: Important hormones that affect renal fluid excretion. A, Antidiuretic hormone (ADH). B, aldosterone. C, atrial natriuretic peptide (ANP).] Copyright © 2017, Elsevier Inc. All rights reserved.

7 Fluid Balance (cont.) Fluid Inlet Fluid Distribution
Thirst regulates fluid intake. ~2300 ml/diameter liquid distribution Extracellular and intracellular vascular and interstitial hormonal influences HAD Renin-Angiotensin-Aldosterone Mechanism Atrial Natriuretic Peptide liquid delivery Through the kidneys, skin, lungs, and gastrointestinal tract imperceptible loss palpable loss [This slide summarizes the components of fluid balance.] Copyright © 2017, Elsevier Inc. All rights reserved. 7

8 Quick test! 1. A patient is diaphoretic and has an oral temperature of 104°F. These are classic signs of: A. ADH deficiency. B. Extracellular fluid loss. C. imperceptible loss of water. D. Sensible water loss. Answer: D Copyright © 2017, Elsevier Inc. All rights reserved.

9 Fluid imbalances ECF imbalances Osmolarity imbalances
Volume in osmolality osmolarity imbalances hypernatremia, “dehydration”; hypertonic hyponatremia, "excess water"; hypotonic clinical dehydration Combined VCE deficit and hypernatremia Imbalances sometimes occur when disease processes, medications, or other factors disrupt fluid intake or excretion. For example, diarrhea increases fluid production and fluid imbalance (dehydration) occurs if fluid intake is not increased enough. Two main types of fluid imbalances are known: volume imbalances and osmolarity imbalances. Volume imbalances are disturbances in the amount of fluid in the extracellular compartment. Osmolality disorders are disorders in the concentration of body fluids. Volume and osmolality disturbances can occur singly or in combination. When there is a volume imbalance in the extracellular fluid (ECF), there is either too little (ECV deficit) or too much isotonic fluid (ECV excess). ECV deficiency and excess are abnormal isotonic fluid volumes that manifest as sudden changes in body weight and changes in vascular and interstitial volume markers. An ECV deficiency is present when isotonic fluid in the extracellular compartment is insufficient. Keep in mind that regular ECF is high in sodium. In CVD deficiency, isotonic fluid production exceeds sodium-containing fluid intake. Since the ECF is both vascular and interstitial, the signs and symptoms are due to volume depletion in both compartments. [Review Table 42-3, Fluid Imbalances, with students.] Excess CVD occurs when too much isotonic fluid is found in the extracellular compartment. Intake of sodium-containing isotonic fluids exceeded fluid production. For example, if you eat more salty foods than usual and drink water, your knuckles may swell or the rings on your fingers may tighten and you may gain 1 kg or more overnight. These are manifestations of a slight excess of ECV. With an osmolarity imbalance, body fluids become hypertonic or hypotonic and this causes osmotic shifts of water across cell membranes. Osmolarity disorders are known as hypernatremia and hyponatremia. The osmolar imbalance causes body fluids to become hypertonic or hypotonic, resulting in osmotic shifts of water across cell membranes. Osmolarity disorders are known as hypernatremia and hyponatremia. Hypernatremia, also called dehydration, is a hypertensive condition. One of two common causes causes bodily fluids to become too concentrated: losing relatively more water than salt or gaining relatively more salt than water. When the interstitial fluid becomes hypertonic, water moves out of the cells by osmosis and they shrink. The signs and symptoms of hypernatremia are brain dysfunctions that occur when brain cells atrophy. Hyponatremia, also called excess water or water intoxication, is a condition of hypotension. It results from gaining relatively more water than salt or losing relatively more salt than water. The overly dilute state of the interstitial fluid causes water to enter the cells by osmosis, causing the cells to swell. Signs and symptoms of brain dysfunction occur when brain cells swell. ECV deficiency and hypernatremia often coexist; this combination is called clinical dehydration. The ECV is too low and the body fluids are too concentrated. Clinical dehydration is common in gastroenteritis or other causes of severe vomiting and diarrhea when people are unable to replace fluid secretions with an adequate intake of dilute sodium-containing fluids. Signs and symptoms of clinical dehydration include ECV deficiency and hypernatremia. [Figure 42-7: Fluid volume and osmolarity imbalances shown.] Copyright © 2017, Elsevier Inc. All rights reserved.

10 Electrolyte balance input and absorption distribution output
Plasma concentrations of K+, Ca2+, Mg+, and phosphate (Pi) are very low compared to their concentrations in cells and bones. Differences in concentration are necessary for the normal functioning of muscles and nerves. Salida urine, feces and sweat Vomiting, discharge and fistulas You can better understand electrolyte balance by considering the three processes involved in electrolyte homeostasis: electrolyte uptake and absorption, electrolyte distribution, and electrolyte production. [Refer to Table 42-4, Electrolyte Intake and Absorption, Distribution, and Loss, with students.] Plasma concentrations of K+, Ca2+, Mg2+, and phosphate are very low compared to their concentrations in cells and bones. Entry is through food and drink. Some substances enhance or prevent the absorption of electrolytes. Although sodium is an electrolyte, it is not included here since serum sodium imbalances are the osmolarity imbalances discussed above. Electrolyte production occurs through normal excretion in urine, feces, and sweat. Drainage also occurs through vomiting, drainage tubes, and fistulas. As electrolyte production increases, electrolyte intake must increase to maintain electrolyte balance. When electrolyte production is decreased, as in oliguria, electrolyte uptake must also be decreased to maintain balance. Copyright © 2017, Elsevier Inc. All rights reserved.

11 electrolyte disorder
Potassium (K+) hypokalemia hyperkalemia Calcium (Ca2+) hypocalcemia hypercalcemia Magnesio (Mg2+) Hypomagnesemia Hipermagnesemia [Hypernatremia and hyponatremia have been discussed in osmolality imbalances.] [Ask students: Use your knowledge of word origins to analyze the terms on the slide. Discuss: -emia means condition of the blood; hyper means excessive; hypo- means deficient; and the three roots of the word (kal, calc, and magnes) represent the three elements potassium, calcium, and magnesium.] Factors such as diarrhea, endocrine disorders, and medications that disrupt electrolyte homeostasis cause electrolyte imbalances. Electrolyte intake greater than electrolyte production, or a shift of electrolytes from cells or bones to the ECF, causes excess plasma electrolytes. Electrolyte intake below electrolyte production or electrolyte shift from ECF to cells or bone causes a plasma electrolyte deficit. Hypokalemia is an abnormally low level of potassium in the blood. Hypokalemia results from decreased potassium uptake and absorption, a shift of potassium from the ECF to cells, and increased potassium production. Common causes of hypokalemia due to increased potassium production include diarrhea, recurrent vomiting, and use of potassium-lowering diuretics. People with these conditions need to increase their potassium intake to reduce the risk of hypokalemia. Hypokalemia causes muscle weakness that becomes life-threatening when it involves the respiratory muscles and a life-threatening cardiac arrhythmia. [Refer to Table 41-5, Electrolyte Imbalances, with students.] Hyperkalemia is an abnormally high concentration of potassium ions in the blood. Its common causes are increased potassium uptake and absorption, potassium shift from cells to extracellular fluid, and decreased potassium production. People with oliguria (decreased urine output) are at high risk of hyperkalemia due to decreased potassium production, unless their potassium intake is also significantly decreased. If you understand this principle, you may want to consider checking your urine output before giving potassium-containing solutions intravenously. Hyperkalemia can cause muscle weakness, potentially fatal cardiac arrhythmias, and cardiac arrest. Hypocalcemia is an abnormally low level of calcium in the blood. The physiologically active form of calcium in the blood is ionized calcium. Total blood calcium also contains inactive forms that are bound to plasma proteins and small anions such as citrate. Factors that cause excess ionized calcium to be converted to bound forms cause symptomatic ionized hypocalcemia. People with acute pancreatitis often develop hypocalcemia because calcium is bound to undigested fat in the feces and is excreted. This process decreases the absorption of calcium from the diet and increases calcium production, preventing the reabsorption of calcium contained in gastrointestinal fluids. Hypocalcemia increases neuromuscular excitability, which is the basis of its signs and symptoms. Hypercalcemia is an abnormally high concentration of calcium in the blood. Hypercalcemia results from increased calcium intake and absorption, translocation of calcium from bone to extracellular fluid, and decreased calcium production. Cancer patients often develop hypercalcemia because some cancer cells secrete chemicals related to parathyroid hormone into the blood. When these chemicals reach the bones, they cause calcium to move from the bones to the ECF. This weakens the bones, and sometimes the person develops pathologic fractures (that is, broken bones caused by forces that would not break healthy bone). Hypercalcemia decreases neuromuscular excitability, which underlies its other signs and symptoms, the most common of which is lethargy. Hypomagnesemia is an abnormally low level of magnesium in the blood. Its common causes include decreased magnesium intake and absorption, a change in plasma magnesium to its inactive bound form, and increased magnesium production. Signs and symptoms are similar to those of hypocalcemia because hypomagnesemia also increases neuromuscular excitability. Hypermagnesemia is an abnormally high concentration of magnesium in the blood. End-stage renal disease causes hypermagnesemia unless a person decreases magnesium intake to compensate for decreased production. Signs and symptoms are caused by decreased neuromuscular excitability, the most common being lethargy and decreased deep tendon reflexes. Copyright © 2017, Elsevier Inc. All rights reserved.

12 Case study (continued) Dr. Reynolds admitted her for observation and a blood sample was taken for electrolyte levels, a complete blood count (CBC), and an electrocardiogram (ECG). Orders include nothing oral, IV infusion of 0.9% saline at 125 mL/hr, I&O and vital signs every 4 hours, and daily weigh-ins. [Ask students: What assessment activities do you think Robert will do? To discuss: Ask Ms. Reynolds to describe her nausea and the associated signs and symptoms she is experiencing. Perform an examination of gastrointestinal and urinary function. Evaluate your vital signs. Evaluate the skin and mucous membranes of the woman. Reynolds for dehydration indicators. Evaluation of your laboratory values ​​and electrocardiogram (ECG) results.] Copyright © 2017, Elsevier Inc. All rights reserved.

13 acid-base balance Acid production, buffering, and elimination all interact to create a balance. Acids release hydrogen ions (H+); Bases (alkaline substances) absorb H+ ions The degree of acidity is given as a pH value pH scale: 1.0 (very acidic) to 14.0 (very basic) pH of 7.0 is neutral; normal arterial blood is 7.35 to 7.45 Maintaining the pH within this normal range is very important for optimal cell function. Normal acid-base balance is maintained, with acid removal equal to acid production. Acids release hydrogen ions (H+); Bases (alkaline substances) absorb H+ ions. The more H+ ions there are, the more acidic the solution. When the pH is out of the normal range, the enzymes in the cells do not work properly; Hemoglobin does not deliver enough oxygen; and serious physiological problems occur, including death. Laboratory tests of a sample of arterial blood, called arterial blood gases (ABG), are used to check a patient's acid-base balance. [Refer to Table 42-6, Arterial Blood Gas Measurements, with students.] Copyright © 2017, Elsevier Inc. All rights reserved.

14 Acid-Base Balance (continued)
acid production CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3− Carbon dioxide + water ↔ carbonic acid ↔ hydrogen ion + bicarbonate Production: Cellular metabolism constantly produces two types of acids: carbonic acid and metabolic acids. Cells produce carbon dioxide (CO2), which acts like an acid in the body and is converted to carbonic acid. Metabolic acids are all acids except carbonic acid. These include citric acid, lactic acid, and many others. [Figure 42-8 is shown: Acid production and excretion.] Copyright © 2017, Elsevier Inc. All rights reserved.

quince Acid-Base Balance (continued)
acid buffer Buffers are pairs of chemicals that work together to maintain the normal pH of body fluids. HCO3− + H+ ↔ H2CO3 bicarbonate + hydrogen ion ↔ carbonic acid H2CO3 ↔ H+ + HCO3− Carbonic acid ↔ hydrogen ion + bicarbonate Buffering: When there are too many free H+ ions, a buffer occupies them so that they are no longer free. When there are too few of them, a buffer can release H+ ions to prevent acid-base imbalance. Shock absorbers work fast, in seconds. All bodily fluids contain buffers. The main buffer in the ECF is the bicarbonate (HCO3-) buffer system, which buffers metabolic acids. It is made up of a lot of bicarbonate and little carbonic acid (usually in a 20:1 ratio). The addition of H+ released by a metabolic acid to a bicarbonate ion creates more carbonic acid. Now the H+ is no longer free and will not lower the pH of the blood. When there are too few H+ ions, the carbonic portion of the buffer pair releases some, increasing bicarbonate and returning the pH to normal. Other buffers include hemoglobin, protein buffers, and phosphate buffers. Cell and bone plugs also contribute. Buffers normally prevent blood from becoming too acidic as acids produced by cells circulate to the lungs and kidneys for excretion. Copyright © 2017, Elsevier Inc. All rights reserved.

sixteen Acid-Base Balance (continued)
Acid removal systems: lungs and kidneys The lungs excrete carbonic acid. The kidneys excrete metabolic acids. carbonic acid excretion When you exhale, you excrete carbon dioxide in the form of CO2 and water. excretion of metabolic acids The kidneys eliminate all acids except carbonic acid. The body has two acid removal systems: the lungs and the kidneys. The lungs excrete carbonic acid; the kidneys excrete metabolic acids. When you exhale, you excrete carbon dioxide in the form of CO2 and water. When PaCO2 (the level of CO2 in the blood) increases, chemoreceptors trigger faster, deeper breaths to expel the excess. When PaCO2 falls, chemoreceptors trigger slower, shallower breathing, allowing more CO2 produced by cells to remain in the blood to make up for the deficit. These changes in respiratory rate and depth maintain the carbonation of the acid-base balance. People with lung disease sometimes have problems with the normal removal of carbonic acid, which causes it to build up and make the blood more acidic. The kidneys eliminate all acids except carbonic acid. They secrete H+ into the renal tubular fluid and, at the same time, transport HCO3− back to the blood. When there are too many H+ ions in the blood, the kidney cells transport more H+ ions to the renal tubules for excretion, retaining more HCO3- in the process. If there are few H+ ions in the blood, the kidney cells excrete fewer H+ ions. Phosphate buffers in the renal tubular fluid prevent urine from becoming too acidic when the kidneys excrete H+ ions. When the kidneys need to excrete a large amount of H+, the renal tubular cells excrete ammonia, which combines with H+ ions in the tubules to form NH4+, ammonium ions. Phosphate buffering and NH4+ formation convert free H+ ions to other molecules in renal tubular fluid. This process allows excretion of metabolic acid in the urine without making the urine too acidic. People with kidney disease often have problems with the normal elimination of metabolic acids. Copyright © 2017, Elsevier Inc. All rights reserved.

17 Quick test! 2. The body's fluid and electrolyte balance is maintained in part by hormonal regulation. Which of the following statements demonstrates an understanding of this mechanism? A. "The pituitary gland secretes aldosterone" B. "The kidneys secrete antidiuretic hormone" C. "The adrenal cortex secretes antidiuretic hormone" D. "The pituitary gland secretes antidiuretic hormone" Answer: D Copyright © 2017, Elsevier Inc. All rights reserved.

18 Acid-base imbalance Types of acidosis: respiratory and metabolic
Types of alkalosis: respiratory and metabolic respiratory acidosis Caused by alveolar hypoventilation The lungs cannot remove enough CO2 Excess carbonic acid in the blood lowers the pH. respiratory alkalosis Caused by alveolar hyperventilation The lungs excrete a lot of CO2 The deficit of carbonic acid in the blood increases the pH value. People develop an acid-base imbalance when their normal homeostatic mechanisms are disrupted or overloaded. The term acidosis describes a condition that tends to make the blood relatively too acidic. Because our cells produce two types of acid, two different types of acidosis have been identified: respiratory acidosis and metabolic acidosis. The term alkalosis describes a condition that tends to make the blood relatively too basic (alkaline). Two types of alkalosis are known: respiratory alkalosis and metabolic alkalosis. The body has compensatory mechanisms that limit the amount of pH change in acid-base imbalances. Compensation involves physiological changes that help normalize pH but do not address the root cause of the problem. If the problem is an acid-base imbalance of the airways, only the lungs can correct the problem, but the kidneys can compensate by altering the amount of metabolic acid in the blood. When the problem is a metabolic acid-base imbalance, only the kidneys can correct the problem, but the lungs can compensate by changing the amount of carbonic acid in the blood. This is how the kidneys balance the acid-base imbalance in the airways; The respiratory system compensates for imbalances in acid-base metabolism. These compensatory mechanisms do not solve the problem, but they help the body to survive by normalizing the pH of the blood. However, if the underlying condition is not corrected, these compensatory mechanisms eventually fail. Respiratory acidosis results from alveolar hypoventilation; the lungs cannot excrete enough CO2. PaCO2 increases, creating excess carbonic acid in the blood, which lowers the pH. The kidneys compensate for this by increasing the excretion of metabolic acids in the urine, which increases bicarbonate in the blood. This compensatory process is slow, generally taking 24 hours to show a clinical effect and 3-5 days to reach a steady state. The decrease in the pH of the cerebrospinal fluid (CSF) and the decrease in the intracellular pH of brain cells cause a decreased level of consciousness. [Look at Table 42.7, Acid-Base Imbalance, with the students.] Respiratory alkalosis arises from alveolar hyperventilation; the lungs excrete a lot of carbonic acid (CO2 and water). PaCO2 decreases, creating a lack of carbonic acid in the blood, which increases the pH. Respiratory alkalosis is usually short-lived; so the kidneys don't have time to compensate. When the pH of the blood, cerebrospinal fluid, and intracellular fluid rises sharply, the excitability of the cell membrane also increases, leading to neurological symptoms such as agitation, confusion, and paresthesia. If the pH rises sharply, central nervous system (CNS) depression may occur. Copyright © 2017, Elsevier Inc. All rights reserved.

19 Acid-Base Imbalance (cont.)
metabolic acidosis Formed from increased metabolic acid or decreased base (bicarbonate) The kidneys cannot excrete enough metabolic acids that accumulate in the blood. Leads to a decreased level of consciousness. metabolic alkalosis As a result of a direct increase in base (bicarbonate) or a decrease in metabolic acid It leads to an increase in bicarbonate in the blood. Metabolic acidosis results from an increase in metabolic acidity or a decrease in base (bicarbonate). The kidneys cannot excrete enough metabolic acids that accumulate in the blood or bicarbonate is directly removed from the body as in diarrhea. In both cases, the HCO3- in the blood decreases and the pH value decreases. With an increase in metabolic acids, HCO3- in the blood decreases, as it serves to buffer metabolic acids. When patients have conditions that cause HCO3− to be removed, the amount of HCO3− in the blood decreases. To identify the specific cause, healthcare professionals and the laboratory calculate the anion gap, a reflection of unmeasured anions in the plasma. The anion gap is calculated by subtracting the sum of the plasma concentrations of Cl− and HCO3− anions from the plasma concentration of the Na+ cation. When reviewing laboratory reports, check the reference values ​​of the laboratory that measured electrolyte concentrations. [See Table 42-8, Anion Gap in Metabolic Acidosis, with Students.] The abnormally low pH in metabolic acidosis stimulates the chemoreceptors, causing the respiratory system to compensate for the acidosis by hyperventilating. Compensatory hyperventilation sets in within minutes and removes carbon dioxide from the body. This process does not solve the problem, but it does help limit the drop in pH. Metabolic acidosis reduces consciousness. Metabolic alkalosis is the result of a direct increase in base (HCO3-) or a decrease in metabolic acidity, which causes HCO3- to rise in the blood and relieves it of its buffering function. Common causes are vomiting and sucking in the stomach. The respiratory compensation for metabolic alkalosis is hypoventilation. Due to the reduction in respiratory rate and depth, carbonic acid in the blood increases, which can be seen in the increase in PaCO2. Oxygen demand may limit the degree of respiratory compensation for metabolic alkalosis. Because HCO3- has difficulty crossing the blood-brain barrier, neurologic signs and symptoms are less severe or even absent in metabolic alkalosis. Copyright © 2017, Elsevier Inc. All rights reserved.

20 care of the knowledge base
Leverage the scientific knowledge base in clinical decision making to deliver safe and optimal fluid therapy. Apply your knowledge of risk factors for fluid imbalances and the physiology of normal aging when evaluating older adults, knowing that this age group is at high risk for fluid imbalances. Ask questions to identify risk factors for fluid, electrolyte, and acid-base imbalances. Perform clinical evaluations for signs and symptoms of these imbalances. You will apply your knowledge of fluid, electrolyte, and acid-base imbalances to many clinical situations. They will incorporate nursing and cooperative interventions to maintain or restore fluid and electrolyte balance. Skills and techniques for safe intravenous therapy are an essential area of ​​the nursing knowledge base and are the focus of much nursing research to support evidence-based practice. Copyright © 2017, Elsevier Inc. All rights reserved.

21 critical thinking Successful critical thinking requires a synthesis of knowledge, experience, information collected from patients, critical thinking attitudes, and intellectual and professional standards. For fluid, electrolyte, and acid-base balance, integrates knowledge of physiology, pathophysiology, and pharmacology with prior experience and information collected from patients. Clinical evaluations require you to anticipate the information needed to analyze the data and make decisions about patient care. During the assessment, consider all the elements that go into making an appropriate nursing diagnosis. A critical analysis of the data allows one to understand how fluid, electrolyte, and acid-base imbalances affect an individual patient and their family. Additionally, critical thinking attitudes such as responsibility, discipline, and integrity help identify appropriate nursing diagnoses and plan successful interventions. Professional standards, such as the Infusion Nurses Society (INS) Standards of Practice, provide valuable guidance for proper assessment. Copyright © 2017, Elsevier Inc. All rights reserved.

22 Nursing process: evaluation
Through the eyes of the patient history of nursing Age: very young and old are at risk Environment: too hot? Food intake: Fluids, salt, foods rich in potassium, calcium and magnesium Lifestyle: History of alcohol use Medications: These include over-the-counter (OTC) and herbal medications, as well as prescription medications. Using a systematic assessment approach, it can help patients safely maintain or restore fluid, electrolyte, and acid-base balance. A patient's fluid, electrolyte, or acid-base imbalance is sometimes so severe that it precludes initial discussion of their expressed needs, values, and preferences. However, if a patient is awake enough to talk about care, he or she must collect that information. Focus on the patient's experience with fluid, electrolyte, or acid-base changes and their perception of the disease. Ask about the patient's top water status concerns to set the stage for an active partnership in planning, implementing, and evaluating patient-centered care. Clinical evaluation begins with a patient history, the goal of which is to discover risk factors that cause or contribute to fluid, electrolyte, and acid-base imbalances. Ask specific, focused questions to identify factors contributing to the patient's potential imbalances. [Review Table 42-9, Risk Factors for Fluid, Electrolyte, and Acid-Base Imbalances, and Table 42-1, Nursing Assessment Questions with students.] First, assess the age of the patient. The percentage of total body water in a child (70% to 80% of total body weight) is greater than that of children or adults. Babies and young children have higher water needs and immature kidneys (Hockenberry and Wilson, 2015). They are at greater risk of ECV deficiency and hypernatremia because the loss of body water per kilogram of weight is proportionally greater. Children between the ages of 2 and 12 usually respond to illness with higher and longer-lasting fevers than adults (Hockenberry and Wilson, 2015). At any age, fever increases the rate of imperceptible water loss. Juveniles exhibit increased metabolism and water production due to their rapid growth changes. Fluctuations in fluid balance are greater in adolescent girls due to hormonal changes associated with the menstrual cycle. Older adults experience a number of age-related changes that can affect fluid, electrolyte, and acid-base balance. [Review Box 42-2, Focus on Older Adults: Factors Affecting Fluid, Electrolyte, and Acid-Base Balance with students.] Surroundings. Hot environments increase fluid production through perspiration. Sweat is a hypotonic fluid that contains sodium. Excessive sweating without adequate salt and water replacement can lead to CVD deficiency, hypernatremia, or clinical dehydration. Ask clients about their normal physical work and whether they exercise vigorously in hot environments. Is saline fluid replacement available for patients during exercise and activity? Assess fluid intake in the diet; Salt; and foods rich in potassium, calcium and magnesium. Ask patients if they follow weight loss diets. Starvation and high-fat, carbohydrate-free diets often lead to metabolic acidosis. Also, assess the patient's ability to chew and swallow, which, when impaired, interferes with the proper absorption of electrolyte-rich foods and fluids. Take a history of alcohol use. Chronic alcohol abuse often causes hypomagnesemia, in part by increasing renal excretion of magnesium. Obtain a complete list of your patient's current medications, including over-the-counter and herbal supplements, to assess risks for fluid, electrolyte, and acid-base imbalances. Use a reliable drug reference book or online database to check the potential effects of other drugs. Specifically, ask about the use of sodium bicarbonate as an antacid, which can lead to excessive ECV due to its high sodium content that traps water in the extracellular compartments. Ask people who use laxatives about the consistency and frequency of their stools. Multiple loose stools remove fluid and electrolytes from the body, causing numerous imbalances. [Review Box 42-3, Common Medications That Cause Fluid, Electrolyte, and Acid-Base Imbalances with students.] Copyright © 2017, Elsevier Inc. All rights reserved.

23 Nursing Process: Assessment (continued)
medical history Recent surgery (physiological stress) culpa gastrointestinal Acute illness or trauma respiratory diseases Burns Trauma chronic disease Krebs heart failure oliguric kidney disease Patients who are very young or very old, who have fluid and/or electrolyte intake imbalances, or who have multiple chronic illnesses or trauma are at high risk for fluid, electrolyte, and acid-base imbalances. Surgery causes a physiologic stress response that is increased by extensive surgery and blood loss. On the second to fifth postoperative day, the increased release of aldosterone, glucocorticoids, and ADH causes an increase in ECV, a decrease in osmolarity, and an increase in potassium excretion. These imbalances are easily resolved in healthy patients, but patients with pre-existing conditions or additional risk factors often require treatment during this time. Increased fluid production by the gastrointestinal tract is a common and important cause of fluid, electrolyte, and acid-base imbalances that need careful investigation. Acute conditions that put patients at high risk for electrolyte and acid-base disturbances include respiratory disease, burns, trauma, gastrointestinal disturbances, and acute oliguric kidney disease. Many acute respiratory diseases predispose patients to respiratory acidosis. For example, bacterial pneumonia causes the alveoli to fill with exudate that impairs gas exchange, causing the patient to retain carbon dioxide, increasing PaCO2 and respiratory acidosis. Burns put patients at high risk of CVD deficiency due to multiple mechanisms, including displacement of plasma into the interstitial fluid and increased production and evaporation of exudate. The greater the body surface area burned, the greater the fluid loss. Bleeding from any type of trauma causes ECV deficit due to blood loss. Some types of trauma create additional risks. For example, crush injuries destroy cell structure and cause hyperkalemia through massive release of intracellular K+ into the blood. Head trauma often alters ADH secretion. It can cause diabetes insipidus (ADH deficiency), in which patients pass large amounts of very dilute urine and develop hypernatremia. Conversely, head injury can cause the syndrome of inappropriate antidiuretic hormone (SIADH), in which excessive ADH secretion causes hyponatremia by retaining too much water and concentrating the urine. Chronic disease. Many chronic illnesses result in ongoing risks of fluid, electrolyte, and acid-base imbalances. Furthermore, treatment regimens for chronic diseases often lead to imbalances. The specific fluid and electrolyte imbalances seen in cancer depend on the type and progression of the cancer and the treatment regimen. Many cancer patients develop hypercalcemia when their cancer cells secrete chemicals that circulate in the bones and cause calcium to enter the blood. Other fluid and electrolyte imbalances occur in cancer because some types of tumors cause metabolic and endocrine abnormalities. In addition, cancer patients are at risk for fluid and electrolyte imbalances as a result of side effects (eg, anorexia, diarrhea) of chemotherapy, biologic response modifiers, or radiation. Patients with chronic heart failure have reduced cardiac output, which decreases renal blood flow and activates the RAAS. The action of aldosterone on the kidneys causes an excess of ECV and risk of hypokalemia. Most diuretics used to treat heart failure increase the risk of hypokalemia while reducing excess ECV. Dietary sodium restriction is important in heart failure because Na+ retains water in the ECF and exacerbates excess ECV. In severe heart failure, sodium and fluid restriction are prescribed to reduce the workload on the heart by reducing excess circulating fluid volume. Oliguria occurs when the kidneys have a decreased ability to produce urine. Some diseases, such as acute B. nephritis, cause a sudden onset of oliguria, while other diseases, eg. B. Chronic kidney disease, leading to chronic oliguria. Oliguric kidney disease prevents normal elimination of metabolic fluids, electrolytes, and acids, resulting in excessive ECV, hyperkalemia, hypermagnesemia, hyperphosphatemia, and metabolic acidosis. The severity of these imbalances is proportional to the degree of renal failure. Copyright © 2017, Elsevier Inc. All rights reserved.

24 Physical assessment Daily weights Fluid intake and excretion (I&O)
liquid status indicator use the same terms Fluid intake and excretion (I&O) 24/7 I&O: Compare input to output Intake includes all fluids ingested, drunk, or administered intravenously. Stress = urine, diarrhea, vomiting, gastric suction, wound drainage laboratory study Data collected through a focused physical examination validates and augments the information collected in the patient's medical record. [Siehe Tabelle 42-10, Focused Nursing Assessments for Patients with Fluid, Electrolyte, and Acid-Base Imbalances, with Students.] Daily weight is an important indicator of fluid status. Each kilogram (2.2 pounds) of weight gained or lost overnight is equivalent to 1 liter of fluid retained or lost. These fluid gains or losses indicate changes in the amount of total body fluid, usually ECF, but not a change between body compartments. Weigh patients with heart failure and patients at high risk or with actual ECV excess daily. Daily weight is also useful for patients with clinical dehydration or other causes or risk of ECV deficiency. Weigh the patient on the same scale at the same time each day after the patient has urinated. Calibrate the scale daily or routinely. The patient must wear the same clothes or clothes of the same weight; If you use a bed scale, place the same number of sheets on the scale each time you weigh it. Compare each day's weight to the day before to determine fluid gain or loss. Observe the weights over several days to spot trends. Interpretation of daily weights guides therapy and medical care. Teach heart failure patients to measure and record their daily weight at home, and to contact the doctor if the weight suddenly increases by a certain amount (ask the doctor for the parameter). It is important to recognize trends in daily weights measured at home. Research shows that patients hospitalized for congestive heart failure often experience a steady increase in daily weight in the week prior to hospitalization. Measuring and recording all fluid inputs and outputs during a 24-hour period is an important aspect of fluid balance assessment. Compare a patient's 24-hour intake to the patient's 24-hour output. The two measurements should be about the same if the person has normal hydration levels. To interpret situations where the I&Os are significantly different, consider the individual patient. For example, if uptake is significantly greater than excretion, there are two options: the patient may gain excess fluid, or they may return to a normal fluid state by replacing fluid previously lost from the body. Also, when intake is significantly less than excretion, two possibilities are known: the patient may lose the necessary body fluids and develop ECV deficit and/or hypernatremia, or return to normal fluid status by excreting previously purchased excess fluid. . In most healthcare settings, the I&O measurement is a nursing assessment. Some agencies require a request from a health care provider for I&O. If you want to measure I&O in a fluid-compromised patient, check your agency's guidelines to see if you can submit them or if you need a physician's order. Fluid intake includes any liquid a person eats (eg, gelatin, ice cream, soup), drinks (eg, water, coffee, juice), or receives through a nasogastric or jejunostomy tube. Intravenous fluids (continuous and intermittent IVs in the back) and blood components are also sources of ingestion. Water ingested while taking pills and liquid medications counts as ingestion. A tube-fed patient is usually given various liquid medications and water is used to flush the tube before and/or after medication. Over a 24-hour period, these fluids represent a significant intake and are always recorded in the I&O log. Ask awake and oriented patients to help measure their oral intake and tell family members not to drink from the patient's water jug ​​or eat from the patient's tray. Fluid production includes urine, diarrhea, vomiting, gastric suction, and drainage from postoperative wounds or other tubes. Record the patient's urine output after each void. Instruct alert, oriented, and ambulatory patients to store their urine in a calibrated insert that attaches to the rim of the toilet bowl. Teach patients and their families the purpose of I&O measurements. Teach them to alert the nurse or nursing staff (NAP) to empty a cup of voiding fluid, or show them how to measure and empty the cup and correctly report the results. Accurate I&O facilitates continuous assessment of the patient's hydration status. Review the patient's laboratory test results and compare them to normal ranges for more objective data on fluid, electrolyte, and acid-base balance. Serum electrolyte tests are usually routinely performed on every patient admitted to hospital to check for imbalances and serve as a basis for future comparisons. [Look with students at Figure 42-9, Critical Thinking Model for Assessing Fluid, Electrolyte, and Acid-Base Balance.] Copyright © 2017, Elsevier Inc. All rights reserved.

25 Case study (continued) Woman. Reynolds states that she has no appetite, she has had nausea, vomiting and diarrhea for the past 7 days. Bowel sounds are hyperactive in all four quadrants. The patient has had only two loose stools since midnight. Urination with difficulty, with dark yellow urine. His intake in 24 hours was 1850 ml; the excretion of it was 2200 ml (of which only 1000 ml was urine). temperature 99.6°F; heart rate 100 bpm; BP 110/60 mmHg without changes in standing position. Respirations are 18 breaths per minute and are not associated with clear bilateral breath sounds on auscultation. Robert notices that Mrs. Reynolds is dry and that the turgor has decreased. Examination of the mucous membranes shows that they are dry with thick and clear mucus. The patient's weight of 143 lbs has decreased by 1 lb since admission. [Ask students: What conclusions can Robert draw from this information? To discuss.] Copyright © 2017, Elsevier Inc. All rights reserved.

26 Measurement of urine output.
[Figure 42-10 is shown: Container for measuring urine output.] Copyright © 2017, Elsevier Inc. All rights reserved.

27 Case Study (continued) Conclusions from Ms. Reynolds:
Hematocrit 44% (suggesting hypovolemia) Potassium 3.6 mEq/L and sodium 138 mEq/L (both normally low due to persistent vomiting and diarrhea) The ECG showed normal sinus rhythm. [Ask students: Which nursing diagnosis should Robert choose? To discuss.] Copyright © 2017, Elsevier Inc. All rights reserved.

28 Nursing diagnosis • Decreased cardiac output • Acute confusion
• Impaired gas exchange • Excess fluid volume • Risk of electrolyte imbalance • Little knowledge of disease management risk of injury • Low fluid volume The use of critical thinking in formulating nursing diagnoses is especially important when caring for patients with suspected fluid, electrolyte, and acid-base imbalances. Assessment data demonstrating risk or the actual presence of a nursing diagnosis in these areas can be subtle, and patterns and trends only emerge when intelligent assessment is made. Often multiple body systems are involved; A careful grouping of the defining characteristics leads to the selection of appropriate diagnoses. [Discuss with students how each diagnosis is determined.] [Review, Table 42-4, Nursing diagnostic process: Inadequate fluid volume associated with gastrointestinal fluid loss from vomiting, with students.] In addition to accurately collecting assessment data, an important part of formulating nursing diagnoses is identifying the relevant causal or related factor. They choose interventions that treat or modify the associated factor to resolve the diagnosis. Copyright © 2017, Elsevier Inc. All rights reserved.

29 Case study (continued) Robert chooses this nursing diagnosis: Deficient fluid levels associated with excessive diarrhea, vomiting, and potassium-depleting diuretics Its objectives are: Mrs. Reynolds' fluid volume will return to normal by the time she is discharged. Woman. Reynolds achieves a normal electrolyte balance through shock. [Ask students: What expected results would Robert set for these goals? To discuss.] Copyright © 2017, Elsevier Inc. All rights reserved.

30 Quick test! 3. A senior nursing student delegates the on/off task to a new nursing assistant. The student acknowledges that the nursing assistant understands the I&O task when the nursing assistant says: A. "I will record the total amount of urine passed." B. "I will not count liquid stool as eliminated." C. "I won't record mocha as a main course." D. "I will record sweating and record it as a small or large amount." Answer to Copyright © 2017, Elsevier Inc. All rights reserved.

31 Plan goals and results Set priorities
Create an individual patient care plan for each nursing diagnosis set priorities The clinical condition of the patient determines which of the nursing diagnoses has the highest priority. Team work and collaboration During the planning process, use critical thinking to synthesize information from various resources. Make sure the patient care plan integrates nursing and scientific knowledge and all the information you have collected about the individual patient. If the patient's condition is not treated in a timely manner, the fluid, electrolyte and acid-base balance will deteriorate. For example, if a patient experiences vomiting and diarrhea, it should be treated immediately, especially if the patient is young, elderly, or has a chronic illness. Do not delegate IV fluid administration and hemodynamic assessment to the NAP. When the patient is stable, you can delegate daily weighing, I&O, and direct physical care to the NAP. Cooperative care may include other services, such as discharge planning, nutritional support, and pharmacy. Ongoing communication and consultation are important as a patient's condition can change rapidly. Begin early discharge planning for patients with acute or chronic fluid and electrolyte imbalances, and consider the needs of the patient and family as they transition to a different environment. At the hospital, working collaboratively with other members of the health care team ensures that care continues at home or in long-term care with few interruptions. They ensure that therapeutic regimens established in one setting continue to completion in the next setting. [Check with students Figure 42.11, Critical Thinking Model for Planning Fluid, Electrolyte, and Acid-Base Balances.] [See Figure 42-12, Ms. Beck's concept map, with students.] Copyright © 2017, Elsevier Inc. All rights reserved.

32 Case Study (continued) Fluid Balance Electrolyte and Acid-Base Balance
Urinary excretion corresponds to an intake of ~1500 ml in 2 days. Mucous membranes will be moist within 24 hours. Skin turgor returns to normal within 24 hours. The daily weight does not change by more than 2 pounds for the next 2 days. Electrolyte and acid-base balance Serum electrolytes and complete blood count will be within normal limits within 48 hours. Woman. Reynolds will not have nausea or vomiting for 24 hours. [Ask students: What additional expected outcome would be included? Discuss: Mrs. Reynolds will not have more than 1 bowel movement per day for 3 days.] [Ask students: What interventions can you expect? To discuss.] Copyright © 2017, Elsevier Inc. All rights reserved.

33 Implementation of health promotion Information on fluid replacement
Educate patients with chronic conditions about risk factors and signs and symptoms of imbalances. Health promotion activities focus primarily on patient education. Teach patients and caregivers to recognize risk factors for developing imbalances and take appropriate preventive measures. Parents need to understand that babies and children need fluid replacement when they vomit or have diarrhea. Adults, especially the elderly and frail, also need to replace fluids when they sweat more. Patients with chronic health disorders are generally at risk of developing electrolyte and acid-base imbalances. They need to understand their own risk factors and the steps to take to avoid imbalances. Educate chronically ill patients and their caregivers about the early signs and symptoms of fluid, electrolyte, and acid-base imbalances that are at risk and what to do when they occur. Copyright © 2017, Elsevier Inc. All rights reserved.

34 Implementation (continued)
acute care Enteral fluid replacement fluid restriction Parenteral fluid and electrolyte replacement NPT crystalloids (electrolytes) colloids (blood and blood components) Intensive care nurses administer oral and intravenous medications and fluids to correct fluid and electrolyte deficiencies or to maintain normal homeostasis; They also help limit intake as part of overeating therapy. Prevention and treatment of CVD deficiency, hypernatremia, and electrolyte deficiencies are achieved by enteral or parenteral administration of an appropriate fluid. Enteral substitutes. Oral fluid and electrolyte replacement is appropriate unless the patient is so physiologically unstable that oral fluids cannot be replaced rapidly. Oral fluid replacement is contraindicated if the patient has mechanical obstruction of the gastrointestinal tract, high risk of aspiration, or difficulty swallowing. Some patients who cannot tolerate solid foods can still drink fluids. Strategies to encourage fluid intake include frequent sips of fluids, popsicles, and ice chips. Take half the volume of ice chips in the I&O measurement. Note each patient's preferred temperature for oral fluids. Cultural beliefs about the proper temperature of fluids can interfere with fluid intake unless fluid is available at the desired temperature. [See Table 42-5, Cultural Aspects of Nursing: Fluid Therapy, with students.] When replacing oral fluids in a CVD-deficient patient, choose fluids that contain sodium. Patients with hyponatremia often require restricted water intake. Patients with very severe ECV excess sometimes have sodium and fluid limitations. Patients often find it difficult to restrict their fluid balance, especially if they are taking medications that dry out the oral mucosa or are mouth breathers. In intensive care, fluid restrictions typically allocate half of total oral fluids between 7 a.m. and 5 p.m. m. and 3 p.m. m., when patients are most active, they eat two meals and take most of their medications orally. Offer remaining fluids during afternoon and evening shifts. Water-restricted patients require frequent oral care to hydrate the mucous membranes, reduce the risk of dryness and tearing of the mucosa, and maintain comfort. Fluids and electrolytes can be replaced by infusing fluids directly into the veins (intravenously) instead of through the digestive system. Parenteral replacement includes parenteral nutrition (PN), intravenous fluid and electrolyte (crystalloid) therapy, and administration of blood and blood components (colloids). IV devices are called peripheral IVs when the tip of the catheter is in a vein at one end; Central venous infusions are called when the tip of the catheter is in the central circulatory system (eg, in the vena cava near the right atrium of the heart). When administering parenteral fluids, practice standard bodily fluid precautions. PN, also called total parenteral nutrition (TPN), is the intravenous administration of a complex and highly concentrated solution containing nutrients and electrolytes tailored to the needs of the patient. Depending on the osmolality, NP solutions are administered through a central intravenous catheter (high osmolality) or peripherally (lower osmolality). Chapter 45 provides an overview of the principles and guidelines for administering PN when patients cannot be adequately nourished by oral or enteral feeding. [Figure 42-13 shown: Central venous lines supply intravenous fluid to the superior vena cava near the heart. CVAD, central venous access device.] Copyright © 2017, Elsevier Inc. All rights reserved.

35 Intravenous Therapy IV Therapy: Types of Crystalloid Solutions
isotonic hypoton hypertonic Caution: Infusing intravenous fluid too quickly or too much can cause serious problems. vascular access devices The purpose of intravenous fluid administration is to correct or prevent fluid and electrolyte imbalances. Infusions allow direct access to the vascular system and allow continuous infusion of fluids over a period of time. To provide safe and appropriate therapy to patients requiring intravenous fluids, you must know the correct solution requested, why the solution was requested, the equipment needed, the procedures needed to start an infusion, how the infusion rate system is regulated , how to identify and solve problems, and how to stop the infusion. [See Table 42-11, Intravenous Solutions, with students.] An IV solution can be isotonic, hypotonic, or hypertonic. Isotonic solutions have the same effective osmolarity as body fluids. Isotonic sodium-containing solutions, eg, normal saline, are indicated for CVD replacement to prevent or treat CVD deficiency. Hypotonic solutions have a lower effective osmolality than body fluids, and therefore a lower osmolality by diluting body fluids and moving water into cells. Hypertonic solutions have a higher effective osmolarity than body fluids. If they are hypertonic solutions containing sodium, they rapidly increase osmolarity and starve cells of water, causing them to shrink. The decision to use a hypotonic or hypertonic solution is based on the patient's specific fluid and electrolyte imbalance. Additives such as potassium chloride (KCl) are common in IV solutions. A request from a health care provider is required if additives have been added to an IV line. Administer KCl with caution as hyperkalemia can cause fatal cardiac arrhythmia. Under no circumstances should it be given as an IV injection (directly through a port on the IV line). Ensure that the patient has adequate renal function and urine output before administering a potassium-containing intravenous solution. Patients with normal renal function who are not receiving anything by mouth should add potassium to intravenous solutions. The body cannot store potassium, and the kidneys continue to excrete potassium even when plasma levels fall. Without potassium intake, hypokalemia develops rapidly. Vascular access devices (VADs) are catheters or infusion ports designed for repeated access to the vasculature. Peripheral catheters are for short-term use (eg, to restore fluids after surgery and for short-term administration of antibiotics). Long-term use devices include central lines and implanted ports that drain into a central vein. Remember that the term hub refers to the location of the catheter tip, not the insertion site. Peripherally inserted central catheters (PICC lines) enter a peripheral vein in the arm and travel through the venous system to the superior vena cava, where they terminate. Other central lines enter a central vein, such as the subclavian or jugular vein, or tunnel through the subcutaneous tissue before entering a central vein. Central catheters are more effective than peripheral catheters for delivering large volumes of fluids, parenteral nutrition (PN), and drugs or fluids that irritate veins. Proper care of central line insertion sites is essential to prevent catheter-related bloodstream infections (CRBSIs). Siehe Kasten 42-6, Evidence-Based Practice: Prevention of Central Line-Associated Bloodstream Infections (CLABSI), mit Studenten.] Copyright © 2017, Elsevier Inc. All rights reserved.

36 IV Therapy (continued)
gear Vascular access devices (VADs), tourniquets, clean gloves, bandages, IV fluid containers, various types of tubing, and Electronic Infusion Devices (EIDs), also called infusion pumps Starting the IV line infusion flow regulation Proper selection and preparation of intravenous equipment aids in the rapid and safe placement of the intravenous access. Because the fluids are infused directly into the bloodstream, sterile technique is required. Place all devices at the bedside for efficient insertion. IV equipment includes vascular access devices (VADs), tourniquets, clean gloves, bandages, IV fluid containers, various types of tubing, and electronic infusion devices (EIDs), also called infusion pumps. VADs, which are short peripheral intravenous catheters, are available in a variety of gauges, such as: B. the commonly used 20 and 22 gauge. A larger diameter indicates a smaller diameter catheter. A peripheral VAD is called an over-the-needle catheter; It consists of a small plastic tube or catheter that is threaded onto a sharp stylet (needle). After inserting the stylet and advancing the catheter into the vein, remove the stylet and leave the catheter in place. These devices have a safety mechanism that covers the sharp pin when it is removed to reduce the risk of a needlestick injury. Needle-free systems allow you to make needle-free connections, reducing needlestick injuries. The main intravenous fluid used in a continuous infusion flows through a tube called a main line. The primary line is connected to the intravenous catheter. Injectable drugs, such as antibiotics, are usually placed in a small IV bag and given as a secondary set in the primary line or combined as a primary intermittent infusion over a period of 30 to 60 minutes. The type and amount of solution are prescribed by the patient's physician and depend on the added medication and the patient's physiological state. If an IV infusion is connected to an EID, use the dedicated tubing for that EID. For gravity flow (non-EID) IVs, select tubing as described in the Skill Add IV Extension Tubing equipment list to increase the length of the primary line, thereby reducing tubing resistance and increasing patient mobility by change position. After collecting the set at the patient's bedside, prepare to insert the IV line by examining the patient for a venipuncture site. The most common IV sites are on the inside of the arm. When evaluating a patient for potential venipuncture sites, consider conditions that exclude certain sites. Venipuncture is contraindicated at a site that shows signs of infection, infiltration, or thrombosis. Venipuncture is a technique in which a vein is pierced through the skin with a sharp rigid stylet (like a metal needle). The stylet is partially covered with a plastic catheter or a needle attached to a syringe. [Review Table 42-7, Focus on Older Adults: Skin and Vein Protection During IV Therapy, with Students.] After starting a peripheral IV infusion and checking its patency, adjust the infusion rate as directed by your physician. For patient safety, avoid uncontrolled flow of intravenous fluid to the patient. You are responsible for calculating the flow rate (mL/hr) that the IV fluid will deliver during the prescribed period of time. Proper IV infusion rate ensures patient safety by avoiding administration of IV fluids too slowly or too quickly. Electronic Infusion Devices (EIDs), also called IV pumps or infusion pumps, provide a precise IV infusion rate per hour. EIDs use positive pressure to deliver a measured amount of fluid over a specified unit of time (for example, 125 mL/hr). Familiarize yourself with the EID tag used at your agency so you can accurately establish the flow rate. Many EIDs have features that allow single or multiple solution infusions at different rates. Electronic detectors and alarms respond to air in IV lines, occlusion, end of infusion, high and low pressure, and low battery. Regardless of the device used, periodically monitor the patient for adequate infusion of intravenous fluids. Bending an extremity, especially at the wrist or elbow, can decrease the IV flow rate by compressing the vein. [Figure 42-14: Catheter over needle for venipuncture and Figure 42-15: Common intravenous sites shown. A, inside of the arm. B, dorsal surface of hand.] Copyright © 2017, Elsevier Inc. All rights reserved.

37 Initiation of IV therapy System maintenance
Keep the system sterile and intact It involves (1) keeping the system sterile and intact; (2) replacement of IV fluid containers, tubing, and dressings from contaminated sites; (3) assist the patient in self-care activities so as not to disrupt the system; and (4) follow-up for complications of IV therapy. The frequency and options for system maintenance are specified in agency policies. An important part of patient care is maintaining the integrity of an IV line to prevent infection. Insertion of an intravenous line using correct aseptic technique reduces the likelihood of contamination of the patient's skin microflora. Post-insertion, diligent application of infection control principles, including thorough hand hygiene before and after handling any part of the intravenous system and maintaining sterility of the system during tubing and fluid container changes They will avoid infection. Always preserve the integrity of an IV system. Never disconnect the tubing as it may become tangled or make it more convenient to position or move a patient or put on a gown. If a patient needs more room to maneuver, use aseptic technique to connect an extension tube to an IV line. However, keep the use of extension pipe to a minimum, as any pipe connection presents the potential for contamination. Never let the IV line touch the floor. The IV tubing contains needle-free injection ports through which syringes or other adapters can be inserted to deliver medication. Thoroughly clean an injection port with 2% chlorhexidine (preferred), 70% alcohol, or povidone-iodine solution and allow to dry before accessing the system. Protection devices designed to prevent inadvertent movement or displacement of a VAD are called catheter stabilization devices. These devices are available in many hospitals and nurses choose whether or not to use them when starting an IV line. This is a patient safety issue. Movement of the VAD in a vein can cause phlebitis and infiltration; VAD relocation requires the use of a different VAD at a new IV infusion site. The Infusion Nurses Society (INS) standards indicate that the use of these devices is preferable to dressing whenever possible. [Figure 42-16: Potential Vascular Access Device Contamination Sites and Figure 42-17: Catheter Stabilization System shown.] [Review Exercise 42-1, Principles of Therapy IV, with students.] [Review Skill 42-2, Regulation of Intravenous Flow Rate, with students.] Copyright © 2017, Elsevier Inc. All rights reserved.

38 Initiation of IV therapy (cont.)
Changing intravenous fluid containers, tubing and dressings Assist the patient in self-care activities. complications Fluid overload, infiltration, extravasation, phlebitis, local infection, infusion site bleeding Peripheral IV line removal Patients receiving intravenous therapy for several days require regular changes of the intravenous fluid containers. It is important to organize tasks so that you can quickly change containers before a thrombus forms in the catheter. The recommended frequency of IV tubing changes depends on whether it is used for continuous or intermittent infusions. [Review Skill 42-3, IV System Maintenance, with students.] [Repeat Exercise 42-4, Peripheral IV Dressing Change, with students.] To avoid accidental disconnection of an intravenous system, the patient usually requires assistance with hygiene, comfort measures, meals, and ambulation. A potentially dangerous complication of IV therapy is circulatory overload from the IV solution, which occurs when a patient is given too fast or receives an excessive amount of fluid. The results of the evaluation depend on the type of IV solution that is infused in excess. A potentially dangerous complication of IV therapy is circulatory overload from the IV solution, which occurs when a patient is given too fast or receives an excessive amount of fluid. The results of the evaluation depend on the type of IV solution that is infused in excess. [Review Table 42-12, Complications of Intravenous Therapy with Nursing Interventions, with students.] Infiltration occurs when an intravenous catheter becomes loose or ruptures a vein and intravenous fluids accidentally leak into the subcutaneous tissue around the venipuncture site. When intravenous fluid contains additives that damage tissue, extravasation occurs. [Look at Table 42-13, Infiltration Scale, with students.] Phlebitis (ie, inflammation of a vein) results from chemical, mechanical, or bacterial causes. Risk factors for phlebitis include acidic or hypertonic intravenous solutions; rapid IV rate; Intravenous medications such as KCl, vancomycin, and penicillin; DAV inserted in the flexor area, poorly fixed catheter; poor hand hygiene; and lack of aseptic technique (Wallis et al., 2014). Typical signs of inflammation (eg, warmth, erythema [redness], pressure pain) occur along the vein. Phlebitis can be dangerous because blood clots (thrombophlebitis) form along the vein and, in some cases, cause embolism. This can permanently damage the veins. [Look at Table 42-14, Phlebitis Scale, with students.] Routine changes to peripheral intravenous lines to reduce infection are not recommended. Bleeding may occur around the venipuncture site during the infusion or through the catheter or tubing if it is accidentally dislodged (see Table 42-12). Bleeding is more common in people who take heparin or other blood thinners, or who have a bleeding disorder (eg, hemophilia or thrombocytopenia). Complete the IV line after infusing the prescribed amount of fluid; with infiltration, phlebitis or local infection; or if the intravenous catheter develops a thrombus at its tip. Copyright © 2017, Elsevier Inc. All rights reserved.

39 blood transfusion Blood component therapy = IV administration of whole blood or blood components blood groups and types autologous transfusion blood transfusion Transfusion reactions and other side effects Blood transfusion, or blood component therapy, is the intravenous administration of whole blood or a blood component, such as packed red blood cells (RBCs), platelets, or plasma. The goals of administering blood transfusions include (1) increasing circulating blood volume after surgery, trauma, or hemorrhage; (2) increase red blood cell count and maintain hemoglobin levels in patients with severe anemia; and (3) provide selected cellular components as replacement therapy (eg, coagulation factors, platelets, albumin). The care of patients who receive blood transfusions or blood products is the responsibility of nursing. They must thoroughly examine the patient, compare the blood product with the prescriptions of the prescribing physician, compare the blood product with the patient's identifications, and monitor for side effects. Blood transfusions are never considered routine; Neglecting small details can result in dangerous and fatal events for a patient. Blood transfusions must be adjusted to each patient to avoid incompatibilities. Red blood cells have antigens on their membranes; Plasma contains antibodies against specific erythrocyte antigens. When incompatible blood is transfused (ie, the antigens on a patient's red blood cells differ from those being transfused), the patient's antibodies trigger the destruction of the red blood cells in a potentially dangerous transfusion reaction. The most important grouping for transfusion purposes is the ABO system, which identifies blood groups A, B, O, and AB. Blood group is based on the presence or absence of red blood cell (RBC) A and B antigens. People with type A blood have A antigens on their red blood cells and anti-B antibodies in their plasma. People with type B blood have B antigens on their red blood cells and anti-A antibodies in their plasma. A person with blood type AB has A and B antigens on red blood cells and has no antibodies against either antigen in plasma. A type O person has neither A nor B antigens on the red blood cells, but anti-A and anti-B antibodies in the plasma. [Review Table 42-15, ABO Compatibilities for Transfusion Therapy, with students.] People with the O blood group are considered universal blood donors because they can donate red blood cells and platelets to people with any ABO blood group. People with AB blood are known as universal blood recipients because they can receive packed red blood cells and platelets of all ABO types. Autologous blood transfusion (autologous blood transfusion) is the removal and reinfusion of the patient's own blood. Blood for autologous transfusion is usually obtained from a preoperative donation up to 6 weeks before a planned operation (eg, cardiology, orthopedic, plastic, or gynecologic). A patient can donate several units of blood depending on the type of surgery and their ability to maintain an acceptable hematocrit. Blood for autologous transfusion is also obtained at the time of surgery by normovolemic hemodilution or by blood salvage (eg, during liver transplantation, trauma, or vascular and orthopedic disease). After the operation, blood is drawn from draining chest tubes or joint cavities. Autologous transfusions are safer for patients because they reduce the risk of incompatible blood and exposure to blood-borne infectious agents. The transfusion of blood or blood components is a healthcare procedure that requires the order of a healthcare professional. Patient safety is a top priority in care, and patient assessment, verification of the healthcare provider's order, and verification of the correct blood products for the correct patient are essential. Perform a thorough assessment of the patient before initiating a transfusion and monitor carefully during and after the transfusion. Evaluation is critical due to the risk of transfusion reactions. Always check agency policies and procedures before beginning any blood therapy. For patient safety, always check three things: that the blood components delivered are those requested; that the blood supplied to the patient is compatible with the blood group recorded in the medical record; and that the right patient gets the blood. If you are going to give a transfusion, you will need an intravenous catheter of the appropriate size and a blood administration tube with a special inline filter. [See Figure 42-18, Filling the Blood Tube.] If a transfusion reaction is anticipated or suspected, you will obtain more vital signs. [Review Table 42-16, Acute Side Effects of Transfusions, with Students.] The transfusion rate is usually specified in the doctor's prescription. When patients experience severe blood loss, such as B. bleeding, they are usually given rapid transfusions through a central venous catheter. Since the tip of the central venous catheter is in the superior vena cava above the right atrium, a blood warming device is often required. Rapid administration of cold blood can cause cardiac arrhythmias. Patients receiving large-volume citrate-containing blood transfusions are at high risk of hyperkalemia, hypocalcemia, hypomagnesemia, and metabolic alkalosis and therefore should be carefully monitored. A transfusion reaction is an immune system response to a transfusion ranging from a mild reaction to severe anaphylactic shock or acute intravascular haemolysis, which can be fatal. If you suspect acute intravascular hemolysis, do the following: Stop the transfusion immediately. Keep the IV line patent by replacing the IV tubing to the catheter hub with a new tubing and administering 0.9% sodium chloride (normal saline). Do not turn off the blood, just turn on the 0.9% sodium chloride solution (normal saline) connected to the Y-tube infusion set, as this would cause any remaining blood in the IV tubing to flow to the patient. Even a small amount of incompatible blood can cause a major reaction. Notify medical professionals or emergency personnel immediately. Stay with the patient, observing signs and symptoms every 5 minutes and monitoring vital signs. Prepare to administer rescue medications such as antihistamines, vasopressors, fluids, and corticosteroids as directed or by the healthcare professional's protocol. Prepare for CPR. Save the blood container, tube, accompanying labels, and transfusion protocol for return to the blood bank. Collect blood and urine samples as directed or as directed by your healthcare provider's protocol. Another category of adverse transfusion reactions are diseases transmitted through blood from infected donors who are asymptomatic. Symptoms of these conditions can appear long after the transfusion. Transfusion-transmitted diseases include hepatitis B and hepatitis C, human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) infections, and cytomegalovirus infections. In the United States, all units of blood at blood banks are tested for HIV, hepatitis B and C viruses, syphilis, and West Nile virus, reducing the risk of contracting these transmitted infections for the blood [Figure 42-18: Filling the tube for blood administration is shown.] Copyright © 2017, Elsevier Inc. All rights reserved.

40 Case study (continued) Robert will administer intravenous fluids (0.9% normal saline) at 125 mL/h. Becomes Mrs. Reynolds an additional 16 ounces of decaffeinated oral fluid every 8 hours. He or she will give you bismuth subsalicylate on demand (Pepto Bismol) for diarrhea. Maintains accurate I&O measurements. She becomes Mrs. Reynolds every day and monitors the trends. He will advise Mrs. Reynolds and her family on specific dietary changes (foods high in potassium). [Ask students: What are the reasons for these interventions? To discuss: Replacement of body fluids restores blood volume and normal serum electrolyte levels; An isotonic solution expands the volume of intravascular fluid in the body without causing the fluid to shift from one compartment to another. Pepto-Bismol is an antidiarrheal drug and is administered to inhibit gastrointestinal secretions, stimulate fluid and electrolyte absorption, inhibit intestinal inflammation, and suppress the growth of Helicobacter pylori. I&O documents hydration and fluid balance to guide therapy. Daily weights provide reliable data on fluid balance. Furosemide (Lasix) is a diuretic that destroys potassium. The body does not store potassium and therefore requires potassium-rich supplements.] Copyright © 2017, Elsevier Inc. All rights reserved.

41 Interventions Interventions for electrolyte imbalances
Support prescribed medical therapies The goal is to reverse the existing acid-base imbalance. provide patient safety Interventions for acid-base imbalances blood gases In addition to administering prescribed medical therapies, nursing procedures may be performed to maintain or restore electrolyte imbalance. Educate patients the rationale for their therapies and the importance of balancing I&O electrolytes to avoid imbalances in the future. Acid-base balance nursing measures support prescribed medical therapies and aim to correct an existing acid-base imbalance while ensuring patient safety. Patients with an acid-base imbalance often require repeat arterial blood gas (ABG) analysis. Determining the acid-base status of a patient requires drawing a sample of arterial blood for laboratory analysis. The ABG analysis shows the acid-base status and the adequacy of ventilation and oxygenation. A qualified RN or other health care provider draws arterial blood from a peripheral (usually radial) artery or from an existing arterial line (see agency policies and procedures). Before taking an arterial blood sample, perform an Allen's test, which assesses arterial blood flow in the hand. When performing the Allen test, apply pressure to the patient's radial and ulnar arteries in the selected hand. The fingers of the hand should be pale and whitish, indicating a lack of arterial blood flow. Release the pressure on the ulnar artery and note if the color returns to the fingers and hand, indicating that the hand and fingers are adequately perfused via the ulnar artery. Allen's test ensures that the patient has adequate blood flow to the hand when the radial artery is damaged. If the color does not return, do not perforate the radial artery in that arm. After the ABG puncture, apply pressure to the puncture site for at least 5 minutes to reduce the risk of hematoma formation. More time is required if the patient is taking anticoagulant medication. Reassess the radial pulse after removing the pressure. After collecting the sample, make sure that no air enters the syringe, as this will alter the blood gas values. To reduce oxygen consumption of the blood cells, immerse the syringe in crushed ice and transport to the laboratory immediately. Copyright © 2017, Elsevier Inc. All rights reserved.

42 Implementation of Restorative Care Home Intravenous Therapy
nutritional support drug safety medicine over the counter drugs herbal preparations Following acute changes in fluid, electrolyte, or acid-base balance, patients often require ongoing maintenance to prevent recurrence of health changes. Older adults require special considerations to avoid complications. IV therapy is generally continued at home in patients who require prolonged hydration, PN, or long-term medication administration. Initiate patient referral for discharge planning to social lines, counselors, or home care coordinators to assess patient and community resources. A home IV therapy nurse works closely with the patient to ensure that a sterile IV system is maintained and that complications can be prevented or identified in a timely manner. [See Table 42-8, Teaching the Patient: IV Home Therapy with Students.] Most patients with electrolyte imbalances or acid-base disorders require ongoing nutritional support. Depending on the type of disorder, fluid or food intake may be promoted or restricted. Patients or family members responsible for preparing meals should learn to understand the nutritional content of foods and read labels on commercially produced foods. Many medications, over-the-counter medications, and herbal supplements contain ingredients or cause potential side effects that can upset fluid and electrolyte balance. Chronic disease patients receiving multiple medications and patients with kidney disease are at significant risk of imbalances. Once patients return to a restorative care setting, whether at home, in a long-term care facility, or in another setting, medication safety is of paramount importance. It is important to educate the patient and family about possible side effects and drug interactions that can alter the fluid, electrolyte, or acid-base balance. Review all medications with patients and encourage them to consult their local pharmacist, especially if they want to try a new over-the-counter medication or herbal supplement. Copyright © 2017, Elsevier Inc. All rights reserved.

43 Case Study (cont.) Roberts Nursing Acts: Perspectives
Monitor electrolyte levels and daily weight. Examine the buccal mucosa; Assess the turgor of the skin. Evaluate I&O trends over the next 48 hours. discoveries Serum electrolyte levels: potassium 4.0 mEq/L and sodium 140 mEq/L. mucous membranes remain dry; Normal skin turgor. Ms. Reynolds' 24-hour intake is 2800 mL and output is 2200 mL with 1800 mL of urine. Urine specific gravity is 1.025 and weight is back to 143 pounds. Robert is from Mrs. Reynolds. Robert talks to Mrs. Reynolds and writes this documentation note: “He denies being sick and reports that he feels better. No more diarrhea since yesterday afternoon around 3pm. On examination, the buccal mucosa remains dry, with no lesions or inflammation. Skin turgor is normal. Bowel sounds are normal in all four quadrants, abdomen tender to palpation. 0.9% normal saline solution is administered i.v. infused into the left cephalic vein in the forearm at 40 ml/h per medical prescription. No tenderness or swelling at the IV site. You can identify five dietary sources of potassium to include in your diet. He is resting comfortably, out of bed in a chair, all his breakfast has been eaten. I'll keep watching." Copyright © 2017, Elsevier Inc. All rights reserved.

44 Assessment through the eyes of the patient Patient outcomes
Discuss with patients how their main concerns about fluid, electrolyte, or acid-base problems have been alleviated or addressed. patient outcomes Evaluate the effectiveness of the interventions against the objectives and results established for the nursing diagnoses of the patient. Assessment of a patient's clinical status is particularly important when there is an acute fluid, electrolyte, and/or acid-base imbalance. A patient's condition can change very rapidly, and it is important to anticipate future problems by integrating information about their current risk factors, clinical status, the impact of the current treatment regimen, and potential pathogens. To assess, you need to know how various pathophysiological conditions affect fluid, electrolyte, and acid-base balance; the effects of drugs and liquids; and the current clinical condition of the patient. Compare the results of your current assessment with the patient's previous assessment. For example, a patient's hypokalemia improves when serum potassium normalizes and the physical signs and symptoms of hypokalemia begin to resolve or decrease in intensity. In particular, the patient's heart rhythm becomes more regular and bowel function returns to normal. In patients with less acute changes, the evaluation is likely to be done over a longer period of time. In this situation, the assessment may focus more on behavior changes (eg, patient compliance with dietary restrictions and medication regimens). Another important element of the assessment is the family's ability to anticipate changes and prevent problems from happening again. The patient's progress will determine whether it is necessary to continue or revise the plan of care. If no results are obtained, the following questions can be asked: "How difficult is it for you to measure and record your I&O on a daily basis?" "What obstacles do you face in getting the potassium-rich foods you need?" "Do you still have frequent loose stools or diarrhea?" "Did you buy an antacid or do you still use baking soda as an antacid?" [Look with students at Figure 42-19, Critical Thinking Model for Assessing Fluid, Electrolyte, and Acid-Base Balance.] Copyright © 2017, Elsevier Inc. All rights reserved.