CHAPTER 10 Acid–Base Imbalances 155 2. To determine if a patient has metabolic acidosis, the nurse should assess for which of the following signs or symptoms? (a) The cause of or risk factor for hyperventilation (b) A pH of 7.49 and an HCO 3 of 22 mEq/L (c) A low potassium concentration with dysrhythmia (d) A history of prolonged diarrhea 3. Which of the following symptoms indicates a complication that is likely to occur with prolonged acidosis? (a) Cardiac dysrhythmia owing to hypokalemia (b) Respiratory failure owing to workload on the lungs (c) Fluid overload owing to chloride reabsorption and intoxication (d) Renal calculi owing to hypercalcemia from protein release of Ca + References Needham A. Comparative and Environmental Physiology Acidosis and Alkalosis. 2004. Pagana KD, Pagana TJ. Mosby’s Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis: Mosby Elsevier, 2006. Saladin K. Anatomy and Physiology: The Unity of Form and Function, 4th ed. New York: McGraw-Hill, 2007. Web Site http://en.wikipedia.org/wiki/Acidosis This page intentionally left blank PART THREE Applications for Fluid and Electrolyte Concepts Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. This page intentionally left blank CHAPTER 11 Multisystem Conditions Related to Fluid, Electrolyte, and Acid–Base Imbalances Learning Objectives At the end of this chapter, the student will be able to 1 Identify aspects of a condition that places the patient at risk for fl uid, electrolyte, or acid–base imbalance. 2 Relate the physiologic conditions associated with extreme youth and extreme age that put a patient at high risk for fl uid, electrolyte, or acid–base imbalance. Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. 160 Fluids and Electrolytes Demystifi ed 3 Evaluate select conditions for risk factors related to fl uid imbalance. 4 Evaluate select conditions for risk factors related to electrolyte imbalance. 5 Evaluate select conditions for risk factors related to acid–base imbalance. 6 Relate symptoms to the identifi ed imbalance(s). 7 Identify diagnostic values associated with imbalances caused by selected conditions. 8 Discuss the potential complications related to treatment of selected conditions. 9 Determine the nursing implications relative to fl uid, electrolyte, and acid–base imbalances related to treatment of selected conditions. Key Terms Afterload Age extremes Aldosterone Atelectasis Burn injury Cardiomyopathy Debridement Depolarization Dialysis Dysrhythmia Hemolysis Hyaline membrane disease Hypokalemia Hyperkalemia Hypoproteinemia Osteopenia Osteoporosis Pregnancy Preload Renal insuffi ciency Renal failure Respiratory distress syndrome (RDS) Senescence Overview Most conditions will cause an imbalance in more than just electrolytes. Fluid imbalance will follow certain electrolyte imbalances, and acid–base imbalance will result from certain electrolyte imbalances. As stated in previous chapters, acid–base CHAPTER 11 Conditions Related to Imbalances 161 imbalances can cause and result from electrolyte imbalances. With this in mind, the nurse must think about all levels of imbalance and anticipate problems that might occur. This is particularly important when treatments for one condition place the patient at risk for another condition or treatment for one imbalance places the patient at risk for the opposite electrolyte, fl uid, or acid–base imbalance. Since conditions are multifactorial and involve multiple systems, the nurse must think in terms of multisystem reality and consider that multiple imbalances can and often do occur simultaneously in one patient. Symptoms and history can be invaluable when determining what imbalances may be present in a patient. The nurse must ask questions to obtain details of dietary practices, exercise habits, work environment, and personal habits such as smoking or drinking to determine if the patient is at risk for conditions that have, up to this point, been undiagnosed. Providing this historical data, along with admission laboratory results and physical assessment data, can assist the primary- care provider in making a diagnosis and will help the nurse advocate for the patient to minimize complications that could worsen the patient’s condition. Symptoms can be confusing because many symptoms are shared by several electrolyte or acid–base imbalances and can be present owing to a combination of imbalances. Gathering as much historical information as possible could help to distinguish the imbalances that are most likely present and guide the laboratory testing and treatment ordered. Understanding the normal ranges of electrolytes, arterial blood gases, and other laboratory test values is critical to determining what is important and essential data to report and act on. Laboratory data often will be included as a routine part of the patient’s treatment to monitor effectiveness. Close monitoring of laboratory values by the nurse in concert with the medication or treatment administration can prevent overcompensation for one imbalance that might cause another imbalance. Whenever possible, the nurse should be aware of laboratory results before administering the medication or fl uid challenge. If the nurse has standing orders or the authority to order or perform screening diagnostic tests, such as a urine osmolality or sending a blood sample for electrolyte determination, particularly potassium, he or she should obtain the urine or blood for these tests and note the results in advance of administering treatment. In many cases, an ounce of prevention can be worth a pound of treatment or cure. This sampling of conditions will not address all conditions the nurse must be alert for as placing the patient at risk for fl uid, electrolyte, and acid–base imbalances. These are examples of some common conditions known to cause imbalances. The reader should review these conditions and consider how other conditions may affect similar organs of the body or similar functions in the body and place the patient at risk for fl uid, electrolyte, or acid–base imbalances. 1 162 Fluids and Electrolytes Demystifi ed Age Extremes While an age extreme does not qualify as a disease or illness state, certain physiologic differences that accompany extreme youth or extreme age can place a patient at risk for fl uid, electrolyte, and acid–base imbalances. The nurse should be aware of risk factors for young (newborn) or elderly (> 65 years of age) patients and take steps to avoid imbalances when possible or work with the primary-care provider to promote early treatment of imbalances when needed. The changes discussed here are not guaranteed to occur in every young or elderly patient but are possible risk factors that may predispose the patient to imbalances. NEWBORNS Newborns have less developed function of some organs at birth, with premature infants being at greatest risk for demonstrating diminished organ function. The most common organ function that is not fully developed is that of the kidneys. Additionally, the respiratory function of premature infants may be diminished, as well as the function of the liver. The complications associated with diminished organ function can result in a number of fl uid, electrolyte, and acid–base imbalances. The nurse should be alert for these imbalances. 1 Renal System • The kidneys are not fully developed at birth and have a decreased ability to concentrate the urine. • Water loss is high, and the need for fl uid intake is high for body weight relative to that of an adult. • The potential for dehydration is increased for an infant owing to fl uid loss. • The potential for hypernatremia is increased owing to dehydration and hemoconcentration. 1 Thus the nurse should monitor intake and output, weight, and signs of dehydration. Respiratory System • Lung function may be diminished in premature infants. • Hyaline membrane disease, also referred to as respiratory distress syndrome (RDS), is a defi ciency of pulmonary surfactant resulting in CHAPTER 11 Conditions Related to Imbalances 163 alveoli collapse (i.e., atelectasis) with exhalation and requires great effort for reinfl ation. • Should the atelectasis be unresolved, the patient is at risk for decreased gas exchange, which could result in a risk for hypoxia and anaerobic metabolism with lactic acidosis. • Decreased gas exchange also could result in carbon dioxide buildup with a resulting respiratory acidosis. 1 Liver • Diminished liver function might be demonstrated in a premature infant. The primary defi cit resulting from decreased liver function is the inability to synthesize adequate amounts of the protein albumin. • The lack of intravascular albumin results in low protein in the blood (i.e., hypoproteinemia) and would decrease the osmotic pressure that draws fl uid into the blood vessels. As a result, fl uid remains in the tissues and causes edema. • If a signifi cant amount of fl uid is lost into the tissues, hypovolemia could result. • An additional concern related to immature liver function is the decreased ability to process medications; thus medication may affect the patient to a greater degree than adult patients. Side effects of medications are more prevalent, along with the accompanying fl uid, electrolyte, and acid–base imbalances. 1 ELDERS As patients age toward later life, degenerative changes that occur in an organ system after the age of peak effi ciency (i.e., senescence) is noted. Senescence includes • A gradual loss of reserve capacity • Reduced healing ability • A decreased compensation for stress • Increased susceptibility to disease Organ systems degenerate at different rates, with some (e.g., the nervous system) reducing in function only by 10 to 15 percent from ages 30 to 80 and others (e.g., the kidneys) reducing as much as 60 percent in function. The specifi c changes noted in senescence that affect fl uid, electrolyte, and acid–base balance are as follows. 164 Fluids and Electrolytes Demystifi ed Integumentary System • Skin loses elasticity owing to atrophy of sebaceous glands and loss of collagen. The loss of elasticity makes assessment of skin turgor diffi cult for dehydration determination. • Cutaneous vitamin D production is diminished as much as 75 percent, contributing to calcium defi ciency with related muscle weakness and slowed neurotransmission. 1 Skeletal System • Osteopenia (i.e., loss of bone) and osteoporosis (i.e., porous, fragile bone) are noted owing to osteoclasts (i.e., bone-resorbing cells) that are more active than osteoblasts (i.e., bone depositing cells), resulting in decreased bone density and increased bone fragility • The impact of calcium defi cit (i.e., hypocalcemia) on bone may be greater owing to the preexisting bone loss. 1 Muscular System • Replacement of lean body mass with fat and loss of adenosine triphosphate (ATP), creatine phosphate, glycogen, and myoglobin leave muscles weaker. • The impact of potassium, sodium, or calcium imbalance must be assessed carefully based on the patient’s baseline muscle strength and neuromuscular effi ciency. • Historical data are key to establish a patient’s ability compensate for prior to electrolyte imbalances and to determine realistic goals and outcomes of treatment. 1 Nervous System • Peak effi ciency of the nervous system is noted around age 30. • After age 75, the brain weighs 56 percent less and has fewer synapses, less effi cient synaptic transmission, and less neurotransmitter production. • The impact of potassium, sodium, or calcium imbalance must be assessed carefully based on the patient’s baseline muscle strength and neuromuscular effi ciency. 1 • The impact of electrolyte imbalance on the nervous system may be greater in the elderly than in the young owing to the preexisting diminished neurologic function. [...]... which is vascular and plays a critical role in filtration of the blood • Renal tubules—the duct leading away from the glomerulus and toward the renal medulla and collecting ducts 170 Fluids and Electrolytes Demystified Fluids, electrolytes, and bicarbonate are secreted, reabsorbed, and excreted in different areas of the nephron Additionally, drugs administered to remove or retain fluids or electrolytes are... deficits, and accompanying fluid imbalance and anemia with circulatory and oxygenation concerns • Gastric and intestinal mucosae atrophy with decreased production of acid and intrinsic factor needed for absorption of vitamin B12 These changes result in acid–base imbalance and potential circulatory/respiratory problems related to anemia (i.e., hypoxia) 1 Renal System • From the mid-20s to the mid -8 0 s, the... assault 174 Fluids and Electrolytes Demystified • What are the values for the electrolytes, and in addition, what are the current values of the patient’s calcium, phosphate, BUN, and creatinine? Imbalances could indicate renal failure and stage of renal failure present • What is the patient’s urine specific gravity? If the value is low or fixed, it indicates loss of renal ability to concentrate urine and clear... disrupt the function of the skin Five main physical functions of the skin include • Resistance to trauma and infection by keeping most trauma and friction at the surface and keeping organisms at the surface and away from the bloodstream 176 Fluids and Electrolytes Demystified • Other barrier functions, particularly barrier to water to prevent absorption of excess water In addition, skin protects the body... 177 CHAPTER 11 Conditions Related to Imbalances 41/2% 41/2% 18% 18% 41/2% 41/2% 41/2% 41/2% 1% 9% 9% 9% 9% Figure 11–1 “Rule of nines” for an adult Head and neck, 9 percent; arms (each), 9 percent; anterior trunk, 18 percent; posterior trunk, 18 percent; legs (each), 18 percent; and perineum, 1 percent Total, 100 percent vasodilation and fluid and nutrients moving to the area to begin the healing process... irritable and has a blood pressure (BP) of 92/40 mm Hg, pulse (P) of 140 beats/minute, and respiration (R) of 38 breaths/minute, and her skin is cool and pale with pale mucous membranes Arterial blood-gas analysis reveals a pH of 7.32, PCO2 of 33 mm Hg, O2 of 70 percent, and HCO3 of 14 mEq/L Urine output is 200 mL for the past 24 hours Diagnostic tests ordered include an electrolyte panel (Na+, K+, Cl–, and. .. day, and lately, he has been working in the garden in the heat of the day 9 Follow-up assessments and monitoring: The nurse watches Mr Suarez closely for fluid balance, including urine output (becoming lighter gold in color with hydration, 30 mL/h) and weight (4.4 kg below his normal range on admission but now only 3 kg below the normal range), and continues checking intake and outputs The nurse 1 68 Fluids. .. alveoli • Vital capacity, respiratory volume, and expiratory volume decrease • Cough becomes weaker, decreasing clearance of secretions 166 Fluids and Electrolytes Demystified • Chronic obstructive pulmonary disease (COPD) with increased secretions and decreased airway size leads to airway blockage, decreased gas exchange, and hypoxia, which leads to lactic acidosis and carbon dioxide buildup with respiratory... degree—also called partial-thickness injury, involving the epidermis and part of the dermis • Third degree—also referred to as full-thickness injury, involving the epidermis, dermis, and deeper tissue, including muscle on some occasions Additional injury that occurs in burns includes smoke and inhalation injury Numerous consequences are associated with burn injury The degree of injury and impact of the... renal failure and usual treatments are listed in Table 11–1 While treatment of acute renal failure centers on eliminating the underlying cause, managing symptoms, and preventing complications, the care provided in both acute and chronic renal failure is similar for the body systems affected 172 Table 11–1 Fluids and Electrolytes Demystified Primary Manifestations of Acute Renal Failure and Recommended . glomerulus and toward the renal medulla and collecting ducts Renal Conditions 170 Fluids and Electrolytes Demystifi ed Fluids, electrolytes, and bicarbonate are secreted, reabsorbed, and excreted. hydration, 30 mL/h) and weight (4.4 kg below his normal range on admission but now only 3 kg below the normal range), and continues checking intake and outputs. The nurse 1 68 Fluids and Electrolytes. g/kg/day) 174 Fluids and Electrolytes Demystifi ed • What are the values for the electrolytes, and in addition, what are the current values of the patient’s calcium, phosphate, BUN, and creatinine?