Disorders of Fluid, Electrolyte, and Acid-Base Balance Test Bank- Chapter 8 Questions & Answers

Disorders of Fluid, Electrolyte, and Acid-Base Balance Test Bank Chapter 8 Questions & Answers 1.A client develops interstitial edema as a result of decreased: A) Vascular volume B) Hydrostatic pressure C) Capillary permeability D) Colloidal osmotic pressure Ans: D Feedback: Edema can be defined as palpable swelling produced by an increased interstitial fluid volume. The physiologic mechanisms that contribute to edema formation include factors that (1) increase capillary filtration (hydrostatic) pressure, (2) decrease the capillary colloid osmotic pressure, (3) increase capillary permeability, or (4) produce obstruction to lymph flow. 2.A client has been receiving intravenous normal saline at a rate of 125 mL/hour since her surgery 2 days earlier. As a result, she has developed an increase in vascular volume and edema. Which of the following phenomena accounts for this client's edema? A) Obstruction of lymph flow B) Increased capillary permeability C) Decreased capillary colloidal osmotic pressure D) Increased capillary filtration pressure Ans: D Feedback: An increase in vascular volume results in an increase in capillary filtration pressure. Consequently, movement of vascular fluid into the interstitial spaces increases and edema ensues. An increase in vascular volume does not directly result in obstruction of lymph flow, increased capillary permeability, or decreased capillary colloidal osmotic pressure. 3.The most reliable method for measuring body water or fluid volume increase is by assessing: A) Tissue turgor B) Intake and output C) Body weight change D) Serum sodium levels Ans: C Feedback: Daily weights are a reliable index of water volume gain (1 L of water weighs 2.2 pounds). Daily weight measurements taken at the same time each day with the same amount of clothing provide a useful index of water gain due to edema. When an unbalanced distribution of body water exists in the tissues and organs, assessment of surface skin tissue turgor will be inaccurate. Measurement of renal output is unreliable because fluid retention may be a compensatory response, or the renal system may be dysfunctional. Serum sodium levels are affected by multiple variables other than body water volume. 4.A client with a diagnosis of liver cirrhosis secondary to alcohol abuse has a distended abdomen as a result of fluid accumulation in his peritoneal cavity (ascites). Which of the following pathophysiologic processes contributes to this third spacing? A) Abnormal increase in transcellular fluid volume B) Increased capillary colloidal osmotic pressure C) Polydipsia D) Impaired hormonal control of fluid volume Ans: A Feedback: Third spacing represents the loss or trapping of extracellular fluid (ECF) in the transcellular space and a consequent increase in transcellular fluid volume. The serous cavities are part of the transcellular compartment located in strategic body areas where there is continual movement of body structures—the pericardial sac, the peritoneal cavity, and the pleural cavity. Polydipsia and increased fluid intake alone are insufficient to cause third spacing, and increased capillary colloidal osmotic pressure would result in increased intracellular fluid (ICF). The etiology of third spacing does not normally include alterations in hormonal control of fluid balance. 5.A 2-week-old infant (full-term at birth) is admitted to the pediatrics unit with “spitting up large amounts of formula” and diarrhea. The infant has developed a weak suck reflex. Which of the following statements about total body water (TBW) is accurate in this situation? A) About 52% of the infants' weight accounts for the amount of water in their body. B) Because of the infants' higher fat ratio, one should anticipate an increased TBW to as high as 90%. C) Most full-term infants have a TBW of approximately 75% due to their high metabolic rate. D) Most of an infant's TBW remains in the ICF compartment, so they should be able to transfer needed water into the ECF space. Ans: C Feedback: Infants normally have more TBW than older children or adults. TBW constitutes approximately 75% to 80% of body weight in full-term infants and an even greater percentage in premature infants. In males, the TBW decreases in the elderly population to approximately 52% TBW. Obesity decreases TBW, with levels as low as 30% to 40% of body weight in adults. Infants have more than half of their TBW in their ECF compartment, as compared to adults. 6.A client diagnosed with schizophrenia has been admitted to the emergency department (ED) after ingesting more than 2 gallons of water in one sitting. Which of the following pathophysiologic processes may result from the sudden water gain? A) Hypernatremia B) Water movement from the extracellular to the intracellular compartment C) Syndrome of inappropriate secretion of ADH (SIADH) D) Isotonic fluid excess in the extracellular fluid compartment Ans: B Feedback: Excess water ingestion coupled with impaired water excretion (or rapid ingestion at a rate that exceeds renal excretion) in persons with psychogenic polydipsia can lead to water intoxication (hyponatremia). A disproportionate gain of water with no accompanying gain in sodium results in the movement of water from the extracellular to the intracellular compartment. Hyponatremia accompanies this process. Because of the lack of sodium increase, accumulated fluid is hypotonic, not isotonic. SIADH is not a consequence of excess water intake. 7.A nurse caring for a client with a diagnosis of diabetes insipidus (DI) should prioritize the close monitoring of which of the following electrolyte levels? A) Potassium B) Sodium C) Magnesium D) Calcium Ans: B Feedback: The high water intake and high urine output that characterize diabetes insipidus create a risk of sodium imbalance. DI may present with hypernatremia and dehydration, especially in persons without free access to water, or with damage to the hypothalamic thirst center and altered thirst sensation. 8. The syndrome of inappropriate antidiuretic hormone (SIADH) is characterized by: A) Increased osmolality level of 360 mOsm/kg B) Excessive thirst with fluid intake of 7000 mL/day C) Copious dilute urination with output of 5000 mL/day D) Low serum sodium level of 122 mEq/L Ans: D Feedback: SIADH results from a failure of the negative feedback system that regulates the release and inhibition of antidiuretic hormone (ADH). ADH secretion continues even when serum osmolality is decreased, causing water retention and dilutional hyponatremia. Diabetes insipidus, deficiency or decreased response to ADH, is characterized by increased serum osmolality, excessive thirst, and polyuria. Urine output decreases in SIADH despite adequate or increased fluid intake. 9. In isotonic fluid volume deficit, changes in total body water are accompanied by: A) Intravascular hypotonicity B) Increased intravascular water C) Increases in intracellular sodium D) Proportionate losses of sodium Ans: D Feedback: Isotonic fluid volume deficit causes a proportionate loss of sodium and water. Hypotonicity results from water retention or sodium loss. Increased intravascular water causes sodium to move into the cell excessively. 10.A client with a history of heart and kidney failure is brought to the emergency department. Upon assessment/diagnosis, it is determined the client is in decompensated heart failure. Of the following assessment findings, which are associated with excess intracellular water? Select all that apply. A) Lethargy B) Confusion C) Hyperactive deep tendon reflexes D) Seizures E) Firm, rubbery tissue when palpating lower extremities Ans: A, B, D Feedback: Hyponatremia is usually defined as a serum sodium concentration of less than 135 mEq/L. Muscle cramps, weakness, and fatigue reflect the effects of hyponatremia on skeletal muscle function and are often early signs of hyponatremia. The cells of the brain and nervous system are the most seriously affected by increases in intracellular water. Symptoms include apathy, lethargy, and headache, which can progress to disorientation, confusion, gross motor weakness, and depression of deep tendon reflexes. Seizures and coma occur when serum sodium levels reach extremely low levels. Hypovolemia, third spacing (maldistribution of body fluid), and dehydration are associated with hypernatremia and/or hypertonicity. 11. Which of the following assessments should be prioritized in the care of a client who is being treated for a serum potassium level of 2.7 mEq/L? A) Detailed fluid balance monitoring checking for pitting edema B) Arterial blood gases looking for respiratory alkalosis C) Cardiac monitoring looking for prolonged PR interval and flattening of the T wave D) Monitoring of hemoglobin levels and oxygen saturation Ans: C Feedback: The most serious effects of hypokalemia are on the heart, a fact that necessitates frequent electrocardiography or cardiac telemetry. Hypokalemia