Chapter 10: Principles of Fluid and Electrolytes
Which solution is hypotonic? 0.45% NaCl 0.9% NaCl 5% NaCl Lactated Ringer solution
0.45% NaCl Explanation: Half-strength saline is hypotonic. Lactated Ringer solution and normal saline (0.9% NaCl) are isotonic. A 5% NaCl solution is hypertonic.
The physician has prescribed a hypotonic IV solution for a patient. Which IV solution should the nurse administer?
0.45% sodium chloride Explanation: Half-strength saline (0.45% sodium chloride) solution is frequently used as an IV hypotonic solution.
Which is considered an isotonic solution?
0.9% normal saline Explanation: An isotonic solution is 0.9% normal saline (NaCl). Dextran in normal saline is a colloid solution, 0.45% normal saline is a hypotonic solution, and 3% NaCl is a hypertonic solution.
At which serum sodium concentration might convulsions or coma occur?
130 mEq/L (130 mmol/L) Explanation: Normal serum concentration level ranges from 135 to 145 mEq/L (135-145 mmol/L). When the level dips below 135 mEq/L (135 mmol/L), hyponatremia occurs. Manifestations of hyponatremia include mental confusion, muscular weakness, anorexia, restlessness, elevated body temperature, tachycardia, nausea, vomiting, and personality changes. Convulsions or coma can occur if the deficit is severe. Values of 140, 142, and 145 mEq/L (mmol/L) are within the normal range
A client has been admitted to the hospital unit with signs and symptoms of hypovolemia; however, the client has not lost weight. The client exhibits a localized enlargement of her abdomen. What condition could the client be presenting?
?
A client reports tingling in the fingers as well as feeling depressed. The nurse assesses positive Trousseau's and Chvostek's signs. Which decreased laboratory results does the nurse observe when the client's laboratory work has returned?
Calcium Calcium deficit is associated with the following symptoms: numbness and tingling of the fingers, toes, and circumoral region; positive Trousseau's sign and Chvostek's sign; seizures, carpopedal spasms, hyperactive deep tendon reflexes, irritability, bronchospasm, anxiety, impaired clotting time, decreased prothrombin, diarrhea, and hypotension. Electrocardiogram findings associated with hypocalcemia include prolonged QT interval and lengthened ST.
The nurse is caring for a 72-year-old client who has been admitted to the unit for a fluid volume imbalance. The nurse knows which of the following is the most common fluid imbalance in older adults?
Dehydration Explanation: The most common fluid imbalance in older adults is dehydration. Because of reduced thirst sensation that often accompanies aging, older adults tend to drink less water. Use of diuretic medications, laxatives, or enemas may also deplete fluid volume in older adults. Chronic fluid volume deficit can lead to other problems such as electrolyte imbalances
With which condition should the nurse expect that a decrease in serum osmolality will occur?
Kidney failure
A nurse is caring for a client with metastatic breast cancer who is extremely lethargic and very slow to respond to stimuli. The laboratory report indicates a serum calcium level of 12.0 mg/dl, a serum potassium level of 3.9 mEq/L, a serum chloride level of 101 mEq/L, and a serum sodium level of 140 mEq/L. Based on this information, the nurse determines that the client's symptoms are most likely associated with which electrolyte imbalance?
Hypercalcemia Explanation: The normal reference range for serum calcium is 8.6 to 10.2 mg/dl. A serum calcium level of 12 mg/dl clearly indicates hypercalcemia. The client's other laboratory findings are within their normal ranges, so the client doesn't have hypernatremia, hypochloremia, or hypokalemia
Oral intake is controlled by the thirst center, located in which of the following cerebral areas?
Hypothalamus Explanation: Oral intake is controlled by the thirst center located in the hypothalamus. The thirst center is not located in the cerebellum, brainstem, or thalamus
A client in the emergency department reports that he has been vomiting excessively for the past 2 days. His arterial blood gas analysis shows a pH of 7.50, partial pressure of arterial carbon dioxide (PaCO2) of 43 mm Hg, partial pressure of arterial oxygen (PaO2) of 75 mm Hg, and bicarbonate (HCO3-) of 42 mEq/L. Based on these findings, the nurse documents that the client is experiencing which type of acid-base imbalance?
Metabolic alkalosis
A patient with abnormal sodium losses is receiving a regular diet. How can the nurse supplement the patient's diet to provide 1,600 mg of sodium daily?
One beef cube and 8 oz of tomato juice Explanation: For a patient with abnormal losses of sodium who can consume a general diet, the nurse encourages foods and fluids with high sodium content to control hyponatremia. For example, broth made with one beef cube contains approximately 900 mg of sodium; 8 oz of tomato juice contains approximately 700 mg of sodium. The nurse also needs to be familiar with the sodium content of parenteral fluids (see Table 13-5)
Which is the preferred route of administration for potassium?
Oral Explanation: When the client cannot ingest sufficient potassium by consuming foods that are high in potassium, administering oral potassium is ideal because oral potassium supplements are absorbed well. Administration by IV is done with extreme caution using an infusion pump, with the patient monitored by continuous ECG. To avoid replacing potassium too quickly, potassium is never administered by IV push or intramuscularly. Potassium is not administered subcutaneously
The nurse is reviewing client lab work for a critical lab value. Which value is called to the physician for additional orders?
Potassium: 5.8 mEq/L Explanation: Normal potassium level is approximately 3.5 to 5.0 mEq/L. Elevated potassium levels can lead to muscle weakness, paresthesias, and cardiac dysrhythmias.
A client seeks medical attention for an acute onset of severe thirst, polyuria, muscle weakness, nausea, and bone pain. Which health history information will the nurse report to the health care provider?
Takes high doses of vitamin D Explanation: Hypercalcemia can affect many organ systems and symptoms occur when the calcium level acutely rises. Hypercalcemia crisis refers to an acute rise in the serum calcium level. Severe thirst and polyuria are often present. Additional findings include muscle weakness, nausea, and bone pain. Excessive ingestion of vitamin D supplements may cause excessive absorption of calcium. Therefore, the nurse would report this finding to the health care provider. The client's symptoms are not associated with occasional alcohol intake, a high-fiber eating plan, or the client's employment status. These findings would not need to be reported
A nurse is providing client teaching about the body's plasma pH and the client asks the nurse what is the major chemical regulator of plasma pH. What is the best response by the nurse?
bicarbonate-carbonic acid buffer system Explanation: The major chemical regulator of plasma pH is the bicarbonate-carbonic acid buffer system. The renin-angiotensin-aldosterone system regulates blood pressure. The sodium-potassium pump regulate homeostasis. The ADH-ANP buffer system regulates water balance in the body.
A nurse evaluates a client's laboratory results. What is a factor that may be affecting an increase in serum osmolality?
free water loss Explanation: Osmolality measures the solute concentration per kilogram in blood and urine. Water loss in the serum would increase the solute concentration. Free water loss is a factor increasing serum osmolality. Diuretic use, overhydration, and hyponatremia are factors decreasing serum osmolality
A client with cancer is being treated on the oncology unit for bilateral breast cancer. The client is undergoing chemotherapy. The nurse notes the client's serum calcium concentration is 12.3 mg/dL (3.08 mmol/L). Given this laboratory finding, the nurse should suspect that the
malignancy is causing the lyte imbalance
The nurse is analyzing the arterial blood gas (ABG) results of a client diagnosed with severe pneumonia. Which of the following ABG results indicates respiratory acidosis?
pH: 7.20, PaCO2: 65 mm Hg, HCO3-: 26 mEq/L Explanation: Respiratory acidosis is a clinical disorder in which the pH is less than 7.35-7.40 and the PaCO2 is greater than 40-45 mm Hg and a compensatory increase in the plasma HCO3- occurs. Respiratory acidosis may be either acute or chronic. The ABG of pH: 7.32, PaCO2: 40 mm Hg, HCO3-: 18 mEq/L indicates metabolic acidosis. The ABGs of pH: 7.50, PaCO2: 30 mm Hg, and HCO3-: 24 mEq/L indicate respiratory alkalosis. The ABGs of pH 7.40, PaCO2: 40 mm Hg, and HCO3-: 24 mEq/L indicate a normal result/no imbalance
A client is diagnosed with hypocalcemia and the nurse is teaching the client about symptoms. What symptom would the nurse include in the teaching?
tingling sensation in the fingers Explanation: Tingling or numbness in the fingers is a symptom of hypocalcemia. Flank pain, polyuria, and hypertension are symptoms of hypercalcemia
The nurse is correct to state that a client's body needs to have adequate nutrition to maintain energy. Which type of transport of dissolved substances requires adenosine triphosphate (ATP)?
Active transport Explanation: Active transport requires the use of the body's energy molecule (ATP) to meet body needs for fluid and particle transport. Osmosis is the movement of body fluids through a semipermeable membrane that allows not all substances to pass through. Passive diffusion allows the movement of substances from an area of higher concentration to lower concentration. Facilitated diffusion has certain dissolved substances that require the assistance from a carrier module to pass through the semipermeable membrane.
To evaluate a client for hypoxia, the physician is most likely to order which laboratory test?
Arterial blood gas (ABG) analysis Explanation: Red blood cell count, sputum culture, total hemoglobin, and ABG analysis all help evaluate a client with respiratory problems. However, ABG analysis is the only test that evaluates gas exchange in the lungs, providing information about the client's oxygenation status.
The nurse is caring for a client diagnosed with bulimia. The client is being treated for a serum potassium concentration of 2.9 mEq/L (2.9 mmol/L). Which statement made by the client indicates the need for further teaching?
"I can use laxatives and enemas but only once a week." Explanation: The client is experiencing hypokalemia, most likely due to the diagnosis of bulimia. Hypokalemia is defined as a serum potassium concentration <3.5 mEq/L (3.5 mmol/L), and usually indicates a deficit in total potassium stores. Clients diagnosed with bulimia frequently suffer increased potassium loss through self-induced vomiting and misuse of laxatives, diuretics, and enemas; thus, the client should avoid laxatives and enemas. Prevention measures may involve encouraging the client at risk to eat foods rich in potassium (when the diet allows), including fruit juices and bananas, melon, citrus fruits, fresh and frozen vegetables, lean meats, milk, and whole grains. If the hypokalemia is caused by abuse of laxatives or diuretics, client education may help alleviate the problem
The nurse is caring for a client in the intensive care unit (ICU) following a near-drowning event in saltwater. The client is restless, lethargic, and demonstrating tremors. Additional assessment findings include swollen and dry tongue, flushed skin, and peripheral edema. The nurse anticipates that the client's serum sodium value would be
155 mEq/L (155 mmol/L) Explanation: The client is experiencing signs and symptoms (S/S) of hypernatremia. Hypernatremia is a serum sodium concentration >145 mEq/L (>145 mmol/L). A cause of hypernatremia is near drowning in seawater (which contains a sodium concentration of approximately 500 mEq/L). S/S of hypernatremia include thirst, elevated body temperature, swollen and dry tongue and sticky mucous membranes, hallucinations, lethargy, restlessness, irritability, simple partial or tonic-clonic seizures, pulmonary edema, hyperreflexia, twitching, nausea, vomiting, anorexia, elevated pulse, and elevated blood pressure
The nurse is caring for a client in the intensive care unit (ICU) following a near-drowning event in saltwater. The client is restless, lethargic, and demonstrating tremors. Additional assessment findings include swollen and dry tongue, flushed skin, and peripheral edema. The nurse anticipates that the client's serum sodium value would be
155 mEq/L (155 mmol/L) Explanation: The client is experiencing signs and symptoms (S/S) of hypernatremia. Hypernatremia is a serum sodium concentration >145 mEq/L (>145 mmol/L). A cause of hypernatremia is near drowning in seawater (which contains a sodium concentration of approximately 500 mEq/L). S/S of hypernatremia include thirst, elevated body temperature, swollen and dry tongue and sticky mucous membranes, hallucinations, lethargy, restlessness, irritability, simple partial or tonic-clonic seizures, pulmonary edema, hyperreflexia, twitching, nausea, vomiting, anorexia, elevated pulse, and elevated blood pressure
The emergency department (ED) nurse is caring for a client with a possible acid-base imbalance. The physician has ordered an arterial blood gas (ABG). What is one of the most important indications of an acid-base imbalance that is shown in an ABG?
Bicarbonate
When a client's ventilation is impaired, the body retains which substance?
Carbon dioxide Explanation: When ventilation is impaired, the body retains carbon dioxide (CO2) because the carbonic acid level increases in the blood. Sodium bicarbonate is used to treat acidosis. Nitrous oxide, which has analgesic and anesthetic properties, commonly is administered before minor surgical procedures. When ventilation is impaired, the body doesn't retain oxygen. Instead, the tissues use oxygen and CO2 results.
A physician orders regular insulin 10 units I.V. along with 50 ml of dextrose 50% for a client with acute renal failure. What electrolyte imbalance is this client most likely experiencing?
Hyperkalemia Explanation: Administering regular insulin I.V. concomitantly with 50 ml of dextrose 50% helps shift potassium from the extracellular fluid into the cell, which normalizes serum potassium levels in the client with hyperkalemia. This combination doesn't help reverse the effects of hypercalcemia, hypernatremia, or hyperglycemia.
Fluid and electrolyte balance is maintained through the process of translocation. What specific process allows water to pass through a membrane from a dilute to a more concentrated area?
Osmosis Explanation: Osmosis is the movement of water through a semipermeable membrane; one that allows some but not all substances in a solution to pass through from a diluted area to a more concentrated area. Filtration promotes the movement of fluid and some dissolved substances through a semipermeable membrane according to pressure differences. Evaporation is the process of converting water into a vapor. Active transport requires the energy source ATP to drive dissolved chemicals from an area of low concentration to an area of higher concentration; the opposite of passive diffusion.
