Chapter 13: fluid and electrolytes
Which is the most common cause of symptomatic hypomagnesemia?
Alcoholism Explanation: Alcoholism is currently the most common cause of symptomatic hypomagnesemia. Intravenous drug use, sedentary lifestyle, and burns are not the most common causes of hypomagnesemia.
A group of nursing students are studying for a test over acid-base imbalance. One student asks another what the major chemical regulator of plasma pH is. What should the second student respond?
Bicarbonate-carbonic acid buffer system Explanation: The major chemical regulator of plasma pH is the bicarbonate-carbonic acid buffer system. Therefore options A and C are incorrect. Option D does not exist, it is only a distractor for this question.
Air embolism is a potential complication of IV therapy. The nurse should be alert to which clinical manifestation associated with air embolism?
Chest pain Explanation: Manifestations of air embolism include dyspnea and cyanosis; hypotension; weak, rapid pulse; loss of consciousness; and chest, shoulder, and low back pain. Jaundice is not associated with air embolism.
The nurse is caring for a client with multiple organ failure and in metabolic acidosis. Which pair of organs is responsible for regulatory processes and compensation?
Lungs and kidney Explanation: The lungs and kidneys facilitate the ratio of bicarbonate to carbonic acid. Carbon dioxide is one of the components of carbonic acid. The lungs regulate carbonic acid levels by releasing or conserving CO2 by increasing or decreasing the respiratory rate. The kidneys assist in acid-base balance by retaining or excreting bicarbonate ions.
The calcium concentration in the blood is regulated by which mechanism?
Parathyroid hormone (PTH) Explanation: The serum calcium concentration is controlled by PTH and calcitonin. The thyroid hormone, adrenal gland, or androgens do not regulate the calcium concentration in the blood.
A client is to receive hypotonic IV solution in order to provide free water replacement. Which solution does the nurse anticipate administering?
0.45% NaCl Explanation: Half-strength saline (0.45%) is hypotonic. Hypotonic solutions are used to replace cellular fluid because it is hypotonic compared with plasma. Another is to provide free water to excrete body wastes. At times, hypotonic sodium solutions are used to treat hypernatremia and other hyperosmolar conditions. Lactated Ringer solution and normal saline (0.9% NaCl) are isotonic. A solution that is 5% NaCl is hypertonic.
The nurse is caring for a client with a serum sodium concentration of 113 mEq/L (113 mmol/L). The nurse should monitor the client for the development of which condition?
confusion Explanation: Normal serum concentration ranges from 135 to 145 mEq/L (135-145 mmol/L). Hyponatremia exists when the serum concentration decreases below 135 mEq/L (135 mmol/L). When the serum sodium concentration decreases to <115 mEq/L (<115 mmol/L), signs of increasing intracranial pressure, such as lethargy, confusion, muscle twitching, focal weakness, hemiparesis, papilledema, seizures, and death, may occur. General manifestations of hyponatremia include poor skin turgor, dry mucosa, headache, decreased saliva production, orthostatic fall in blood pressure, nausea, vomiting, and abdominal cramping. Neurologic changes, including altered mental status, status epilepticus, and coma, are probably related to cellular swelling and cerebral edema associated with hyponatremia. Hallucinations are associated with increased serum sodium concentrations.
When evaluating arterial blood gases (ABGs), which value is consistent with metabolic alkalosis?
pH 7.48 Explanation: Metabolic alkalosis is a clinical disturbance characterized by a high pH and high plasma bicarbonate concentration. The HCO value is below normal. The PaCO value and the oxygen saturation level are within a normal range.
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.
A nurse can estimate serum osmolality at the bedside by using a formula. A patient who has a serum sodium level of 140 mEq/L would have a serum osmolality of:
280 mOsm/kg. Explanation: Serum osmolality can be estimated by doubling the serum sodium or using the formula: Na × 2 = glucose/18 + BUN/3. Therefore, the nurse could estimate a serum osmolality of 280 mOsm/kg by doubling the serum sodium value of 140 mEq/L.
The nurse is caring for four clients on a medical unit. The nurse is most correct to review which client's laboratory reports first for an electrolyte imbalance?
A 52-year-old with diarrhea Electrolytes are in both intracellular and extracellular water. Electrolyte deficiency occurs from an inadequate intake of food, conditions that deplete water such as nausea and vomiting, or disease processes that cause an excess of electrolyte amounts. The 52-year-old with diarrhea would be the client most likely to have an electrolyte imbalance. The orthopedic client will not likely have an electrolyte imbalance. Myocardial infarction clients will occasionally have electrolyte imbalance, but this is the exception rather than the rule.
The nurse is caring for a client with a serum sodium concentration of 113 mEq/L (113 mmol/L). The nurse should monitor the client for the development of which condition?
Confusion Explanation: Normal serum concentration ranges from 135 to 145 mEq/L (135-145 mmol/L). Hyponatremia exists when the serum concentration decreases below 135 mEq/L (135 mmol/L). When the serum sodium concentration decreases to <115 mEq/L (<115 mmol/L), signs of increasing intracranial pressure, such as lethargy, confusion, muscle twitching, focal weakness, hemiparesis, papilledema, seizures, and death, may occur. General manifestations of hyponatremia include poor skin turgor, dry mucosa, headache, decreased saliva production, orthostatic fall in blood pressure, nausea, vomiting, and abdominal cramping. Neurologic changes, including altered mental status, status epilepticus, and coma, are probably related to cellular swelling and cerebral edema associated with hyponatremia. Hallucinations are associated with increased serum sodium concentrations.
A client was admitted to the unit with a diagnosis of hypovolemia. When it is time to complete discharge teaching, which of the following will the nurse teach the client and family? Select all that apply.
Drink at least eight glasses of fluid each day. Drink water as an inexpensive way to meet fluid needs. Respond to thirst Explanation: In addition, the nurse teaches clients who have a potential for hypovolemia and their families to respond to thirst because it is an early indication of reduced fluid volume; consume at least 8 to 10 (8 ounce) glasses of fluid each day and more during hot, humid weather; drink water as an inexpensive means to meet fluid requirements; and avoid beverages with alcohol and caffeine because they increase urination and contribute to fluid deficits.
Hypokalemia can cause which symptom to occur?
Excessive thirst Explanation: If prolonged, hypokalemia can lead to an inability of the kidneys to concentrate urine, causing dilute urine and excessive thirst. Potassium depletion depresses the release of insulin and results in glucose intolerance. Decreased sensitivity to digitalis does not occur with hypokalemia.
A client has the following arterial blood gas (ABG) values: pH, 7.12; partial pressure of arterial carbon dioxide (PaCO2), 40 mm Hg; and bicarbonate (HCO3-), 15 mEq/L. These ABG values suggest which disorder?
Metabolic acidosis Explanation: This client's pH value is below normal, indicating acidosis. The HCO3- value also is below normal, reflecting an overwhelming accumulation of acids or excessive loss of base, which suggests metabolic acidosis. The PaCO2 value is normal, indicating absence of respiratory compensation. These ABG values eliminate respiratory alkalosis, respiratory acidosis, and metabolic alkalosis.
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 Explanation: A pH over 7.45 with a HCO3- level over 26 mEq/L indicates metabolic alkalosis. Metabolic alkalosis is always secondary to an underlying cause and is marked by decreased amounts of acid or increased amounts of base HCO3-. The client isn't experiencing respiratory alkalosis because the PaCO2 is normal. The client isn't experiencing respiratory or metabolic acidosis because the pH is greater than 7.35
The nurse on a surgical unit is caring for a client recovering from recent surgery with the placement of a nasogastric tube to low continuous suction Which acid-base imbalance is most likely to occur?
Metabolic alkalosis Explanation: Metabolic alkalosis results in increased plasma pH because of an accumulated base bicarbonate or decreased hydrogen ion concentration. Factors that increase base bicarbonate include excessive oral or parenteral use of bicarbonate-containing drugs, a rapid decrease in extracellular fluid volume and loss of hydrogen and chloride ions as with gastric suctioning. Acidotic states are from excess carbonic acid and hydrogen ions in the system. Respiratory alkalosis results from a carbonic acid deficit that occurs when rapid breathing releases more CO2 than necessary.
Which electrolyte is a major cation in body fluid?
Potassium Explanation: Potassium is a major cation that affects cardiac muscle functioning. Chloride, bicarbonate, and phosphate are anions.
A nurse reviews the arterial blood gas (ABG) values of a client admitted with pneumonia: pH, 7.51; PaCO2, 28 mm Hg; PaO2, 70 mm Hg; and HCO3--, 24 mEq/L. What do these values indicate?
Respiratory alkalosis Explanation: A client with pneumonia may hyperventilate in an effort to increase oxygen intake. Hyperventilation leads to excess carbon dioxide (CO2) loss, which causes alkalosis — indicated by this client's elevated pH value. With respiratory alkalosis, the kidneys' bicarbonate (HCO3-) response is delayed, so the client's HCO3- level remains normal. The below-normal value for the partial pressure of arterial carbon dioxide (PaCO2) indicates CO2 loss and signals a respiratory component. Because the HCO3- level is normal, this imbalance has no metabolic component. Therefore, the client is experiencing respiratory alkalosis.
A client experiencing a severe anxiety attack and hyperventilating presents to the emergency department. The nurse would expect the client's pH value to be
7.50 Explanation: The patient is experiencing respiratory alkalosis. Respiratory alkalosis is a clinical condition in which the arterial pH is >7.45 and the PaCO2 is <38 mm Hg. Respiratory alkalosis is always caused by hyperventilation, which causes excessive "blowing off" of CO2 and, hence, a decrease in the plasma carbonic acid concentration. Causes include extreme anxiety, hypoxemia, early phase of salicylate intoxication, gram-negative bacteremia, and inappropriate ventilator settings.
Which is a correct route of administration for potassium?
Oral Explanation: Potassium may be administered through the oral route. Potassium is never administered by IV push or intramuscularly to avoid replacing potassium too quickly. Potassium is not administered subcutaneously.
Which is a correct route of administration for potassium? a) Subcutaneous b) Intramuscular c) Oral d) IV (intravenous) push
Oral Explanation: Potassium may be administered through the oral route. Potassium is never administered by IV push or intramuscularly to avoid replacing potassium too quickly. Potassium is not administered subcutaneously.
A client is taking spironolactone (Aldactone) to control her hypertension. Her serum potassium level is 6 mEq/L. For this client, the nurse's priority should be to assess her:
electrocardiogram (ECG) results. Explanation: Although changes in all these findings are seen in hyperkalemia, ECG results should take priority because changes can indicate potentially lethal arrhythmias such as ventricular fibrillation. It wouldn't be appropriate to assess the client's neuromuscular function, bowel sounds, or respiratory rate for effects of hyperkalemia.
A client with a suspected overdose of an unknown drug is admitted to the emergency department. Arterial blood gas values indicate respiratory acidosis. What should the nurse do first?
Prepare to assist with ventilation. Explanation: Respiratory acidosis is associated with hypoventilation; in this client, hypoventilation suggests intake of a drug that has suppressed the brain's respiratory center. Therefore, the nurse should assume the client has respiratory depression and should prepare to assist with ventilation. After the client's respiratory function has been stabilized, the nurse can safely monitor the heart rhythm, prepare for gastric lavage, and obtain a urine specimen for drug screening.
Early signs of hypervolemia include
increased breathing effort and weight gain. Explanation: Early signs of hypervolemia are weight gain, elevated blood pressure, and increased breathing effort. Eventually, fluid congestion in the lungs leads to moist breath sounds. One of the earliest symptoms of hypovolemia is thirst.
A client admitted with acute anxiety has the following arterial blood gas (ABG) values: pH, 7.55; partial pressure of arterial oxygen (PaO2), 90 mm Hg; partial pressure of arterial carbon dioxide (PaCO2), 27 mm Hg; and bicarbonate (HCO3-), 24 mEq/L. Based on these values, the nurse suspects:
respiratory alkalosis. Explanation: This client's above-normal pH value indicates alkalosis. The below-normal PaCO2 value indicates acid loss via hyperventilation; this type of acid loss occurs only in respiratory alkalosis. These ABG values wouldn't occur in metabolic acidosis, respiratory acidosis, or metabolic alkalosis.
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.
An elderly client takes 40 mg of Lasix twice a day. Which electrolyte imbalance is the most serious adverse effect of diuretic use?
Hypokalemia Explanation: Hypokalemia (potassium level below 3.5 mEq/L) usually indicates a defict in total potassium stores. Potassium-losing diuretics, such as loop diuretics, can induce hypokalemia.
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 weight of a client with congestive heart failure is monitored daily and entered into the medical record. In a 24-hour period, the client's weight increased by 2 lb. How much fluid is this client retaining?
1 L Explanation: A 2-lb weight gain in 24 hours indicates that the client is retaining 1L of fluid.
Which solution is hypotonic?
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.
Which solution is hypotonic? a) Lactated Ringer solution b) 0.45% NaCl c) 0.9% NaCl d) 5% NaCl
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.
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.
A 54-year-old male patient is admitted to the hospital with a case of severe dehydration. The nurse reviews the patient's laboratory results. Which of the following results are consistent with the diagnosis? Select all that apply.
Blood urea nitrogen (BUN) of 23 mg/dL Serum osmolality of 310 mOsm/kg Serum sodium of 148 mEq/L Urine specific gravity of 1.03 Explanation: Severe dehydration is associated with an increased BUN (N = 10 to 20 mg/dL), serum osmolality (N = 275 to 300 mOsm/kg), serum sodium (N = 135 to 145 mEq/L) and urine specific gravity (N = 1.01 to 1.025). Glucose and hematocrit levels would also be elevated but are within normal range for this question.
Which is an insensible mechanism of fluid loss?
Breathing Explanation: Loss of fluid from sweat or diaphoresis is referred to as insensible loss because it is unnoticeable and immeasurable. Losses from urination and bowel elimination are measurable. Nausea does not result in fluid loss, however if the client would develop emesis ( vomiting) this would be considered loss of body fluids and would need measured.
Which condition might occur with respiratory acidosis?
Increased intracranial pressure Explanation: If respiratory acidosis is severe, intracranial pressure may increase, resulting in papilledema and dilated conjunctival blood vessels. Increased blood pressure, increased pulse, and decreased mental alertness occur with respiratory acidosis.
Which of the following arterial blood gas results would be consistent with metabolic alkalosis?
Serum bicarbonate of 28 mEq/L Explanation: Evaluation of arterial blood gases reveals a pH greater than 7.45 and a serum bicarbonate concentration greater than 26 mEq/L.
To compensate for decreased fluid volume (hypovolemia), the nurse can anticipate which response by the body?
Tachycardia Explanation: Fluid volume deficit, or hypovolemia, occurs when the loss of extracellular fluid exceeds the intake of fluid. Clinical signs include oliguia, rapid heart rate, vasoconstriction, cool and clammy skin, and muscle weakness. The nurse monitors for rapid, weak pulse and orthostatic hypotension.
A nurse is conducting an initial assessment on a client with possible tuberculosis. Which assessment finding indicates a risk factor for tuberculosis?
The client had a liver transplant 2 years ago. Explanation: A history of immunocompromised status, such as that which occurs with liver transplantation, places the client at a higher risk for contracting tuberculosis. Other risk factors include inadequate health care, traveling to countries with high rates of tuberculosis (such as southeastern Asia, Africa, and Latin America), being a health care worker who performs procedures in which exposure to respiratory secretions is likely, and being institutionalized.
A client recovering from an acute asthma attack experiences respiratory alkalosis. The nurse measures a respiratory rate of 46 breaths/minute, a heart rate of 110 beats/minute, a blood pressure of 162/90 mm Hg, and a temperature of 98.6° F (37° C). To help correct respiratory alkalosis, the nurse should:
instruct the client to breathe into a paper bag. Explanation: A client recovering from an acute asthma attack who experiences respiratory alkalosis should breathe into a paper bag to increase arterial carbon dioxide tension and ease anxiety (which may exacerbate the alkalosis). An NG tube would be indicated for a client with metabolic alkalosis secondary to ingestion of toxic substances; there is no reason to believe that this has occurred. Fever may cause metabolic (not respiratory) alkalosis and would be treated with acetaminophen. A client with sepsis also may have metabolic alkalosis and probably would receive antibiotics; however, this clinical situation doesn't suggest sepsis.
Which of the following is a factor affecting an increase in serum osmolality?
Free water loss Explanation: Free water loss is a factor increasing serum osmolality. Diuretic use, overhydration, and hyponatremia are factors decreasing serum osmolality.
What foods can the nurse recommend for the patient with hypokalemia?
Fruits such as bananas and apricots Explanation: Sources of potassium include fruit juices and bananas, melon, citrus fruits, fresh and frozen vegetables, lean meats, milk, and whole grains (Crawford & Harris, 2011b).
Which intervention is most appropriate for a client with an arterial blood gas (ABG) of pH 7.5, a partial pressure of arterial carbon dioxide (PaCO2) of 26 mm Hg, oxygen (O2) saturation of 96%, bicarbonate (HCO3-) of 24 mEq/L, and a PaO2 of 94 mm Hg?
Instruct the client to breathe into a paper bag. Explanation: The ABG results reveal respiratory alkalosis. The best intervention to raise the PaCO2 level would be to have the client breathe into a paper bag. Administering a decongestant, offering fluids frequently, and administering supplemental oxygen wouldn't raise the lowered PaCO2 level.
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 Explanation: A pH over 7.45 with a HCO3- level over 26 mEq/L indicates metabolic alkalosis. Metabolic alkalosis is always secondary to an underlying cause and is marked by decreased amounts of acid or increased amounts of base HCO3-. The client isn't experiencing respiratory alkalosis because the PaCO2 is normal. The client isn't experiencing respiratory or metabolic acidosis because the pH is greater than 7.35.
A priority nursing intervention for a client with hypervolemia involves which of the following?
Monitoring respiratory status for signs and symptoms of pulmonary complications. Explanation: Hypervolemia, or fluid volume excess (FVE), refers to an isotonic expansion of the extracellular fluid. Nursing interventions for FVE include measuring intake and output, monitoring weight, assessing breath sounds, monitoring edema, and promoting rest. The most important intervention in the list involves monitoring the respiratory status for any signs of pulmonary congestion. Breath sounds are assessed at regular intervals.
A nurse is caring for a client with acute renal failure and hypernatremia. In this case, which action can be delegated to the nursing assistant?
Provide oral care every 2-3 hours. Explanation: Providing oral care for the client every 2-3 hours is within the scope of practice of a nursing assistant. The other actions should be completed by the registered nurse.
A client with chronic renal failure has a serum potassium level of 6.8 mEq/L. What should the nurse assess first?
Pulse Explanation: An elevated serum potassium level may lead to a life-threatening cardiac arrhythmia, which the nurse can detect immediately by palpating the pulse. In addition to assessing the client's pulse, the nurse should place the client on a cardiac monitor because an arrythmia can occur suddenly. The client's blood pressure may change, but only as a result of the arrhythmia. Therefore, the nurse should assess blood pressure later. The nurse also may delay assessing respirations and temperature because these aren't affected by the serum potassium level.
Which of the following is a function of calcitonin? Select all that apply.
Reduces bone resorption Increases urinary excretion of calcium Increases deposition of calcium in bones Explanation: Calcitonin reduces bones resorption, increasing deposition of calcium and phosphorous in the bones, and increases urinary excretion of calcium and phosphate.
Treatment of FVE involves dietary restriction of sodium. Which of the following food choices would be part of a low-sodium diet, mild restriction (2 to 3 g/day)?
Three ounces of light or dark meat chicken, 1 cup of spaghetti and a garden salad Explanation: Ham (1,400 mg Na for 3 oz) and bacon (155 mg Na/slice) are high in sodium as is tomato juice (660 mg Na/¾ cup) and low fat cottage cheese (918 mg Na/cup). Packaged meals are high in sodium.
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 electrolyte imbalance. Explanation: The client's laboratory findings indicate hypercalcemia. Hypercalcemia is defined as a calcium concentration >10.2 mg/dL (>2.6 mmol/L).The most common causes of hypercalcemia are malignancies and hyperparathyroidism. Malignant tumors can produce hypercalcemia through a variety of mechanisms. The client's calcium level is elevated; there is no indication that the client's diet is lacking in calcium-rich food products. Hyperaldosteronism is not associated with a calcium imbalance. Alcohol abuse is associated with hypocalcemia.
The nurse should assess the patient for signs of lethargy, increasing intracranial pressure, and seizures when the serum sodium reaches what level?
115 mEq/L Explanation: Features of hyponatremia associated with sodium loss and water gain include anorexia, muscle cramps, and a feeling of exhaustion. The severity of symptoms increases with the degree of hyponatremia and the speed with which it develops. When the serum sodium level decreases to less than 115 mEq/L (115 mmol/L), signs of increasing intracranial pressure, such as lethargy, confusion, muscle twitching, focal weakness, hemiparesis, papilledema, seizures, and death, may occur.
Below which serum sodium concentration might convulsions or coma occur?
135 mEq/L (135 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.
The nurse is caring for four clients on a medical unit. The nurse is most correct to review which client's laboratory reports first for an electrolyte imbalance?
A 52-year-old with diarrhea Explanation: Electrolytes are in both intracellular and extracellular water. Electrolyte deficiency occurs from an inadequate intake of food, conditions that deplete water such as nausea and vomiting, or disease processes that cause an excess of electrolyte amounts. The 52-year-old with diarrhea would be the client most likely to have an electrolyte imbalance. The orthopedic client will not likely have an electrolyte imbalance. Myocardial infarction clients will occasionally have electrolyte imbalance, but this is the exception rather than the rule.
A patient complains of 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 patient's laboratory work has returned?
Calcium Explanation: 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.
Which findings indicate that a client has developed water intoxication secondary to treatment for diabetes insipidus?
Confusion and seizures Explanation: Classic signs of water intoxication include confusion and seizures, both of which are caused by cerebral edema. Weight gain will also occur. Sunken eyeballs, thirst, and increased BUN levels indicate fluid volume deficit. Spasticity, flaccidity, and tetany are unrelated to water intoxication.
You are caring for a 72-year-old client who has been admitted to your unit for a fluid volume imbalance. You know 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. Therefore, options A, C, and D are incorrect.
Before seeing a newly assigned client with respiratory alkalosis, a nurse quickly reviews the client's medical history. Which condition is a predisposing factor for respiratory alkalosis?
Extreme anxiety Explanation: Extreme anxiety may lead to respiratory alkalosis by causing hyperventilation, which results in excessive carbon dioxide (CO2) loss. Other conditions that may set the stage for respiratory alkalosis include fever, heart failure, injury to the brain's respiratory center, overventilation with a mechanical ventilator, pulmonary embolism, and early salicylate intoxication. Type 1 diabetes may lead to diabetic ketoacidosis; the deep, rapid respirations occurring in this disorder (Kussmaul's respirations) don't cause excessive CO2 loss. Myasthenia gravis and opioid overdose suppress the respiratory drive, causing CO2 retention, not CO2 loss; this may lead to respiratory acidosis, not alkalosis.
You are caring for a new client on your unit who is third-spacing fluid. You know to assess for what type of edema?
Generalized Explanation: There may be generalized edema in all the interstitial spaces, which sometimes is called brawny edema or anasarca. Options B and D are not part of the process of third-spacing fluid. Option C is a distractor for this question.
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 9 to 11 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.
A client hospitalized for treatment of a pulmonary embolism develops respiratory alkalosis. Which clinical findings commonly accompany respiratory alkalosis?
Light-headedness or paresthesia Explanation: The client with respiratory alkalosis may complain of light-headedness or paresthesia (numbness and tingling in the arms and legs). Nausea, vomiting, abdominal pain, and diarrhea may accompany respiratory acidosis. Hallucinations and tinnitus rarely are associated with respiratory alkalosis or any other acid-base imbalance.
The nurse is caring for a patient with diabetes type I who is having severe vomiting and diarrhea. What condition that exhibits blood values with a low pH and a low plasma bicarbonate concentration should the nurse assess for?
Metabolic acidosis Explanation: Metabolic acidosis is a common clinical disturbance characterized by a low pH (increased H+ concentration) and a low plasma bicarbonate concentration. Metabolic alkalosis is a clinical disturbance characterized by a high pH (decreased H+ concentration) and a high plasma bicarbonate concentration. Respiratory acidosis is a clinical disorder in which the pH is less than 7.35 and the PaCO2 is greater than 42 mm Hg and a compensatory increase in the plasma HCO3 occurs. Respiratory alkalosis is a clinical condition in which the arterial pH is greater than 7.45 and the PaCO2 is less than 38 mm Hg.
A 64-year-old client is brought in to the clinic with thirsty, dry, sticky mucous membranes, decreased urine output, fever, a rough tongue, and lethargy. Serum sodium level is above 145 mEq/L. Should the nurse start salt tablets when caring for this client?
No, sodium intake should be restricted. Explanation: The symptoms and the high level of serum sodium suggest hypernatremia, (excess of sodium). It is necessary to restrict sodium intake. Salt tablets and sodium chloride IV can only worsen this condition but may be required in hyponatremia (sodium deficit). Hypotonic solution IV may be a part of the treatment but not along with the salt tablets.
A client is being treated in the ICU 24 hours after having a radical neck dissection completed. The client's serum calcium concentration is 7.6 mg/dL (1.9 mmol/L). Which physical examination finding is consistent with this electrolyte imbalance?
Presence of Trousseau sign Explanation: After radical neck resection, a client is prone to developing hypocalcemia. Hypocalcemia is defined as a serum value <8.6 mg/dL (<2.15 mmol/L). Signs and symptoms of hypocalcemia include Chvostek sign, which consists of muscle twitching enervated by the facial nerve when the region that is about 2 cm anterior to the earlobe, just below the zygomatic arch, is tapped; and a positive Trousseau sign can be elicited by inflating a blood pressure cuff on the upper arm to about 20 mm Hg above systolic pressure; within 2 to 5 minutes, carpal spasm (an adducted thumb, flexed wrist and metacarpophalangeal joints, and extended interphalangeal joints with fingers together) will occur as ischemia of the ulnar nerve develops. Slurred speech and muscle weakness are signs of hypercalcemia.
A client comes to the emergency department with status asthmaticus. His respiratory rate is 48 breaths/minute, and he is wheezing. An arterial blood gas analysis reveals a pH of 7.52, a partial pressure of arterial carbon dioxide (PaCO2) of 30 mm Hg, PaO2 of 70 mm Hg, and bicarbonate (HCO3??') of 26 mEq/L. What disorder is indicated by these findings?
Respiratory alkalosis Explanation: Respiratory alkalosis results from alveolar hyperventilation. It's marked by a decrease in PaCO2 to less than 35 mm Hg and an increase in blood pH over 7.45. Metabolic acidosis is marked by a decrease in HCO3? to less than 22 mEq/L, and a decrease in blood pH to less than 7.35. In respiratory acidosis, the pH is less than 7.35 and the PaCO2 is greater than 45 mm Hg. In metabolic alkalosis, the HCO3? is greater than 26 mEq/L and the pH is greater than 7.45.
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?
Third-spacing Explanation: Third-spacing describes the translocation of fluid from the intravascular or intercellular space to tissue compartments, where it becomes trapped and useless. The client manifests signs and symptoms of hypovolemia with the exception of weight loss. There may be signs of localized enlargement of organ cavities (such as the abdomen) if they fill with fluid, a condition referred to as ascites. Pitting edema occurs when indentations remain in the skin after compression. Anascara is another term for generalized edema, or brawny edema, in which the interstitial spaces fill with fluid. Hypovolemia (fluid volume deficit) refers to a low volume of extracellular fluid.
A patient is diagnosed with hypocalcemia. The nurse advises the patient and his family to immediately report the most characteristic manifestation. What is the most characteristic manifestation?
Tingling or twitching sensation in the fingers Explanation: All the choices are signs and symptoms of hypocalcemia, but tetany is the most characteristic manifestation that occurs when the calcium level is less than 4.4 mg/dL.
What does the nurse understand is the primary method by which fluid volume is regulated?
Urine excretion Explanation: Fluid volume is regulated primarily by the excretion of water in the form of urine and the promotion of thirst. Breathing, bowel elimination, and perspiration are methods the body uses to excrete fluid, but they are not the primary regulatory method for fluid volume.
A nurse is reviewing a report of a client's routine urinalysis. Which value requires further investigation?
Urine pH of 3.0 Explanation: Normal urine pH is 4.5 to 8; therefore, a urine pH of 3.0 is abnormal and requires further investigation. Urine specific gravity normally ranges from 1.010 to 1.025, making this client's value normal. Normally, urine contains no protein, glucose, ketones, bilirubin, bacteria, casts, or crystals. Red blood cells should measure 0 to 3 per high-power field; white blood cells, 0 to 4 per high-power field. Urine should be clear, with color ranging from pale yellow to deep amber.
Which set of arterial blood gas (ABG) results requires further investigation?
pH 7.49, PaCO2 30 mm Hg, PaO2 89 mm Hg, and HCO3- 18 mEq/L Explanation: The ABG results pH 7.49, PaCO2 30 mm Hg, PaO2 89 mm Hg, and HCO3- 18 mEq/L indicate respiratory alkalosis. The pH level is increased, and the HCO3- and PaCO2 levels are decreased. Normal values are pH 7.35 to 7.45; PaCO2 35 to 45 mm Hg; HCO3- 22 to 26 mEq/L.
A client with Guillain-Barré syndrome develops respiratory acidosis as a result of reduced alveolar ventilation. Which combination of arterial blood gas (ABG) values confirms respiratory acidosis?
pH, 7.25; PaCO2 50 mm Hg Explanation: In respiratory acidosis, ABG analysis reveals an arterial pH below 7.35 and partial pressure of arterial carbon dioxide (PaCO2) above 45 mm Hg. Therefore, the combination of a pH value of 7.25 and a PaCO2 value of 50 mm Hg confirms respiratory acidosis. A pH value of 7.5 with a PaCO2 value of 30 mm Hg indicates respiratory alkalosis. A ph value of 7.40 with a PaCO2 value of 35 mm Hg and a pH value of 7.35 with a PaCO2 value of 40 mm Hg represent normal ABG values, reflecting normal gas exchange in the lungs.
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 and the PaCO2 is greater than 42 mm Hg and a compensatory increase in the plasma HCO3- occurs. It 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 7.42, PaCO2: 45 mm Hg, and HCO3-: 22 mEq/L indicate a normal result/no imbalance.
