CH 13 fluid and electrolyte

The nurse is providing care for a patient with chronic obstructive pulmonary disease. When describing the process of respiration the nurse explains how oxygen and carbon dioxide are exchanged between the pulmonary capillaries and the alveoli. The nurse is describing what process? A) Diffusion B) Osmosis C) Active transport D) Filtration

Ans: A Feedback: Diffusion is the natural tendency of a substance to move from an area of higher concentration to one of lower concentration. It occurs through the random movement of ions and molecules. Examples of diffusion are the exchange of oxygen and carbon dioxide between the pulmonary capillaries and alveoli and the tendency of sodium to move from the ECF compartment, where the sodium concentration is high, to the ICF, where its concentration is low. Osmosis occurs when two different solutions are separated by a membrane that is impermeable to the dissolved substances; fluid shifts through the membrane from the region of low solute concentration to the region of high solute concentration until the solutions are of equal concentration. Active transport implies that energy must be expended for the movement to occur against a concentration gradient. Movement of water and solutes occurring from an area of high hydrostatic pressure to an area of low hydrostatic pressure is filtration.

The nurse is caring for a patient in metabolic alkalosis. The patient has an NG tube to low intermittent suction for a diagnosis of bowel obstruction. What drug would the nurse expect to find on the medication orders? A) Cimetidine B) Maalox C) Potassium chloride elixir D) Furosemide

Ans: A Feedback: H2 receptor antagonists, such as cimetidine (Tagamet), reduce the production of gastric HCl, thereby decreasing the metabolic alkalosis associated with gastric suction. Maalox is an oral simethicone used to break up gas in the GI system and would be of no benefit in treating a patient in metabolic alkalosis. KCl would only be given if the patient were hypokalemic, which is not stated in the scenario. Furosemide (Lasix) would only be given if the patient were fluid overloaded, which is not stated in the scenario.

A patient has questioned the nurse's administration of IV normal saline, asking whether sterile water would be a more appropriate choice than "saltwater." Under what circumstances would the nurse administer electrolyte-free water intravenously? A) Never, because it rapidly enters red blood cells, causing them to rupture. B) When the patient is severely dehydrated resulting in neurologic signs and symptoms C) When the patient is in excess of calcium and/or magnesium ions D) When a patient's fluid volume deficit is due to acute or chronic renal failure

Ans: A Feedback: IV solutions contain dextrose or electrolytes mixed in various proportions with water. Pure, electrolyte-free water can never be administered by IV because it rapidly enters red blood cells and causes them to rupture.

You are the nurse evaluating a newly admitted patient's laboratory results, which include several values that are outside of reference ranges. Which of the following would cause the release of antidiuretic hormone (ADH)? A) Increased serum sodium B) Decreased serum potassium C) Decreased hemoglobin D) Increased platelets

Ans: A Feedback: Increased serum sodium causes increased thirst and the release of ADH by the posterior pituitary gland. When serum osmolality decreases and thirst and ADH secretions are suppressed, the kidney excretes more water to restore normal osmolality. Levels of potassium, hemoglobin, and platelets do not directly affect ADH release.

You are the nurse caring for a patient who is to receive IV daunorubicin, a chemotherapeutic agent. You start the infusion and check the insertion site as per protocol. During your most recent check, you note that the IV has infiltrated so you stop the infusion. What is your main concern with this infiltration? A) Extravasation of the medication B) Discomfort to the patient C) Blanching at the site D) Hypersensitivity reaction to the medication

Ans: A Feedback: Irritating medications, such as chemotherapeutic agents, can cause pain, burning, and redness at the site. Blistering, inflammation, and necrosis of tissues can occur. The extent of tissue damage is determined by the medication concentration, the quantity that extravasated, infusion site location, the tissue response, and the extravasation duration. Extravasation is the priority over the other listed consequences.

You are the nurse caring for a 77-year-old male patient who has been involved in a motor vehicle accident. You and your colleague note that the patient's labs indicate minimally elevated serum creatinine levels, which your colleague dismisses. What can this increase in creatinine indicate in older adults? A) Substantially reduced renal function B) Acute kidney injury C) Decreased cardiac output D) Alterations in ratio of body fluids to muscle mass

Ans: A Feedback: Normal physiologic changes of aging, including reduced cardiac, renal, and respiratory function, and reserve and alterations in the ratio of body fluids to muscle mass, may alter the responses of elderly people to fluid and electrolyte changes and acid-base disturbances. Renal function declines with age, as do muscle mass and daily exogenous creatinine production. Therefore, high-normal and minimally elevated serum creatinine values may indicate substantially reduced renal function in older adults. Acute kidney injury is likely to cause a more significant increase in serum creatinine.

You are caring for a patient admitted with a diagnosis of acute kidney injury. When you review your patient's most recent laboratory reports, you note that the patient's magnesium levels are high. You should prioritize assessment for which of the following health problems? A) Diminished deep tendon reflexes B) Tachycardia C) Cool, clammy skin D) Acute flank pain

Ans: A Feedback: To gauge a patient's magnesium status, the nurse should check deep tendon reflexes. If the reflex is absent, this may indicate high serum magnesium. Tachycardia, flank pain, and cool, clammy skin are not typically associated with hypermagnesemia.

You are doing discharge teaching with a patient who has hypophosphatemia during his time in hospital. The patient has a diet ordered that is high in phosphate. What foods would you teach this patient to include in his diet? Select all that apply. A) Milk B) Beef C) Poultry D) Green vegetables E) Liver

Ans: A, C, E Feedback: If the patient experiences mild hypophosphatemia, foods such as milk and milk products, organ meats, nuts, fish, poultry, and whole grains should be encouraged.

A gerontologic nurse is teaching students about the high incidence and prevalence of dehydration in older adults. What factors contribute to this phenomenon? Select all that apply. A) Decreased kidney mass B) Increased conservation of sodium C) Increased total body water D) Decreased renal blood flow E) Decreased excretion of potassium

Ans: A, D, E Feedback: Dehydration in the elderly is common as a result of decreased kidney mass, decreased glomerular filtration rate, decreased renal blood flow, decreased ability to concentrate urine, inability to conserve sodium, decreased excretion of potassium, and a decrease of total body water.

The nurse caring for a patient post colon resection is assessing the patient on the second postoperative day. The nasogastric tube (NG) remains patent and continues at low intermittent wall suction. The IV is patent and infusing at 125 mL/hr. The patient reports pain at the incision site rated at a 3 on a 0-to-10 rating scale. During your initial shift assessment, the patient complains of cramps in her legs and a tingling sensation in her feet. Your assessment indicates decreased deep tendon reflexes (DTRs) and you suspect the patient has hypokalemia. What other sign or symptom would you expect this patient to exhibit? A) Diarrhea B) Dilute urine C) Increased muscle tone D) Joint pain

Ans: B Feedback: Manifestations of hypokalemia include fatigue, anorexia, nausea, vomiting, muscle weakness, leg cramps, decreased bowel motility, paresthesias (numbness and tingling), and dysrhythmias. If prolonged, hypokalemia can lead to an inability of the kidneys to concentrate urine, causing dilute urine (resulting in polyuria, nocturia) and excessive thirst. Potassium depletion suppresses the release of insulin and results in glucose intolerance. Decreased muscle strength and DTRs can be found on physical assessment. You would expect decreased, not increased, muscle strength with hypokalemia. The patient would not have diarrhea following bowel surgery, and increased bowel motility is inconsistent with hypokalemia.

You are the surgical nurse caring for a 65-year-old female patient who is postoperative day 1 following a thyroidectomy. During your shift assessment, the patient complains of tingling in her lips and fingers. She tells you that she has an intermittent spasm in her wrist and hand and she exhibits increased muscle tone. What electrolyte imbalance should you first suspect? A) Hypophosphatemia B) Hypocalcemia C) Hypermagnesemia D) Hyperkalemia

Ans: B Feedback: Tetany is the most characteristic manifestation of hypocalcemia and hypomagnesemia. Sensations of tingling may occur in the tips of the fingers, around the mouth, and, less commonly, in the feet. Hypophosphatemia creates central nervous dysfunction, resulting in seizures and coma. Hypermagnesemia creates hypoactive reflexes and somnolence. Signs of hyperkalemia include paresthesias and anxiety.

A medical nurse educator is reviewing a patient's recent episode of metabolic acidosis with members of the nursing staff. What should the educator describe about the role of the kidneys in metabolic acidosis? A) The kidneys retain hydrogen ions and excrete bicarbonate ions to help restore balance. B) The kidneys excrete hydrogen ions and conserve bicarbonate ions to help restore balance. C) The kidneys react rapidly to compensate for imbalances in the body. D) The kidneys regulate the bicarbonate level in the intracellular fluid.

Ans: B Feedback: The kidneys regulate the bicarbonate level in the ECF; they can regenerate bicarbonate ions as well as reabsorb them from the renal tubular cells. In respiratory acidosis and most cases of metabolic acidosis, the kidneys excrete hydrogen ions and conserve bicarbonate ions to help restore balance. In respiratory and metabolic alkalosis, the kidneys retain hydrogen ions and excrete bicarbonate ions to help restore balance. The kidneys obviously cannot compensate for the metabolic acidosis created by renal failure. Renal compensation for imbalances is relatively slow (a matter of hours or days).

A patient with a longstanding diagnosis of generalized anxiety disorder presents to the emergency room. The triage nurse notes upon assessment that the patient is hyperventilating. The triage nurse is aware that hyperventilation is the most common cause of which acid-base imbalance? A) Respiratory acidosis B) Respiratory alkalosis C) Increased PaCO2 D) CNS disturbances

Ans: B Feedback: The most common cause of acute respiratory alkalosis is hyperventilation. Extreme anxiety can lead to hyperventilation. Acute respiratory acidosis occurs in emergency situations, such as pulmonary edema, and is exhibited by hypoventilation and decreased PaCO2. CNS disturbances are found in extreme hyponatremia and fluid overload.

You are caring for a patient with a diagnosis of pancreatitis. The patient was admitted from a homeless shelter and is a vague historian. The patient appears malnourished and on day 3 of the patient's admission total parenteral nutrition (TPN) has been started. Why would you know to start the infusion of TPN slowly? A) Patients receiving TPN are at risk for hypercalcemia if calories are started too rapidly. B) Malnourished patients receiving parenteral nutrition are at risk for hypophosphatemia if calories are started too aggressively. C) Malnourished patients who receive fluids too rapidly are at risk for hypernatremia. D) Patients receiving TPN need a slow initiation of treatment in order to allow digestive enzymes to accumulate

Ans: B Feedback: The nurse identifies patients who are at risk for hypophosphatemia and monitors them. Because malnourished patients receiving parenteral nutrition are at risk when calories are introduced too aggressively, preventive measures involve gradually introducing the solution to avoid rapid shifts of phosphorus into the cells. Patients receiving TPN are not at risk for hypercalcemia or hypernatremia if calories or fluids are started to rapidly. Digestive enzymes are not a relevant consideration.

The physician has ordered a peripheral IV to be inserted before the patient goes for computed tomography. What should the nurse do when selecting a site on the hand or arm for insertion of an IV catheter? A) Choose a hairless site if available. B) Consider potential effects on the patient's mobility when selecting a site. C) Have the patient briefly hold his arm over his head before insertion. D) Leave the tourniquet on for at least 3 minutes.

Ans: B Feedback: Ideally, both arms and hands are carefully inspected before choosing a specific venipuncture site that does not interfere with mobility. Instruct the patient to hold his arm in a dependent position to increase blood flow. Never leave a tourniquet in place longer than 2 minutes. The site does not necessarily need to be devoid of hair.

The nurse in the medical ICU is caring for a patient who is in respiratory acidosis due to inadequate ventilation. What diagnosis could the patient have that could cause inadequate ventilation? A) Endocarditis B) Multiple myeloma C) Guillain-Barré syndrome D) Overdose of amphetamines

Ans: C Feedback: Respiratory acidosis is always due to inadequate excretion of CO2 with inadequate ventilation, resulting in elevated plasma CO2 concentrations and, consequently, increased levels of carbonic acid. Acute respiratory acidosis occurs in emergency situations, such as acute pulmonary edema, aspiration of a foreign object, atelectasis, pneumothorax, overdose of sedatives, sleep apnea, administration of oxygen to a patient with chronic hypercapnia (excessive CO2 in the blood), severe pneumonia, and acute respiratory distress syndrome. Respiratory acidosis can also occur in diseases that impair respiratory muscles, such as muscular dystrophy, myasthenia gravis, and Guillain-Barré syndrome. The other listed diagnoses are not associated with respiratory acidosis.

The ICU nurse is caring for a patient who experienced trauma in a workplace accident. The patient is complaining of having trouble breathing with abdominal pain. An ABG reveals the following results: pH 7.28, PaCO2 50 mm Hg, HCO3- 23 mEq/L. The nurse should recognize the likelihood of what acid-base disorder? A) Respiratory acidosis B) Metabolic alkalosis C) Respiratory alkalosis D) Mixed acid-base disorder

Ans: D Feedback: Patients can simultaneously experience two or more independent acid-base disorders. A normal pH in the presence of changes in the PaCO2 and plasma HCO3- concentration immediately suggests a mixed disorder, making the other options incorrect.

The community health nurse is performing a home visit to an 84-year-old woman recovering from hip surgery. The nurse notes that the woman seems uncharacteristically confused and has dry mucous membranes. When asked about her fluid intake, the patient states, "I stop drinking water early in the day because it is just too difficult to get up during the night to go to the bathroom." What would be the nurse's best response? A) "I will need to have your medications adjusted so you will need to be readmitted to the hospital for a complete workup." B) "Limiting your fluids can create imbalances in your body that can result in confusion. Maybe we need to adjust the timing of your fluids." C) "It is normal to be a little confused following surgery, and it is safe not to urinate at night." D) "If you build up too much urine in your bladder, it can cause you to get confused, especially when your body is under stress. "

Ans: B Feedback: In elderly patients, the clinical manifestations of fluid and electrolyte disturbances may be subtle or atypical. For example, fluid deficit may cause confusion or cognitive impairment in the elderly person. There is no mention of medications in the stem of the question or any specific evidence given for the need for readmission to the hospital. Confusion is never normal, common, or expected in the elderly. Urinary retention does normally cause confusion.

A nurse in the neurologic ICU has orders to infuse a hypertonic solution into a patient with increased intracranial pressure. This solution will increase the number of dissolved particles in the patient's blood, creating pressure for fluids in the tissues to shift into the capillaries and increase the blood volume. This process is best described as which of the following? A) Hydrostatic pressure B) Osmosis and osmolality C) Diffusion D) Active transport

Ans: B Feedback: Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. Hydrostatic pressure refers to changes in water or volume related to water pressure. Diffusion is the movement of solutes from an area of greater concentration to lesser concentration; the solutes in an intact vascular system are unable to move so diffusion normally should not be taking place. Active transport is the movement of molecules against the concentration gradient and requires adenosine triphosphate (ATP) as an energy source; this process typically takes place at the cellular level and is not involved in vascular volume changes.

The nurse is preparing to insert a peripheral IV catheter into a patient who will require fluids and IV antibiotics. How should the nurse always start the process of insertion? A) Leave one hand ungloved to assess the site. B) Cleanse the skin with normal saline. C) Ask the patient about allergies to latex or iodine. D) Remove excessive hair from the selected site.

Ans: C Feedback: Before preparing the skin, the nurse should ask the patient if he or she is allergic to latex or iodine, which are products commonly used in preparing for IV therapy. A local reaction could result in irritation to the IV site, or, in the extreme, it could result in anaphylaxis, which can be life threatening. Both hands should always be gloved when preparing for IV insertion, and latex-free gloves must be used or the patient must report not having latex allergies. The skin is not usually cleansed with normal saline prior to insertion. Removing excessive hair at the selected site is always secondary to allergy inquiry.

One day after a patient is admitted to the medical unit, you note that the patient is oliguric. You notify the acute-care nurse practitioner who orders a fluid challenge of 200 mL of normal saline solution over 15 minutes. This intervention will achieve which of the following? A) Help distinguish hyponatremia from hypernatremia B) Help evaluate pituitary gland function C) Help distinguish reduced renal blood flow from decreased renal function D) Help provide an effective treatment for hypertension-induced oliguria

Ans: C Feedback: If a patient is not excreting enough urine, the health care provider needs to determine whether the depressed renal function is the result of reduced renal blood flow, which is a fluid volume deficit (FVD or prerenal azotemia), or acute tubular necrosis that results in necrosis or cellular death from prolonged FVD. A typical example of a fluid challenge involves administering 100 to 200 mL of normal saline solution over 15 minutes. The response by a patient with FVD but with normal renal function is increased urine output and an increase in blood pressure. Laboratory examinations are needed to distinguish hyponatremia from hypernatremia. A fluid challenge is not used to evaluate pituitary gland function. A fluid challenge may provide information regarding hypertension-induced oliguria, but it is not an effective treatment.

You are performing an admission assessment on an older adult patient newly admitted for end-stage liver disease. What principle should guide your assessment of the patient's skin turgor? A) Overhydration is common among healthy older adults. B) Dehydration causes the skin to appear spongy. C) Inelastic skin turgor is a normal part of aging. D) Skin turgor cannot be assessed in patients over 70.

Ans: C Feedback: Inelastic skin is a normal change of aging. However, this does not mean that skin turgor cannot be assessed in older patients. Dehydration, not overhydration, causes inelastic skin with tenting. Overhydration, not dehydration, causes the skin to appear edematous and spongy.

You are making initial shift assessments on your patients. While assessing one patient's peripheral IV site, you note edema around the insertion site. How should you document this complication related to IV therapy? A) Air emboli B) Phlebitis C) Infiltration D) Fluid overload

Ans: C Feedback: Infiltration is the administration of nonvesicant solution or medication into the surrounding tissue. This can occur when the IV cannula dislodges or perforates the wall of the vein. Infiltration is characterized by edema around the insertion site, leakage of IV fluid from the insertion site, discomfort and coolness in the area of infiltration, and a significant decrease in the flow rate. Air emboli, phlebitis, and fluid overload are not indications of infiltration.

You are caring for a 65-year-old male patient admitted to your medical unit 72 hours ago with pyloric stenosis. A nasogastric tube placed upon admission has been on low intermittent suction ever since. Upon review of the morning's blood work, you notice that the patient's potassium is below reference range. You should recognize that the patient may be at risk for what imbalance? A) Hypercalcemia B) Metabolic acidosis C) Metabolic alkalosis D) Respiratory acidosis

Ans: C Feedback: Probably the most common cause of metabolic alkalosis is vomiting or gastric suction with loss of hydrogen and chloride ions. The disorder also occurs in pyloric stenosis in which only gastric fluid is lost. Vomiting, gastric suction, and pyloric stenosis all remove potassium and can cause hypokalemia. This patient would not be at risk for hypercalcemia; hyperparathyroidism and cancer account for almost all cases of hypercalcemia. The nasogastric tube is removing stomach acid and will likely raise pH. Respiratory acidosis is unlikely since no change was reported in the patient's respiratory status.

You are called to your patient's room by a family member who voices concern about the patient's status. On assessment, you find the patient tachypnic, lethargic, weak, and exhibiting a diminished cognitive ability. You also find 3+ pitting edema. What electrolyte imbalance is the most plausible cause of this patient's signs and symptoms? A) Hypocalcemia B) Hyponatremia C) Hyperchloremia D) Hypophosphatemia

Ans: C Feedback: The signs and symptoms of hyperchloremia are the same as those of metabolic acidosis: hypervolemia and hypernatremia. Tachypnea; weakness; lethargy; deep, rapid respirations; diminished cognitive ability; and hypertension occur. If untreated, hyperchloremia can lead to a decrease in cardiac output, dysrhythmias, and coma. A high chloride level is accompanied by a high sodium level and fluid retention. With hypocalcemia, you would expect tetany. There would not be edema with hyponatremia. Signs or symptoms of hypophosphatemia are mainly neurologic.

The nurse is assessing the patient for the presence of a Chvostek's sign. What electrolyte imbalance would a positive Chvostek's sign indicate? A) Hypermagnesemia B) Hyponatremia C) Hypocalcemia D) Hyperkalemia

Ans: C Feedback: You can induce Chvostek's sign by tapping the patient's facial nerve adjacent to the ear. A brief contraction of the upper lip, nose, or side of the face indicates Chvostek's sign. Both hypomagnesemia and hypocalcemia may be tested using the Chvostek's sign.

A nurse educator is reviewing peripheral IV insertion with a group of novice nurses. How should these nurses be encouraged to deal with excess hair at the intended site? A) Leave the hair intact. B) Shave the area. C) Clip the hair in the area. D) Remove the hair with a depilatory.

Ans: C Feedback: Hair can be a source of infection and should be removed by clipping; it should not be left at the site. Shaving the area can cause skin abrasions, and depilatories can irritate the skin.

A nurse is planning care for a nephrology patient with a new nursing graduate. The nurse states, "A patient in renal failure partially loses the ability to regulate changes in pH." What is the cause of this partial inability? A) The kidneys regulate and reabsorb carbonic acid to change and maintain pH. B) The kidneys buffer acids through electrolyte changes. C) The kidneys regenerate and reabsorb bicarbonate to maintain a stable pH. D) The kidneys combine carbonic acid and bicarbonate to maintain a stable pH.

Ans: C Feedback: The kidneys regulate the bicarbonate level in the ECF; they can regenerate bicarbonate ions as well as reabsorb them from the renal tubular cells. In respiratory acidosis and most cases of metabolic acidosis, the kidneys excrete hydrogen ions and conserve bicarbonate ions to help restore balance. The lungs regulate and reabsorb carbonic acid to change and maintain pH. The kidneys do not buffer acids through electrolyte changes; buffering occurs in reaction to changes in pH. Carbonic acid works as the chemical medium to exchange O2 and CO2 in the lungs to maintain a stable pH whereas the kidneys use bicarbonate as the chemical medium to maintain a stable pH by moving and eliminating H+.

You are an emergency-room nurse caring for a trauma patient. Your patient has the following arterial blood gas results: pH 7.26, PaCO2 28, HCO3 11 mEq/L. How would you interpret these results? A) Respiratory acidosis with no compensation B) Metabolic alkalosis with a compensatory alkalosis C) Metabolic acidosis with no compensation D) Metabolic acidosis with a compensatory respiratory alkalosis

Ans: D Feedback: A low pH indicates acidosis (normal pH is 7.35 to 7.45). The PaCO3 is also low, which causes alkalosis. The bicarbonate is low, which causes acidosis. The pH bicarbonate more closely corresponds with a decrease in pH, making the metabolic component the primary problem.

When planning the care of a patient with a fluid imbalance, the nurse understands that in the human body, water and electrolytes move from the arterial capillary bed to the interstitial fluid. What causes this to occur? A) Active transport of hydrogen ions across the capillary walls B) Pressure of the blood in the renal capillaries C) Action of the dissolved particles contained in a unit of blood D) Hydrostatic pressure resulting from the pumping action of the heart

Ans: D Feedback: An example of filtration is the passage of water and electrolytes from the arterial capillary bed to the interstitial fluid; in this instance, the hydrostatic pressure results from the pumping action of the heart. Active transport does not move water and electrolytes from the arterial capillary bed to the interstitial fluid, filtration does. The number of dissolved particles in a unit of blood is concerned with osmolality. The pressure in the renal capillaries causes renal filtration.

A patient's most recent laboratory results show a slight decrease in potassium. The physician has opted to forego drug therapy but has suggested increasing the patient's dietary intake of potassium. Which of the following would be a good source of potassium? A) Apples B) Asparagus C) Carrots D) Bananas

Ans: D Feedback: Bananas are high in potassium. Apples, carrots, and asparagus are not high in potassium.

You are caring for a patient with a secondary diagnosis of hypermagnesemia. What assessment finding would be most consistent with this diagnosis? A) Hypertension B) Kussmaul respirations C) Increased DTRs D) Shallow respirations

Ans: D Feedback: If hypermagnesemia is suspected, the nurse monitors the vital signs, noting hypotension and shallow respirations. The nurse also observes for decreased DTRs and changes in the level of consciousness. Kussmaul breathing is a deep and labored breathing pattern associated with severe metabolic acidosis, particularly diabetic ketoacidosis (DKA), but also renal failure. This type of patient is associated with decreased DTRs, not increased DTRs.

Diagnostic testing has been ordered to differentiate between normal anion gap acidosis and high anion gap acidosis in an acutely ill patient. What health problem typically precedes normal anion gap acidosis? A) Metastases B) Excessive potassium intake C) Water intoxication D) Excessive administration of chloride

Ans: D Feedback: Normal anion gap acidosis results from the direct loss of bicarbonate, as in diarrhea, lower intestinal fistulas, ureterostomies, and use of diuretics; early renal insufficiency; excessive administration of chloride; and the administration of parenteral nutrition without bicarbonate or bicarbonate-producing solutes (e.g., lactate). Based on these facts, the other listed options are incorrect.

A 73-year-old man comes into the emergency department (ED) by ambulance after slipping on a small carpet in his home. The patient fell on his hip with a resultant fracture. He is alert and oriented; his pupils are equal and reactive to light and accommodation. His heart rate is elevated, he is anxious and thirsty, a Foley catheter is placed, and 40 mL of urine is present. What is the nurse's most likely explanation for the low urine output? A) The man urinated prior to his arrival to the ED and will probably not need to have the Foley catheter kept in place. B) The man likely has a traumatic brain injury, lacks antidiuretic hormone (ADH), and needs vasopressin. C) The man is experiencing symptoms of heart failure and is releasing atrial natriuretic peptide that results in decreased urine output. D) The man is having a sympathetic reaction, which has stimulated the renin-angiotensin-aldosterone system that results in diminished urine output.

Ans: D Feedback: Renin is released by the juxtaglomerular cells of the kidneys in response to decreased renal perfusion. Angiotensin-converting enzyme converts angiotensin I to angiotensin II. Angiotensin II, with its vasoconstrictor properties, increases arterial perfusion pressure and stimulates thirst. As the sympathetic nervous system is stimulated, aldosterone is released in response to an increased release of renin, which decreases urine production. Based on the nursing assessment and mechanism of injury, this is the most likely causing the lower urine output. The man urinating prior to his arrival to the ED is unlikely; the fall and hip injury would make his ability to urinate difficult. No assessment information indicates he has a head injury or heart failure.

The baroreceptors, located in the left atrium and in the carotid and aortic arches, respond to changes in the circulating blood volume and regulate sympathetic and parasympathetic neural activity as well as endocrine activities. Sympathetic stimulation constricts renal arterioles, causing what effect? A) Decrease in the release of aldosterone B) Increase of filtration in the Loop of Henle C) Decrease in the reabsorption of sodium D) Decrease in glomerular filtration

Ans: D Feedback: Sympathetic stimulation constricts renal arterioles; this decreases glomerular filtration, increases the release of aldosterone, and increases sodium and water reabsorption. None of the other listed options occurs with increased sympathetic stimulation.

You are caring for a patient who is being treated on the oncology unit with a diagnosis of lung cancer with bone metastases. During your assessment, you note the patient complains of a new onset of weakness with abdominal pain. Further assessment suggests that the patient likely has a fluid volume deficit. You should recognize that this patient may be experiencing what electrolyte imbalance? A) Hypernatremia B) Hypomagnesemia C) Hypophosphatemia D) Hypercalcemia

Ans: D Feedback: The most common causes of hypercalcemia are malignancies and hyperparathyroidism. Anorexia, nausea, vomiting, and constipation are common symptoms of hypercalcemia. Dehydration occurs with nausea, vomiting, anorexia, and calcium reabsorption at the proximal renal tubule. Abdominal and bone pain may also be present. Primary manifestations of hypernatremia are neurologic and would not include abdominal pain and dehydration. Tetany is the most characteristic manifestation of hypomagnesemia, and this scenario does not mention tetany. The patient's presentation is inconsistent with hypophosphatemia.

You are working on a burns unit and one of your acutely ill patients is exhibiting signs and symptoms of third spacing. Based on this change in status, you should expect the patient to exhibit signs and symptoms of what imbalance? A) Metabolic alkalosis B) Hypermagnesemia C) Hypercalcemia D) Hypovolemia

Ans: D Feedback: Third-spacing fluid shift, which occurs when fluid moves out of the intravascular space but not into the intracellular space, can cause hypovolemia. Increased calcium and magnesium levels are not indicators of third-spacing fluid shift. Burns typically cause acidosis, not alkalosis.

A newly graduated nurse is admitting a patient with a long history of emphysema. The new nurse's preceptor is going over the patient's past lab reports with the new nurse. The nurse takes note that the patient's PaCO2 has been between 56 and 64 mm Hg for several months. The preceptor asks the new nurse why they will be cautious administering oxygen. What is the new nurse's best response? A) The patient's calcium will rise dramatically due to pituitary stimulation. B) Oxygen will increase the patient's intracranial pressure and create confusion. C) Oxygen may cause the patient to hyperventilate and become acidotic. D) Using oxygen may result in the patient developing carbon dioxide narcosis and hypoxemia.

Ans: D Feedback: When PaCO2 chronically exceeds 50 mm Hg, it creates insensitivity to CO2 in the respiratory medulla, and the use of oxygen may result in the patient developing carbon dioxide narcosis and hypoxemia. No information indicates the patient's calcium will rise dramatically due to pituitary stimulation. No feedback system that oxygen stimulates would create an increase in the patient's intracranial pressure and create confusion. Increasing the oxygen would not stimulate the patient to hyperventilate and become acidotic; rather, it would cause hypoventilation and acidosis.

You are caring for a patient who has a diagnosis of syndrome of inappropriate antidiuretic hormone secretion (SIADH). Your patient's plan of care includes assessment of specific gravity every 4 hours. The results of this test will allow the nurse to assess what aspect of the patient's health? A) Nutritional status B) Potassium balance C) Calcium balance D) Fluid volume status

Ans: D Feedback: A specific gravity will detect if the patient has a fluid volume deficit or fluid volume excess. Nutrition, potassium, and calcium levels are not directly indicated.

A patient who is being treated for pneumonia starts complaining of sudden shortness of breath. An arterial blood gas (ABG) is drawn. The ABG has the following values: pH 7.21, PaCO2 64 mm Hg, HCO3 = 24 mm Hg. What does the ABG reflect? A) Respiratory acidosis B) Metabolic alkalosis C) Respiratory alkalosis D) Metabolic acidosis

Ans:A Feedback: The pH is below 7.40, PaCO2 is greater than 40, and the HCO3 is normal; therefore, it is a respiratory acidosis, and compensation by the kidneys has not begun, which indicates this was probably an acute event. The HCO3 of 24 is within the normal range so it is not metabolic alkalosis. The pH of 7.21 indicates an acidosis, not alkalosis. The pH of 7.21 indicates it is an acidosis but the HCO3 of 24 is within the normal range, ruling out metabolic acidosis.