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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.
Correct Answer: C
Rationale: 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+.
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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 nurses 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 reninangiotensinaldosterone system that results in diminished urine output.
Correct Answer: D
Rationale: 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.
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 acidbase imbalance?
- A. Respiratory acidosis
- B. Respiratory alkalosis
- C. Increased PaCO2
- D. CNS disturbances
Correct Answer: B
Rationale: 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.
A newly graduated nurse is admitting a patient with a long history of emphysema. The new nurses preceptor is going over the patients past lab reports with the new nurse. The nurse takes note that the patients 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 nurses best response?
- A. The patients calcium will rise dramatically due to pituitary stimulation.
- B. Oxygen will increase the patients 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.
Correct Answer: D
Rationale: 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 patients calcium will rise dramatically due to pituitary stimulation. No feedback system that oxygen stimulates would create an increase in the patients 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.
A medical nurse educator is reviewing a patients 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.
Correct Answer: B
Rationale: 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).
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 that 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
Correct Answer: D
Rationale: 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.