ATI RN
Fluid and Electrolytes ATI
1. A patient who is in renal failure partially loses the ability to regulate changes in pH because the kidneys:
- A. Regulate and reabsorb carbonic acid to change and maintain pH
- B. Buffer acids through electrolyte changes
- C. Regenerate and reabsorb bicarbonate to maintain a stable pH
- D. Combine carbonic acid and bicarbonate to maintain a stable pH
Correct answer: C
Rationale: The correct answer is C. In renal failure, the kidneys lose the ability to regulate pH by controlling bicarbonate levels in the extracellular fluid (ECF). The kidneys can regenerate and reabsorb bicarbonate ions to maintain a stable pH. Choices A, B, and D are incorrect because the kidneys do not primarily regulate or reabsorb carbonic acid, buffer acids through electrolyte changes, or combine carbonic acid and bicarbonate to maintain pH. The key function of the kidneys in maintaining pH balance lies in the control of bicarbonate levels.
2. The nurse is assessing the patient for the presence of a Chvostek's sign. What electrolyte imbalance does a positive Chvostek's sign indicate?
- A. Hypermagnesemia
- B. Hypomagnesemia
- C. Hypocalcemia
- D. Hyperkalemia
Correct answer: C
Rationale: Chvostek's sign is characterized by a brief contraction of the upper lip, nose, or side of the face and is indicative of hypocalcemia, making choice C the correct answer. Hypomagnesemia (choice B) is associated with Trousseau's sign, not Chvostek's sign. Hypermagnesemia (choice A) is not related to Chvostek's sign. Hyperkalemia (choice D) is not typically associated with Chvostek's sign; instead, it may present with muscle weakness and cardiac arrhythmias.
3. When selecting a site on the hand or arm for insertion of an IV catheter, the nurse should:
- A. Choose a proximal site.
- B. Choose a distal site.
- C. Have the patient hold their arm in a dependent position.
- D. Leave the tourniquet on for no longer than 2 minutes.
Correct answer: B
Rationale: When selecting a site for insertion of an IV catheter, the nurse should choose a distal site, not a proximal site. Opting for a distal site ensures that upper veins remain available for future cannulations. Instructing the patient to hold their arm in a dependent position can enhance blood flow, aiding in the procedure. It is crucial never to leave a tourniquet on for more than 2 minutes as prolonged restriction can lead to complications. Choice A is incorrect because a proximal site is not preferred for IV insertion. Choice C is incorrect as having the patient hold their arm over their head is not necessary and may impede proper blood flow. Choice D is incorrect as leaving the tourniquet on for at least 5 minutes is excessive and can be harmful.
4. The nurse is admitting a patient with a suspected fluid imbalance. The most sensitive indicator of body fluid balance is:
- A. Daily weight
- B. Serum sodium levels
- C. Measured intake and output
- D. Blood pressure
Correct answer: A
Rationale: Daily weight is the most sensitive indicator of body fluid balance because it can show trends over time, helping in assessing the effectiveness of interventions and medications. While serum sodium levels provide objective data on electrolyte balance, they may not accurately reflect fluid balance, especially if a patient is dehydrated. Measured intake and output are crucial for assessing fluid balance, but it can be challenging to match the two due to various ways fluid is lost from the body. Blood pressure and other vital signs may not always be reliable indicators of fluid balance as they can be influenced by other factors beyond fluid status.
5. The triage nurse notes upon assessment in the emergency room that the patient with anxiety is hyperventilating. The nurse is aware that hyperventilation is the most common cause of which acid-base imbalance?
- A. Respiratory acidosis
- B. Respiratory alkalosis
- C. Metabolic acidosis
- D. Metabolic alkalosis
Correct answer: B
Rationale: The correct answer is B: Respiratory alkalosis. Hyperventilation is the most common cause of acute respiratory alkalosis. When a patient hyperventilates due to anxiety or other causes, they blow off excessive carbon dioxide, leading to a decrease in PaCO2 and a rise in pH. Choices A, C, and D are incorrect because hyperventilation leads to a decrease in PaCO2, causing respiratory alkalosis, not respiratory acidosis, metabolic acidosis, or metabolic alkalosis.
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