a nurse in the medical surgical unit has a newly admitted patient who is oliguric the acute care nurse practitioner orders a fluid challenge of 100 to

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Fluid and Electrolytes ATI

1. A nurse in the medical-surgical unit has a newly admitted patient who is oliguric; the acute care nurse practitioner orders a fluid challenge of 100 to 200 mL of normal saline solution over 15 minutes. The nurse is aware this intervention will help:

A. Distinguish hyponatremia from hypernatremia
B. Evaluate pituitary gland function
C. Distinguish reduced renal blood flow from decreased renal function
D. Provide an effective treatment for hypertension-induced oliguria

Correct answer: C

Rationale: Administering a fluid challenge in oliguric patients helps to distinguish reduced renal blood flow from decreased renal function. This intervention aids in determining whether the oliguria is due to reduced renal blood flow (such as in fluid volume deficit or prerenal azotemia) or decreased renal function (such as in acute tubular necrosis). The response to this challenge can indicate the underlying cause. Choices A, B, and D are incorrect as they do not align with the purpose of a fluid challenge in oliguric patients.

2. What is the function of aldosterone?

A. Regulates body temperature.
B. Decreases blood pressure.
C. Increases sodium reabsorption.
D. Promotes water excretion.

Correct answer: C

Rationale: Aldosterone increases the reabsorption of sodium in the kidneys, which leads to an increase in blood volume and blood pressure. Choice A is incorrect as aldosterone does not regulate body temperature. Choice B is incorrect as aldosterone increases blood pressure by increasing sodium reabsorption. Choice D is incorrect as aldosterone promotes water retention by increasing sodium reabsorption.

3. 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.

4. A nurse in the medical-surgical unit is giving a patient with low blood pressure a hypertonic solution, which will increase the number of dissolved particles in his blood, creating pressure for fluids in the tissues to shift into the capillaries and increase the blood volume. Which of the following terms is associated with this process?

A. Hydrostatic pressure
B. Osmosis and osmolality
C. Diffusion
D. Active transport

Correct answer: B

Rationale: Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. The number of dissolved particles contained in a unit of fluid determines the osmolality of a solution, which influences the movement of fluid between the fluid compartments. Giving a patient who has low blood pressure a hypertonic solution will increase the number of dissolved particles in the blood, creating pressure for fluids in the tissues to shift into the capillaries and increase the blood volume. Option A is incorrect; hydrostatic pressure refers to changes in water or volume related to water pressure. Option C is incorrect; 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 should not normally take place. Option D is incorrect; active transport is the movement of molecules against the concentration gradient and requires ATP as an energy source. This process typically takes place at the cellular level and is not involved in vascular volume changes.

5. 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.