ATI RN
ATI Fluid and Electrolytes
1. 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
Correct answer: A
Rationale: Corrected Rationale: To assess a patient's magnesium status, the nurse should check deep tendon reflexes. Diminished deep tendon reflexes may indicate high serum magnesium levels, as hypermagnesemia can lead to neuromuscular effects. Tachycardia, cool clammy skin, and acute flank pain are not typically associated with high magnesium levels and are not priority assessments in this situation.
2. An increase in capillary blood pressure would tend to:
- A. increase interstitial fluid volume.
- B. increase plasma volume.
- C. decrease interstitial fluid volume.
- D. increase plasma volume and decrease interstitial fluid volume.
Correct answer: A
Rationale: An increase in capillary blood pressure leads to a higher force pushing fluid out of the capillaries into the interstitial space, thereby increasing interstitial fluid volume. Choice B is incorrect because capillary blood pressure affects the movement of fluid into the interstitial space, not into the plasma. Choice C is incorrect as an increase in capillary blood pressure would not decrease interstitial fluid volume. Choice D is incorrect as it combines contradictory effects when capillary blood pressure increases.
3. Which hormone reduces the amount of water in the body?
- A. ADH
- B. aldosterone
- C. ANH
- D. ADH and aldosterone
Correct answer: B
Rationale: The correct answer is 'aldosterone.' Aldosterone is the hormone that reduces the amount of water in the body by increasing the reabsorption of sodium and water from the kidney tubules. ANH (atrial natriuretic hormone) actually works to increase the excretion of sodium and water by the kidneys, leading to a reduction in blood volume and pressure. ADH (antidiuretic hormone) works to increase water reabsorption by the kidneys, thereby increasing blood volume. Therefore, choices A (ADH) and D (ADH and aldosterone) are incorrect in the context of reducing the amount of water in the body.
4. Which of the following is not considered an extracellular fluid?
- A. Cerebrospinal fluid
- B. The humors of the eye
- C. Lymph
- D. Cerebrospinal fluid and the humors of the eye
Correct answer: D
Rationale: The correct answer is D. Cerebrospinal fluid and the humors of the eye are not considered extracellular fluids. Extracellular fluids are fluids found outside the cells, such as interstitial fluid and lymph. Cerebrospinal fluid is found within the central nervous system, while the humors of the eye (aqueous humor and vitreous humor) are located within the eyeball, making them distinct from extracellular fluids.
5. 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
Correct answer: B
Rationale: The correct answer is B: Osmosis and osmolality. Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. In this case, the hypertonic solution increases the number of dissolved particles in the blood, causing fluids to shift into the capillaries due to the osmotic pressure gradient. Osmolality refers to the concentration of solutes in a solution. Hydrostatic pressure refers to changes in water or volume related to water pressure, not the movement of fluids due to solute concentration differences. Diffusion is the movement of solutes from an area of greater concentration to lesser concentration; in an intact vascular system, solutes are unable to move freely, so diffusion does not play a significant role in this scenario. Active transport involves the movement of molecules against the concentration gradient with the use of energy, typically at the cellular level, and is not related to the vascular volume changes described in the question.
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