CRNI Fluid and Electrolyte Balance Questions and Answers

Question 1

A patient is admitted with severe dehydration secondary to gastroenteritis. The physician orders an intravenous solution to correct the fluid volume deficit. Which type of IV fluid is most appropriate for initial fluid resuscitation in this patient?

Accepted Answer

0.9% Sodium Chloride (Normal Saline)

Answer

0.9% Sodium Chloride, also known as Normal Saline, is an isotonic solution, meaning it has the same concentration of solutes as blood plasma. This makes it the ideal choice for initial fluid resuscitation in cases of dehydration because it expands the extracellular fluid volume without causing a significant shift of fluid into or out of the cells. Hypotonic solutions like 0.45% NaCl would cause fluid to move into the cells, which is not the primary goal in correcting a fluid volume deficit. D5W is initially isotonic but becomes hypotonic as the dextrose is metabolized, and hypertonic solutions like 3% NaCl are reserved for severe, symptomatic hyponatremia.

Question 2

A CRNI is assessing a patient with a serum calcium level of 7.2 mg/dL. Which of the following physical examination findings would be most consistent with this laboratory value?

Accepted Answer

Positive Chvostek's sign

Answer

A serum calcium level of 7.2 mg/dL indicates hypocalcemia. Hypocalcemia increases neuromuscular excitability. A positive Chvostek's sign, which is the twitching of facial muscles in response to tapping over the facial nerve, is a classic sign of this increased excitability. Depressed reflexes and muscle flaccidity are associated with hypercalcemia, while peaked T waves are characteristic of hyperkalemia.

Question 3

A post-operative patient who received large doses of opioid analgesia is noted to have a respiratory rate of 8 breaths per minute, is difficult to arouse, and has a PaCO2 of 55 mm Hg. The CRNI should recognize these findings as indicative of which acid-base imbalance?

Accepted Answer

Respiratory Acidosis

Answer

The patient is demonstrating hypoventilation (RR of 8) likely due to the central nervous system depressant effects of opioids. Hypoventilation leads to the retention of carbon dioxide (evidenced by the high PaCO2 of 55 mm Hg). An excess of dissolved CO2 in the blood results in an increased concentration of hydrogen ions, causing the pH to drop and leading to respiratory acidosis.

Question 4

When developing a plan of care for a patient with a serum sodium level of 125 mEq/L and signs of euvolemic hyponatremia, which intervention is the priority for the CRNI to include?

Accepted Answer

Implementing a fluid restriction of 1 L per day.

Answer

For euvolemic hyponatremia, the primary issue is an excess of total body water relative to sodium. Therefore, the cornerstone of management is restricting free water intake to allow the kidneys to excrete excess water and the serum sodium to rise gradually. Administering isotonic saline may not be effective and could worsen the condition if the underlying cause is SIADH. A high-sodium diet may be helpful but is not the priority intervention. Insulin is used to treat hyperkalemia, not hyponatremia.

Question 5

A patient with end-stage renal disease has a serum potassium level of 6.8 mEq/L. Which of the following ECG changes should the CRNI anticipate and report immediately?

Accepted Answer

Tall, peaked T waves

Answer

Hyperkalemia, a serum potassium level above 5.0-5.5 mEq/L, alters cardiac membrane potential, leading to characteristic ECG changes. One of the earliest and most common findings is the appearance of tall, peaked T waves, especially as the level rises above 6.5 mEq/L. As hyperkalemia worsens, the PR interval becomes prolonged and the QRS complex widens. Prominent U waves and ST depression are associated with hypokalemia.

CRNI Exam Practice Test

CRNI Exam Practice Test

CRNI Fluid and Electrolyte Balance Questions and Answers