Correct Answer: B

Rationale: In pre-renal acute kidney injury, there is a decrease in perfusion to the kidneys. Myocardial infarction can lead to decreased blood flow to the kidneys, causing pre-renal AKI. Pyelonephritis is an intrinsic/intrarenal cause of AKI involving kidney damage. Bladder cancer and kidney stones are post-renal causes of AKI due to urinary flow obstruction, not related to perfusion issues seen in pre-renal AKI.

Correct Answer: A

Rationale: An elevated blood urea nitrogen (BUN)/creatinine ratio can indicate various conditions such as dehydration, urinary obstruction, catabolism, or a high-protein diet. The initial action the nurse should take is to assess the client's dietary habits to determine if the elevated ratio is related to diet. Inquiring about the use of NSAIDs is important as they can impact kidney function, but dietary causes should be ruled out first. Holding metformin or contacting the health care provider without assessing the dietary habits would be premature actions as they may not address the underlying cause of the elevated BUN/creatinine ratio.

Correct Answer: C

Rationale: Severe hyperkalemia, with a potassium level of 6.9 mEq/L, requires aggressive treatment with Kayexalate and sorbitol to increase the body's excretion of potassium. The normal range for serum potassium is 3.5 to 5.5 mEq/L, so patients with the other potassium levels would not be treated aggressively or would need potassium supplementation. Therefore, option C (Sodium 135 mEq/L and potassium 6.9 mEq/L) is the correct choice as it indicates severe hyperkalemia warranting the administration of Kayexalate and sorbitol. Options A, B, and D have either potassium levels within normal limits, which would not necessitate this aggressive treatment, or potassium levels that are lower than what would typically prompt the need for Kayexalate and sorbitol.

Correct Answer: D

Rationale: The correct action for the nurse to take to insert a nasogastric tube safely and easily is asking the client to swallow as the tube is being advanced. This action helps facilitate the passage of the tube through the esophagus into the stomach. Placing the tube in warm water (Choice A) is not a recommended practice for nasogastric tube insertion. Hyperextending the head (Choice B) can cause discomfort and is not necessary for safe insertion. Removing the tube if resistance is met (Choice C) is incorrect as it may cause harm or discomfort to the client. Asking the client to swallow helps the tube pass more smoothly and comfortably.

Correct Answer: C

Rationale: In this scenario, the patient has hyponatremia with a serum sodium level of 130 mEq/L. For a serum sodium level between 125 and 135 mEq/L, the appropriate treatment is intravenous normal saline 0.9%. Normal saline helps to increase the sodium content in the vascular fluid. Diuretic therapy would exacerbate sodium and fluid depletion, which is not suitable for a patient already dehydrated from severe vomiting. Intravenous hypertonic 5% saline is typically reserved for severe hyponatremia with a serum sodium level below 120 mEq/L. Oral sodium supplements are not feasible in this case as the patient is vomiting and may not be able to tolerate oral intake easily.