Correct Answer: B

Rationale: The correct answer is B because considering potential effects on the patient's mobility is crucial when selecting a site for IV insertion. Mobility can be affected if the IV is placed in a joint area or on the dominant hand. This could limit the patient's ability to move freely during and after the procedure. Therefore, it is important to choose a site that will not hinder the patient's movement. A: Choosing a hairless site is not the most important factor when selecting a site for IV insertion. C: Having the patient hold his arm over his head before insertion is not necessary and may cause discomfort for the patient. D: Leaving the tourniquet on for at least 3 minutes is not recommended as it can lead to complications such as venous stasis.

Correct Answer: A

Rationale: The correct answer is A: Extravasation of the medication. Extravasation occurs when the infused medication leaks into surrounding tissues, potentially causing tissue damage and necrosis. This is a serious concern with vesicant medications like daunorubicin. If left untreated, it can lead to severe complications. Choice B: Discomfort to the patient is incorrect because while discomfort may occur with infiltration, the main concern is the potential for tissue damage from extravasation. Choice C: Blanching at the site is incorrect as it is a common sign of infiltration, but the main concern is the possibility of extravasation and tissue damage. Choice D: Hypersensitivity reaction to the medication is incorrect as it is a different type of reaction that is not directly related to infiltration or extravasation.

Correct Answer: C

Rationale: The correct answer is C: Metabolic alkalosis. Pyloric stenosis can lead to vomiting, causing loss of gastric acid and chloride ions, leading to metabolic alkalosis. Low potassium levels are common in metabolic alkalosis due to potassium shifting into cells to compensate for the alkalosis. Hypercalcemia (choice A) is not associated with pyloric stenosis. Metabolic acidosis (choice B) typically presents with low pH and bicarbonate levels. Respiratory acidosis (choice D) is caused by impaired gas exchange in the lungs, not related to pyloric stenosis.

Correct Answer: D

Rationale: Rationale: The correct answer is D. Hydrostatic pressure resulting from the pumping action of the heart causes water and electrolytes to move from the arterial capillary bed to the interstitial fluid. This occurs due to the force exerted by the heart's pumping action, pushing fluid out of the capillaries into the interstitial space. This process is known as filtration and is essential for maintaining fluid balance in the body. Summary of other choices: A: Active transport of hydrogen ions does not directly cause the movement of water and electrolytes between capillaries and interstitial fluid. B: The pressure in renal capillaries specifically relates to the kidneys, not the general movement of water and electrolytes in the body. C: The dissolved particles in blood do not directly contribute to the movement of water and electrolytes between capillaries and interstitial fluid.

Correct Answer: D

Rationale: The correct answer is D: Using oxygen may result in the patient developing carbon dioxide narcosis and hypoxemia. In patients with chronic emphysema, their respiratory drive is often triggered by low oxygen levels rather than high carbon dioxide levels. Administering supplemental oxygen can suppress their respiratory drive, leading to carbon dioxide retention (carbon dioxide narcosis) and worsening hypoxemia. This phenomenon is known as "hypoxic drive." Choice A is incorrect because administering oxygen does not lead to a dramatic rise in calcium levels due to pituitary stimulation. Choice B is incorrect because administering oxygen does not typically increase intracranial pressure or cause confusion. Choice C is incorrect because administering oxygen does not directly cause hyperventilation and acidosis in this scenario.