A nurse is teaching a graduating nurse about fluid volume deficit. Which of the following concepts about water balance should the nurse explain to the graduating nurse?

A. Take this medication with a full glass of water or fruit juice: Levothyroxine should be taken with a full glass of water, but it should not be taken with fruit juice as it can interfere with the absorption of the medication, reducing its effectiveness. Water is the best option for taking levothyroxine.
B. Take this medication before a meal or several hours after a meal: Levothyroxine should be taken on an empty stomach, typically 30 minutes to 1 hour before breakfast or at least several hours after a meal. Food, especially dairy or high-fiber foods, can interfere with the absorption of the medication.
C. Take this medication during your morning meal: Levothyroxine should not be taken with food, as food can decrease the absorption of the medication, reducing its effectiveness. It is recommended to take the medication on an empty stomach to ensure proper absorption.
D. Take this medication with high-protein foods: High-protein foods may also interfere with the absorption of levothyroxine. It is best to avoid taking levothyroxine with meals or foods that may impact its effectiveness, including high-protein foods.

A. Guillain-Barré syndrome: Guillain-Barré syndrome causes respiratory failure due to neuromuscular weakness, leading to hypoventilation. It does not typically cause a ventilation-perfusion (V/Q) mismatch because the lungs themselves remain structurally intact. The issue lies in impaired respiratory muscle function, not mismatched gas exchange.
B. Emphysema: Emphysema is a chronic obstructive pulmonary disease (COPD) characterized by alveolar wall destruction, which leads to impaired gas exchange and areas of the lung being ventilated but poorly perfused, or vice versa. This results in a V/Q mismatch, making it a common cause of respiratory failure due to this mechanism.
C. Congestive heart failure: While CHF can cause pulmonary edema and impair oxygen exchange, it typically leads to hypoxemia through fluid buildup in the alveoli rather than classic V/Q mismatch. The primary problem is poor oxygen diffusion due to fluid, not mismatched ventilation and perfusion.
D. Flail chest: Flail chest results in respiratory failure primarily due to paradoxical chest wall movement and impaired ventilation mechanics. Although oxygenation may be compromised, it is not primarily a V/Q mismatch but rather ineffective ventilation from the instability of the chest wall.