A nurse is reinforcing teaching to a newly licensed nurse about risk factors for subarachnoid hemorrhage (SAH). Which of the following should the nurse include in the teaching?

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.

• Chest pain: Crushing, retrosternal chest pain is highly suggestive of cardiac ischemia or acute coronary syndrome. It requires immediate evaluation due to the risk of myocardial infarction. The presence of fatigue and weakness adds to the urgency. Chest pain is always prioritized due to its life-threatening potential.
• Visual disturbance: Visual changes may indicate hypertension, hyperglycemia, or neurological issues. While concerning, they are typically not immediately life-threatening. These symptoms can be evaluated after cardiac causes are ruled out. They support further systemic investigation.
• Fatigue: Fatigue is a nonspecific symptom seen in many chronic conditions like diabetes, anemia, or heart failure. It does not signal an emergency on its own. It may be related to underlying cardiac issues but is not prioritized over chest pain.
• Increased urination: Polyuria often indicates uncontrolled blood glucose levels or diabetes. It should prompt further testing but does not require immediate intervention. It is a chronic symptom rather than an acute, life-threatening one.