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. Malignant brain tumors often originate from another part of the body: While malignant brain tumors can spread from other body parts (metastatic tumors), primary brain tumors, such as gliomas or meningiomas, originate in the brain itself. Malignant brain tumors that metastasize to the brain are relatively less common.
B. Primary CNS tumors commonly spread to other parts of the body: Primary central nervous system (CNS) tumors generally do not spread to other parts of the body. Most CNS tumors are localized, and their spread is usually restricted to the surrounding neural tissue, not to distant organs.
C. Most CNS tumors are spinal tumors: Most central nervous system (CNS) tumors are actually brain tumors, not spinal tumors. Brain tumors are more common in adults, while spinal tumors are rarer in comparison.
D. Ependymomas are primarily brain tumors: Ependymomas are a type of tumor that originates from the ependymal cells in the central nervous system. While they can occur in both the brain and spinal cord, they are more frequently found in the brain, especially in the ventricles. Thus, ependymomas are primarily considered brain tumors.

A. Decreased pulmonary vascular resistance: Pulmonary embolism typically causes increased pulmonary vascular resistance, not decreased. The clot obstructs blood flow in the pulmonary arteries, increasing pressure within the pulmonary vasculature and impairing gas exchange, which can strain the right side of the heart.
B. Hypercapnia: Hypercapnia (elevated carbon dioxide levels) is not commonly seen in the early stages of a pulmonary embolism. Instead, patients tend to hyperventilate in response to hypoxia and anxiety, which lowers CO₂ levels rather than raising them.
C. Hypoventilation: Hypoventilation is not expected with a pulmonary embolism. In fact, most patients initially experience hyperventilation due to the body’s attempt to compensate for impaired oxygenation, leading to decreased CO₂ levels.
D. Respiratory alkalosis: Respiratory alkalosis occurs as a result of hyperventilation caused by anxiety, pain, and hypoxemia in response to the embolism. This leads to excessive loss of CO₂, increasing blood pH and resulting in respiratory alkalosis, which is a common initial finding in pulmonary embolism.