Which of the following is a postoperative risk factor specifically associated with older adults?

A. Lymphocytes are a type of white blood cell that plays a crucial role in the immune system, specifically in the response to infections and in immune regulation. They do not have a role in the transport of oxygen in the blood.
B. Neutrophils are another type of white blood cell that is essential for fighting bacterial infections. They are part of the body's immune response but do not transport oxygen.
C. Platelets are small cell fragments that are crucial for blood clotting and wound repair. They do not have a role in oxygen transport.
D. Hemoglobin is the primary molecule responsible for transporting oxygen in the blood. It is a protein found in red blood cells (erythrocytes) that binds to oxygen in the lungs and releases it in tissues throughout the body. Hemoglobin carries the majority of oxygen in the bloodstream and is essential for effective oxygen transport and delivery.

A. A nonrebreather mask is used to deliver high-flow oxygen, not low-flow. It provides the highest concentration of oxygen compared to other types of masks, which is crucial for patients with severe hypoxemia. The high-flow oxygen helps in achieving a higher concentration of oxygen in the blood.
B. It is essential that a nonrebreather mask fits snugly over the client's face to ensure that the patient receives the maximum amount of oxygen and to prevent room air from mixing with the oxygen being delivered. A proper seal is necessary to achieve the desired level of oxygenation and to avoid oxygen leakage.
C. The reservoir bag on a nonrebreather mask should not collapse with each breath. Ideally, the bag should remain partially inflated even during inspiration. If the bag collapses completely, it indicates that the patient is not receiving enough oxygen, and the mask may not be functioning correctly.
D. A nonrebreather mask itself does not cause drying of the mucous membranes. However, high-flow oxygen can sometimes lead to dryness of the mucous membranes if not managed properly. Humidification may be required to prevent dryness, but this is not a direct effect of the mask itself.