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

A. Metabolic acidosis is characterized by a primary decrease in bicarbonate (HCO₃⁻) levels, which is not typically a direct result of COPD. However, if a patient with COPD has an additional condition like kidney failure or severe sepsis, they could potentially develop metabolic acidosis. But, this is not the primary concern in COPD.
B. Respiratory alkalosis is caused by hyperventilation, where there is excessive loss of CO₂ leading to an increase in blood pH. This is less common in COPD patients, as they typically have difficulty exhaling CO₂ rather than hyperventilating.
C. Metabolic alkalosis involves an increase in blood pH due to elevated bicarbonate levels or loss of acid. This is not typically associated with COPD, unless there is an unrelated condition causing metabolic alkalosis.
D. COPD is characterized by impaired airflow and reduced ability to expel carbon dioxide (CO₂) effectively. As CO₂ accumulates in the blood, it combines with water to form carbonic acid, which lowers the blood pH, leading to respiratory acidosis.

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.