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

A. Lisinopril is an ACE inhibitor used to treat hypertension and heart failure. It can affect blood pressure regulation and might impact intraoperative and postoperative blood pressure control, but it is not generally associated with increased surgical bleeding risk.
B. Acetaminophen is a pain reliever and antipyretic used for mild to moderate pain and fever. It does not have a significant impact on bleeding risk or interfere with clotting mechanisms. It is generally considered safe for use around the time of surgery.
C. Aspirin is an antiplatelet medication that inhibits platelet aggregation and can increase the risk of bleeding. It affects blood clotting and can lead to excessive bleeding during and after surgery. It is often recommended to stop aspirin use several days before surgery to reduce this risk, unless specifically directed otherwise by the healthcare provider.
D. Metoprolol is a beta-blocker used to manage hypertension and heart conditions. It is generally not associated with increased bleeding risk.

A. pH: Elevated (above 7.45), indicating alkalosis. PaCO₂: Decreased (below 35 mm Hg), reflecting hyperventilation and CO₂ loss. HCO₃⁻: Usually normal (around 24 mEq/L) or slightly decreased, as metabolic compensation might not be immediate. The results here show an elevated pH, decreased PaCO₂, and normal HCO₃⁻, which are consistent with respiratory alkalosis.
B. pH: Decreased (acidic), indicating acidosis. PaCO₂: Slightly elevated (near normal), not indicative of respiratory alkalosis. HCO₃⁻: Normal (around 26 mEq/L), suggesting no significant metabolic component or compensation. This profile does not match respiratory alkalosis; it is more consistent with a mixed or different type of acid-base imbalance.
C. pH: Decreased (acidic), indicating acidosis. PaCO₂: Elevated (above 45 mm Hg), indicating CO₂ retention, which is characteristic of respiratory acidosis, not alkalosis. HCO₃⁻: Normal (around 23 mEq/L), showing no significant metabolic compensation or disturbance. This profile indicates respiratory acidosis rather than respiratory alkalosis.
D. pH: Elevated (alkaline), which is consistent with alkalosis. PaCO₂: Normal (around 40 mm Hg), indicating that CO₂ levels are not the primary cause of the alkalosis. HCO₃⁻: Elevated (above 28 mEq/L), suggesting a metabolic alkalosis or compensation for a respiratory acidosis, but not respiratory alkalosis alone.