Which patient characteristic is a risk factor for respiratory depression?

• A. Elderly
• B. Asthma
• C. Postoperative infection
• D. Young age

Answer: (A)

Older adults have less physiologic reserve, which makes them more susceptible to respiratory depression from central nervous system depressants like opioids or sedatives. Age brings changes that blunt the brain’s response to CO2 and increase sensitivity to these drugs, so ventilation can fall more quickly. At the same time, pharmacokinetic changes occur with aging—reduced liver blood flow and renal function slow metabolism and clearance, allowing the drug to linger and deepen its depressant effects. The combination of decreased respiratory muscle strength, stiffer chest wall, and reduced lung compliance also means the body has a harder time compensating for hypoventilation, raising the risk of hypoxemia. In contrast, asthma is an airway condition, not a predictor of drug-induced respiratory depression; postoperative infection can affect respiration through other mechanisms but doesn’t directly increase depressant sensitivity; and young age involves different considerations, not the increased risk seen with aging.