A 62-year-old man who lives below sea level plans to visit the Colorado mountains. After 8 days of hiking to reach the base of camp he looks fatigued and dyspneic otherwise. He has a history of coronary artery disease . The patient is a lifetime nonsmoker and has no history of lung disease. Physical examination shows mild hypoxemia, clear lungs, an S4, and no extremity edema. Which of the following respiratory changes most likely contributed to this patient's presentation?

Question

A 62-year-old man who lives below sea level plans to visit the Colorado mountains. After 8 days of hiking to reach the base of camp he looks fatigued and dyspneic otherwise. He has a history of coronary artery disease . The patient is a lifetime nonsmoker and has no history of lung disease.  Physical examination shows mild hypoxemia, clear lungs, an S4, and no extremity edema. Which of the following respiratory changes most likely contributed to this patient's presentation?

Quizplus · Accepted Answer

Eductional Objective: Age-related changes to the respiratory system include decreased chest wall compliance and decreased alveolar elastic recoil with resulting alveolar enlargement and air trapping. These changes limit the potential increase in tidal volume and also increase the alveolar-arterial O₂gradient (ie, decrease the efficiency of alveolar-capillary gas exchange), reducing the ability to compensate for hypoxemia.

A 62-Year-Old Man Who Lives Below Sea Level Plans to Visit