A 21-year-old man presents to his physician because he has been feeling increasingly tired and short of breath at work. He has previously had these symptoms but cannot recall the diagnosis he was given. Chart review reveals the following results: Oxygen tension in inspired air = 150 mmHg Alveolar carbon dioxide tension = 50 mmHg Arterial oxygen tension = 71 mmHg Respiratory exchange ratio = 0.80 Diffusion studies reveal normal diffusion distance. The patient is administered 100% oxygen but the patient's blood oxygen concentration does not improve. Which of the following conditions would best explain this patient's findings?
ASeptal defect since birth
BUse of opioid medications
CPulmonary fibrosis
DPulmonary embolism
EVacation at the top of a mountain
A 35-year-old woman volunteers for a study on respiratory physiology. Pressure probes A and B are placed as follows: Probe A: between the parietal and visceral pleura Probe B: within the cavity of an alveolus The probes provide a pressure reading relative to atmospheric pressure. To obtain a baseline reading, she is asked to sit comfortably and breathe normally. Which of the following sets of values will most likely be seen at the end of inspiration?
AProbe A: -6 mm Hg; Probe B: 0 mm Hg
BProbe A: 0 mm Hg; Probe B: -1 mm Hg
CProbe A: -4 mm Hg; Probe B: 0 mm Hg
DProbe A: -4 mm Hg; Probe B: -1 mm Hg
EProbe A: -6 mm Hg; Probe B: -1 mm Hg
In which of the following pathological states would the oxygen content of the trachea resemble the oxygen content in the affected alveoli?
AEmphysema
BExercise
CPulmonary embolism
DPulmonary fibrosis
EForeign body obstruction distal to the trachea
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