#may2020mccqe1
A 60-year-old man is hospitalized because of progressive dyspnea during the past month. He has a 45-pack-year smoking history, but he has no other medical problems. On physical examination, he is cyanotic and has paradoxical respiratory movements of his rib cage and abdomen. Blood pressure is 140/78 mm Hg, pulse rate is 105/min, and respiration rate is 28/min. Jugular venous distention is present. The lungs are clear. The remainder of the examination is normal.
Pulmonary function studies:
Total lung capacity 85% of predicted
Residual volume 72% of predicted
FVC 60% of predicted
FEV1 63% of predicted
FEV1/FVC ratio 105%
Residual volume/total lung capacity 163%
Maximum inspiratory pressure 36% of predicted Maximum expiratory pressure 45% of predicted DLCO 82% of predicted
Arterial blood gases studies show a pH of 7.3, a PO2 of 42 mm Hg (5.6 kPa), a PCO2 of 55 mm Hg (7.3 kPa), and a bicarbonate level of 27 meq/L (27 mmol/L).
Which of the following is the most likely cause of his respiratory failure?
(A) Chronic obstructive pulmonary disease
(B) Idiopathic pulmonary fibrosis
(C) Neuromuscular weakness
(D) Pulmonary arterial hypertension
A 60-year-old man is hospitalized because of progressive dyspnea during the past month. He has a 45-pack-year smoking history, but he has no other medical problems. On physical examination, he is cyanotic and has paradoxical respiratory movements of his rib cage and abdomen. Blood pressure is 140/78 mm Hg, pulse rate is 105/min, and respiration rate is 28/min. Jugular venous distention is present. The lungs are clear. The remainder of the examination is normal.
Pulmonary function studies:
Total lung capacity 85% of predicted
Residual volume 72% of predicted
FVC 60% of predicted
FEV1 63% of predicted
FEV1/FVC ratio 105%
Residual volume/total lung capacity 163%
Maximum inspiratory pressure 36% of predicted Maximum expiratory pressure 45% of predicted DLCO 82% of predicted
Arterial blood gases studies show a pH of 7.3, a PO2 of 42 mm Hg (5.6 kPa), a PCO2 of 55 mm Hg (7.3 kPa), and a bicarbonate level of 27 meq/L (27 mmol/L).
Which of the following is the most likely cause of his respiratory failure?
(A) Chronic obstructive pulmonary disease
(B) Idiopathic pulmonary fibrosis
(C) Neuromuscular weakness
(D) Pulmonary arterial hypertension
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