Chapter·PhysiologyV/Q mismatch

V/Q mismatch in COPDDownloads

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1

A 48-year-old man comes to the physician because of a 3-month history of worsening shortness of breath and cough productive of frothy, whitish sputum. One year ago, he had a similar episode lasting 6 months. He has smoked a pack of cigarettes daily for 25 years. Physical examination shows bluish discoloration of the tongue and lips. Scattered expiratory wheezing and rhonchi are heard throughout both lung fields. Further evaluation of this patient is most likely to show which of the following findings?

AIncreased FEV1/FVC ratio

BIncreased diffusing capacity for carbon monoxide

CIncreased pulmonary capillary wedge pressure

DIncreased serum hematocrit

ENormal FEV1

2

A 65-year-old woman presents to her physician with chronic breathlessness. Her condition has been progressively worsening over the last 20 years despite treatment with inhaled salbutamol, inhaled corticosteroids, and multiple courses of antibiotics. She has a 30-pack-year smoking history but quit 20 years ago. Her pulse is 104/min and respirations are 28/min. Physical examination shows generalized wasting. Chest auscultation reveals expiratory wheezes bilaterally and distant heart sounds. Pulmonary function testing shows a non-reversible obstructive pattern. Her carbon monoxide diffusion capacity of the lungs (DLCO) is markedly reduced. Which of the following explains the underlying mechanism of her condition?

ADecreased partial pressure of alveolar oxygen

BContraction of pulmonary smooth muscles

CInflammation of the pulmonary bronchi

DDiminished surface area for gas exchange

EAccumulation of fluid in the alveolar space

3

A 22-year-old man volunteers for a research study on lung function. He has no history of lung disease or allergies and does not smoke. His pulmonary blood flow is measured in the various labeled segments of the lungs while standing. Then the volunteer, still standing, is given very low continuous positive airway pressure and the blood flow measured again. Which of the following sets of findings are most likely to be present in the second measurements relative to the first?

AIncreased blood flow in zone 2

BReduced blood flow in zone 3

CReduced blood flow in zone 1

DIncreased blood flow in zone 3

EIncreased blood flow in zone 1

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