LearnWithTest

1 A 45-year-old man with long-standing COPD presents with worsening dyspnea. ABG shows pH 7.32, PaCO₂ 60 mmHg, PaO₂ 55 mmHg. Which primary physiological abnormality explains his chronic hypercapnia?

Increased alveolar ventilation Reduced diffusion capacity for carbon dioxide Alveolar hypoventilation due to loss of elastic recoil Impaired hemoglobin binding to carbon dioxide

2 A 30-year-old woman with acute asthma develops severe wheezing and prolonged expiration. Which physiological factor is primarily responsible for increased work of breathing?

Reduced lung compliance Increased airway resistance due to reduced airway radius Increased alveolar surface tension Reduced pulmonary blood flow

3 A patient with pulmonary fibrosis complains of exertional dyspnea. At rest, ABG is normal. During exercise, PaO₂ falls significantly. What explains this finding?

Ventilation perfusion mismatch alone Diffusion limitation due to reduced capillary transit time Reduced hemoglobin concentration Central hypoventilation

4 A patient with massive pulmonary embolism has normal PaCO₂ initially despite severe hypoxemia. What explains this phenomenon?

Reduced dead space ventilation Compensatory hyperventilation Impaired oxygen diffusion Reduced oxygen content of blood

5 A neonate born at 26 weeks gestation develops respiratory distress syndrome. Which physiological change is most responsible for alveolar collapse?

Reduced pulmonary blood flow High airway resistance Increased surface tension due to surfactant deficiency Low hemoglobin concentration

6 A patient breathes rapidly and deeply during panic attack. Which immediate cerebral effect is most likely?

Cerebral vasodilation Increased intracranial pressure Cerebral vasoconstriction Increased cerebral oxygen delivery

7 A patient with left ventricular failure develops dyspnea when lying flat. Which receptor activation contributes to this sensation?

Pulmonary stretch receptors Central chemoreceptors Juxtacapillary (J) receptors Upper airway mechanoreceptors

8 A patient has normal spirometry but reduced DLCO. Which underlying pathology best explains this finding?

Bronchial asthma Pulmonary fibrosis Chest wall deformity Neuromuscular weakness

9 A patient with anemia has normal PaO₂ and SaO₂ but reduced tissue oxygen delivery. Which parameter is primarily reduced?

Alveolar oxygen tension Oxygen content of blood Oxygen diffusion capacity Ventilation perfusion ratio

10 A man at high altitude develops respiratory alkalosis initially. Which renal response occurs after several days?

Increased hydrogen ion secretion Increased bicarbonate reabsorption Increased bicarbonate excretion Reduced ammonium production

11 A patient with emphysema shows airway collapse during forced expiration. Which pressure-related phenomenon explains this?

Increased transpulmonary pressure Reduced alveolar pressure Distal shift of equal pressure point Increased pleural negativity

12 A patient inhales 100% oxygen for prolonged duration. Which complication is most likely?

Bronchospasm Pulmonary fibrosis Absorption atelectasis Increased hypoxic drive

13 A patient with severe kyphoscoliosis develops hypoventilation. Which lung parameter is most reduced?

Residual volume Total lung capacity Dead space volume Diffusion capacity

14 A patient suddenly stops breathing after receiving opioids. Which respiratory center is directly depressed?

Pneumotaxic center Apneustic center Medullary respiratory center Peripheral chemoreceptors

15 During heavy exercise, arterial PaO₂ remains near normal despite increased oxygen consumption. What explains this?

Increased hemoglobin concentration Increased diffusion capacity and capillary recruitment Reduced ventilation perfusion matching Decreased alveolar ventilation