What should a person do to prevent a pulmonary embolus from occurring?

Choice A reason: Prolonged nasogastric suctioning removes gastric acid (HCl), reducing hydrogen ions in the blood, leading to metabolic alkalosis. This is reflected by elevated pH (7.50) and increased HCO3 (28 mEq/L), with normal PaCO2 as the lungs have not yet compensated. This matches the expected acid-base imbalance, making it correct.

Choice B reason: This result shows a slightly acidic pH (7.34) with normal PaCO2 and low HCO3, suggesting metabolic acidosis. Nasogastric suctioning causes loss of acid, not base, so it does not lead to acidosis. This imbalance is inconsistent with the alkalosis expected from gastric acid loss, making it incorrect.

Choice C reason: This result indicates a low pH (7.32) and elevated PaCO2, suggesting respiratory acidosis with partial compensation (normal HCO3). Nasogastric suctioning affects gastric acid, causing metabolic, not respiratory, alkalosis. The respiratory parameters here do not align with the condition’s pathophysiology, making this choice incorrect.

Choice D reason: This result shows an elevated pH (7.46) and low PaCO2, indicating respiratory alkalosis, likely from hyperventilation, with normal HCO3. Nasogastric suctioning causes metabolic alkalosis due to acid loss, not respiratory changes. The low PaCO2 does not fit the expected metabolic profile, making this choice incorrect.

Choice A reason: Facial trauma may increase aspiration risk if swallowing is impaired, but a 21-year-old typically has a robust immune system, reducing pneumonia risk. The trauma does not directly compromise lung defenses or immune function significantly, making this individual less likely to develop pneumonia compared to an immunocompromised person.

Choice B reason: Osteoarthritis and chronic knee pain in a 72-year-old may limit mobility, slightly increasing pneumonia risk due to reduced lung expansion. However, this condition does not directly impair immune function or lung clearance mechanisms, making it a lower risk compared to immunodeficiency, which severely predisposes to infections.

Choice C reason: Elevated cholesterol in a 48-year-old increases cardiovascular risk but does not directly affect lung function or immune response to infections. Without respiratory or immune compromise, this individual has a lower risk of pneumonia compared to someone with a primary immunodeficiency disorder, making this choice incorrect.

Choice D reason: A 69-year-old with a primary immunodeficiency disorder has a severely compromised immune system, impairing the ability to fight respiratory infections like pneumonia. Age-related lung changes and reduced immune response increase susceptibility to pathogens, making this individual at the highest risk for developing pneumonia, which is why this is correct.