Which tests may be indicated to exclude differential diagnoses in the evaluation of nosocomial pneumonia?

Updated: Apr 15, 2021
  • Author: Kartika Shetty, MD, FACP; Chief Editor: John L Brusch, MD, FACP  more...
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Electrocardiograms (ECGs) and ventilation-perfusion scans help to eliminate pneumonia mimics. ECGs, cardiac enzymes, and Swan-Ganz readings may rule out left ventricular failure caused by exacerbation of heart failure or new myocardial infarction.

Obtain other tests that are related to the possible underlying causes of the pulmonary infiltrates; for example, if lupus pneumonitis is suspected, ask the patient about a history of SLE pneumonitis. Afterward, serologic tests should be performed to assess for SLE.

ABG studies are useful in assessing the degree of severity of lung dysfunction but not in determining the specific etiology. In general, bacterial nosocomial pneumonia/ventilator-associated pneumonia (VAP) have low A-a gradients (<35).

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