The following capnogram was recorded on a patient receiving mechanical ventilation in the ICU. What is the most likely interpretation of this capnogram?

  1. Emphysema
  2. Atelectasis
  3. Pulmonary fibrosis
  4. Esophageal intubation

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1. Emphysema


A steady rise in the amount of exhaled CO2 is observed by the upward slope of the curve. This shark fin appearance indicates airway obstruction exists. A normal curve should appear as a flat plateau rather than a sharp upward slope. Patients with emphysema require more time to empty their lungs. Therefore, exhaled CO2 continues to rise during the alveolar phase of the capnogram.