Capnogram after single lung transplantation in a patient with COPD

The capnogram (A) was observed as soon as ventilation to the transplanted lung was commenced. This shows an initial gradual uprising in CO₂ concentration, probably representing the CO₂ emanating from the new lung allograft. Capnogram (A) changed gradually over the next 10 minutes into capnogram (B), showing the typical biphasic capnogram after left single lung transplantation in a patient with COPD. The initial peak of CO₂ represents the recruited alveoli from the allografted lung, and the later peak represents the emphysematous native lung that has prolonged expiratory characteristics indicating that hyperinflation, breath-stacking, and auto-PEEP are occurring in the native lung. Note that exhalation is not complete prior to the next breath being initiated (ie, end-tidal CO₂ is still rising).