Capnography is an effective and non-invasive method for monitoring patients during general anesthesia and can reflect the changes in both the respiratory function as well as the circulatory function. In this paper, we present four cases of lobectomy in which we observed a "chair-like" waveform on performing capnography after the surgery. In all the cases, the appearance of this "chair-like" waveform led to the suspicion of a blockage in the pulmonary artery perfusion, which was then confirmed to be an obstruction in the pulmonary artery on further investigation. This suggests that during lobectomy, capnography can help confirm that the pulmonary circulation is unobstructed. We believe that it is very important to observe the changes of end-tidal carbon dioxide pressure and capnogram during one-lung ventilation, particularly in cases of pulmonary artery anastomosis.
Keywords: Capnography; End-tidal carbon dioxide pressure (PetCO2); Lobectomy; Pulmonary artery perfusion.