The characteristic features of capnogram in endobronchial intubation are dependent on the extent of endobronchial intubation. The ETCO2 can increase if the consequent one lung ventilation results in hypoventilation. On the other hand, if the tube is far down resulting in over all reduced ventilation (small tidal volumes), then ETCO2 can decrease (not adequate ventilation). However, if the endobronchial intubation results in a airway obstruction, the capnogram may have prolonged phase II and phase III with increased slope. The author has observed several such capnograms during cesarean section general anesthesia (because of intubation circumstances of cesarean section) and capnograms revert to normal once adjustment of the endotracheal tube are made (The tube probably too close to carina).