A 19-year-old male presented with history of massive hemoptysis. The patient was kept on mechanical ventilation because of severe hypoxia. Lung protective ventilation with low tidal volume was given in view of very poor pulmonary compliance. During the course of treatment, the patient developed a very high CO 2 level of 373 mmHg. The patient was successfully weaned off on the 9 th day without any obvious adverse consequences.