The use of intubating laryngeal mask airway (LMA-Fastrach) is indicated to facilitate endotracheal intubation in a patient with cervical spine disorder or suspected difficult airway. A 65-year-old female patient was referred to our hospital for cervical spine surgery under general anesthesia. During anesthesia induction, an LMA-Fastrach was used to facilitate intubation and an airway exchange catheter (AEC) was used to exchange the accompanying armored silicone endotracheal tube for a polyvinyl chloride (PVC) endotracheal tube. However, the pulse oximeter showed a fall of oxygen saturation (SpO2) after insertion of the AEC. As massive pneumothorax associated with subcutaneous emphysema was disclosed by chest roentgenography, a chest drainage was performed immediately. This article discourses the possible mechanism, diagnosis and treatment of pneumothorax during the course of general anesthesia and the prevention of lower airway injury by AEC is also touched.