Tracheal intubation: Tracheal intubation has become an important measure in the process of cardiopulmonary resuscitation and resuscitation of patients with respiratory dysfunction in acute and critically ill patients. Tracheal intubation can promptly suction out endotracheal secretions or foreign bodies, prevent foreign bodies from entering the airway, keep the airway open, perform effective manual or mechanical ventilation, and prevent patients from hypoxia and carbon dioxide retention. Possible complications: respiratory tract injury: the process of intubation may cause tooth loss, or damage the mucosa of the mouth, nose and throat, causing bleeding. If the condition is severe and the tracheal tube cannot be removed within a short period of time, it can easily cause laryngeal edema and even laryngeal granuloma if left for a long time. Excessive stress: During anesthesia and surgery, endotracheal intubation is the strongest stimulus for patients, which can cause violent choking, breath-holding or bronchospasm, and sometimes bradycardia, arrhythmia, or even cardiac arrest or tachycardia, elevated blood pressure, premature ventricular contractions, and ventricular fibrillation due to overexcitation of the autonomic nervous system. Respiratory obstruction or pulmonary atelectasis: Some patients have more respiratory secretions, which accumulate and become dry in the catheter, narrowing the inner diameter of the catheter or even blocking it, affecting the patient’s normal ventilation and leading to carbon dioxide retention.