Tracheotomy comes from the Greek words "tracheotomy" and "incision". Tracheotomy refers to cutting the front wall of the patient's trachea to assist breathing. Catheters allow air to enter the trachea and lungs directly without passing through the nose, pharynx and larynx.

The trachea is located in the middle of the neck, and its upper segment is shallow, about1.5 ~ 2 cm away from the skin; The lower segment gradually becomes deeper, about 4 ~ 4.5 cm away from the skin on the upper edge of the sternum. The front of trachea is covered by skin, subcutaneous tissue, superficial fascia and platysma. Between the superficial fascia and platysma, there are many small veins (anterior jugular vein plexus) flowing into the anterior jugular vein.

The deep layer of platysma is shallow deep fascia, which surrounds both anterior cervical muscles and connects with a white fascia line at the midline. Behind the superficial layer of deep fascia is the middle layer of deep fascia, trachea and anterior fascia of trachea. The anterior tracheal fascia is attached to the anterior tracheal wall. The thyroid gland is located on both sides of the trachea, and the thyroid isthmus is located in front of the third and fourth tracheal rings and surrounded by the anterior tracheal fascia.

During the operation, the isthmus of thyroid should be pushed up or cut off before cutting off the trachea. There are thyroid artery, vein and azygos vein plexus on both sides of the trachea, and the main blood vessels in the neck are on the outside. Therefore, during tracheotomy, the incision must be within the safe triangle of the neck (the upper corner of the triangle is located at the junction of cricoid cartilage and sternocleidomastoid muscle, and the lower corner is located at the midpoint of sternal notch).

The purpose of pneumonectomy is to treat upper airway obstruction, prevent airway aspiration and make tracheobronchial secretions easy to remove, which is helpful to use ventilator for mechanical ventilation, reduce ventilation dead space and treat obstructive sleep apnea.

Advantages of gas cutting: less sedation, easier tolerance, less breathing work, less dead space, convenient sputum suction and oral health care.

Tracheostomy tube can reduce the physiological dead space of upper respiratory tract by at most 150ml or 50%(Pritchard, 1994). Compared with oral intubation, this is beneficial to relieve the patient's dyspnea, reduce airway resistance and improve alveolar ventilation.