Zero-dead-cavity drainage type laryngeal mask respiratory system

The invention relates to a zero-dead-cavity drainage type laryngeal mask respiratory system, which comprises a laryngeal mask assembly, an L-shaped joint, a dismountable Y-shaped joint and an anaesthesia machine connecting tube, wherein the laryngeal mask assembly comprises a mask body, a guide tube, an inflating guide tube and an inflating valve; a drainage cavity and a laryngeal mask ventilationtube are arranged in the guide tube; a drainage opening is formed in the patient insertion end of the mask body; the drainage cavity communicates with the drainage opening. The zero-dead-cavity drainage type laryngeal mask respiratory system is characterized in that three cavities are formed in the axis position inside the laryngeal mask ventilation tube and are respectively an expiration cavity,an inspiration cavity and a gas sampling cavity; the gas sampling cavity is positioned in the adjacent position of the expiration cavity and the inspiration cavity; a drainage cavity is arranged in the guide tube positioned b