Disclosed herein are novel designs of a medical tube for delivering a respiratory gas to a subject in respiratory therapy, wherein the medical tube is in fluid connection with a user interface and a respiratory device. The medical tube has a tubular body, a first rib helically extending along the outer surface of the tubular body, and optionally, a second rib disposed next to the first rib, and optionally, a membrane encapsulating the first and/or second ribs thereby creating a helical space along the outer surface of the tubular body. In some embodiments, the first rib has a lumen and at least one wire disposed outside the lumen. In other embodiments, the first rib is free of any lumen and includes one or more wires extended therethrough. The lumen of the first rib or the helical space created by membrane encapsulation is configured to monitor the temperature, humidity, flow rate or pressure of the respiratory gas or an exhaled/inhaled gas of a subject.
