An add-on device and method for an Endo-Tracheal Tube (ETT), the add-on device including a lengthy body having a major arc-shaped cross section sized and shaped to tightly fit over an ETT, at least one longitudinal cavity passing along the lengthy body, including a distal suction cavity ending with a suction inlet at a distal end of the lengthy body; and a distal suction outlet channel extending from a proximal end of the lengthy body, the channel is a continuous extension of the distal suction cavity and configured to provide suction to the distal suction cavity. The add-on device senses moisture at a distal end of the add-on device, and in case of detection of excessive wetness, provides suction to the distal end of the device through a cavity passing along the device, the suction is provided via a suction outlet channel extending from a proximal end of the device.