Abstract: The present disclosure relates to a monitoring device for measuring and monitoring breathing parameters and, optionally, oxygenation and/or vital sign parameters of a mechanically ventilated patient, the monitoring device being removably arrangeable at a portion of a ventilator breathing circuit provided between and in fluid connection with a mechanical ventilator and an airway of the patient. The monitoring device comprises a first sensor arrangeable at the fluid connection for measuring parameters related to an airflow in the fluid connection to obtain measurement data; a processor adapted to receive the measurement data from the first sensor and configured to process the measurement data into at least one breathing parameter; and a transmitter adapted to transmit data comprising the at least one breathing parameter to an external device.