A portable mechanical device designed to continuously measure tidal and/or minute volume of a spontaneously-breathing or mechanically-ventilated patient, for the evaluation of the patient’s ventilatory status during intensive care treatment, anaesthesia, and postoperative recovery; it may also be used to measure tidal/minute volume and respiration rate delivered to a patient via the expiratory ports of resuscitation devices to evaluate their performance. It consists of an airflow-driven turbine/dial which indicates the air volume passed.