The Medisize® Blue HMEF filters are a combined heat and moisture exchanger with a filter for bacteria and viruses. The filters are intended to take over the function of the upper part of the patient’s respiratory tract during periods of artificial respiration in intensive care units or when under anesthesia. The filters can, in consultation with the doctor, be used as an alternative to an active humidifier. The filters are intended for patients with a breathing volume of more than 150ml. The filters come with a luer-lock