Bacteria Filters HME Filter also known as bacterial/viral filters or breathing system filters, is used in the respiratory circuits of mechanical ventilators or anesthesia machines to prevent the passage of bacteria, viruses, and other microorganisms from the patient to the equipment and vice versa. They are designed to protect both the patient and healthcare providers from the risk of infection or cross-contamination. They typically have a high filtration efficiency and are capable of removing particles as small as 0.3 microns or even smaller. Bacteria Filters HME Filter is usually placed in the inspiratory and expiratory limbs of the breathing circuit, ensuring that the air entering and leaving the patient's lungs is filtered.