A Heat and Moisture Exchange Filter is actually a humidification system used for mechanically ventilated patients helping to prevent complications due to the drying-out of the respiratory mucosa
Avoids both excessive and insufficient humidification
Regulates the temperature, thus avoiding the danger of airway burns
Also acts as a filter, thus keeping out bacteria and reducing the chance of lung infection
Due to an only minute dead space, it will not reduce the efficacy of the ventilation