According to the American Association for Respiratory Care Clinical Practice

According to the American Association for Respiratory Care Clinical Practice Guideline: Humidification During Invasive and Non-Invasive Mechanical Ventilation, a heat moisture exchanger (HME) should:

A) not be used for more than 12 hours
B) not be used for more than 24 hours
C) not be used for more than 48 hours
D) not be used for more than 96 hours