In a healthy airway, gas is heated and humidified by the upper airway during inspiration, and is fully saturated with water vapor at core body temperature (typically 37 °C, 44 mg/L) when it reaches the distal airways.1 

However, during invasive ventilation the upper airway is bypassed, along with its natural airway protection and humidification mechanisms; therefore, heating and humidifying gases while this treatment is being delivered is important.1,2 


Why is humidification important? 

Medical gas is typically cold and dry (≤ 15°C, < 2% Relative Humidity) compared to ambient air (22 °C, 50% Relative Humidity). The delivery of cold, dry gas to the airway is associated with increased water and heat loss, inflammation in the airway epithelium, and an increased risk of airway injury. Insufficient humidification may also impair secretion clearance and increase the risk of airway blockages. These effects are amplified in preterm infants, where a few minutes of ventilation with insufficient humidification has been shown to increase airway resistance, reduce lung compliance, increase the risk of air leaks, and the need for supplemental oxygen delivery.1,2 

There are several key benefits associated with humidification.3-6 

Image of the Neonatal Airway

Assists natural defense mechanisms in the airway 

Delivering heated and humidified gas during respiratory support assists with secretion mobilization and removal. 

Promotes conservation of energy for growth and development  

Infants need energy for growth and development therefore, assisting in thermoregulation can help conserve energy for these tasks.

Comfort Therapy for infants

Supports patient comfort and therapy tolerance  

Humidification is associated with clearance of retained secretions and prevention of airway drying. Adequate humidification during respiratory support may improve patient comfort and therapy tolerance. 

Invasive ventilation circuits  

The Fisher & Paykel Healthcare Evaqua™ 2 breathing circuits help minimize mobile condensate in the expiratory limb by allowing water vapor to diffuse through the tubing wall.