Neonatal invasive ventilation therapy

Invasive ventilation is a mode of respiratory support that replaces spontaneous breathing in neonates with an artificial airway. Heating and humidifying respiratory gases is the standard practice during invasive ventilation in neonates.

Invasive ventilation breathing circuits

Evaqua™ 2 technology within Fisher & Paykel Healthcare’s breathing circuits helps minimize mobile condensate in the expiratory limb by allowing water vapor to diffuse through the tubing wall.

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Heated and humidified gases

In a healthy airway, gas is heated and humidified by the upper airway during inspiration and fully saturated with water vapor at core body temperature (typically 37 °C, 44 mg/L H2O ) 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 crucial.1,2

Why is humidification important?

Medical gas is typically cold and dry (≤ 23°C, < 2% relative humidity) compared with ambient air (23 °C, 40% relative humidity).3 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 and reduce lung compliance.​1,2

There are several key benefits associated with humidification.
Assists natural defense mechanisms in the airway

Delivering heated and humidified gas during respiratory support assists with secretion mobilization and removal.4,6
Promotes conservation of energy for growth and development

Infants need energy for growth and development so minimizing the heat and water demand needed to condition gases supports conservation of energy for these tasks and thermoregulation.5
Supports patient comfort and therapy tolerance

Humidification is associated with clearance of retained secretions and prevention of airway drying.6

Adequate humidification during respiratory support may improve patient comfort and therapy tolerance.7



A newborn’s respiratory system is reliant on humidity to maintain physiological balance, assist natural defense mechanisms and conserve energy for growth and development.

F&P and Evaqua 2 are trademarks of Fisher & Paykel Healthcare Limited. For patent information, see