Effect of Humidifier Temperature During Non-invasive Ventilation on Water Condensate and Airway Pressure: Newborn Manikin Model

Recommendation for setting humidifier temperature when using non-invasive ventilation in newborn infants has been changed from low range (32-34 C) to high rang (37 C). However, there is no evidence comparing benefit and hazard between the two settings. To compare the effect of two temperature settings of humidifier during non-invasive ventilation on nasopharyngeal temperature, water condensate and airway pressure. We applied nasal intermittent positive pressure ventilation in a newborn manikin with artificial lungs. The temperature of humidifier was set at high range or low range. We measured nasopharyngeal temperature, water condensate in ventilator circuit and airway pressure in an artificial lung at 0, 8 and 16 hours after starting ventilation. The experiments were conducted 3 times for each setting of humidifier. Comparisons between the groups were analyzed by using Peason’s correlation. Nasopharyngeal temperature with humidifier temperature at high range 34.0 +- 0.1 C was significantly higher than that at low range 32.1 +- 0.2 C (p < 0.001). Volume of water condensate in ventilator circuit was strongly correlated with airway pressure in artificial lungs (r= - 0.828 for PIP, r= -0.948 for PEEP). Water condensate in ventilator circuit significantly decreased airway pressure and interfered with ventilator function. When using non-invasive ventilation, setting humidifier temperature at high range produces substantial water condensate resulting in significantly decreased airway pressure. Therefore, water drainage should be emphasized as an important respiratory care. Funding: Phramongkutklao Foundation