Introduction Nasal Continuous Positive Airway Pressure (nCPAP) is an established treatment for respiratory distress in neonates. Most modern ventilators are able to provide nCPAP. Compared to traditional nCPAP delivery systems ventilators are more complex and allow correction for leakage. There have been no large studies examining the response to leakage for nCPAP delivered by ventilators. The aim of this pilot study was to compare pressure stability for nCPAP delivered by ventilators using simulated neonatal breathing and constant leakage.
Methods Neonatal breathing was simulated by using a mechanical lung simulator. Seven ventilators were tested with recommended prongs, humidifier and tubing. Tests were performed with a breath profile from a 3.4 kg infant and nCPAP of 4 cm H2O. Constant leakage at 1-2-3-4 l/min was introduced after 30 breaths. Pressure stability was measured as pressure increase and decrease from mean pressure. Leakage stability was measured as change in mean pressure. Calculations were performed for each breath.
Results The pressure stability of the tested ventilators showed large variations before introducing leakage. Fabian, Evita XL and SERVO-i were the most pressure stable systems (with and without leakage). Changes in mean pressure with leakage also showed large variations. Four of the ventilators had leakage compensation.
Conclusion The tested ventilators showed large variations in pressure stability and ability to maintain pressure when exposed to leakage. Ability to maintain mean pressure and provide pressure stable nCPAP are different aspects of nCPAP systems. Being able to compensate for leakage does not necessarily give more pressure stable nCPAP.