Comparison of noise levels caused by four different neonatal high-frequency ventilators

Objective: To test the hypothesis that neonatal high-frequency ventilators create different noise levels depending upon ventilator settings and device -specific properties. Materials: Three neonatal ventilators with built-in high-frequency options (Babylog 8000, Infant Star, Stephanie) and an exclusive high-frequency osci llator (SensorMedics 3100A). Measurements: Noise levels were recorded by a microphone and measured by a decibel recording device at a defined distance from a test lung. Results: Noise levels were highest for the SensorMedics and the Babylog (70 dB and 62 dB, respectively). Whereas the SensorMedics increased noise prod uction with amplitude, the Babylog remained at a constant level. The Infant Star (52 dB) and the Stephanie (54 dB) were significantly less noisy at th eir maximum levels of amplitude (40 mbar and 50 mbar, respectively). Conclusion: Most levels recorded were below those measured within an incuba tor without the use of a ventilator. We conclude that neonatal high-frequen cy ventilators do not represent a major contribution to noise levels for ne wborns in neonatal intensive care units (NICUs).