Abstract 1794

Background: Reduction of noise levels in neonatal intensive care units has been increasingly focused on recently. The widespread use of various high-frequency devices is subjectively associated with an increase in noise created in the proximity of newborn premature and term infants.

Materials: Four neonatal ventilators with either a built-in high-frequency option or an exclusive high-frequency oscillator (Babylog 8000, Infant Star, Stephanie, SensorMedics 3100A).

Measurements: Noise levels were recorded by a microphone and measured by a decibel recording device in a defined distance from a test lung. For each device mean airway pressure and frequency were kept at the same level while amplitude was modified.

Results: Noise level were highest for the SensorMedics and the Babylog, whereas the SensorMedics increased noise with amplitude, the Babylog kept its decibel levels constant. With the Infant Star and the Stephanie far lower noise levels were recorded. Apart from the Babylog all other devices tested increased their decibel levels with higher amplitudes. (Figure)

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Conclusion: The high-frequency devices tested caused different levels of noise in a defined distance from a test lung. The majority of ventilators increased their production of noise with higher amplitudes. Noise levels at the high range of amplitudes were recorded only marginally above those measured within an incubator without the use of a ventilator [i.e. 65dB(A)]. We conclude that high-frequency ventilators do not represent a major contribution to noise levels occurring in the proximity of infants treated in neonatal intensive care units.