Noise Produced by Neonatal Ventilators Inside and Outside of the Incubators

Insufficient data are available about the noise produced by modern neonatal ventilators. We aimed to measure their noise under different ventilatory modes and parameters.

This was a bench study measuring the noise produced by 9 neonatal ventilators set in conventional or high-frequency oscillatory ventilation (HFOV), nasal mask-delivered CPAP with variable- or continuous-flow configuration, or bi-level positive airway pressure (considered as noninvasive ventilation [NIV]). Conventional ventilation and HFOV were tested in 2 distinct settings with moderate or higher parameters. Sound measurements were performed inside and outside an incubator mimicking the clinical setting and using a high-end meter meeting the international ISO 226:2003 standard.

Four ventilators remained below the internationally recommended safety threshold but only for measurements outside the incubator. Conventional ventilation (49.1 [3.4] dBA) and HFOV (56.3 [5.2] dBA) were the least and most noisy respiratory support technique, respectively. Noise was greater inside than outside the incubators (P < .0001) and different between the ventilators (P < .0001); better results were achieved by Servo-u and Fabian family devices for conventional ventilation; by fabian HFO for HFOV; and by Servo-u, VN500, and fabian family devices for CPAP and NIV. Noise levels were similar when using moderate or higher parameters in conventional ventilation (P = .81) and in HFOV (P = .45).

Modern ventilators often produce relevant noise, independent of the respiratory support modality, with acceptable noise levels being measured only outside the incubator. Better results were achieved with Servo-u, VN500, and Fabian family devices.