Noise Produced by Neonatal Ventilators Inside and Outside of the Incubators

Abstract

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

Methods: 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.

Results: 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).

Conclusions: 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.

Keywords: NICU; neonate; respiratory support; safety; sound; ventilation.