Noninvasive Respiratory Therapy and Neonatal Exposure to Sound.

Background and Significance: Noninvasive respiratory management used to treat neonatal respiratory distress syndrome is standard practice. Common noninvasive modalities include nasal cannula, high-flow nasal cannula, Vapo-therm (VT), RAM Cannula (RAM), nasal continuous positive airway pressure, and noninvasive positive pressure ventilation. The developing auditory system relies on low-frequency sounds predominant in utero, which is necessary to provide stimulation for auditory maturation. The auditory center within the cerebral cortex continues to develop throughout infancy and childhood. The major structures of the auditory system are well developed by 25 weeks' gestation. Preterm infants hear sounds and send signals to the brainstem, yet the auditory system is not yet mature enough to process complex sounds prevalent within the neonatal intensive care unit environment. Neonates may be subjected to potentially noxious noise emitted during noninvasive respiratory therapy delivered nasally in close proximity to auditory structures. The negative short- and long-term effects of excessive neonatal noise exposure have been well studied and include increased agitation, disruption of restorative sleep patterns, and negative neurodevelopmental outcomes. The American Academy of Pediatrics Committee on Environmental Hazards has recommended environmental sound levels in the neonatal intensive care unit less than 45 dBA. Purpose: This study determined the environmental noise, defined as mean decibel level produced by various noninvasive respiratory care modalities used to treat neonatal respiratory distress syndrome. Methods: A prospective descriptive design using purposive sampling was used to obtain baseline levels of environmental noise during noninvasive respiratory support. The Giraffe Omnibed was the standard incubator to provide consistent background noise level. dBA measurements were obtained approximately 2 inches from the quiet infant's resting position using a commercial sound meter. De-identified biologic and descriptive measurements were recorded on the researcher-developed data collection sheet. Descriptive analysis was conducted for demographics and sound measures. Results: Baseline noise measurements for sampled Giraffe Omnibed during warming ranged from 39 to 46 dBA. Based on sample size estimate a priori, 360 neonates were divided into 12 groups (n = 30) based on type and flow level of noninvasive respiratory therapy. Measured sound levels during VT, RAM, and high-flow nasal cannula at flow levels 4 lpm or more and continuous positive airway pressure more than 3 cm H 2 O were 58 to 76 dBA. Noninvasive positive pressure ventilation sound measurements were 52 to 68 dBA for rates 20 to 40 with peak inspiratory pressure more than 20 regardless of positive end expiratory pressure. Implications for Practice: Negative effects of noise levels more than 45 dBA have been correlated with increased agitation, disruption of restorative sleep patterns, and negative neurodevelopmental outcomes. Auditory protection from environmental noise includes correct fit of noninvasive respiratory device to best eliminate air leaks during therapy. Baseline measurements of incubator heater noise increased with age. Recommendations include routine preventative maintenance on incubators with replacement as indicated. Implications for Research: Short- and long-term effects of neonatal sound exposure have been studied, yet baseline data during routine respiratory care are lacking. External ear coverings have been suggested as a method to reduce noise to the auditory system without efficacy trials. The implications of close proximity between the nasal structures and auditory system of the preterm infant during administration of flow and/or ventilation have not been studied. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Neonatal Care (Lippincott Williams & Wilkins) is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)