Noise Levels In The Neonatal Intensive Care Unit: A Systematic Review

Advisor: Carol A. Silverman, Ph.D., M.P.H. Objective: The purpose of this systematic review is to investigate noise levels in the Neonatal Intensive Care Unit (NICU) in order to see if they are in compliance with the American Academy of Pediatrics (AAP) proposed standards. This investigation also aims to compare noise levels among various NICU conditions in order to best hospital conditions for noise reduction. Methods: A comprehensive search of the literature utilizing various peer-reviewed databases through the City University of New York (CUNY) Graduate Center Library was conducted to identify relevant studies on noise levels in the NICUs. Articles that were included in the systematic review were those that assessed noise levels in NICUs. Studies were excluded if the measurements were obtained in order to evaluate intervention strategies or if measurements were taken in unoccupied NICUs. Results: Thirteen articles met the inclusion criteria for this systematic review. Nearly all of the studies (85%) utilized either a sound level meter (SLM) or dosimeter in order to obtain sound level measurements of the NICU. Noise levels obtained by each study were compared to the AAP standards, which state that the combined background and operational noises in the NICU should not exceed an hourly Leq of 45 dBA or an hourly L10 of 50 dBA. Transient, Lmax sounds should not exceed 65 dBA. In all studies, noise levels were out of compliance for at least one of the proposed standards. Investigators also found that noise levels were greater in incubators than in the NICU room (3 of 4 or 75%) and were greater in open NICU spaces than closed NICU rooms (3 of 3 studies or 100%). Noise levels were more intense during day shifts than night shifts and noise levels peaked during shift changes and physician rounds (4 of 6 studies or 66.7%). Investigators also noted that noise levels were significantly lower in NICUs that were newer and built with noise attenuation in mind as compared with noise levels in older NICUs (2 of 2 studies or 100%). Discussion: Noise levels in the NICU are overwhelmingly out of compliance with the AAP standards. These elevated noise levels in the NICU have the potential to cause permanent hair cell damage and possible noise-induced hearing loss in NICU babies. Some NICU conditions, however, provide better sound attenuation than others. Conclusions: Elevated noise levels in the NICUs are a problem that must be addressed as they can cause irreversible damage to the auditory system of infants. The building of NICUs should consider sound attenuation characteristics and should make use of sound absorbing materials. The NICU staff should be trained in noise reduction techniques and equipment noise levels and alarm sounds should be reduced as much as possible