NICU Noise and Vibration and High Risk Infant Outcomes: A Review of the Literature

Friday, 20 July 2018: 11:25 AM

Valerie L. Willis, PhD, RN, PPCNP-BC, PCNS-BC
Hahn School of Nursing, Beyster Institute for Nursing Research, Advanced Practice, & Simulation, University of San Diego Hahn School of Nursing & Health Science, San Diego, CA, USA


The purpose of this scholarly endeavor was to conduct a comprehensive review of the literature surrounding noise and vibration in the neonatal intensive care unit (NICU).


Noise, defined as "any unwanted or disagreeable sound and is often dismissed simply as a nuisance" (Environmental Protection Agency [EPA], 2009), can be detrimental to physical and psychological well being. Concerns regarding noise in the patient care environment are not new. Pioneer nurse scientist, Florence Nightingale (1860) penned, "Unnecessary noise, then, is the most cruel absence of care which can be inflicted either on the sick or well" (p. 44). More recently, professional organizations and regulatory entities such as the World Health Organization [WHO] (2009), the Joint Committee on Infant Hearing [JCIH] (2007), the EPA (2013), and the American Academy of Nursing (Lechlitner Lusk, McCullagh, Vaughan Dickson, & Xu, 2016) reported concern or have established recommendations for a therapeutic soundscape in newborn nursery environments: a maximum of 45 dB during the day and 35 dB at night, a little louder than a whisper. Despite recommendations, ambient noise levels in the NICU remain an ongoing concern and challenge.

Formation of the human external ear begins during the fifth week of embryonic development (Locher et al., 2013). The ability of the human ear to interpret sound is dependent on the formation of two essential structures that are present at 12 weeks gestation: cochlear hair cells and cranial nerve VIII, also known as the auditory or vestibularcochlear nerve. Typically, hearing begins around 20 weeks gestation and 25 weeks marks complete auditory system maturation. In conjunction with interpretation, the human brain perceives sound based on three physical characteristics: amplitude or loudness measured in decibels (dB), frequency or pitch measured in hertz (Hz), and duration of exposure (Ulrich & Zimring, 2004). Once damaged by excessive acoustic exposure, cochlear hair cells are unable to regenerate (Cristobal & Oghalai, 2008).

Vibration, the frequency of oscillatory cycles as measured in Hz, often accompanies excessive noise and has the potential to cause harm to humans (Schierholz, 2010). In addition, as hospitals utilize construction/renovation as a strategy to promote patient safety and enhance patient satisfaction, patients may be exposed to even higher levels of noise and vibration (Zalk, et al., 2011), particularly in instances when the NICU is in proximity, yet not relocated.


A comprehensive literature search was conducted for evidence-based publications identified by online databases, search engines, and hand search of reference lists for relevant citations.


Myriad researchers have reported noise levels in the ambient NICU environment of care exceed recommended limits for a therapeutic soundscape. A typical urban, level III NICU generates noise levels of 53.9 dB-62.5 dB, equivalent to conversational speech (Darcy, Hancock, & Ware, 2008; Pineda, Durant, Mathur, Inder, Wallendorf, & Schlaggar, 2017), with bursts of 134 dB, similar to fireworks (Matook, Sullivan, Salisbury, Miller, & Lester, 2010). Immediate effects of noise on the developing neonate, especially those of low birth weight or premature birth include unstable cardiorespiratory parameters, disturbed sleep, and alterations in behavioral response, while deferred outcomes include auditory impairment, neurologic abnormalities, and developmental issues (Darcy, et al., 2008; American Academy of Pediatrics [AAP], 1997; National Institute for Occupational Safety & Health [NIOSH], 2013; Peng, et al., 2013; Pickler, et al., 2010; Salavitabar, Haidet, Adkins, Susman, Palmer, & Storm, 2010; Wachman & Lahav, 2011; Viet, Dellarco, Dearborn, & Nietzel, 2014). Increasingly, the role of the exposome, the sum of environmental exposures that may cause or prevent human disease, is more widely studied and deemed particularly relevant during critical periods of development and susceptibility (Buck Louis & Sundaram, 2012; Juarez, et al., 2014; Vrijheid, et al., 2014; Wild, 2012).

In the case of construction noise, a jackhammer engaged in construction related demolition/ renovation generates 109 dB-125 dB, equivalent to a jet plane at take-off (NIOSH, 2013). The reverberation of sound off of interior walls further intensifies noise levels (Ulrich & Zimring, 2004). Two studies directly addressed hospital construction and the NICU. Trickey, Arnold, Parmar, and Lasky (2012) explored pre-, concurrent, and post-construction sound levels and patient outcomes during renovation above the 104-bed NICU at a large teaching hospital. Findings suggested NICU patients were not adversely affected by construction renovation noise based on the dependent variables of ventilator days, length of stay, discharge weight, and discharge home on oxygen. Evans (2000) conducted a multi-year case study to determine simulated noise and vibration measurement of construction power tools and identify noise and vibration mitigation strategies for planned demolition and renovation in proximity to NICU. Findings showed audible noise and perceivable vibration within the NICU and several collaborative strategies for noise and vibration abatement, including schedule coordination, engineering/architectural structural modifications, and optimal function of construction equipment.

Excessive whole-body vibration in adults that exceeds the recommended oscillatory frequency of 250 Hz can cause adverse cardiorespiratory effects, increased metabolism, fatigue, irritability, abdominal pain, motion sickness, and blurred vision (Karlsson, et al., 2012; NIOSH, 2013; Schierholz, 2010). The effects of whole-body vibration on neonates is not widely studied and extant literature is limited to vibration associated with neonatal inter-facility transport and high frequency oscillatory ventilation with peaks during transport often exceeding recommended limits resulting in cardiovascular variability (Bouchut, Van Lancker, Chritin, & Gueugniaud, 2011; Karlsson, et al., 2012).


Detrimental effects of excessive noise on the NICU population are a well-documented, persistent problem that compels collective advocacy. A litany of stakeholders, including healthcare professionals, acoustic subject matter experts, institutional leadership, regulatory agencies, policy makers, and families, can and must expedite remediation of this widespread patient safety concern at the individual and population level. More research is needed to determine proven, cost-effective noise and vibration mitigation strategies in the NICU; barriers to implementation of evidence-based noise and vibration abatement approaches; and the relationship between construction noise and vibration and high risk infant outcomes both in and beyond the NICU.