Noise: The Importance of Silencing the Loud NICU

Abstract

In utero, the growing fetus is subject to low-frequency noises. However, the high-risk neonate experiences much harsher sounds in the extrauterine environment. Despite many advances, modern Neonatal Intensive Care units cannot mimic the womb environment for preterm infants. Neonates are exposed to a stressful noisy environment where sleep is frequently interrupted and physiologic consequences alter development. Undesirable noise can be generated from simple conversation, use of equipment, overhead announcements, surrounding objects, and vibration. Noise levels above the American Academy of Pediatrics (AAP) recommendation (under 35–45 decibels [dB]) are associated with adverse outcomes and hearing loss. Noise level in the NICU is an important patient safety issue and should be regularly addressed by healthcare providers. Understanding modifiable and non-modifiable noise can influence daily practices, NICU design, staff education, and unit-specific quality improvement programs.

1. Introduction

In utero, the growing fetus is subject to low-frequency noises. However, the high-risk neonate experiences much harsher sounds in the extra uterine environment [1]. The Neonatal Intensive Care Unit (NICU) is a place, in theory, that should mimic the womb for preterm infants. However, the NICU is a stressful environment where sleep is frequently interrupted by procedures and loud unpredictable noises. Undesirable and excessive noise results from medical activities, monitor alarms, conversations, and visitors. Calikusu-Incekar and Balci [1] reported that the two biggest sources of noise in the NICU are monitor alarms and human voices. In addition, NICU architecture, devices used and the type of incubator may determine a neonate’s exposure to noxious sounds [2, 3, 4, 5].

The American Academy of Pediatrics (AAP) recommends limiting noise in the NICU to <45 decibels [dB] and states that exposure to higher noise levels can have deleterious effects on high-risk newborns [3, 6, 7, 8, 9]. Noise can cause alterations in blood pressure, heart rate, and respiratory rate [8]. Due to impaired autoregulation of cerebral perfusion in preterm neonates, these fluctuations can contribute to intraventricular hemorrhage (IVH) and cerebral ischemia [10, 11]. Grades 3 and 4 IVH are associated with neurodevelopmental delays [12].

Noise exerts stress on both infants and staff in the NICU. For infants, stress from noise increases the consumption of calories and disrupts normal growth and development [6, 13]. These can contribute to increased length of NICU stay, more need for rehabilitative care, and increased health care costs [14]. For staff, excessive noise stress is associated with suboptimal performance and job burnout [3, 5, 6, 14, 15, 16, 17].

Nevertheless, noise levels in NICU regularly exceed 45 dB and often rise to levels as high as 120 dB. Several approaches have been reported to promote a “culture of silence,” including quiet time protocols, staff education programs, visual noise feedback monitors, and staff “sound compliance supervisors” [5, 18, 19, 20, 21]. Ongoing staff education programs, coupled with monitoring noise levels, are essential to sustaining a commitment to noise reduction in the NICU. Parents and family members can also be supported to engage in developmentally appropriate care to become competent caregivers and advocates for the neuroprotection of their babies [22, 23]. Quiet time protocols may significantly decrease exposure to electronic sounds and voices, increasing restful sleep and promoting growth [5, 24]. In contrast, some other interventions, such as the use of earmuffs, do not have clear benefits [25, 26, 27].

The physiologic consequence of unpredictable loud sounds and the negative effect on neonatal growth and development is a clinical concern and an important patient safety issue that should be regularly addressed by healthcare providers.

2. What is noise?

Sound encompasses everything we can hear, while noise is characterized as undesirable sound or disturbing sound often linked to its volume [28, 29, 30]. Noise has also been described as that which exceeds the human auditory tolerance thresholds [31]. Undesirable noise has been associated with negative long-term impacts on humans, other forms of life, and biodiversity, leading to approximately 1 million disability-adjusted life-years lost each year in Western Europe, as estimated by The World Health Organization (WHO). Noise can cause direct injury to the auditory system causing hearing impairment, tinnitus, increased incidence of cardiovascular diseases, disturbed sleep patterns, and impaired cognitive performance [29].

Four primary types of noise have been described: continuous, sporadic, impulsive, and low-frequency. Continuous noise is sound that has the same frequency, volume, and quality, uninterrupted over time remaining stable and constant. Sporadic noise also referred to as intermittent or variable, tends to be inconsistent, increasing and decreasing rapidly. Impulsive noise can be defined as impact noise in which extremely short bursts of loud sounds last for short durations of time. Low-frequency noise is the faint background soundscape humming or buzzing emitted from equipment, electronic devices, and ventilation systems [30, 31].

Noise can also be described in terms of colors. Each color is defined denoting a specific frequency of sound wave. High-frequency sounds are perceived as higher pitched and low-frequency sounds are lower pitched. There are many different hues of noise but the most well-known and studied are white, pink, and brown noises [32].

Humans perceive different types of noise based on the number of times the sound waves repeat per second. White noise contains every frequency that a human ear can hear, spanning 20–20,000 Hertz (Hz) (a unit measuring frequency, equal to one cycle per second [33]). This range of noise frequencies is fast and random similar to radio static. Pink noise is a more balanced spectrum than white, dampening the volume of higher frequencies resembling steady rainfall or a mother’s heartbeat heard by a fetus in the womb. Brown noise further suppresses high frequencies, creating deeper masking sounds, such as distant thunder, drawing inspiration from Brownian motion, the random movement of microscopic particles suspended in liquid or gas [32, 34].

2.1 Measurements of noise

Noise levels are quantified using Sound Pressure Level (SPL), expressed in decibels (dB). SPL represents the amplitude, strength, or force of a sound wave [35], measuring the difference between the sound wave pressure and the ambient pressure of what the sound is traveling through. Sound pressure level uses Pascal’s initially as its unit of measurement then is converted into the decibel scale. This conversion helps give a numerical value to noise and helps to define acceptable levels to prevent hearing loss and other noise-related health concerns. The dB scale is logarithmic. For example, if a sound registers 80 dB, it is 10 times more intense than 70 dB. The A-weighted decibels (dBa) measurement is commonly used when measuring sound for healthy versus unhealthy levels. A-weighted decibels consider the human ear’s sensitivity to sound intensity, different frequencies, and how the human ear responds whereas dB is based only on sound intensity [36, 37, 38].

3. Developing neonate and noise exposure

Preterm birth interrupts the normal physiologic developmental pattern of many organs and introduces external conditions necessitating adaptation and alternate maturational processes that can be detrimental to neonates’ maturation and long-term developmental outcomes. Fetal avoidance of noxious stimuli is supported by in-utero mechanisms. The developing fetus is protected from trauma by cushioning amniotic fluid, infection by amniotic membranes, malnutrition by placental nutrient transfer, and excessive light and noise by layers of amniotic fluid and maternal structures. The first sounds the fetus is exposed to are maternal heartbeat, digestive sounds, and muffled outside noises. These sounds are transmitted via bone conduction and fluid medium, as the air conduction system is not developmentally mature until close to full term [39]. The majority of sounds transmitted to fetuses are low-frequency (<500 Hz) positive sounds (human language) and periodic, rhythmic, and even predictable sounds (e.g.: heartbeat). Structural components of the inner ear (labyrinth and cochlear) are formed by 15 weeks but are not functional until 24–25 weeks gestation. Electrophysiologic data [39, 40] demonstrates preterm brainstem evoked potentials between 25 and 32 weeks. At this time the hearing threshold is around 40 dB [41]. Before 27 weeks gestation no fetuses respond to higher frequencies (>500 Hz). After 34 weeks gestation age (GA), the spiral ganglion neurons and cochlea have adequate neural connections that evolve and populate the path toward the auditory cortex. Responses to higher frequencies (>1000 Hz) are observed after 34 weeks. GA, as speech patterns are recognizable and learning and memory formations begin [41, 42]. Development of the inner cells of the cochlea is a pre-determined, ordered process with specific topography of hair cells. This topography ensures the maturation of “low-frequency” regions first, protecting neurons from high-frequency injury as they are mildly unresponsive to random, high-frequency sounds. This process is referred to as “frequency-dependent plasticity” and is imperative to prevent injury to developing structures.

As pregnancy progresses maternal structures and tissues thin out and higher-frequency sounds are gradually transmitted through. There is a preference for naturalistic sounds such as voice recognition, vowel discrimination, and soft classical music [5, 24, 43, 44]. Interruption of physiologic topographic maturity and exposure to developmentally inappropriate frequencies injures migrating neurons, hair cells, and cochlea fluid composition, leading to cell injury, inflammation, and eventually poor frequency resolution, hearing loss, and stressful response to noises leading to systemic manifestations [44, 45]. These findings have been demonstrated in animal studies upon exposure to poor-quality, random, high-frequency noise. These models revealed malformed topographic maps, injured neurons and supportive cells, inflammation, and premature neuronal firing culminating in decreased hearing quality and accelerated age-related hearing loss [39, 45].

3.1 Short-term pathologic changes in responses to noise

Noise levels above the recommendations (under 35–45 decibels (dB)) as determined by the AAP, the World Health Organization (WHO), and the Environmental Protection Agency (EPA) are associated with alterations in vital signs, such as blood pressure, heart rate and respiratory rate [3, 6, 8, 13, 14, 15, 28, 46, 47, 48].

3.1.1 Heart rate (HR)

Exposure to high-frequency noise has been shown to elicit inappropriate tachycardia in neonates. Preterm babies may not be able to compensate for prolonged tachycardia, leading to bradycardia and altered oxygen delivery. Blood pressure (BP) fluctuations may follow, leading to the transmission of inappropriate blood pressure to cerebral vasculature via passive cerebral circulation and increased risk of intraventricular hemorrhage [48]. The cardiac response to loud noise depends on a history of previous noise exposure, habituation with exposure, behavioral state and integrity of the central nervous system, other insults, and gestation age.

3.1.2 Respiratory rate (RR)

Loud noise induces tachypnea, interfering with normal oxygen delivery to the tissues. Studies have demonstrated decreased oxygen saturation both in awake and sleep states [3]. Other studies noted decreased respiratory rate to pathologic levels, especially with very loud (100 dBA) frequencies [48].

3.1.3 Growth

Studies demonstrated an increase in intracranial pressure and changes in electromyography readings during HR and BP fluctuations due to noise. Interestingly, the changes negatively affect the neuroendocrine system as well as the immune system [6]. Stress activates the hypothalamic-pituitary-adrenal axis and causes growth-inhibiting effects, likely via corticosteroid action [6, 10, 11].

Changes in HR, RR, and oxygen saturation demand increased caloric expenditure. Preterm neonates, in particular, have immature mechanisms for calming themselves and compensating. Prolonged noise exposure leads to poor growth, prolonged stay in the NICU, and delayed acquisition of feeding skills [3]. Investigators have tried to minimize the exposure to noise by providing earmuffs or silicone earplugs. The conclusion is not clear, as some studies show increased stress from just wearing the muffs and others show a decrease in noise transmission without any meaningful physiologic improvement [3]. At this point, universal earmuffs are not recommended for preterm neonates [49].

3.1.4 Impaired sleep

Physiologic habituation to noise is impaired in preterm neonates leading to diminished rapid eye movement (REM) and non-REM sleep. Sleep deprivation can lead to fatigue, agitation, irritability, and even increased intracranial pressure. During the non-REM stage of sleep brain maturation as relates to neurodevelopment takes place. Cerebellum, midbrain, hippocampus, and brainstem growth, differentiation, and synaptogenesis take place mostly during sleep. Reducing noise and light allows the longest and the best quality of sleep [19]. Some studies do show longer sleep in babies provided earplugs or muffs [3]. Some report improved weight gain and greater head circumference, but the numbers are not sufficient to show consistent clinical significance, and more studies are needed. Research suggests that periods of prolonged (at least 90 minutes) quiet time is required to observe meaningful physiologic differences [19].

3.1.5 Perception and response to pain stimuli

Noise diminishes the ability to soothe oneself and tolerate pain. The pathologic response is a disordered neuronal firing, leading to further irritability, crying, and systemic physiologic dysregulation. Repeat stimulation leads to maladaptive behaviors, exaggerated pain, and a startle response. As the topography of neonatal neuronal pain pathways is developing, the long-term responses show hyperactivity, inability to “center” oneself, and exaggerated stress response to future minor stimuli [39, 41, 42].

3.2 Long-term neurodevelopment sequelae

As an infant matures early exposure to caustic noise diminishes linguistic efficiency. Preterm birth switches pre-programmed in-tuning to sound of voice to harmful background noise, that normally would be filtered. Immaturity of the negative feedback leads to over-processing of the pervasive noise, training the immature preterm brain to over-emphasize high-frequency noise that competes with positive speech sounds. In addition, polluting background noises muffle out beneficial speech, leading to delays in language acquisition. Lack of long periods of parental presence in the NICU and exposure to their speech leads to relative “silence” of memory-producing teachable phonetics, despite surrounding caustic noise, leading to hearing deprivation. Likely auditory plasticity persists throughout life and appropriate training can improve language acquisition and clarity [3, 12, 19, 48].

4. Noise–Where does it come from?

Noise can be generated from simple conversation, use of equipment, overhead announcements, vibration from electronic equipment, ventilators, infusion pumps, vital sign monitors, blood pressure machines, suction machines, portable radiograph machines, ultrasound equipment, dragging chairs, isolettes, and extracorporeal membrane oxygenation (ECMO) systems [28].

Emergencies, procedure times, response time to silencing alarms, change of shift reporting, bedside provider rounds, and family visiting all impact the level of noise in the NICU. These sources of noise have been linked to spikes in noise levels and have been barriers to successful noise reduction programs. Other factors contributing to the elevated noise levels in the NICU include healthcare providers talking in loud conversational voices at the bedside and not promptly silencing the monitor alarms, the number of people in the patient room, the number of neonates in the room, the number of alarms activated, infant acuity, and the work-shift type [50, 51]. Staff and visitors’ general attitudes have also been identified as a main source of noise. In one study, conversation constituted 50% of the noise-producing sources. A high number of healthcare professionals, a high patient census, and numerous visitors at any given time are also associated with a significant increase in noise levels. Other sources are the use of telephones, oxygen and compressed air sources, humidifiers, and suction machines. Unwanted harsh increases in noise levels are also produced by overhead announcements and fire alarm notifications. Increased unwanted noise has also stemmed from aging NICU and housekeeping equipment but also from newer electronic equipment such as motion-sensor paper towel dispensers or newer staff communication devices [45].

Neonatal incubators serve as a home to neonates in a NICU for prolonged periods. Modern incubators are advanced, microprocessor-controlled, double plexiglass wall units that utilize special quiet technology. Despite modern advances, the noise level within the incubator varies between 55 and 70 dB. contributing significantly to hearing insults despite theoretically providing partial protection from outside noise [38, 44, 52]. In addition, due to reverberance effects, the incubator amplifies the internal noise produced by the cooling fan as well as magnifies the intensity of the baby’s cry. The cooling fan is known to produce tones at 200, 400, and 600 Hz, which if eliminated could decrease the noise by 4–6 dB. Studies have shown transmission of even higher frequencies through the open doors, lack of incubator protective effects of noise with respiratory equipment in use, and almost zero effect of incubator covers [47, 49]. In addition, incubators boost transmission of low frequencies (below 125 Hz) due to strong resonance [14]. Other incubator-associated activities such as closing doors generate a sound of 85 dB, placing an object on the incubator emits 90 dB, and closing the lower drawer of the incubator leads to an 89 dB level [38, 44, 49, 52].

The second loudest group of devices with a non-modifiable internal noise are respiratory devices, with High-Frequency Jet ventilators leading the way. The Jet patient box is encased in a plexiglass box to minimize the noise it produces, yet harmful high frequencies (up to 2000 Hz or pressure of 12 dB) are transmitted within the incubator [53]. Modern NICUs use a variety of respiratory modalities, all of which represent acoustic hazards. High-frequency oscillatory ventilator produces on average 60 dB intrinsic noise, with variation between 40 and 89. Conventional CPAP as well as bubble CPAP provide a range of 35–95 dB background noise, with an average of 55 dB [54]. That noise is delivered right to the oropharynx and has the potential to be transmitted directly to the middle ear. High-flow nasal cannula provides an average of 58 dB acoustic stimulation but can deliver up to 100 dB depending on the manufacturer and its flow [48, 54].

Eighteen percent of NICU graduates exposed to respiratory devices fail discharge hearing tests and 5% of those have persistent hearing loss on follow-up. Theories exist explaining why we do not see an even higher percentage of hearing loss despite prolonged exposure to noxious noise. One is that cartilage of the eustachian tune is quite soft in preterm neonates and is mostly found in a collapsed state, thus protecting the inner ear against direct noise transmission from the oropharynx to the middle ear [47, 48, 49, 55].

During in-hospital or inter-hospital transports noise levels can be very high. There are ways to reduce noise: reduce the sound from the source, block the sound, and protect the ear from the sound. Studies of disposable ear shells used in transport report reduction of 7–12 dB [54, 56]. Despite that, there is not enough evidence to recommend the routine use of such protectors during transport or in the NICU [40, 56]. Aminudin et al. [56], reported an increase in noise registered in the incubator during transport in babies who wore earmuffs [56]. Additionally, they demonstrated a 5–7% decrease in sound perception with active sound-canceling headphones, a promising technology that has not been widely developed for neonates [56].

5. NICU design

Environmental design research constitutes a distinct discipline that focuses on understanding the relationship between human interactions and the environment with a primary goal of improving the human condition and the well-being of individuals. In the context of the NICU, numerous studies have investigated the impact of architectural design and noise levels, proposing that the layout of the NICU plays a significant role in determining the amount of noise NICU patients and staffs are exposed to. Open bay rooms are characterized by having many patients sharing a single open area. Various sources contribute to a cacophony of noise in the open bay layout. These include essential life support equipment, heating, ventilation, and air conditioning (HVAC) systems, light buzzing, alarms triggered by vital sign monitoring devices, and the noise generated by staff conversation, occasional crying infants, and visiting family members. It is therefore reasonable to conclude that noise levels would be greater in this open environment. Research supports this observation. Open bay rooms were found to be louder than pods or private rooms and contributed to overall noise levels [2, 4, 5, 9].

The increased number of acoustic noise events in an open bay setup arises from the combined activities of patient care, visiting, conversations, and alarm activations [40, 51, 57]. In response to this issue, many modern NICU redesigns have increasingly adopted single or hybrid patient rooms equipped with sound-dampening technology [45]. In a 2018 study by Smith et al., the occurrence of peak sound levels exceeding 84 dB was found to be six times less frequent in private rooms when compared to the open room design [40]. Single-family rooms in the NICU have also demonstrated the potential to offer a more controlled and private environment, which may encourage parental presence and involvement in their infant’s care and may even lead to a reduction in the length of stay [43].

While these design changes contributed to lower noise levels, some concerns have arisen. For instance, Pineda [43] highlighted that infants in quieter environments were exposed to seemingly less meaningful language, especially if they had fewer visitors and less parental engagement [43]. Meaningful language exposure was more evident when parents were present and engaged in their infant’s care, more interactive, and held their infants more frequently [43].

Alternatively, a pod design, which consists of clustering four to six infants in adjoining rooms, may optimize infants’ development and interaction with caregivers while potentially avoiding the isolation and reduction in meaningful language that can occur in private rooms lacking sufficient family engagement [58].

5.1 The effects of unwanted noise on staff

Studies have also evaluated how noisy NICUs and noise reduction strategies impact healthcare professionals. The findings indicate that staff experience significant stress as reported on the validated State-Trait Anxiety Inventory. They also report feelings of fatigue, difficulty concentrating, and tension headaches [17, 45]. Some staff shared that attempting to maintain a quiet environment and speak in low tones was a source of stress and seemed unrealistic especially when the NICU environment can become highly charged during crisis and acute situations [16].

6. NICU noise reduction interventions

Previous research suggests sound-reducing strategies for promoting a quiet NICU include environmental redesign, staff reminders, scheduled daily quiet time, ongoing education, silencing alarms quickly, and improved staffing ratios. In addition, sound levels are higher in Level III NICUs when compared to Level II NICUs, most likely related to the increased medical technologies utilized for the complex care required by Level III NICU patients. Due to the complex nature of a Level III NICU, more healthcare personnel are required giving rise to more HCP conversations, lifesaving interventions, alarms from cardiopulmonary instability, IV pumps, parent visitors, and general activity including environmental factors such as hospital-wide loudspeaker announcements, portable x-ray machines being wheeled into rooms, and recurrent, continuous, and sudden unexpected sounds, such as dropped objects or chairs being pulled across the floor [2, 3, 4, 5].

Several intervention strategies have been evaluated, such as quiet time protocols, the use of visual noise feedback monitors, and staff “sound compliance supervisors” or a “peer-assisted” expert resource. These innovations were found to be effective in decreasing the level of noise during the study periods [5, 18, 19, 20, 21]. In addition, Liszka et al. [24] and Zauche et al. [5] report that quiet time significantly decreased exposure to electronic sounds and voices concluding that a “quiet time” protocol could increase restful sleep and growth as well as foster a neuroprotective environment for at-risk neonates and may help improve cognition and language development in high-risk neonates [5, 24]. However, one study mentioned previously highlighted that infants in quieter environments were exposed to seemingly less meaningful language, especially if they had fewer visitors and less parental engagement [43].

Other strategies implemented included staff education programs, measuring sound levels, and infant position, or the application of earmuffs and eye shields in conjunction with measuring heart rate variability (HRV) or change in cerebral oxygenation during periods of elevated noise [1, 9, 18, 20, 21, 25, 26, 27, 59]. Elser et al. [25] and Gomes et al. [27] had conflicting results regarding the positive effect of positioning on the high-risk neonate’s ability to reach physiologic stability in the presence of elevated noise [25, 27]. Aita et al. [26] looked at HRV and the use of earmuffs and eye shields and found no positive effect from this intervention. Although mixed results were discussed in these studies, it was again concluded that continued staff education and commitment are paramount to a sustained noise reduction program in the NICU [26].

On the horizon are technologies that include noise-canceling equipment. As mentioned earlier, one study examined the use of Bose Corporation QuietComfort 35 noise-canceling headphones on a neonatal mannequin housed within an isolette in an active NICU. Decibel levels were recorded at the mannequin ear level within the isolette and the noise level outside the isolette. It was found that 80% of the external SPL was detected at the mannequin ear with no protection. This was reduced by 5% with active noise-canceling, equivalent to approximately an 18 dB decrease (71 ± 4 dB decrease to 56 ± 1 dB) [56]. Another new technology is the prototype Active Noise Canceling Incubator which proposes to use Artificial Intelligence (AI) technology, and machine learning algorithms with feedback and feedforward to predict, analyze, and recreate an environment within the isolette to be as natural as possible for the NICU [60].

Batoca Silva et al. [52] surveyed health care professionals (HCP), including nurses, physicians, physiotherapists, and technical assistants, and reported that 77% of HCPs considered the NICU too noisy. Despite this perception, the results in our study show behaviors that seemed to demonstrate a lack of awareness of what they might be doing to decrease noise; for example, behaviors such as using a loud conventional voice at the bedside, failing to promptly silence alarms, and loudly opening and closing doors. Some HCPs may view their work environment as part of their personal space and not that of the sensitive environment of the developing preterm neonate [52].

Although the literature differs greatly in the forms of interventions and type of study design, the common themes in these studies support the evidence that noise in the NICU needs to be reduced. Future sound-reduction strategies should include adapting evidence to the local context, assessing barriers and facilitators to practice change, and including all HCPs and families in the planned design and implementation of interventions [51]. In addition, it is important to have a unit commitment to promote the growth and development of the neonate.

7. Authors’ experience with a noise-reducing campaign

A pre- and post-observational study was conducted in a Level IV NICU in New York City. Interventions to reduce noise included: (1) novel approaches to multidisciplinary staff education program that included 22 disciplines involved in NICU care, including visual cues for when noise targets are exceeded, (2) parent education, including access to personal decibel meters, and (3) technical improvements to monitor alarm volume and electronic doors. Defined quiet (“HUSH”) times were also instituted for 2 hours/shift. Educational and technical improvements were found to decrease median noise levels in the stepdown unit, but not in the acute care NICU. It was evident that the visual display failed to promote behaviors for noise reduction as noted in a study by Mayhew et al. [51]. In contrast, the HUSH program effectively reduced both noise and severe noise in both locations. Enforced focus on noise during the quiet times resulted in decreased noise levels throughout the day and night. Although there were limitations identified throughout this initiative, the HUSH strategy may be a sustainable way to decrease noise toxicity in the NICU to align with the American Academy of Pediatrics recommendations which remains a consistent observation as the literature available in addition to emphasizing staff education and a commitment to a “culture of silence.”

8. Conclusion

Ample data supports the importance of developmentally appropriate noise exposure in utero and the NICU. Understanding the short-term pathologic sequelae as well as long-term growth and neurodevelopmental morbidities should encourage neonatal practitioners to monitor sound in the NICU. Ideally, as proposed by the US Environmental Protection Agency, a noise exceeding 45 dB will be avoided. Realistically, it is a very challenging task to implement consistently. Despite the challenge, units should implement quality improvement and education programs aiming to minimize exposure to high-frequency noise. Parental education on the importance of natural sounds must be provided and parent’s presence, speech, and touch must be encouraged.

Medical practitioners should partner with industry to develop devices conducive to hearing protection, in addition to minimizing device-inherent noise generation. Modern NICU design should consider noise exposure as an important priority, influencing materials and construction surrounding our infants.

Based on our own experience, we believe that changing “the culture” of the unit is at the heart of sustainable change. Increasing staff awareness, providing education, instituting continuous audits, and “in real time” reminders can achieve consistently lower noise levels.