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A Descriptive Study of Noise in the Neonatal Intensive Care Unit: Ambient Levels and Perceptions of Contributing Factors

Darcy, Ashley E. BSN, RN1; Hancock, Lauren E. BSN, RN1; Ware, Emily J. BSN, RN2

Section Editor(s): Mainous, Rosalie O. PHD, RNC, NNP

doi: 10.1097/01.ANC.0000337268.85717.7c
Original Research

PURPOSE: To examine the baseline acoustic environment in several mid-Atlantic region neonatal intensive care units (NICUs) and investigate the perceived factors contributing to noise levels in these NICUs.

SUBJECTS: Quantitative data were collected from 3 urban, mid-Atlantic level IIIB and level IIIC NICUs. Qualitative data were collected via interview from 2 RNs employed in each of the study NICUs.

DESIGN: This was an exploratory descriptive study utilizing a mixed-methods approach. A quantitative method was used for sound-level data collection, and a qualitative method was utilized during interviews with nurses to examine perceptions of factors contributing to noise.

METHODS: Ambient sound levels, measured in decibels, were taken at 5-minute intervals over a 2-hour period during both day and night shifts in a central location at each NICU. In addition, nurses were interviewed using a standardized interview questionnaire, and these interviews were then reviewed to determine themes regarding perceived factors contributing to sound levels.

MAIN OUTCOME MEASURES: Hourly mean sound levels in each NICU ranged from 53.9 dB to 60.6 dB, with no statistically significant difference between noise levels recorded on day shift versus night shift, and no statistically significant difference among sites. Qualitative data showed that nurses' believed day shift to be louder than night shift and many perceived their own NICU as “pretty quiet.” Key contributing factors to increased sound levels were stated as monitors or alarms, performing invasive procedures, presence of family, nurses or doctors giving report or rounds, and ringing phones.

PRINCIPAL RESULTS: Noise levels were found to be above the American Academy of Pediatrics–recommended 45-dB level and often louder than the 50-dB level, which should not be exceeded more than 10% of the time. The recommended impulse maximum of 65 dB was also exceeded. Environmental Protection Agency recommendations for hospitals include sound levels no louder than 35 dB on night shift; this standard was also violated.

CONCLUSIONS: Elevated sound levels need to be addressed in individual NICUs around the country. Further exploratory studies, as well as research regarding effective methods of decreasing sound levels in the NICU environment, are necessary. NICUs can implement behavioral and structural changes that can decrease the sound levels in the NICU environment and decrease the potential for exposure of patients to the harmful physiological effects of increased sound levels.

1NICU, Hospital of the University of Pennsylvania, Philadelphia, 2ED Children's National Medical Center, Washington, DC.

Address correspondence to Ashley E. Darcy, BSN, RN, University of Pennsylvania, School of Nursing, Center for Behavioral Health, 420 Guardian Drive, Philadelphia, PA 19104;

Original Research conducted at Georgetown University School of Nursing & Health Studies. In kind contribution from Georgetown University School of Nursing & Health Studies.

Originally published in the June 2008 issue of Advances in Neonatal Care

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Even before birth, humans are interacting with their environment. Sensory perceptions are constantly present and play a crucial role in the normal development of the fetus and infant.1 While in utero, the fetus experiences many loud, low frequency background noises and identifies the maternal voice as a distinct entity against these background inputs.2 This is in contrast to the auditory environment outside the womb, which can be much more harsh to the developing sensory systems. Full term infants have achieved proper neurosensory development within a confined and nurturing environment, but those infants born prior to the optimal 37-week experience an interruption in this important developmental process. Premature infants typically spend most of their first months after birth in the Neonatal Intensive Care Unit (NICU), where they are exposed to continuous and unpredictable noise.2

“Noise is undesirable sound. Sound is vibration in a medium, usually air.”3(p724) Sound exists as a constant component of our environment, and these vibrations, in high levels, can become dangerous. Levels of sound are characterized by intensity, loudness, frequency (pitch), periodicity, and duration; the loudness of sound can be measured in units called decibels (dB).3 Individuals respond differently to levels of noise, but sounds with higher intensities and loudness levels may be associated with numerous health problems including hearing loss and elevated blood pressure.3

To protect the health and well-being of all people, the US Environmental Protection Agency (EPA) has mandated neighborhood sound levels to be no higher than 55 dB during waking hours and 45 dB during sleeping hours. It is further recommended that hospitals adhere to even stricter standards of 45 dB during daytime hours and 35 dB during night time hours.4 The reduced levels seen in reference to hospitals are echoed in the American Academy of Pediatrics (AAP) directive to reduce sound levels in these institutions, particularly within the NICU.3 In response to this directive, a Sound Study Group–established criteria for noise in the NICU; overall continuous sound in any occupied bed space or patient care area should not exceed an hourly loudness equivalent (Leq) of 45 dB; hourly sound levels should not exceed 50 dB 10% of the time, nor should sound exceed a 1-second maximum level (Lmax) of 65 dB.5,6 These recommendations have been reviewed and endorsed by the Council of International Neonatal Nurses as well as the Institute for Family-Centered Care.6 Despite these recommendations, evidence has shown that the acoustic environment in the average NICU can often fluctuate between 40 and 90 dB with impulses as high as 140 dB.7,8

Given the data previously reported, it is probable that many NICUs are operating with a level of sound that is above the acceptable ranges set by the AAP and EPA. Research has shown that not only NICUs but all Intensive Care Units are thought to be operating at levels above EPA recommendations.9 Previous data suggest that elevated noise levels in the NICU continue to be a problem, and that research regarding this problem as well as increased awareness among NICU staff are needed.

It is known that many stressors and other challenges exist for preterm babies in the NICU. Although full-term newborns are born with the physiological capability to adapt to the extrauterine environment, premature infants “may lack the autonomic and functional maturity to do so.”10(p180) Premature infants are especially vulnerable to environmental harm. Compared with term infants, premature infants have many physiological limitations, often experience central nervous system immaturity, and have an increased need for intensive care.11 These factors make preterm infants much more susceptible to the possible negative effects of the NICU environment, including the harmful effects of increased sound levels.

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The purpose of this descriptive, exploratory pilot study was to measure noise levels in 3 different level IIIB and level IIIC NICUs in the mid-Atlantic region of the United States. The mixed-method design employed quantitative and qualitative perspectives. The quantitative data were obtained to determine how average noise levels in these NICUs compared with the established national guidelines, and therefore, obtain a current perspective on the compliance with national guidelines among the 3 sample NICUs. The qualitative perspective was used for the purpose of identifying professional nurses' perceptions of the factors contributing to noise levels in the units studied.

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Review of Literature

It has been well established in the literature that the level of noise in a modern-day NICU is above recommended guidelines.8–10,21 Although AAP and EPA guidelines are already in place, many units are not in compliance with the recommendations. Gray and Philbin's17 research regarding sound levels concluded that although staff education and unit renovation can have a significant impact on sound levels, some sound level recommendations were still exceeded in the unit studied.17 Similarly, Byers and his colleagues16 found that even after a redesign of the unit and additional staff training, sound levels were above the recommended guidelines.16 As recently as 2007, a study of 2 “large, busy state-of-the-art units” found most sound levels exceeding recommendations, even in a NICU that had been recently constructed with a focus on noise abatement.18 In addition, sound levels have been found to be higher in level III NICUs than in level II NICUs, implying that increased noise is associated with increased acuity and level of care, and the associated technologies that are utilized within this complex care environment.22

In addition to data indicating that NICUs operate with sound levels above established standards, there are many studies demonstrating the adverse physical and physiologic effects these increased sound levels can have on a neonate, for example, increased blood pressure, increased heart rate, and hearing loss. Cardiac monitors, oxygen supply, ventilators, infusion pumps, isolettes, and suction equipment are only a few of the many devices seen in a typical, upper-level NICU. Studies have demonstrated that a variety of factors contribute to increased noise in the NICU, including respiratory equipment, alarms, staff talking, and infant fussiness.16

Parents, visitors, nursing staff, medical staff, and other members of the healthcare team have also been considered aggravating factors related to increased noise. Studies have documented a direct cause and effect relationship between personnel conversation and increased noise levels in the NICU.2,9,10 According to a recent study, the problem extends beyond the bedside to other areas, such as the entrance to the unit, sinks, and staff computer areas.8 These areas are especially prone to staff congregation and are associated with higher sound levels.8 Time periods involving physician rounds and RN report can also result in increased sound levels. Visitors and family members, particularly those with young children, often engage in conversation or behavior that contributes to the overall noise level.

Although it has been shown that ambient sound levels within an incubator can be lower than those in a warmer bed, the incubator itself can contribute to increased sound exposure for the infant.16 While incubators provide a variety of positive attributes for a neonate's extrauterine experience, the auditory environment is far from benign. Objects striking the plastic walls, doors snapping shut, and professionals using the incubator as a writing surface can contribute to additional noise.7 Simply closing an incubator porthole can create sound levels in excess of 100 dB,15 which is far above the previously mentioned 1-second impulse recommendation of 65 dB.4

Ambient sound within the NICU includes the heating, ventilation, and air-conditioning systems, as well as plumbing, and the physical layout of the environment.17 Space restrictions can lead to crowding of the unit, which can further increase sound levels. At this time, many nurseries have not been explicitly designed for a quiet environment, especially those constructed in the 1970s or earlier, prior to concern regarding the impact of noise on the neonate. This is in contrast with many other healthcare, business, and residential environments in which noise levels are often a factor in the architecture and design.23 Several studies have examined modern-day NICUs that have been completely renovated or newly constructed that include a plan for decreasing noise, thus creating a more developmentally appropriate environment for the neonate. These renovated NICUs have been shown to have significantly decreased ambient sound levels than their older, louder counterparts.16–21 Suggestions for environmental alterations that can decrease the NICU noise level include increased space at the bedside, weather stripping on cabinets and doors, surfaces constructed of sound absorbent materials, replacing metal trash cans with those made of rubber, carpet installation, use of incubator covers, and installing individually controlled lighting and engineered acoustical control.12,23 A single patient room design of a NICU has been shown to decrease average sound levels.21 One study found that the use of acoustical foam within an incubator can result in a decrease in sound levels within the incubator.13 Environmental changes, such as those discussed above and the installation of bacteriostatic carpet and acoustic ceiling materials, changes in air duct systems, and replacement of large steel scrub sinks with smaller ones, have been shown to decrease noise more than staff education alone.16–21 Architectural changes, and changes to structural layout greatly decrease the amount of noise present in a NICU.24

The effects of increased noise may have long-lasting implications for the health of the hospitalized infant after discharge and even throughout his or her lifespan. As far back as 1980, a possible impact of sound on the brain was documented in a study, which noticed changes in measurements of cerebral blood flow accompanying noise bursts.14 Studies have also found that excessive sound levels contribute to negative health outcomes, including cochlear damage and speech and hearing delays.5 The hearing loss experienced by post-NICU patients is in part because of irreversible cochlear damage, which is the result of exposure to noise and other environmental factors in the NICU.3 The AAP also suggests that a hearing loss may disrupt the normal growth and development in a child, presenting a particular concern in a patient population already experiencing problems as a result of prematurity.3

To combat noise exposure, the idea of small ear coverings for neonates was examined in research by Zahr,10 but the concept proved to have little measurable success in comparison to the risk, annoyance, and potential complications created by these devices for the premature infants on whom they were tested.25 Although ear coverings may be beneficial in reducing noise for short-term events, they require a tight seal around the ear and long-term use introduces the potential for breakdown of the fragile skin of the neonate.25 They also have the potential long-term detrimental effect of blocking all sound inputs and, therefore, negatively influencing the development of speech recognition for the infant.24

Hearing loss is not the only adverse effect that seems to correlate with increased sound in the NICU. The immediate effects of elevated levels of sound show that environmental noise can be a major source of stressful stimulation, can cause agitation and bring about complications in the medical management of the neonate.5 Agitation can be measured by the behavioral and physiological responses of infants to the stress of loud noises in the NICU. One research study revealed that “seventy-eight percent of infants changed their behavioral state in response to noise or nursing interventions, indicating that premature infants are not as capable as full-term infants in shutting off environmental stimuli.”10(p181) For instance, term infants are able to habituate to noise and sleep through noise. The preterm infant is more likely to change behavior states, going from sleep to wake, for instance, in response to noise. The stress of loud environments affects all humans by stimulating the autonomic nervous system and elevating the level of cortisol within the body.26 These effects are even more pronounced and dangerous in a neonate and research suggests that increased light and sound levels may be more detrimental for developing infants than for adults.12 Alterations in health status can be directly monitored on patients in the NICU and these alterations may correlate with an increased level of noise. Possible effects include abrupt fluctuations of blood pressure, heart rate, respirations, and oxygen saturation.2,10 Life-threatening situations can result from episodes of acute distress caused by sudden noises; these episodes include decreases in oxygen saturation and periods of apnea, and it is recommended that special nursing considerations be taken for oxygen-supported and ventilator-dependent infants.2,13

The potential for harmful health effects related to increased sound levels is widely recognized, and creating a quieter NICU environment conducive to the proper neurosensory development of the premature infant should be a priority.15 Experts in the field of perinatology agree that the adverse effects are severe enough to warrant detailed investigation, arguing that hospitals hold an obligation to measure sound levels in infant nurseries and within incubators, and that “clinicians need to know the parameters of their own nurseries' acoustic environments and improve conditions in both incubators and rooms accordingly.”23(p578) The issue of undesirable sound in general is one that deserves attention because of the potential health effects of noise on the hospitalized newborn. It is the responsibility of the entire healthcare workforce to become aware of the implications of these noise levels and bring attention to this important issue.

National data have effectively established general sound level guidelines for NICUs as well as other areas, but is difficult to apply these guidelines to the specific needs of local hospitals. Considering the information that is available regarding sound levels in the hospital, the AAP recommends supplementary investigation, stating, “noise-induced health effects on fetuses and newborns merit further study as clinical and public health concerns.”3(p726) A closer look at regional and local NICU sound levels is needed.3

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Research Questions

1. What are the average sound levels in 3 sample level IIIB and level IIIC mid-Atlantic NICUs and how do these levels compare to the guidelines set forth by the EPA and AAP?

2. Are there differences between the average sound levels during day shift and night shift?

3. What are the perceptions of a sample of registered nurses from the selected units regarding factors contributing to the level of noise in that particular NICU?

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Quantitative Component

The quantitative portion of the study employed descriptive methods that involved sound meter data collection during both day and night nursing shifts at each of the 3 participating hospital NICUs.

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Sample Population

After receiving approval from the university human protections committee, 3 NICUs were contacted to participate in the study. The study itself did not directly affect NICU patients or their medical records and was granted expedited review by the institutional review board. The study commenced at the sample institutions after approval was obtained. The NICUs, located in large urban hospitals in the mid-Atlantic region of the United States, were either level IIIB (n = 1) units or level IIIC (n = 2) units.

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Sound was measured using the Sper Scientific Mini Sound Meter (Model No. 840014C). (Sper Scientific, Scottsdale, AZ) The instrument was certified to meet the specifications of the manufacturer and was calibrated in a controlled environment at 94.0-dB sound pressure level, single point with a 1 kHz frequency. The device was calibrated using standards with values traceable to the National Institute of Standards and Technology. The sound meter's range was 32 to 130 dB, A-weighted, with 0.1-dB resolution and an accuracy of ±1.5 dB.

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The study protocol required that sound levels be measured for at least 2 different hours during the day shift (7:00 AM to 7:00 PM) and the night shift (7:00 PM to 7:00 AM) in each of the participating NICUs. Twelve data readings were collected each hour (1 measurement every 5 minutes) for each institution, creating a total of 72 noise-level readings. Readings were taken using A-weighted levels and slow meter responses, settings that have been recommended in the literature as best suited for measuring sound in hospital nurseries.27 A sound meter was used: a dosimeter was unavailable because of financial restrictions. Each sound-level reading was a result of the average sound level over the majority of the 5-minute observation period, according to the researcher. For example, a high-sound reading for one 5-minute period does not indicate an impulse sound peak (such as a phone ringing) but instead indicates that the sound level was high for the majority of that 5-minute period. This method of data collection created an imperfect approximation of the Leq (average sound level)27; however, a true Leq was not recorded because of the lack of a dosimeter. Lmax (maximum level recorded for a short, predetermined period of time)28 and Ln (sound level exceeded n% of the time)27 were unable to be recorded because of the lack of a dosimeter for use in recording of sound levels.

The time of the first sound-level meter reading was documented, and subsequent readings were taken every 5 minutes for a total time of one hour. The procedure was then repeated for 1 more hour on the opposite shift. Data were recorded on a standardized Data Collection Form developed by the research team. The back of the form was used for the researcher to draw a map of the unit to note the location of the sound-level meter and the location of activity areas most likely to be noise-producing.

The units varied in architecture. Two units were open units with no architectural structures (walls, rooms, etc) separating the space. The third unit was set up as pods with 4 to 6 babies per pod and 4 pods total throughout the unit. The pods did not vary in acuity or staffing, so the decision on where to place the dosimeter in this unit was randomly assigned to pod B. Every effort was made to place the sound meter in an area of each unit that would be representative of ambient sound levels in a central unit location, without being intrusive to patient care and not too close to anything that would artificially increase sound levels but still near patient care areas where ambient sound levels would affect infants. No attempt was made to conceal data acquisition. The researchers' presence on the unit could have had an unintentional effect on nursing actions and the level of sound they created and/or perceived themselves as creating (eg, the Hawthorne Effect).

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Analysis of Data

The quantitative data collection resulted in 12 noise-level readings per hour from each collection site on each shift. Therefore, 36-day shift data points and 36 night shift data points (a total of 72 sound-level readings) were collected. Data were examined with descriptive analyses (frequencies, range, measures of central tendencies) using the SPSS data analysis program (SPSS Inc., Chicago, Illinois), and simple descriptive statistics were obtained. Subsequently, means and patterns were compared across sites (A, B, or C) and shifts (day shift or night shift).

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Mean day shift and night shift noise levels across all 3 research sites were above the national guidelines, which recommend an hourly mean level below 45 dB and impulses below 65 dB.6 As compiled in Table 1, the hourly mean sound levels across all sites and shifts ranged from 53.9 dB to 60.6 dB, with negligible variation between the mean sound levels of each of the sites.

Overall, the mean night shift noise levels were higher than day shift levels at 2 of the sites (sites A and C). However, there was minimal difference between day shift measurements and night shift measurements overall across the 3 sites. The mean noise level for the 3 sites on the day shift was 57.183 dB, and the mean noise level for the night shift across all 3 sites was 57.063 dB. Figure 1 illustrates that all of the day shift noise levels were higher than the recommended limit of 45 dB. The trends in noise levels over each hour measured provided further information.

Figure 1 shows that when comparing across sites on day shift, the NICUs differed in the consistency of noise levels. For example, site A had fairly consistent, albeit high, noise levels over time, whereas sites B and C demonstrated more variability in noise levels. That site B had a lower mean noise level than site A or C, may be due to one noise level reading, which was much lower than the others, indicating a 5-minute period of relative quiet during sound level recording at that site.

The same trends in consistency of noise levels were also noted during the night shift. In Figure 2, the recommended 45-dB noise level (marked on the graph) was exceeded for all data points. The majority of the data points illustrate that, even on the night shift, the noise levels in the NICUs studied exceed the recommended limit of 50 dB more than 10% of the time.

Figures 3 and 4 illustrate that noise levels far exceed the recommended standard of 45 dB for all day shift data points. In fact, far more than the recommended 10% are above the 50-dB maximum and the recommended impulse maximum of 65 dB was exceeded several times during the daytime shift with 1 reading exceeding 75 dB (this particular point was a period of several minutes with multiple noise-producing events, such as overhead pages, alarms and ringing phones, at a particular site). The 65-dB impulse maximum was exceeded during the night shift as well. Furthermore, none of the readings from either shift fall below the EPA recommendation for hospitals that noise levels be 35 dB at night.4

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Qualitative Component

In this exploratory study, a qualitative descriptive approach was used to discover NICU nurses' perceptions of ambient noise levels in their respective units. “The purpose of qualitative descriptive research is not to interpret participants' experience in depth, but to provide a broad overview of a phenomenon or an experience.… The method is extremely valuable when description is the goal particularly when little is known about a phenomenon.”29(p334) Qualitative descriptive studies offer a comprehensive summary of an event in the everyday terms of those events.30 The sample size in this case refers to the number of persons being sampled. As with most qualitative research, the events and experiences, not people per se, are the objects of purposeful sampling.31

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Sample Population

A nonprobability sampling method was chosen for the qualitative portion of this study. Convenience sampling was implemented in this study because it uses the most readily accessible persons as subjects in a study. The subjects were convenient and accessible to the research team.32 Nurses ranged in experience to capture their perceptions across a wide range of nursing practice. Two nurses in each of the participating NICUs (n = 6) were interviewed using a qualitative interview guide developed for this study. A total of 6 nurses were asked about their perceptions of noise and the acoustic environment in their unit. The criteria for subject participation included a minimum of 18 years of age, current licensure as a registered nurse, ability to communicate fluently in spoken English, and employment in the NICU at the participating institution. Subjects ranged in their experience on the unit (2 1/2 months to 9 years) and their employment status: full time (n = 5) or part time (n = 1). Half of the nurses were working on day shift and half were working on night shift at the time of the interview.

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The research team developed an open-ended, qualitative survey guide, to pose broad questions regarding nurses' clinical experiences with noise levels in the NICU. This format was consistent with the descriptive study design; it was used to discover the “who, what, and where” of events. General themes were presented in the form of questions to focus participants' attention while encouraging open expression of thoughts and feelings.30 The interview format was designed to address nurses' perceptions of noise on the unit, the effects of noise on the health and well-being of the infants on the units, and policies or practices the unit or institution has made to address the noise levels in the unit.

Initially, background information was collected from the RN being interviewed, including the nurse's role on the unit, her length of employment on the unit, and employment status (full time vs part time). The bulk of the interview consisted of questions regarding whether the RN thought time of day influenced noise level, which areas of the unit generated more noise than others, and what the RN believed were the major factors contributing to noise on the unit. Questions were then posed as to the RN's knowledge regarding the effect of increased noise levels on the health of infants, and her opinion about what the unit has done to address noise levels. Finally, a question was posed about the RN's thoughts regarding policies that would help decrease noise levels. See the Appendix for a copy of the questions posed.

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The researcher provided an informational flyer to eligible nurses on the unit to explain the nature of the qualitative interview data collection. The flyer did not describe the nature of the study, only represented a “Student Research Study,” and asked for 10 to 15 minutes for an interview. Registered nurses from various experience levels and shifts were interviewed using the guide developed for the study. Field notes from the interviews were documented on the guide, and no individual identifiers (eg, nurse's name) were documented to protect the participant's confidentiality.

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Analysis of Data

The qualitative data collection resulted in the compilation of interview notes recorded by the researchers from interviews with 6 NICU nurses. These data sheets were analyzed to identify factors that the nurses perceived as contributing to noise. The interviews were not transcribed, coded, and analyzed because of the small sample size. Therefore, trends were readily extracted from the researcher's interview notes. Qualitative responses were examined for patterns.

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The responses of nurse participants indicated that the factors they perceived as most contributing to noise in the NICU included monitors/alarms, invasive procedures, presence of family, physicians performing rounds, nurses giving report, babies crying, ventilator alarms sounding, and phones ringing. Qualitative interview data showed that all of the nurses believed that the night shift was quieter than the day shift. Half of the nurses interviewed perceived their units to have low noise levels, or even “pretty quiet,” relative to their own perception of loudness in a nursery.

Registered nurses' responses showed that they were aware of interventions that could possibly decrease the noise levels in the NICU. They noted that quieter alarms, prompt silencing of alarms, and presilencing alarms before procedures (eg, endotracheal tube suctioning) could lower noise levels. Additional interventions such as reminding people on the unit (eg, visitors, staff, and physicians) to keep the noise level down, and moving conversations to the lounge area, would also lower noise in care areas. Finally, the use of curtains, screens, and other barriers could be used to decrease noise levels around the infants. Although RNs reported their knowledge of useful interventions, not all reported that they consistently advocated for decreased noise in every situation. The qualitative data show that nurses are aware that increased noise levels in a NICU have detrimental physiological effects for the newborn, including alterations in sleep/wake cycles, immediate changes in vital signs, and problems with appropriate growth and development.

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One limitation of this study was having a convenience sample, which consisted of a limited number of NICUs in urban hospitals. The major disadvantage of a convenience sample is that the risk of bias is high because it depends on voluntary participation.32 Moreover, time and finances limited the period of data collection. Additional data collection would have resulted in a more accurate representation of the sound levels on the units studied. The use of a dosimeter, instead of a simple sound meter, would have provided more accurate data and a better representation of Leq, Lmax, and Ln.

There were no level I or level II units involved in this study; therefore, NICUs that have patients with lower acuity levels were not assessed. This study was unable to control for variability among the participating NICUs with regards to layout, number of patients, hospital personnel, or other factors unique to each unit.

The qualitative portion of the study consisted of a brief interview and did not involve a recorded, transcribed, coded, and analyzed interview process, but rather was based solely on the notes of the researcher. Moreover, a larger sampling of interviewees would have created a better representation of nurses' perceptions. Although qualitative description is less interpretive than other qualitative measures in the sense that the researcher chooses this method to stay close to his data and to the surface of the words, it certainly is not devoid of being “filtered through (human) perceptions.”33(p13) The interpretation the author gives to the data, however minimal, still produces some bias.

Finally, our presence on the unit studying sound levels could have potentially caused the nurses to go about their actions in a quieter manner. This can be explained as the Hawthorne effect, which refers to an unintentional but usually beneficial effect on the system being studied.28 Knowledge of the nature of the study could also have influenced the answers of nurses to the questions posed in the qualitative portion of the study.

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Discussion and Clinical Implications

Noise levels in the 3 NICUs studied are above recommended national guidelines. The data indicate that while these NICU environments maintain higher than recommended sound levels, care providers do not perceive the sound levels to be elevated. The nurses surveyed reported a commitment to keeping a quieter NICU environment for the well-being of the infants, and an awareness of the many contributing factors that can lead to increased NICU noise levels, but they reported that they did not consistently advocate to decrease NICU noise.

The interventions reported by RNs to decrease sound levels are based mainly on behavioral modifications of those present in the NICU. Attempts to institute behavioral changes have been met with resistance; nurseries often tend to be loud and attempts at making them quieter by changing staff behavior appear to be only marginally successful.23 In addition, research has shown that these modifications are not as effective in the long term as interventions that focus on the physical environment of the NICU.23 Registered nurses were not as aware of physical environmental changes as they were of behavioral changes, although it has been shown that changes to the physical environment of the unit are more effective than behavioral modification and staff/visitor education.

Unfortunately, not every NICU has the ability or funds to completely remodel the care environment to decrease sound levels. In this situation, behavioral modifications may be the only intervention that is practical. In that case, constant reminders are key. Sound levels and sound awareness must be kept in the minds of staff and families on the unit. Intermittent sound-level monitoring of the caregiving environment can also be beneficial in evaluating the NICU sound levels and increasing staff awareness of NICU decibel readings.13 It has been shown that the installation of a noise sensor light alarm can increase staff awareness and decrease noise on the unit.34 Staff awareness of noise and continuous dedication to decreasing noise levels by all care providers, including families, are essential to effectively decreasing noise levels within a NICU.13

Staff education regarding noise levels, its effect on infants, and the approximate levels that are recommended for the care environment are crucial to increasing awareness and decreasing overall noise levels. Although staff may believe they are doing everything they can to decrease NICU sound levels, noise may still be above the recommended levels. This provides an opportunity for nurses and other care providers to develop innovative unit-specific policies and procedures to decrease sound levels. Potential solutions such as encouraging nurses to silence alarms promptly, using quieter alarms or lights, and encouraging conversation away from the bedside can all help decrease the noise level in a NICU that has not been designed for decreased sound, and further decrease noise in a remodeled or newly constructed NICU.

There are many ideas presented in the literature about ways to decrease sound in the NICU. Some studies suggest that staff and parent educational programs should be the first step toward promoting awareness and decreasing sound levels,8 whereas others argue that noise control protocols should focus on environmental interventions.13 Ultimately, modifications to the physical environment of the NICU will provide the most long-term effectiveness, but educational programs and staff awareness are also important steps in modifying the sound environment of a NICU.

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Recommendations for Future Research

It has been reported that increased noise levels in a NICU have negative effects on the physiological development of infants. Future research is needed to evaluate sound levels in NICUs to establish base levels within individual care environments and across various levels of care.

It is important to compile information regarding sound levels for NICUs in individual hospitals to directly assess local practices, making unit-based evaluations essential. Future research should use the information gathered regarding local sound levels to establish policies and protocols for individual units regarding sound levels in an attempt to minimize noise. Moreover, it is important to assess what the factors are that contribute to high levels of noise in each particular hospital setting. Evaluating the effectiveness of various interventions in the reduction of sound levels is important so that effective yet practical solutions can be developed.

Caring for neonates means that nurses should provide an environment in which neonates can grow and flourish. Advocating for decreased noise levels and decreasing environmental stimuli are imperative parts of clinical nursing practice in this setting.

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We thank the Georgetown University School of Nursing and Health studies for their kind contributions and those who have assisted us for their constant support and guidance. Special thanks to Dr R. Kevin Mallinson, Ms Jean Farley, and Dr Catherine Cox.

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Appendix. Interview Guide


1. What is your position on this unit?

2. How long have you been working on this unit?

3. How often do you work? (full time, part time, PRN, # of shifts per week)

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4. What do you think about the level of noise on this unit?

a. How do you think time of day or shift might affect noise levels?

b. Tell me what areas of the unit are noisier than others.

c. What do you think might be the main contributing factors to increased noise in a NICU?

5. What do you know about the effect of activity or noise on the health of infants?

6. What do you think this unit has done to address noise levels?

7. Tell me about any changes in policy or practice you think may affect noise levels.

Cited Here...


acoustic environment; environmental standards; noise; Neonatal Intensive Care Unit; sound

© 2008 National Association of Neonatal Nurses