Quantitative noise analysis in a modern hospital

Acoustic environments of intensive care units during the COVID-19 pandemic

This study aims to investigate the typical noise levels and noise sources in an intensive care unit (ICU) during the COVID-19 pandemic. Acoustic experiments were conducted over 24 hrs in patient wards and at nurse stations in four Chinese hospitals. From the measurements, noise levels and sources were analysed in terms of the A-weighted equivalent sound pressure levels (L _Aeq) and A-weighted maximum Fast time-weighted sound pressure levels (L _AFmax) over three different time periods during the day (i.e. day, evening and night). Overall, noise levels (L _Aeq) for 24 hrs in all hospitals exceeded the World Health Organisation's (WHO) guide levels, varying from 51.1 to 60.3 dBA. The highest maximum noise level reached 104.2 dBA. The single-bedded wards (side rooms) were quieter than multi-bedded wards, and night time noise levels were quieter than daytime and evening across all hospitals. It was observed that the most dominant noise sources were talking/voices, door-closing, footsteps, and general activities (e.g. noise from cleaning equipment and cutlery sound). Footsteps became an unexpected dominant noise source during the pandemic because of the staff's disposable shoe covers which made footsteps noisier. Patient alarms and coughing varied significantly between patients. Talking/voices produced the highest maximum median values of the sound exposure level (SEL) and the maximum noise level at all sites. Noise levels in all the patient rooms were more than the WHO guidelines. The pandemic control guidelines had little impact on the noise levels in the ICUs.

Clustering acoustical measurement data in pediatric hospital units

The previous hospital acoustic literature has highlighted some important considerations and various complexities regarding objective noise measurements. However, extensive use of conventional acoustical metrics such as logarithmically averaged equivalent sound pressure levels (L_eq) do not sufficiently describe hospital acoustical environments and often lack considerations of the room-based activity status that can significantly influence the soundscape. The goal of this study was to explore utilizing statistical clustering techniques in healthcare settings with a particular aim of identifying room-activity conditions. The acoustic measurements were conducted in the patient rooms of two pediatric hospital units and subsequently classified based on two room-activity conditions-active and non-active conditions-by applying statistical clustering analyses with standard k-means and fuzzy c-means algorithms. The results of this study demonstrate the most probable noise levels and degree of associations of the measured noise levels for the two room-activity conditions. The results were further validated in terms of the clustered levels, the number of conditions, and parameter dependency. The clustering approach allows for a more thorough soundscape characterization than single-number level descriptors alone by providing a method of identifying and describing the noise levels associated with typical, intrinsic activity conditions experienced by occupants.

Voice Relative Fundamental Frequency Via Neck-Skin Acceleration in Individuals With Voice Disorders

PURPOSE

This study investigated the use of neck-skin acceleration for relative fundamental frequency (RFF) analysis.

METHOD

Forty individuals with voice disorders associated with vocal hyperfunction and 20 age- and sex-matched control participants were recorded with a subglottal neck-surface accelerometer and a microphone while producing speech stimuli appropriate for RFF. Rater reliabilities, RFF means, and RFF standard deviations derived from the accelerometer were compared with those derived from the microphone.

RESULTS

RFF estimated from the accelerometer had slightly higher intrarater reliability and identical interrater reliability compared with values estimated with the microphone. Although sensor type and the Vocal Cycle × Sensor and Vocal Cycle × Sensor × Group interactions showed significant effects on RFF means, the typical RFF pattern could be derived from either sensor. For both sensors, the RFF of individuals with vocal hyperfunction was lower than that of the controls. Sensor type and its interactions did not have significant effects on RFF standard deviations.

CONCLUSIONS

RFF can be reliably estimated using an accelerometer, but these values cannot be compared with those collected via microphone. Future studies are needed to determine the physiological basis of RFF and examine the effect of sensors on RFF in practical voice assessment and monitoring settings.

The influence of APACHE II score on the average noise level in an intensive care unit: an observational study

Background

Noise levels in hospitals, especially in intensive care units (ICUs) are known to be high, potentially affecting not only the patients’ well-being but also their clinical outcomes. In an observational study, we made a long-term measurement of noise levels in an ICU, and investigated the influence of various factors on the noise level, including the acute physiology and chronic health evaluation II (APACHE II) score.

Methods

The average noise level was continuously measured for three months in all (eight) patient rooms in an ICU, while the patient data were also registered, including the APACHE II score. The 24-hour trend of the noise level was obtained for the patients of length-of-stay (LOS) ≥1 day, which was compared to the timeline of the ICU routine events. For the patients with LOS ≥4 days, the average noise levels in the first four days were analyzed, and regression models were established using the stepwise search method based on the Akaike information criterion.

Results

Features identified in the 24-hour trends (n = 55) agreed well with the daily routine events in the ICU, where regular check-ups raised the 10-minute average noise level by 2~3 dBA from the surrounding values at night, and the staff shift changes consistently increased the noise level by 3~5 dBA. When analyzed in alignment with the patient’s admission (n=22), the daytime acoustic condition improved from Day 1 to 2, but worsened from Day 2 to 4, most likely in relation to the various phases of patient’s recovery. Regression analysis showed that the APACHE II score, room location, gender, day of week and the ICU admission type could explain more than 50 % of the variance in the daily average noise level, L_Aeq,24h. Where these factors were argued to have causal relations to L_Aeq,24h, the APACHE II score was found to be most strongly correlated: L_Aeq,24h increased by 1.3~1.5 dB when the APACHE II score increased by 10 points.

Conclusions

Patient’s initial health condition is one important factor that influences the acoustic environment in an ICU, which needs to be considered in observational and interventional studies where the noise in healthcare environments is the subject of investigation.

Noise in hospital rooms and sleep disturbance in hospitalized medical patients

OBJECTIVES

Hospitalized patients are vulnerable to sleep disturbances because of environmental stresses including noise. While most previous studies on hospital noise and sleep have been performed for medical machines in intensive care units, there is a limited data for patients hospitalized in medical wardrooms. The purpose of present study was to measure noise level of medical wardrooms, identify patient-perceived sources of noise, and to examine the association between noise levels and sleep disturbances in hospitalized patients.

METHODS

Noise dosimeters were used to measure noise level in 29 inpatient wardrooms at a university hospital. Sleep pattern and disturbance were assessed in 103 hospitalized patients, using the Pittsburgh Sleep Quality Index (PSQI) and Leeds Sleep Evaluation Questionnaire.

RESULTS

The mean equivalent continuous noise level for 24 hours was 63.5 decibel A (dBA), which was far higher than 30 dBA recommended by the World Health Organization for hospital wardrooms. Other patients sharing a room were perceived as the most common source of noise by the patients, which was usually preventable. Of the patients in the study, 86% had bad sleep as assessed by the PSQI. The sleep disturbance was significantly correlated with increasing noise levels in a dose response manner.

CONCLUSIONS

Systemic organizational interventions are needed to keep wardrooms private and quiet to reduce sleep disturbance.

Effects of familiar voices on brain activity

This study aimed to examine the extent to which a familiar voice influences brain activity. Participants were nine healthy female volunteers aged 21-34 years old (with a mean age of 25.78 ± 4.04 years). Brain activity was recorded during periods of silence, familiar and unfamiliar voices. Electroencephalographic data were collected and analyzed using a frequency rate set at 5 min. To account for emotional influences imbedded into the contents of the voice stimuli, both the voice of a familiar family member and the voice of a stranger were used to record a well-known Japanese fairy tale, 'Momotaro'. Results revealed that listening to familiar voices increased the rate of the β band (13-30 Hz) in all four brain areas (F3, F4, C3 and C4). In particular, increased activity was observed at F4 and C4. Findings revealed that in study, participants' familiar voices activated cerebral functioning more than unfamiliar voices.

Noise in an intensive care unit

Patients and staff in hospitals are exposed to a complex sound environment with rather high noise levels. In intensive care units, the main noise sources are hospital staff on duty and medical equipment, which generates both operating noise and acoustic alarms. Although noise in most cases is produced during activities for the purpose of saving life, noise can induce significant changes in the depth and quality of sleep and negatively affect health in general. Results of a survey of hospital staff are presented, as well as measurements in two German hospital wards: a standard two-bed room and a special intermediate care unit (IMC-Unit), each in a different intensive care unit (ICU). Sound pressure data were collected over a 48 hour period and converted into different levels (L(AFeq), L(AFmax) L(AFmin), L(AF 5%)), as well as a rating level L(Ar), which is used to take tonality and impulsiveness into account. An analysis of the survey and the measured data, together with a comparison of thresholds of national and international regulations and standards describe the acoustic situation and its likely noise effects on staff and patients.

Effects of intensive care unit noise on patients: a study on coronary artery bypass graft surgery patients

AIMS AND OBJECTIVES

The aim of this study was to measure the noise levels in specific locations of an intensive care unit and determine the disturbance levels of patients owing to noise.

BACKGROUND

Studies have shown that hospital noise is a potential stressor for patients. Noise levels measured in the intensive care unit are mostly far beyond the recommended standards for hospitals, and generally measured around 60-70 dB (A). Although there are a few studies on noise levels in the intensive care unit, no study could be found that compares 24-hour intensive care unit noise measurement data at several locations of intensive care unit.

METHODS

The study was conducted with 35 coronary artery bypass graft surgery patients. The intensive care unit noise level was measured by using Bruel & Kjaer 2144 Model Frequency Analyzer next to the bed of each patient. A patient's disturbance owing to the intensive care unit noise was questioned.

RESULTS

Noise levels ranged between 49 and 89 dB (A) with a mean of 65 dB (A). Peak noise levels were measured as high as 89 dB (A). The noise levels measured at different locations in the intensive care unit did not differ significantly. Noises created by other patients, those who were admitted from emergency room and operating room into intensive care unit, monitor alarms, conversations among staff were the most disturbing noise sources for patients.

CONCLUSION

The patients who were located in the bed which was closer to the nurses' station were more affected by the intensive care unit noise than other patients. Having a previous intensive care unit experience also affected the patients' disturbance levels owing to noise.

RELEVANCE TO CLINICAL PRACTICE

Nurses are in key positions where they can identify physical, psychological and social stressors that affect patients during their hospital stay. Staff education, planned nursing activities and proper design of intensive care unit may help combat this overlooked problem.

Characterizing noise and perceived work environment in a neurological intensive care unit

The hospital sound environment is complex. Alarms, medical equipment, activities, and ventilation generate noise that may present occupational problems as well as hinder recovery among patients. In this study, sound measurements and occupant evaluations were conducted in a neurological intensive care unit. Staff completed questionnaires regarding psychological and physiological reactions to the sound environment. A-weighted equivalent, minimum, and maximum (L(Aeq),L(AFMin),L(AFMax)) and C-weighted peak (L(CPeak)) sound pressure levels were measured over five days at patient and staff locations. Acoustical descriptors that may be explored further were investigated, including level distributions, restorative periods, and spectral content. Measurements near the patients showed average L(Aeq) values of 53-58 dB. The mean length of restorative periods (L(Aeq) below 50 dB for more than 5 min) was 9 and 13 min for day and night, respectively. Ninety percent of the time, the L(AFMax) levels exceeded 50 dB and L(CPeak) exceeded 70 dB. Dosimeters worn by the staff revealed higher noise levels. Personnel perceived the noise as contributing to stress symptoms. Compared to the majority of previous studies, this study provides a more thorough description of intensive care noise and aids in understanding how the sound environment may be disruptive to occupants.

Noise levels in a general intensive care unit: a descriptive study

The aim of this small-scale study was to measure, analyse and compare levels of acoustic noise, in a nine-bedded general intensive care unit (ICU). Measurements were undertaken using the Norsonic 116 sound level meter recording noise levels in the internationally agreed 'A' weighted scale. Noise level data were obtained and recorded at 5 min over 3 consecutive days. Results of noise level analysis indicated that mean noise levels within this clinical area was 56.42 dB(A), with acute spikes reaching 80 dB(A). The quietest noise level attained was that of 50 dB(A) during sporadic intervals throughout the 24-h period. Parametric testing using analysis of variance found a positive relationship (p <or= 0.001) between the nursing shifts and the day of the week. However, Scheffe multiple range testing showed significant differences between the morning shift, and the afternoon and night shifts combined (p <or= 0.05). There was no statistical difference between the afternoon and night shifts (p >or= 0.05). While the results of this study may seem self-evident in many respects, what it has highlighted is that the problem of excessive noise exposure within the ICU continues to go unabated. More concerning is that the prolonged effects of excessive noise exposure on patients and staff alike can have deleterious effect on the health and well-being of these individuals.

Noise levels in Johns Hopkins Hospital

This article presents the results of a noise survey at Johns Hopkins Hospital in Baltimore, MD. Results include equivalent sound pressure levels (L(eq)) as a function of location, frequency, and time of day. At all locations and all times of day, the L(eq) indicate that a serious problem exists. No location is in compliance with current World Health Organization Guidelines, and a review of objective data indicates that this is true of hospitals throughout the world. Average equivalent sound levels are in the 50-60 dB(A) range for 1 min, 1/2, and 24 h averaging time periods. The spectra are generally flat over the 63-2000 Hz octave bands, with higher sound levels at lower frequencies, and a gradual roll off above 2000 Hz. Many units exhibit little if any reduction of sound levels in the nighttime. Data gathered at various hospitals over the last 45 years indicate a trend of increasing noise levels during daytime and nighttime hours. The implications of these results are significant for patients, visitors, and hospital staff.

What knowledge do ICU nurses have with regard to the effects of noise exposure in the Intensive Care Unit?

This small-scale study was undertaken to assess what knowledge nursing staff from a General Intensive Care Unit held with regard to noise exposure. To assess knowledge a self-administered multiple-choice questionnaire was used. Rigorous peer-review insured content validity. This study produced poor results in terms of the knowledge nurses held with regard to noise related issues in particular the psychophysiological effects and current legislation concerning its safe exposure. Non-parametric testing, using Kruskal-Wallis found no significant difference between nursing grades, however, descriptive analysis demonstrated that the staff nurse grade (D and E) performed better overall. Whilst the results of this study may seem self-evident in some respects, it is the problems of exposure to excessive noise levels for both patients and hospital personnel, which are clearly not understood. The effects noise exposure has on individuals for example decreased wound healing; sleep deprivation and cardiovascular stimulation must be of concern especially in terms of patient care but more so for nursing staff especially the effects noise levels can have on cognitive task performance.

Noise levels in a general surgical ward: a descriptive study

AIMS AND OBJECTIVES

This study was undertaken to measure and analyse levels of acoustic noise in a General Surgical Ward.

METHOD

Measurements were undertaken using the Norsonic 116 sound level meter (SLM) recording noise levels in the internationally agreed 'A' weighted scale. Noise level data and observational data as to the number of staff present were obtained and recorded at 5-min intervals over three consecutive days.

RESULTS

Results of noise level analysis indicated that mean noise level within this clinical area was 42.28 dB with acute spikes reaching 70 dB(A). The lowest noise level attained was that of 36 dB(A) during the period midnight to 7 a.m. Non-parametric testing, using Spearman's Rho (two-tailed), found a positive relationship between the number of staff present and the level of noise recorded, indicating that the presence of hospital personnel strongly influences the level of noise within this area.

RELEVANCE TO CLINICAL PRACTICE

Whilst the results of this may seem self-evident in many respects the problems of excessive noise production and the exposure to it for patients, hospital personnel and relatives alike continues unabated. What must be of concern is the psychophysiological effects excessive noise exposure has on individuals, for example, decreased wound healing, sleep deprivation and cardiovascular stimulation.

Qualificação e quantificação da exposição sonora ambiental em uma unidade de terapia intensiva geral

Os níveis de ruído hospitalares encontram-se excessivamente elevados, especialmente no ambiente de UTI, em decorrência dos inúmeros alarmes e equipamentos, além da conversação da própria equipe hospitalar. Diante disso, esse ambiente, que deveria ser silencioso e tranqüilo, torna-se ruidoso, transformando-se em um grande fator de estresse e podendo gerar distúrbios fisiológicos e psicológicos tanto nos pacientes como nos funcionários dessa unidade. OBJETIVO: O objetivo deste estudo foi verificar o nível de pressão sonora equivalente em uma UTI geral, procurando estabelecer o período de maior exposição e comparando os resultados com as recomendações nacionais e internacionais. FORMA DE ESTUDO: Estudo observacional. MATERIAL E MÉTODO: Medição do ruído ambiental da UTI do Hospital São Paulo através do analisador de ruído modelo 2260 (Brüel & Kjaer), em período total de 6.000 minutos e aferições a cada 27 segundos, configurado da seguinte forma: tempo de resposta rápido (Fast), medindo em decibel o nível de pressão sonora e usando a ponderação em freqüência A, de setembro de 2001 a junho de 2002 e sem o conhecimento dos funcionários do setor. RESULTADOS: O nível de pressão sonora equivalente (Leq) apresentou média de 65,36 dB(A) variando de 62,9 a 69,3 dB(A). Durante o período diurno a média do Leq foi de 65,23 dB(A) e para o período noturno, 63,89 dB(A). O L FMax encontrado foi de 108,4 dB(A) e o L FMin de 40 dB(A). CONCLUSÕES: O nível de ruído encontrado nessa UTI está acima do recomendado pela literatura em todos os períodos analisados. Dessa forma, as fontes produtoras de ruído excessivo precisam ser melhor identificadas para que possam ser tomadas as devidas medidas para atenuação desse ruído e tornar esse ambiente um local mais silencioso, beneficiando a função laborativa dos profissionais e a recuperação dos pacientes.

Reducing noise pollution in the hospital setting by establishing a department of sound: a survey of recent research on the effects of noise and music in health care

A proposal for a solution to reduce stress and anxiety in the hospital setting by combining the problems of excess noise in a hospital setting with the efficacy of music therapy is supported through an analysis of research in the field of noise, hospital noise pollution, and music medicine. Included in this overview are articles describing the effects of noise on health, the problems of noise pollution in the health care setting, and the benefits of replacing noise with music to reduce heart rate, blood pressure, breathing rate, emotional anxiety, and pain. By combining these areas of research, the authors propose the establishment of a department assigned to (1) control the amount of noise in a hospital and (2) provide a center of music therapy for all individuals in the hospital setting, including in-patients, out-patients, doctors, and staff. Due to the large specificity of these areas, this unifying source, or "Department of Sound," is suggested to aid in thoroughly addressing and combining these two concepts most effectively.

Noise levels in an urban hospital and workers' subjective responses

Internal noise levels were measured in a 232-point grid that encompassed the main building of a major University Hospital in Valencia, Spain. Most noise equivalent sound levels that were obtained exceeded 55 dBA, and in some instances these sound levels were very high. Hospital workers' subjective responses to noise were evaluated with a self-answered questionnaire. A total of 295 workers volunteered to participate. Their answers revealed that the most important noise sources were located primarily inside the hospital. Noise levels were perceived to be sufficiently high to interfere with their work, and noise levels were also thought to affect patients' comfort and recovery. Most subjects thought it feasible to reduce noise levels in the hospital, and some preventive measures were proposed.

Noise pollution in the anaesthetic and intensive care environment

Noise in the operating theatre, recovery room and intensive care unit is above internationally recommended levels. The psychological and physiological effects of noise are reviewed. Equipment and conversation among the staff are major sources of noise in these areas. Equipment design, modification of nursing care procedures, and increased awareness of noise created by the staff may be effective in reducing noise pollution in these areas.

Noise in the ICU

OBJECTIVE

The growing number of technical devices in ICUs makes noise exposure a major stressor. The purpose of this study was to assess noise levels during routine operation in our ICU.

DESIGN

Our ICU is an open ward with four rooms, constructed in the 1960s. During the study period, 4 patients were in the controlled room and were treated by 4 nurses during the day and by 2 at night. A-weighted sound pressure levels (SPL) were measured continuously for 2 days and nights. Also measured were the alarms of various appliances. For gross overall evaluation it is customary to state the Leq, i.e. the energy-averaged level during measurement. The annoyance caused by noise depends more on rare events of high intensity. Therefore, the distribution of SPL values (Ln) over time was also analysed.

RESULTS

SPL was roughly the same during the day and at night, with Leq between 60-65 dB(A) and peaks up to 96 dB(A). Most alarms reach an SPL of 60-70 dB(A), but some exceed 80 dB(A). During teaching rounds Leq exceeds 65 dB(A).

CONCLUSION

During the day and at night SPL always surpasses the permissible noise exposure for 24 h of 45 db(A) recommended by the US Environmental Protection Agency. Alarms cause the most irritating noise. Hospital management should pay attention to internal noise, and SPL should be measured routinely.

Stress effects of personal control over hospital noise

Hospital critical care unit (CCU) sounds, instruction in personal control over noise, and stress were studied in 105 female volunteers attempting to sleep overnight in a simulated hospital environment. Subjects were randomly assigned to three groups--instruction in personal control over noise, no instruction in personal control over noise, or a quiet condition. The two noise conditions heard audiotaped recorded playback of CCU nighttime sounds. The subjects with instruction in personal control received directions for using a sound conditioner to block out unwanted sounds. This intervention failed to result in less stress. The results of group comparisons provided strong support for a causal relationship between CCU sounds and greater subjective stress (p less than .000) but not for physiological stress measured by urinary epinephrine. As predicted, scores for sensitivity of the person to noise were positively correlated with scores for noise-induced subjective stress (r = .226, p less than .05). Hierarchical multiple regression revealed that CCU sound levels independently accounted for 54% (p less than .001) and sensitivity to noise for 5% (p less than .01) of the variance in subjective stress.

Noise pollution in the operating theatre

Sound levels during a typical major operation were measured to identify the main sources of noise in the operating theatre. Although overall sound levels were within the recommended levels for a satisfactory working environment, loud intermittent noises of up to 108 dB were emitted from sources such as suckers, "intercoms", and alarms on anaesthetic monitoring devices. The noisiest time was usually during the preparation period of the operation; during surgery, noise levels were much higher than levels of normal speech between staff. Preferred speech interference levels were often exceeded which made communication difficult and sometimes impossible. Communication and concentration were also disrupted by unnecessary background conversation.