Preliminary noise reduction efforts in a medical intensive care unit

The Effectiveness of the Interventions to Reduce Sound Levels in the ICU: A Systematic Review

Excessive noise is ubiquitous in the ICU, and there is growing evidence of the negative impact on work performance of caregivers. This study aims to determine the effectiveness of interventions to reduce noise in the ICU.

DATA SOURCES

Databases of PubMed, EMBASE, PsychINFO, CINAHL, and Web of Science were systematically searched from inception to September 14, 2022.

STUDY SELECTION

Two independent reviewers assessed titles and abstracts against study eligibility criteria. Noise mitigating ICU studies were included when having at least one quantitative acoustic outcome measure expressed in A-weighted sound pressure level with an experimental, quasi-experimental, or observational design. Discrepancies were resolved by consensus, and a third independent reviewer adjudicated as necessary.

DATA EXTRACTION

After title, abstract, and full-text selection, two reviewers independently assessed the quality of each study using the Cochrane's Risk Of Bias In Nonrandomized Studies of Interventions tool. Data were synthesized according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, and interventions were summarized.

DATA SYNTHESIS

After screening 12,652 articles, 25 articles were included, comprising either a mixed group of healthcare professionals (n = 17) or only nurses (n = 8) from adult or PICU settings. Overall, the methodological quality of the studies was low. Noise reduction interventions were categorized into education (n = 4), warning devices (n = 3), multicomponent programs (n = 15), and architectural redesign (n = 3). Education, a noise warning device, and an architectural redesign significantly decreased the sound pressure levels.

CONCLUSIONS

Staff education and visual alert systems seem promising interventions to reduce noise with a short-term effect. The evidence of the studied multicomponent intervention studies, which may lead to the best results, is still low. Therefore, high-quality studies with a low risk of bias and a long-term follow-up are warranted. Embedding noise shielding within the ICU-redesign is supportive to reduce sound pressure levels.

The relationship between sensory stimuli and the physical environment in complex healthcare settings: A systematic literature review

OBJECTIVES

This systematic review presented the current status of literature on the outcomes resulted from sensory stimuli in critical care environments as well as the environmental interventions that can improve or impede the impact of such sensory stimuli.

METHODS

Articles found through a systematic search of PsycINFO, Web of Science, and PubMed databases, in combination with a hand search, were reviewed for eligibility by two independent coders. Reporting and quality appraisals were based on PRISMA and MMAT guidelines.

RESULTS

Out of 1118 articles found, and only 30 were eligible. Final articles were comprised of issues related to noise, lighting, and temperature. Identified sensory stimuli resulted in psychological and physiological outcomes among both patients and staff. Examples include impacts on stress, delirium, sleep disturbances, poor performance and communication. The environmental factors that influence sensory stimuli included layout, room size, artificial lighting, presence of windows and acoustical interventions.

CONCLUSION

Literature on the impact of sensory stimuli on staff is scarce compared to patients. Studies on environmental interventions are inadequate and lack structure. The physical environment can impact the patient and staff outcome resulting from noise, lighting, and temperature. When applied strategically, sensory stimuli can result in positive outcomes among patients and staff.

Contribution of alarm noise to average sound pressure levels in the ICU: An observational cross-sectional study

OBJECTIVES

To explore sound levels, alarm frequencies and the association between alarms and sound levels.

DESIGN

A single center observational cross-sectional study.

SETTING

Four intensive care units.

MAIN OUTCOME MEASURES

Contribution of alarms: red (life threatening), yellow (indicate excess of limits) and blue (technical) to sound pressure levels dB(A) at nursing stations.

RESULTS

Mean sound pressure levels differed significantly between day (56.1 ± 5.5), evening (55.1 ± 5.7) and night periods 53.6 ± 5.6; p < 0.01. 175,996 alarms were recorded of which 149,764 (85%) were yellow, 18,080 (10%) were red and 8,152 (5%) were blue. The mean sound levels without alarms (background) is 56.8 dB(A), with only red: 56.0 dB(A), only yellow: 55.6 dB(A), only blue: 56.0 dB(A) and mixed alarms: 56.3 dB(A). Yellow alarms (b = -0.93; 95% CI: -1.26 to -0.6; p < 0.001) were weakly but significantly associated with mean sound levels and lead to a slight decrease in noise level (1 dB), Red alarms (b = -0.3; 95% CI: -1.237 to 0.63; p = 0.52). The R Square of the model with all alarms was 0.01 (standard error of estimate, 6.9; p < 0.001).

CONCLUSIONS

Sound levels were high during all day-periods. Alarms exceeding limits occurred most frequently. However, the contribution of alarms to sound levels measured at the nursing station is clinically limited.

The effectiveness of noise interventions in the ICU

PURPOSE OF REVIEW

Excessive noise has direct adverse physiological and psychological effects, and may also have indirect negative health consequences by reducing sleep quality and quantity. This review presents a synthesis of the epidemiology of noise in the ICU, and the potential interventions designed to attenuate noise and protect patients.

RECENT FINDINGS

Noise increases cortisol release, oxygen consumption, and vasoconstriction. ICU noise levels are excessive throughout the 24-h cycle, irrespective of level of intervention or whether the patient is in a side room or open ward. Direct measurement suggests that noise is a substantial contributor to poor sleep quantity and quality in the ICU and is frequently recalled by survivors of critical illness as a negative experience of ICU admission. Noise abatement, environmental masking and pharmacological interventions may all reduce the impact of noise on patients. However, the sustainability of behavioural interventions remains uncertain and high-quality evidence demonstrating the benefit of any intervention on patient-centered outcomes is lacking.

SUMMARY

Noise levels in the ICU are consistently reported to reach levels likely to have both direct and indirect adverse health consequences for both patients and staff. Noise reduction, abating the transmission of noise and pharmacological modulation of the adverse neural effects of noise are all potentially beneficial strategies, although definitive evidence of improved patient-centered outcomes is lacking.

"They can rest at home": an observational study of patients' quality of sleep in an Australian hospital

Background

Poor sleep is known to adversely affect hospital patients’ recovery and rehabilitation. The aim of the study was to investigate the perceived duration and quality of patient sleep and identify any environmental factors associated with patient-reported poor sleep in hospital.

Method

A cross-sectional study was conducted involving 15 clinical units within a 672-bed tertiary-referral hospital in Australia. Semi-structured interviews to determine perceptions of sleep quantity and quality and factors that disturb nocturnal sleep were conducted with patients and nursing staff. Environmental noise, light and temperature were monitored overnight, with concurrent logging of noise sources by observers.

Results

Patients reported a mean reduction in hospital sleep duration, compared to home, of 1.8 h (5.3 vs. 7.1 h; p < 0.001). The proportions of patients reporting their sleep quality to be poor/very poor, fair and of good quality were 41.6, 34.2 and 24.2% respectively. Patients reported poorer sleep quality than nurses (p < 0.05). Patients, nurses and observers all reported the main factors associated with poor sleep as clinical care interventions (34.3%) and environmental noise (32.1%). Noise levels in all 15 clinical areas exceeded WHO recommended levels of < 30 dB [A] by 36.7 to 82.6%, with peak noise levels of 51.3 to 103.3 dB (A).

Conclusion

Hospital in-patients are exposed to factors which reduce the duration and quality of their sleep. These extrinsic factors are potentially modifiable through behaviour change and reconfiguration of the clinical environment. The findings from this study provided the foundation for a quality improvement project currently underway to improve patients’ sleep.

Quality Improvement Initiative to Reduce Pediatric Intensive Care Unit Noise Pollution With the Use of a Pediatric Delirium Bundle

OBJECTIVES:

Noise pollution in pediatric intensive care units (PICU) contributes to poor sleep and may increase risk of developing delirium. The Environmental Protection Agency (EPA) recommends <45 decibels (dB) in hospital environments. The objectives are to assess the degree of PICU noise pollution, to develop a delirium bundle targeted at reducing noise, and to assess the effect of the bundle on nocturnal noise pollution.

METHODS:

This is a QI initiative at an academic PICU. Thirty-five sound sensors were installed in patient bed spaces, hallways, and common areas. The pediatric delirium bundle was implemented in 8 pilot patients (40 patient ICU days) while 108 non-pilot patients received usual care over a 28-day period.

RESULTS:

A total of 20,609 hourly dB readings were collected. Hourly minimum, average, and maximum dB of all occupied bed spaces demonstrated medians [interquartile range] of 48.0 [39.0-53.0], 52.8 [48.1-56.2] and 67.0 [63.5-70.5] dB, respectively. Bed spaces were louder during the day (10AM to 4PM) than at night (11PM to 5AM) (53.5 [49.0-56.8] vs. 51.3 [46.0-55.3] dB, P < 0.01). Pilot patient rooms were significantly quieter than non-pilot patient rooms at night (n=210, 45.3 [39.7-55.9]) vs. n=1841, 51.2 [46.9-54.8] dB, P < 0.01). The pilot rooms compliant with the bundle had the lowest hourly nighttime average dB (44.1 [38.5-55.5]).

CONCLUSIONS:

Substantial noise pollution exists in our PICU, and utilizing the pediatric delirium bundle led to a significant noise reduction that can be perceived as half the loudness with hourly nighttime average dB meeting the EPA standards when compliant with the bundle.

Sound as a supportive design intervention for improving health care experience in the clinical ecosystem: A qualitative study

PURPOSE

Most prior hospital noise research usually deals with sound in its noise facet and is based merely on sound level abatement, rather than as an informative or orientational element. This paper stimulates scientific research into the effect of sound interventions on physical and mental health care in the clinical environment.

METHODS

Data sources comprised relevant World Health Organization guidelines and the results of a literature search of ISI Web of Science, ProQuest Central, MEDLINE, PubMed, Scopus, JSTOR and Google Scholar.

RESULTS

Noise induces stress and impedes the recovery process. Pleasant natural sound intervention which includes singing birds, gentle wind and ocean waves, revealed benefits that contribute to perceived restoration of attention and stress recovery in patients and staff.

CONCLUSIONS

Clinicians should consider pleasant natural sounds perception as a low-risk non-pharmacological and unobtrusive intervention that should be implemented in their routine care for speedier recovery of patients undergoing medical procedures.

Comparing average levels and peak occurrence of overnight sound in the medical intensive care unit on A-weighted and C-weighted decibel scales

PURPOSE

Sound levels in the intensive care unit (ICU) are universally elevated and are believed to contribute to sleep and circadian disruption. The purpose of this study is to compare overnight ICU sound levels and peak occurrence on A- vs C-weighted scales.

MATERIALS AND METHODS

This was a prospective observational study of overnight sound levels in 59 medical ICU patient rooms. Sound level was recorded every 10 seconds on A- and C-weighted decibel scales. Equivalent sound level (Leq) and sound peaks were reported for full and partial night periods.

RESULTS

The overnight A-weighted Leq of 53.6 dBA was well above World Health Organization recommendations; overnight C-weighted Leq was 63.1 dBC (no World Health Organization recommendations). Peak sound occurrence ranged from 1.8 to 23.3 times per hour. Illness severity, mechanical ventilation, and delirium were not associated with Leq or peak occurrence. Equivalent sound level and peak measures for A- and C-weighted decibel scales were significantly different from each other.

CONCLUSIONS

Sound levels in the medical ICU are high throughout the night. Patient factors were not associated with Leq or peak occurrence. Significant discordance between A- and C-weighted values suggests that low-frequency sound is a meaningful factor in the medical ICU environment.