Noise in hospital intensive care units—a critical review of a critical topic

Better Sleep Experience for the Critically Ill: A Comprehensive Strategy for Designing Hospital Soundscapes

In this paper, the sleep phenomenon is considered in relation to critical care soundscapes with the intention to inform hospital management, medical device producers and policy makers regarding the complexity of the issue and possible modes of design interventions. We propose a comprehensive strategy based on soundscape design approach that facilitates a systematic way of tackling the auditory quality of critical care settings in favor of better patient sleep experience. Future research directions are presented to tackle the knowledge deficits in designing for critical care soundscapes that cater for patient sleep. The need for scientifically-informed design interventions for improving patient sleep experience in critical care is highlighted. The value of the soundscape design approach for resolving other sound-induced problems in critical care and how the approach allows for patient-centred innovation that is beyond the immediate sound issue are further discussed.

Psychogenic stress in hospitalized veterinary patients: Causation, implications, and therapies

OBJECTIVE

To review the sources, adverse effects, diagnosis, treatment, and prevention of psychogenic stress in hospitalized human and veterinary patients.

DATA SOURCES

Data were collected by searching PubMed for veterinary and human literature from the past 10 years.

HUMAN DATA SYNTHESIS

Psychogenic stress has been linked to immune suppression; gastrointestinal, cardiovascular, and cutaneous diseases; delayed wound healing; alterations in pain perception; and neurologic impairment. Sources of psychogenic stress include environmental alterations such as excessive noise and light, social and physical factors, sleep disruption, drugs, and underlying disease. Nonpharmacologic options for stress reduction include environmental and treatment modifications, music therapy, and early mobilization. Pharmacologic options include sedation with benzodiazepines and dexmedetomidine. Trazodone and melatonin have been examined for use in sleep promotion but are not currently recommended as standard treatments in ICU.

VETERINARY DATA SYNTHESIS

Activation of the stress response in veterinary patients is largely the same as in people, as are the affected body systems. Possible sources of stress can include social, physical, and environmental factors. No gold standard currently exists for the identification and quantification of stress. A combination of physical examination findings and the results of serum biochemistry, CBC, and biomarker testing can be used to support the diagnosis. Stress scales can be implemented to identify stressed patients and assess severity. Nonpharmacologic treatment options include low-stress handling, pheromones, environmental modifications, and sleep promotion. Pharmacologic options include trazodone, benzodiazepines, dexmedetomidine, and melatonin.

CONCLUSION

The prevalence and clinical significance of psychogenic stress in hospitalized veterinary patients is unknown. Future studies are needed to specifically examine the causative factors of psychogenic stress and the effects of various therapies on stress reduction. The recognition and reduction of psychogenic stress in veterinary patients can lead to improvements in patient care and welfare.

The effect of a non-talking rule on the sound level and perception of patients in an outpatient infusion center

Noise is a common problem in hospitals, and it is known that social behavior can influence sound levels. The aim of this naturally-occurring field experiment was to assess the influence of a non-talking rule on the actual sound level and perception of patients in an outpatient infusion center. In a quasi-randomized trial two conditions were compared in real life. In the control condition, patients (n = 137) were allowed to talk to fellow patients and visitors during the treatment. In the intervention condition patients (n = 126) were requested not to talk to fellow patients and visitors during their treatment. This study measured the actual sound levels in dB(A) as well as patients’ preferences regarding sound and their perceptions of the physical environment, anxiety, and quality of health care. A linear-mixed-model showed a statistically significant, but rather small reduction of the non-talking rule on the actual sound level with an average of 1.1 dB(A). Half of the patients preferred a talking condition (57%), around one-third of the patients had no preference (36%), and 7% of the patients preferred a non-talking condition. Our results suggest that patients who preferred non-talking, perceived the environment more negatively compared to the majority of patients and perceived higher levels of anxiety. Results showed no significant effect of the experimental conditions on patient perceptions. In conclusion, a non-talking rule of conduct only minimally reduced the actual sound level and did not influence the perception of patients.

The Effect of Listening to Holy Quran Recitation on Weaning Patients Receiving Mechanical Ventilation in the Intensive Care Unit: A Pilot Study

Mechanical ventilation (MV) causes high level of stress in hospitalized patients. Weaning is the gradual process of decreasing ventilator support that in turn lead to termination of MV and increased respiratory effort, which may exacerbate symptoms and prolong MV. This study aimed to investigate the effect of listening to Holy Quran recitation (HQR) as a non-pharmacological intervention in patients during weaning from mechanical ventilation. This is a randomized controlled trial in which 55 patients admitted in the intensive care unit (ICU) and on mechanical ventilation were recruited. Patients were divided into experimental (case) and control group. In the experimental group, patients received 30 min of HQR, whereas in the control group, patients had 30 min of rest in bed before the start of the weaning. The physiological and/or clinical parameters of weaning were recorded. These parameters include rapid shallow breathing index, respiratory rate, heart rate, oxygen saturation, exhaled carbon dioxide, and blood pressure. The baseline demographic data for groups were presented in tables. The mean age was 54 ± 0.5 years for the experimental and 56.4 ± 18.5 years for the control groups. The physiological and clinical parameters were compared between case and control and found no significant difference. The preliminary findings of this pilot study suggest that there is no negative effect of HQR on weaning patients from mechanical ventilation in the ICU. The results also outline and explorthe possible utility of HQR further in ICU patients as an intervention in weaning patients off from ventilator in the ICU. Although there remains much to be done, our work generates important findings in the field of critical care management.

Quiet Time: A Noise Reduction Initiative in a Neurosurgical Intensive Care Unit

BACKGROUND

High noise levels in intensive care units are common. Increased noise levels can lead to sleep deprivation, increased pain perception, and delirium. The most common cause of reducible noise in intensive care units often is attributed to staff conversations.

OBJECTIVES

In January 2015, the neurosurgical intensive care unit staff identified noise as a problem, referencing complaints from other disciplines and family members. Quiet times from 3 am to 5 am and from 3 pm to 5 pm were agreed upon. An improvement plan was developed with a goal to decrease noise levels by 10 decibels in 6 months.

METHODS

Using a decibel meter, noise data were collected in 4 locations every 30 minutes during the chosen times for 8 days. Quiet time was implemented 1 week after staff, patient, and family education was completed. Decibel data were collected and evaluated after 60 days.

RESULTS

There were statistically significant reductions in noise levels at nurses' station left (P = .04) and the bed 9 entrance (P = .02). Noise levels were lower, but not significantly so, for nurses' station right (P = .12) and the bed 4 entrance (P = .06). Noise levels during quiet time decreased to an average of 10 to 15 decibels lower than baseline data.

CONCLUSIONS

Sharing baseline data was effective to heighten noise awareness. During quiet time, limiting conversations, eliminating environmental noise, and dimming the lights as a reminder to be quiet are 3 simple strategies that can be implemented to lessen noise.

Identifying determinants of noise in a medical intensive care unit

Continuous and intermittent exposure to noise elevates stress, increases blood pressure, and disrupts sleep among patients in hospital intensive care units. The purpose of this study was to determine the effectiveness of a behavior-based intervention to reduce noise and to identify determinants of noise in a medical intensive care unit. Staff were trained for 6 weeks to reduce noise during their activities in an effort to keep noise levels below 55 dBA during the day and below 50 dBA at night. One-min noise levels were logged continuously in patient rooms 8 weeks before and after the intervention. Noise levels were compared by room position, occupancy status, and time of day. Noise levels from flagged days (>60 dBA for >10 hr) were correlated with activity logs. The intervention was ineffective, with noise frequently exceeding project goals during the day and night. Noise levels were higher in rooms with the oldest heating, ventilation, and air-conditioning system, even when patient rooms were unoccupied. Of the flagged days, the odds of noise over 60 dBA occurring was 5.3 dBA higher when high-flow respiratory support devices were in use compared to times with low-flow devices in use (OR = 5.3, 95% CI = 5.0-5.5). General sources, like the heating, ventilation, and air-conditioning system, contribute to high baseline noise and high-volume (>10 L/min) respiratory-support devices generate additional high noise (>60 dBA) in Intensive Care Unit patient rooms. This work suggests that engineering controls (e.g., ventilation changes or equipment shielding) may be more effective in reducing noise in hospital intensive care units than behavior modification alone.

SoundEar noise warning devices cause a sustained reduction in ambient noise in adult critical care

Introduction

Elevated sound levels in critical care are associated with sleep deprivation and an increased incidence of delirium. We aimed to determine whether a sound-activated visual noise display meter could cause a sustained reduction in sound levels overnight in an adult critical care unit.

Method

Sound levels were recorded overnight for eight days before and after the introduction of a visual noise display meter, with a further eight days recorded four months later after continued use of the visual noise display meter.

Results

Median ambient sound levels were significantly reduced from 57.4 dB by 3.9 dB, with a sustained reduction of 3.6 dB from baseline after four months of the device operating. Peak ambient sound levels had a small but significant reduction from 66.0 dB by 0.7 dB, with a sustained reduction of 0.8 dB after four months.

Discussion

Sound-activated visual noise display meters can be effective in providing a sustained reduction in ambient sound overnight in adult critical care units, which would appear to be driven by behavioural change.

Noise level in neonatal incubators: A comparative study of three models

BACKGROUND

Preterm infants usually have to spend a long time in an incubator, excessive noise in which can have adverse physiological and psychological effects on neonates. In fact, incubator noise levels typically range from 45 to 70 dB but differences in this respect depend largely on the noise measuring method used. The primary aim of this work was to assess the extent to which noise in an incubator comes from its own fan and how efficiently the incubator can isolate external noise.

METHODS

Three different incubator models were characterized for acoustic performance by measuring their internal noise levels in an anechoic chamber, and also for noise isolation efficiency by using a pink noise source in combination with an internal and an external microphone that were connected to an SVAN958 noise analyzer.

RESULTS

The incubators studied produced continuous equivalent noise levels of 53.5-58 dB and reduced external noise by 5.2-10.4 dB.

CONCLUSIONS

A preterm infant in an incubator is exposed to noise levels clearly exceeding international recommendations even though such levels usually comply with the limit set in the standard IEC60601-2-19: 2009 (60 dBA) under normal conditions of use.

Looking for light in the din: An examination of the circadian-disrupting properties of a medical intensive care unit

OBJECTIVE

Critically ill patients exhibit profound disturbances of circadian rhythmicity, most commonly in the form of a phase delay. We investigated the specific zeitgeber properties of a medical intensive care unit to develop a model that explained these abnormalities.

RESEARCH METHODOLOGY

Prospective, observational study conducted during 2013-2014. Twenty-four-hour ambient light (lux, 672 hours) and sound pressure levels (dBA, 504 hours) were measured in patient rooms. Patients and families were surveyed regarding their perceptions of the environment.

SETTING

University-based adult medical intensive care unit.

MAIN OUTCOME MEASURES

The timing and intensity of the ambient light-dark cycle and sound environment and the relationship of these measurements to patient/family perceptions.

RESULTS

Twenty-four-hour light-dark cycles were extremely weak and phase delayed relative to the solar cycle. Morning light averaged 12.1 (4.8, 37.2) lux, when only 24.9% ± 10.9% of available light was utilised; yet patients and families did not identify low daytime light levels as problematic. Median noise levels were invariably excessive (nighttime 47.9 [45.0, 51.3] dBA) with minimal variation, consistent with the absence of a defined rest period.

CONCLUSION

The intensive care unit functions as a near-constant routine protocol disconnected from solar time. Behavioural interventions to promote entrainment should be supported by objective measurements of light and sound.

WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Effects on Sleep

To evaluate the quality of available evidence on the effects of environmental noise exposure on sleep a systematic review was conducted. The databases PSYCINFO, PubMed, Science Direct, Scopus, Web of Science and the TNO Repository were searched for non-laboratory studies on the effects of environmental noise on sleep with measured or predicted noise levels and published in or after the year 2000. The quality of the evidence was assessed using GRADE criteria. Seventy four studies predominately conducted between 2000 and 2015 were included in the review. A meta-analysis of surveys linking road, rail, and aircraft noise exposure to self-reports of sleep disturbance was conducted. The odds ratio for the percent highly sleep disturbed for a 10 dB increase in Lnight was significant for aircraft (1.94; 95% CI 1.61-2.3), road (2.13; 95% CI 1.82-2.48), and rail (3.06; 95% CI 2.38-3.93) noise when the question referred to noise, but non-significant for aircraft (1.17; 95% CI 0.54-2.53), road (1.09; 95% CI 0.94-1.27), and rail (1.27; 95% CI 0.89-1.81) noise when the question did not refer to noise. A pooled analysis of polysomnographic studies on the acute effects of transportation noise on sleep was also conducted and the unadjusted odds ratio for the probability of awakening for a 10 dBA increase in the indoor Lmax was significant for aircraft (1.35; 95% CI 1.22-1.50), road (1.36; 95% CI 1.19-1.55), and rail (1.35; 95% CI 1.21-1.52) noise. Due to a limited number of studies and the use of different outcome measures, a narrative review only was conducted for motility, cardiac and blood pressure outcomes, and for children's sleep. The effect of wind turbine and hospital noise on sleep was also assessed. Based on the available evidence, transportation noise affects objectively measured sleep physiology and subjectively assessed sleep disturbance in adults. For other outcome measures and noise sources the examined evidence was conflicting or only emerging. According to GRADE criteria, the quality of the evidence was moderate for cortical awakenings and self-reported sleep disturbance (for questions that referred to noise) induced by traffic noise, low for motility measures of traffic noise induced sleep disturbance, and very low for all other noise sources and investigated sleep outcomes.

Assessment and characterization of sound pressure levels in Portuguese neonatal intensive care units

In the NICU, systematic exposure to sound-pressure above the recommended level can affect both neonates and staff. This study aimed to evaluate the sound pressure levels in three Portuguese NICUs and the noise perceptions of staff. The measurements were performed with a sound-level meter, considering the location of the main sources of noise and the layout of the units. A questionnaire was applied to assess noise perceptions of professionals. Among the staff, 41.1% classified the environment (regarding noise) as "slightly uncomfortable"; 48.4% considered it as "acceptable." The majority (55.5%) considered "equipment" the most annoying source of noise. The results showed that noise levels were excessive in all the evaluated areas of the NICUs, exceeding international guidelines, with levels ranging between 48.7 dBA to 71.7 dBA. Overall, there is a need for more research to verify the effectiveness of some actions and strategies to reduce the effect of noise in the NICU.

A Sleep Education and Hypnotics Reduction Program for Hospitalized Patients at a General Hospital

OBJECTIVE

We applied a program of sleep education and hypnotics reduction for inpatients (the i-sleep program). This study explored whether the i-sleep program is effective for reducing the prescription rate of sleeping pills to inpatients in a general hospital.

METHODS

We estimated the proportion of inpatients prescribed hypnotics at admission to and discharge from the hospital, excluding pediatric care units, before (2014) and after (2015) the program. In addition, we estimated the proportion of inpatients prescribed sleeping pills among all inpatients on the first day of each month of 2014 and 2015.

RESULTS

The proportion of inpatients prescribed hypnotics as discharge medication among inpatients who had been prescribed them at the time of admission decreased significantly, from 57.0% to 46.8%, after the i-sleep program (RR=0.82, 95% CI: 0.79-0.86). The proportion of inpatients newly prescribed sleeping pills after admission to the hospital did not significantly decrease (1.97% to 2.00%; RR=1.01, 95% CI: 0.96-1.07). The mean prescription rate of sleeping pills per day was 8.18% in 2014 and 7.78% in 2015.

CONCLUSION

The i-sleep program reduced the proportion of inpatients who continued to take sleeping pills from admission until discharge, although it did't reduce the prescription rate per day.

Index of Microcirculatory Resistance at the Time of Primary Percutaneous Coronary Intervention Predicts Early Cardiac Complications: Insights From the OxAMI (Oxford Study in Acute Myocardial Infarction) Cohort

Background

Early risk stratification after primary percutaneous coronary intervention (PPCI) for ST‐segment–elevation myocardial infarction is currently challenging. Identification of a low‐risk group may improve triage of patients to alternative clinical pathways and support early hospital discharge. Our aim was to assess whether the index of microcirculatory resistance (IMR) at the time of PPCI can identify patients at low risk of early major cardiac complications and to compare its performance against guideline‐recommended risk scores.

Methods and Results

IMR was measured using a pressure–temperature sensor wire. Cardiac complications were defined as the composite of cardiac death, cardiogenic shock, pulmonary edema, malignant arrhythmias, cardiac rupture, and presence of left ventricular thrombus either before hospital discharge or within 30‐day follow‐up. In total, 261 patients undergoing PPCI who were eligible for coronary physiology assessment were prospectively enrolled. Twenty‐two major cardiac complications were reported. Receiver operating characteristic curve analysis confirmed the utility of IMR in predicting complications and showed significantly better performance than coronary flow reserve, the Primary Angioplasty in Myocardial Infarction II (PAMI‐II), and Zwolle score (P≤0.006). Low microvascular resistance (IMR ≤40) was measured in 159 patients (61%) of the study population and identified all patients who were free of major cardiac complications (sensitivity: 100%; 95% CI, 80.5–100%).

Conclusions

IMR immediately at the end of PPCI for ST‐segment–elevation myocardial infarction reliably predicts early major cardiac complications and performed significantly better than recommended risk scores. These novel data have implications for early risk stratification after PPCI.

An experimental model to measure the ability of headphones with active noise control to reduce patient's exposure to noise in an intensive care unit

Background

Defining the association between excessive noise in intensive care units, sleep disturbance and morbidity, including delirium, is confounded by the difficulty of implementing successful strategies to reduce patient’s exposure to noise. Active noise control devices may prove to be useful adjuncts but there is currently little to quantify their ability to reduce noise in this complex environment.

Methods

Sound meters were embedded in the auditory meatus of three polystyrene model heads with no headphones (control), with headphones alone and with headphones using active noise control and placed in patient bays in a cardiac ICU. Ten days of recording sound levels at a frequency of 1 Hz were performed, and the noise levels in each group were compared using repeated measures MANOVA and subsequent pairwise testing.

Results

Multivariate testing demonstrated that there is a significant difference in the mean noise exposure levels between the three groups (p < 0.001). Subsequent pairwise testing between the three groups shows that the reduction in noise is greatest with headphones and active noise control. The mean reduction in noise exposure between the control and this group over 24 h is 6.8 (0.66) dB. The use of active noise control was also associated with a reduction in the exposure to high-intensity sound events over the course of the day.

Conclusions

The use of active noise cancellation, as delivered by noise-cancelling headphones, is associated with a significant reduction in noise exposure in our model of noise exposure in a cardiac ICU. This is the first study to look at the potential effectiveness of active noise control in adult patients in an intensive care environment and shows that active noise control is a candidate technology to reduce noise exposure levels the patients experience during stays on intensive care.

Noise level in a neonatal intensive care unit in Santa Marta - Colombia

Introduction:

The environment of neonatal intensive care units is influenced by numerous sources of noise emission, which contribute to raise the noise levels, and may cause hearing impairment and other physiological and psychological changes on the newborn, as well as problems with care staff.

Objective:

To evaluate the level and sources of noise in the neonatal intensive care unit.

Methods:

Sampled for 20 consecutive days every 60 seconds in A-weighting curves and fast mode with a Type I sound level meter. Recorded the average, maximum and minimum, and the 10th, 50th and 90th percentiles. The values are integrated into hours and work shift, and studied by analysis of variance. The sources were characterized in thirds of octaves.

Results:

The average level was 64.00 ±3.62 dB(A), with maximum of 76.04 ±5.73 dB(A), minimum of 54.84 ±2.61dB(A), and background noise of 57.95 ±2.83 dB(A). We found four sources with levels between 16.8-63.3 dB(A). Statistical analysis showed significant differences between the hours and work shift, with higher values in the early hours of the day.

Conclusion:

The values presented exceed the standards suggested by several organizations. The sources identified and measured recorded high values in low frequencies.

Innovative Designs for the Smart ICU

Successfully designing a new ICU requires clarity of vision and purpose and the recognition that the patient room is the core of the ICU experience for patients, staff, and visitors. The ICU can be conceptualized into three components: the patient room, central areas, and universal support services. Each patient room should be designed for single patient use and be similarly configured and equipped. The design of the room should focus upon functionality, ease of use, healing, safety, infection control, communications, and connectivity. All aspects of the room, including its infrastructure; zones for work, care, and visiting; environment, medical devices, and approaches to privacy; logistics; and waste management, are important elements in the design process. Since most medical devices used at the ICU bedside are really sophisticated computers, the ICU needs to be capable of supporting the full scope of medical informatics. The patient rooms, the central ICU areas (central stations, corridors, supply rooms, pharmacy, laboratory, staff lounge, visitor waiting room, on-call suite, conference rooms, and offices), and the universal support services (infection prevention, finishings and flooring, staff communications, signage and wayfinding, security, and fire and safety) work best when fully interwoven. This coordination helps establish efficient and safe patient throughput and care and fosters physical and social cohesiveness within the ICU. A balanced approach to centralized and decentralized monitoring and logistics also offers great flexibility. Synchronization of the universal support services in the ICU with the hospital's existing systems maintains unity of purpose and continuity across the enterprise and avoids unnecessary duplication of efforts.

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.

Assessment of Medical-Surgical Patients' Perception of Hospital Noises and Reported Ability to Rest

OBJECTIVES

The purpose was to determine if an enhanced privacy curtain (1) impacted ability to rest while hospitalized in the acute care setting and (2) improved patient satisfaction associated with environmental noise.

METHODS

The project evaluated a privacy curtain designed to increase speech privacy and intelligibility and reduce reverberation time (echo). The curtain was similar to the existing privacy curtain with 2 exceptions: the curtain panel had pocket inserts that absorbed sound, and curtain panels could be zipped together to reduce sound transmission through gaps. Curtains were evaluated on 2 medical-surgical units. Patients with at least 2 nights' stay and were alert and oriented without behavioral concerns were asked to complete a 12-item restful environment assessment.

RESULTS

The project demonstrated some impact on ability to rest. One unit saw an increase in the patient experience sleep measure score and demonstrated a small increase in the patient's self- reported ability to rest during the day and night when using the enhanced curtain.

CONCLUSION

Patients on medical-surgical units were bothered by the noises typically heard in those units. Small improvements in patient experience with the enhanced curtain were outweighed by cost and increased housekeeping and laundry staff workload.

Effect of environmental noise and music on dexmedetomidine-induced sedation in dogs

Background

Previous studies in human patients suggest depth of sedation may be affected by environmental noise or music; however, related data in domestic animals is limited. The objective of the current study was to investigate the effect of noise and music on dexmedetomidine-induced (DM- 10 µg/kg, IM) sedation in 10 dogs.

Methods

In a crossover design, post-DM injection dogs were immediately subjected to recorded human voices at either 55–60 decibel (dB) (Noise 1) or 80–85 dB (Noise 2); classical music at 45–50 dB (Music); or background noise of 40–45 dB (Control+). Control− included IM saline injection and exposure to 40–45 dB background noise. Sedation was assessed via monitoring spontaneous behavior and accelerometry (delta-g) throughout three 20-min evaluation periods: baseline, noise exposure, and post-treatment. Sedation was further assessed during two restraint tests at 30 min (R1) and 40 min (R2) post-injection. A mixed model for crossover design was used to determine the effect of noise exposure and time on either spontaneous behavior scores or delta-g. The restraint scores were analyzed using a two-way repeated measures ANOVA.

Results

Spontaneous behavior scores indicated less sedation during Noise 2 compared to Control+ (P = 0.05). R2 restraint scores for all DM treatments except Noise 2 indicated significantly higher sedation than Control− [C+ (P = 0.003), M (P = 0.014) and N1 (P = 0.044)].

Discussion

Results suggest that the quality of sedation is negatively impacted by high-intensity noise conditions (80–85 dB), but exposure to music did not improve sedation in this population of research dogs.

The nocturnal acoustical intensity of the intensive care environment: an observational study

BACKGROUND

The intensive care unit (ICU) environment exposes patients to noise levels that may result in substantial sleep disruption. There is a need to accurately describe the intensity pattern and source of noise in the ICU in order to develop effective sound abatement strategies. The objectives of this study were to determine nocturnal noise levels and their variability and the related sources of noise within an Australian tertiary ICU.

METHODS

An observational cross-sectional study was conducted in a 24-bed open-plan ICU. Sound levels were recorded overnight during three nights at 5-s epochs using Extech (SDL 600) sound monitors. Noise sources were concurrently logged by two research assistants.

RESULTS

The mean recorded ambient noise level in the ICU was 52.85 decibels (dB) (standard deviation (SD) 5.89), with a maximum noise recording at 98.3 dB (A). All recorded measurements exceeded the WHO recommendations. Noise variability per minute ranged from 9.9 to 44 dB (A), with peak noise levels >70 dB (A) occurring 10 times/hour (SD 11.4). Staff were identified as the most common source accounting for 35% of all noise. Mean noise levels in single-patient rooms compared with open-bed areas were 53.5 vs 53 dB (p = 0.37), respectively.

CONCLUSION

Mean noise levels exceeded those recommended by the WHO resulting in an acoustical intensity of 193 times greater than the recommended and demonstrated a high degree of unpredictable variability, with the primary noise sources coming from staff conversations. The lack of protective effects of single rooms and the contributing effects that staffs have on noise levels are important factors when considering sound abatement strategies.

Neonatal Intensive Care Unit Layout and Nurses’ Work

Neonatal intensive care units (NICUs) remain one of the few areas in hospitals that still use an open bay (OPBY) design for patient stays greater than 24 hr, housing multiple infants, staff, and families in one large room. This creates high noise levels, contributes to the spread of infection, and affords families little privacy. These problems have given rise to the single-family room NICU. This represents a significant change in the care environment for nurses. This literature review answers the question: When compared to OPBY layout, how does a single family room layout impact neonatal nurses’ work? Thirteen studies published between 2006 and 2015 were located. Many studies reported both positive and negative effects on nurses’ work and were therefore sorted by their cited advantages and disadvantages. Advantages included improved quality of the physical environment; improved quality of patient care; improved parent interaction; and improvements in nurse job satisfaction, stress, and burnout. Disadvantages included decreased interaction among the NICU patient care team, increased nurse workload, decreased visibility on the unit, and difficult interactions with family. This review suggests that single-family room NICUs introduce a complex situation in which trade-offs occur for nurses, most prominently the trade-off between visibility and privacy. Additionally, the literature is clear on what elements of nurses’ work are impacted, but how the built environment influences these elements, and how these elements interact during nurses’ work, is not as well understood. The current level of research and directions for future research are also discussed.

[Environmental noise levels in 2 intensive care units in a tertiary care centre]

INTRODUCTION

The World Health Organisation (WHO) has established a maximum noise level of 40 decibels (dB) for an intensive care unit. The aim of this study was to compare the noise levels in 2 different intensive care units at a tertiary care centre.

METHODS

Using a cross-sectional design study, an analysis was made of the maximum noise level was within the intensive coronary care unit and intensive care unit using a digital meter. A measurement was made in 4 different points of each room, with 5minute intervals, for a period of 60minutes 7:30, 14:30, and 20:30. The means of the observations were compared with descriptive statistics and Mann-Whitney U. An analysis with Kruskal-Wallis test was performed to the mean noise level.

RESULTS

The noise observed in the intensive care unit had a mean of 64.77±3.33dB (P=.08), which was similar to that in the intensive coronary care unit, with a mean of 60.20±1.58dB (P=.129). Around 25% or more of the measurements exceeded the level recommended by the WHO by up to 20 points.

CONCLUSIONS

Noise levels measured in intensive care wards exceed the maximum recommended level for a hospital. It is necessary to design and implement actions for greater participation of health personnel in the reduction of environmental noise.

Striving for Optimum Noise-Decreasing Strategies in Critical Care: Initial Measurements and Observations

To identify baseline sound levels, patterns of sound levels, and potential barriers and facilitators to sound level reduction. The study setting was neonatal and pediatric intensive care units in a tertiary care hospital. Participants were staff in both units and parents of currently hospitalized children or infants. One 24-hour sound measurements and one 4-hour sound measurement linked to observed sound events were conducted in each area of the center's neonatal intensive care unit. Two of each measurement type were conducted in the pediatric intensive care unit. Focus groups were conducted with parents and staff. Transcripts were analyzed with descriptive content analysis and themes were compared against results from quantitative measurements. Sound levels exceeded recommended standards at nearly every time point. The most common code was related to talking. Themes from focus groups included the critical care context and sound levels, effects of sound levels, and reducing sound levels-the way forward. Results are consistent with work conducted in other critical care environments. Staff and families realize that high sound levels can be a problem, but feel that the culture and context are not supportive of a quiet care space. High levels of ambient sound suggest that the largest changes in sound levels are likely to come from design and equipment purchase decisions. L10 and Lmax appear to be the best outcomes for measurement of behavioral interventions.

Monitoring sound and light continuously in an intensive care unit patient room: A pilot study

PURPOSE

To determine the feasibility of continuous recording of sound and light in the intensive care unit (ICU).

MATERIALS AND METHODS

Four 1-hour baseline scenarios in an empty ICU patient room by day and night (doors open or closed and maximal or minimal lighting) and two daytime scenarios simulating a stable and unstable patient (quiet or loud devices and staff) were conducted. Sound and light levels were continuously recorded using a commercially available multisensor monitor and transmitted via the hospital's network to a cloud-based data storage and management system.

RESULTS

The empty ICU room was loud with similar mean sound levels of 45 to 46 dBA for the day and night simulations. Mean levels for maximal lighting during day and night ranged from 1306 to 1812 lux and mean levels for minimum lighting were 1 to 3 lux. The mean sound levels for the stable and unstable patient simulations were 61 and 81 dBA, respectively. The mean light levels were 349 lux for the stable patient and 1947 lux for the unstable patient.

CONCLUSIONS

Combined sound and light can be continuously and easily monitored in the ICU setting. Incorporating sound and light monitors in ICU rooms may promote an enhanced patient- and staff-centered healing environment.

Reduction of false arrhythmia alarms using signal selection and machine learning

In this paper, we propose an algorithm that classifies whether a generated cardiac arrhythmia alarm is true or false. The large number of false alarms in intensive care is a severe issue. The noise peaks caused by alarms can be high and in a noisy environment nurses can experience stress and fatigue. In addition, patient safety is compromised because reaction time of the caregivers to true alarms is reduced. The data for the algorithm development consisted of records of electrocardiogram (ECG), arterial blood pressure, and photoplethysmogram signals in which an alarm for either asystole, extreme bradycardia, extreme tachycardia, ventricular fibrillation or flutter, or ventricular tachycardia occurs. First, heart beats are extracted from every signal. Next, the algorithm selects the most reliable signal pair from the available signals by comparing how well the detected beats match between different signals based on [Formula: see text]-score and selecting the best match. From the selected signal pair, arrhythmia specific features, such as heart rate features and signal purity index are computed for the alarm classification. The classification is performed with five separate Random Forest models. In addition, information on the local noise level of the selected ECG lead is added to the classification. The algorithm was trained and evaluated with the PhysioNet/Computing in Cardiology Challenge 2015 data set. In the test set the overall true positive rates were 93 and 95% and true negative rates 80 and 83%, respectively for events with no information and events with information after the alarm. The overall challenge scores were 77.39 and 81.58.

Noise Affects Performance on the Montreal Cognitive Assessment

L’objectif était d’investiguer l’impact de la présence d’un bruit de fond sur la performance au Montreal Cognitive Assessment (MoCA). Deux versions du MoCA ont été administrées, utilisant écouteurs, avec des niveaux bas et élevés de bruit de fond à deux groupes de personnes âgées (un groupe présentant une audition cliniquement normale, le second présentant une perte d’audition) ainsi qu’à un groupe de jeunes adultes. Les niveaux d’intensité utilisés pour présenter la parole et le bruit étaient personnalisés en fonction des habiletés des participants présentant une perte de l’ouïe, et ce en vue de créer un niveau de difficulté uniforme à travers les participants dans la condition de bruit plus élevé. Les deux groupes de personnes âgées ont obtenu des scores plus faibles au MoCA en comparaison aux jeunes adultes. Il est également important de souligner que tous les participants ont obtenu des scores plus faibles au MoCA lorsque le test était administré dans un contexte de bruit élevé (M = 22,7/30), en comparaison à un contexte de bruit faible (M = 25,7/30, p < .001). Ces résultats suggèrent que le bruit de fond présent dans un contexte d’évaluation devrait être pris en considération au moment de l’administration de tests cognitifs ainsi que dans l’interprétation des résultats, en particulier lors de l’essai des adultes plus âgés.

Quiet time for mechanically ventilated patients in the medical intensive care unit

OBJECTIVE

Sleep disruption occurs frequently in critically ill patients. The primary aim of this study was to examine the effect of quiet time (QT) on patient sedation frequency, sedation and delirium scores; and to determine if consecutive QTs influenced physiologic measures (heart rate, mean arterial blood pressure and respiratory rate).

METHOD

A prospective study of a quiet time protocol was conducted with 72 adult patients on mechanical ventilation.

SETTING

A Medical Intensive Care Unit (MICU) in the Midwest region of the United States.

RESULTS

Sedation was given less frequently after QT (p=0.045). Those who were agitated prior to QT were more likely to be at goal sedation after QT (p<0.001). Although not statistically significant, the majority of patients who were negative on the Confusion Assessment Method (CAM-ICU) prior to QT remained delirium free after QT. Repeated measures analysis of variance (ANOVA) for three consecutive QTs showed a significant difference for respiratory rate (p=0.035).

CONCLUSION

QT may influence sedation administration and promote patient rest. Future studies are required to further understand the influence of QT on mechanically ventilated patients in the intensive care unit.

The Effectiveness of Measures Aimed at Noise Reduction in an Intensive Care Unit

Noise is a significant problem for both hospitalized patients and health care workers. This study aimed to determine the effectiveness of noise reduction strategies in an intensive care unit. Noise was measured in two phases. In the first phase, the unit’s present level of noise was established over 3 weeks between January 1, 2012, and February 1, 2012. During the month following initial measurements, noise reduction interventions, including staff education and physical space arrangement, were initiated, and device alarms were checked. The second phase of measurement was conducted during another 3-week period (between June 1, 2012, and July 1, 2012). The noise levels before and after noise reduction interventions were calculated as 67.6 dB-A and 56 dB-A; the difference between the two levels was statistically significant ( p < .05). The interventions were effective in reducing noise in intensive care units; the interventions are relatively easy and low cost.

Noise Levels in Patient Rooms and at Nursing Stations at Three VA Medical Centers

Objectives:

To conduct an assessment of sound, dB(A) levels, in two areas of the hospital: patient rooms and nurse stations using sound meters (SMs).

Background:

The World Health Organization (WHO) recommends sound levels of 35 dB(A) during the day and 30 dB(A) during the night; however, many hospitals exceed these recommended levels. Assessing post-occupancy sound levels enables hospital administrators and healthcare workers to identify whether interventions to improve sound levels are needed.

Methods:

Sound assessments were conducted at three healthcare facilities in both patient rooms and nursing stations, and we include information on facility characteristics. An Amprobe SM-20A Sound Level Meter was placed for a 24-hr period and recorded decibel levels every 8 min. These sound levels were averaged for each hour for reporting purposes. Averages as well as highest and lowest readings are reported for both daytime (8 a.m.–10 p.m.) and nighttime (10 p.m.–8 a.m.) for each facility.

Results:

All three sites are considered urban and are classified with the highest complexity level (1a). Average daytime measurements for patient rooms and their corresponding nurses stations were as follows: Site A—63 dB(A)/56 dB(A), Site B—52 dB(A)/55 dB(A), and Site C—42 dB(A)/59 dB(A). Average nighttime measurements for patient rooms and nurses stations were Site A—62 dB(A)/55 dB(A), Site B—48 dB(A)/55 dB(A), and Site C—42 dB(A)/60 dB(A).

Conclusion:

Our findings, considered independently and collectively, showed that facilities in this study exceeded the WHO-recommended sound levels for patient rooms of 35 dB(A) during daytime and 30 dB(A) during nighttime. Research has reported negative patient outcomes, for example, decreased satisfaction, sleep disturbance, and higher incidence of rehospitalization in patients staying in areas with higher noise levels.

The effectiveness of environmental strategies on noise reduction in a pediatric intensive care unit: creation of single-patient bedrooms and reducing noise sources

PURPOSE

Noise is a substantial problem for both patients and healthcare workers in hospitals. This study aimed to determine the effectiveness of environmental strategies (creating single-patient rooms and reducing noise sources) in noise reduction in a pediatric intensive care unit.

DESIGN AND METHODS

Noise measurement in the unit was conducted in two phases. In the first phase, measurements aimed at determining the unit's present level of noise were performed over 4 weeks in December 2013. During the month following the first measurement phase, the intensive care unit (ICU) was moved to a new location and noise-reducing strategies were implemented. The second phase, in May 2014, measured noise levels in the newly constructed environment.

RESULTS

The noise levels before and after environmental changes were statistically significant at 72.6 dB-A and 56 dB-A, respectively (p < .05).

PRACTICE IMPLICATIONS

Single-patient rooms and noise-reducing strategies can be effective in controlling environmental noise in the ICU.

Defining the Medical Intensive Care Unit in the Words of Patients and Their Family Members: A Freelisting Analysis

BACKGROUND

No validated conceptual framework exists for understanding the outcomes of patient- and family-centered care in critical care.

OBJECTIVE

To explore the meaning of intensive care unit among patients and their families by using freelisting.

METHODS

The phrase intensive care unit was used to prompt freelisting among intensive care unit patients and patients' family members. Freelisting is an anthropological technique in which individuals define a domain by listing all words that come to mind in response to a topic. Salience scores, derived from the frequency with which a word was mentioned, the order in which it was mentioned, and the length of each list, were calculated and analyzed.

RESULTS

Among the 45 participants, many words were salient to both patients and patients' family members. Words salient solely for patients included consciousness, getting better, noisy, and personal care. Words salient solely for family members included sadness, busy, professional, and hope. The words suffering, busy, and team were salient solely for family members of patients who lived, whereas sadness, professionals, and hope were salient solely for family members of patients who died. The words caring and death were salient for both groups.

CONCLUSIONS

Intensive care unit patients and their families define intensive care unit by using words to describe sickness, caring, medical staff, emotional states, and physical qualities of the unit. The results validate the importance of these topics among patients and their families in the intensive care unit and illustrate the usefulness of freelisting in critical care research.

Therapeutic Use of Music and Television in Neurocritical Care: A Practice Survey

INTRODUCTION

Although health care providers often play music via radio, or play television, to calm and soothe patients, limited research is available to guide practice.

METHOD

This study used a 17-item practice survey that was distributed electronically to neurocritical care society members in July 2014. Responses were collated and analyzed using SAS (Version 9.3).

RESULTS

There were 118 completed responses, including from 71 attending physicians, 9 resident or fellow physicians, 30 nurses, and 8 affiliate professional members. The majority of respondents sometimes or always play music (65%) and agree that music is therapeutic (70%). However, there was no clear practice pattern regarding when or why music or TV should be used as an intervention in the neurocritical care unit.

CONCLUSION

The use of music and TV is a common intervention in the neurocritical care unit but lacks a strong scientific foundation and is associated with a high practice variance.

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.

The influence of environmental factors on sleep quality in hospitalized medical patients

Introduction: Sleep–wake disturbances are common in hospitalized patients but few studies have assessed them systematically. The aim of the present study was to assess sleep quality in a group of medical inpatients, in relation to environmental factors, and the switch to daylight-saving time.

Methods: Between March and April 2013, 118 consecutive inpatients were screened and 99 (76 ± 11 years; hospitalization: 8 ± 7 days) enrolled. They slept in double or quadruple rooms, facing South/South-East, and were qualified as sleeping near/far from the window. They underwent daily sleep assessment by standard questionnaires/diaries. Illuminance was measured by a luxmeter at each patient’s eye-level, four times per day. Noise was measured at the same times by a phonometer. Information was recorded on room lighting, position of the rolling shutters and number/type of extra people in the room.

Results: Compliance with sleep-wake assessment was poor, with a range of completion of 2–59%, depending on the questionnaires. Reported sleep quality was sufficient and sleep timing dictated by hospital routine; 33% of the patients reported one/more sleepless nights. Illuminance was generally low, and rolling shutters half-way down for most of the 24 h. Patients who slept near the window were exposed to more light in the morning (i.e., 222 ± 72 vs. 174 ± 85 lux, p < 0.05 before the switch; 198 ± 72 vs. 141 ± 137 lux, p < 0.01 after the switch) and tended to sleep better (7.3 ± 1.8 vs. 5.8 ± 2.4 on a 1–10 scale, before the switch, p < 0.05; 7.7 ± 2.3 vs. 6.6 ± 1.8, n.s. after the switch). Noise levels were higher than recommended for care units but substantially comparable across times/room types. No significant differences were observed in sleep parameters before/after the switch.

Conclusion: Medical wards appear to be noisy environments, in which limited attention is paid to light/dark hygiene. An association was observed between sleep quality and bed position/light exposure, which is worthy of further study.

Learning three sets of alarms for the same medical functions: a perspective on the difficulty of learning alarms specified in an international standard

Three sets of eight alarms supporting eight functions specified in an international medical equipment standard (IEC 60601-1-8) were tested for learnability using non-anaesthetist participants. One set consisted of the tonal alarms specified in the standard. A second set consisted of a set of abstract alarms randomly selected from a database of abstract alarm sounds held by the authors. A third set of alarms was designed as indirect metaphors of the functions. Participants were presented with the alarms and then asked to identify them across ten blocks of eight trials. The results indicated a significant difference in learnability across the three sets of alarms. The indirect metaphors were learned significantly better than both other sets of alarms, and the randomly selected abstract alarms were learned significantly better than the alarms specified in the standard. The results suggest therefore that there are more readily learnable possible designs than those proposed in the standard. The use of auditory icons in particular should be given serious consideration as potential alarms for this application.

Hearing, Listening, Action: Enhancing nursing practice through aural awareness education

Abstract Noise overload within the clinical environment has been found to interfere with the healing process for patients, as well as nurses ability to effectively assess patients. Awareness and responsibility for noise production begins during initial nursing training and consequently a program to enhance aural awareness skills was designed for graduate entry nursing students in an Australian university. The program utilised an innovative combination of music education activities to develop the students' ability to distinguishing individual sounds (hearing), appreciate patient's experience of sounds (listening) and improve their auscultation skills and reduce the negative effects of noise on patients (action). Using a mixed methods approach, students' reported heightened auscultation skills and greater recognition of both patients' and clinicians' aural overload. Results of this pilot suggest that music education activities can assist nursing students to develop their aural awareness and to action changes within the clinical environment to improve the patient's experience of noise.

Contralateral ear occlusion for improving the reliability of otoacoustic emission screening tests

Newborn hearing screening is an established healthcare standard in many countries and testing is feasible using otoacoustic emission (OAE) recording. It is well documented that OAEs can be suppressed by acoustic stimulation of the ear contralateral to the test ear. In clinical otoacoustic emission testing carried out in a sound attenuating booth, ambient noise levels are low such that the efferent system is not activated. However in newborn hearing screening, OAEs are often recorded in hospital or clinic environments, where ambient noise levels can be 60–70 dB SPL. Thus, results in the test ear can be influenced by ambient noise stimulating the opposite ear. Surprisingly, in hearing screening protocols there are no recommendations for avoiding contralateral suppression, that is, protecting the opposite ear from noise by blocking the ear canal. In the present study we have compared transient evoked and distortion product OAEs measured with and without contralateral ear plugging, in environmental settings with ambient noise levels <25 dB SPL, 45 dB SPL, and 55 dB SPL. We found out that without contralateral ear occlusion, ambient noise levels above 55 dB SPL can significantly attenuate OAE signals. We strongly suggest contralateral ear occlusion in OAE based hearing screening in noisy environments.