Investigating the Interplay of Thermal, Lighting, and Acoustics in Intensive Care for Enhanced Patient Well-being and Clinical Outcomes

Abstract

This research explores the interplay among noise levels, thermal conditions, and lighting intensity in an intensive care unit (ICU), focusing on preserving circadian rhythm and promoting nighttime sleep to advance patient-centric care. This investigation assesses lighting levels (Lux), natural versus artificial light ratios, ICU room temperature, and correlations with acoustic data during a field research period and examines the collective impact of patient exposure to sleep linked to delirium and health outcomes, addressing critical gaps in understanding. Findings reveal that noise levels between 60 and 90 dB(A) during patient occupancy exceed sleep disruption thresholds, with daytime averages of 53.6 dB(A) and nighttime averages of 48.5 dB(A) surpassing recommended criteria. Temperature fluctuations, often outside the optimal sleep range, and suboptimal diurnal variations impact patient comfort and clinician challenges. Lux levels mostly fall short of the optimum range, affecting circadian rhythms. Temporal distinctions of these environmental factors directly impact clinicians and patients, with correlated spikes in noise, lighting, and temperature during admission periods requiring heightened attention for optimal care. These cumulative impacts necessitate clinicians to navigate challenges and ensure consistent and effective care. Patients experience sleep disruptions, highlighting the need for a holistic healthcare design addressing interconnected environmental dynamics. The findings underscore the importance of comprehensive approaches to healthcare design, optimizing the ICU environment for patient-centric care and supporting healthcare professionals’ well-being. Recommendations include targeted interventions to improve sleep, reduce delirium incidence, and enhance recovery, advancing ICU design for better patient outcomes; and facilitating effective communication among healthcare practitioners.

Introduction

Due to the rigors of therapy and nursing care, intensive care unit (ICU) patients seldom sleep 7.5 h (Czempik et al., 2020). Utilizing a prospective data collection approach, with observations conducted postoccupancy to assess environmental conditions within the ICU setting, this multidisciplinary research examines how noise, temperature conditions, and lighting intensity affect patient sleep and health outcomes in a 40-bed ICU of a tertiary hospital in Perth, Western Australia. Sleep disturbance in ICUs owing to environmental conditions affects cognitive, physical, metabolic, and immunological capabilities. ICU sleep disturbances can harm patient outcomes in the short and long term.

Building on Jonescu et al. (2024), which focused on ICU acoustic management and its impact on patient well-being, this research expands to include thermal comfort and lighting conditions, essential factors for patient recovery. Conducted without a unit policy on sleep-protected time, the research examines lighting conditions during patient sleep. Similarly, the adjustment of window blinds, a critical factor in regulating ambient light, was also subject to nurse discretion.

The methodology uses both quantitative and qualitative methods, including acoustic monitoring with the Cirrus Optimus CR199B Analyser. Daytime sound levels consistently exceeded Australian/New Zealand Standard AS/NZS 2107:2016 and World Health Organization (WHO) noise guidelines at night. Findings from the acoustic research are synthesized with thermal and lighting data, with the objective of enhancing patient-centered ICU design.

Thermal comfort is crucial for patient satisfaction stress reduction, and recovery, while suboptimal thermal conditions impair sleep quality and metabolic stress, affecting patient recovery. Notwithstanding this, a paucity of research specifically addresses hospital thermal comfort. Optimal nighttime sleep temperature of around 20 degrees Celsius is optimal for sleep in covered individuals (Okamoto-Mizuno & Mizuno, 2012), aligning with the sleep-wake and circadian rhythms, which also affect clinician performance.

Light exposure, duration, intensity, and qualities such as wavelength affect circadian rhythms and sleep quality. A healthy circadian rhythm requires a daytime light intensity of between 1000 and 2000 lux (lx) for at least 30–60 min, (Blume et al., 2019, pp. 151–153) with light therapy studies recommending 10,000 lx for 30–45 min in the morning to promote healthy sleep–wake patterns (Richardson et al., 2018). Lighting research emphasizes the importance of natural light in circadian regulation and reducing stress, which also affects both patients and clinicians in the ICU.

This research integrates findings on noise, temperature, and lighting, to offer a holistic approach to improving patient well-being and clinical outcomes in the ICU.

Background

The brain cycles between rapid eye movement (REM) and non-REM sleep every 90 min during the seven to nine hours of sleep required by humans (Silber et al., 2007). The circadian rhythm is controlled by the suprachiasmic nucleus, with homeostatic neurochemical pathways involving peptides, hormones, and cytokines regulating sleep (Frenette et al., 2012). Both short-term sleep deprivation and chronic sleep loss impair cognitive, physical, metabolic, and immune functions.

Cognitive Function

The longest period without sleep in a human is 264 h, leading to fluctuating mental status and cognitive dysfunction (Durmer & Dinges, 2005; Ross, 1965). Short-term sleep loss affects attention memory, with impairments after 17 h of wakefulness equivalent to 0.05% blood alcohol level (Williamson & Feyer, 2000). Positron emission tomography of healthy sleep-deprived volunteers shows changes in the prefrontal cortex, thalamus, and posterior parietal cortex perfusion, overlapping with patterns of delirium (Lerner & Rosenstein, 2000; Thomas et al., 2000).

Physical, Metabolic, and Immunological Function

Even 30 h of sleep deprivation reduces muscular strength, particularly inspiratory endurance (Chen & Tang, 1989), while sustained sleep loss affects glucose metabolism, immune signaling, and cognition. Four nights of poor sleep reduce protein kinase B insulin signaling approaching levels seen in insulin resistance (Broussard et al., 2012).

Sleep deprivation also increases proinflammatory markers like C-reactive protein, and interleukin-6 levels elevating cardiovascular disease risk (Grandner et al., 2013; Haack et al., 2007). Cytokines which regulate physiological sleep are disrupted by sleep loss further impairing immune function (Krueger et al., 2006). Reduced sleep impairs vaccine response (Prather et al., 2012) and increases susceptibility to rhinovirus (Cohen et al., 2009).

Impact of Critical Illness on Sleep

Critical illness severely disrupts sleep, with ICU patients experiencing longer sleep latency, frequent arousals, and less REM sleep (Elliott et al., 2013; Tembo et al., 2013). Mechanically ventilated patients also show abnormal sleep patterns similar to nonintubated patients (Cooper et al., 2000). Polysomnography has shown significant sleep architecture disruption in ventilated patients regardless of sedation levels (Hardin et al., 2006).

Sleep Disruption and Adverse Outcomes in ICU

Sleep disturbance in ICU patients contributes to delirium, longer hospital stays, and higher mortality (Reade & Finfer, 2014). While sleep loss and delirium share risk factors, evidence linking sleep loss to delirium remains limited (Helton et al., 1980; Weinhouse et al., 2009). Critical illness survivors often face long-term sleep issues (Orr & Stahl, 1977), which are linked to poor psychological recovery following ICU hospitalization (McKinley et al., 2012; Little et al., 2012). Long-term health-related quality of life is also impaired by persistent sleep disruption following severe illness (Orwelius et al., 2008; Parsons et al., 2012).

Multifactorial Contributors to ICU Sleep Disruption

ICU sleep disturbance is multifactorial, with patients frequently citing noise and light as primary contributors (Delaney et al., 2017; Litton et al., 2017). This research explores ICU clinicians’ attitudes toward enhancing sleep and the enablers and barriers to doing so. This forms a critical phase in identifying ICU-tested sleep-improvement interventions, including design strategies. Poor architecture and inadequate acoustic control contribute to sleep deprivation in intensive care units (ICUs), with up to 50% of patients experiencing disruptions, primarily due to noise (Beltrami et al., 2015). Humans require seven to nine hours of sleep, cycling between non-REM and REM sleep in 90 min intervals (Raizen et al., 2008). Short- and long-term sleep deprivation impairs cognitive, physical, metabolic, and immune functions (Huber et al., 2004).

The Importance of Lighting

Research on intestinal photosensitive retinal ganglion cells highlights chronobiological, nonvision-related effects of light circadian regulation (Brown et al., 2022; Lazzerini Ospri et al., 2017). Proper circadian lighting has been shown to improve sleep quality and reduce nocturnal agitation (Figueiro et al., 2014; Richardson et al., 2018). Without sufficient rest, attention, cognitive function, and emotional regulation decline. While ICU standards recommend natural daylight and adjustable artificial lighting, daily intensity remains undefined (Thompson et al., 2012).

Light exposure in the evening suppresses melatonin, delaying the circadian clock and complicating sleep. Brown et al. (2022) suggest a maximum melanopic equivalent daylight illuminance (EDI) of 10 lx in the evening, beginning at least three hours before bedtime, and a daytime (indoor) EDI of 250 lx. Artificial lighting should replicate daylight's shorter wavelengths aligning with the melanopic spectrum (Brown et al., 2022). Circadian lighting transitions from reddish-yellow in the morning to blue midday and back to reddish-yellow in the evening, simulating natural light’s wavelength-dependent shifts (Blume et al., 2019; Centers for Disease Control and Prevention, 2020; Walker et al., 2020), though natural sunlight remains the optimal source for circadian regulation.

Mitigating Sleep Deprivation in the ICU

To mitigate sleep deprivation in the ICU, Czempik et al. (2020) measured light levels during sleep-protected time and found that levels of 11 ± 9 lx did not significantly impact sleep quality or quantity. For context, established lux benchmarks include 80,000lx for a bright sunny day, 5,000lx on a cloudy day, 300lx at a moderately lit workstation, and 100lx in a general room (Szokolay, 2017).

Illumination plays a key role in task-based lighting, safety, observation, thermal load, and solar orientation, to harness the “best light” (Jonescu, 2013, 2017). Natural lighting reduces stress (Morales-Bravo & Navarrete-Hernandez, 2022) and benefits both personnel and patient rehabilitation. The ratio of natural to artificial light should be carefully considered.

Examining the Interactions Between Temperature, Lighting, and Acoustic Elements in ICUs

Our research examines the interactions between temperature, lighting, and acoustic elements in ICUs. Thermal comfort is a mental state linked to satisfaction with surrounding thermal conditions (Szokolay, 2017), yet there is limited literature connecting thermal comfort with health outcomes in hospitals (Khodakarami & Nasrollahi, 2012). Thermal comfort influences patient satisfaction, stress, and psychological well-being (de Dear et al., 2013), while optimal temperature conditions support sleep quality and recovery (Gilbert et al., 2004).

ICU patients, who often have impaired immune systems and altered metabolisms, may face metabolic stress if thermal conditions are inadequate (Simsek et al., 2014). Maintaining optimal thermal conditions in healthcare settings, especially critical care environments, is critical for patient recovery, as well as staff performance (Pereira et al., 2020; Yuan et al., 2022). The circadian rhythm regulated in part by core body temperature (Tcore), affects sleep, with lower Tcore promoting sleep (Czeisler et al., 2005; Okamoto-Mizuno & Mizuno, 2012).

Acoustic, temperature, and lighting dynamics must be studied together to understand their impacts on patient outcomes and clinical care. This research fills an important gap by highlighting the integrated role of these factors in ICU design contributing to patient-centered improvements during critical health vulnerability.

Methodology

This research utilized case study analysis, fieldwork observations, and an environmental data collection approach to comprehensively assess environmental factors influencing the ICU. The field research involved placing acoustic, temperature, and light data loggers in Room 109, a single-occupancy ICU room of the 40-bed Fiona Stanley Hospital ICU, a tertiary referral center in Perth, Western Australia (Institutional Review Board Approval No. 46840), from 10 a.m. Tuesday, August 16, 2022, to 7:00 a.m. Tuesday, August 23, 2022 (approximately 1 week) see Tables 1 and 2. There are no accessible outdoor grounds or gardens visible from the patient's room that could influence lighting conditions.

Table 1.

Room 109 ICU Admission and Discharge Times During the Study Period.

Admission	Discharge
August 15, 2022, 08:15	August 17, 2022, 17:45
August 19, 2022, 12:12	August 20, 2022, 15:30
August 23, 2022, 10:34	August 23, 2022, 19:00
August 23, 2022, 22:00	August 26, 2022, 10:15

Note. ICU = intensive care unit. Each entry reflects the stay of an individual patient in the single-occupancy ICU room, with a total of four unique patient admissions recorded. The times and dates can be cross-referenced with Figures 1–4 for a comprehensive analysis of environmental conditions during each patient's stay. The environmental conditions in the ICU—noise, temperature, and lighting—impact all patients and clinicians equally, regardless of the number of occupants. Establishing environmental factors against benchmarks for these variables is essential, as they consistently affect recovery outcomes and staff performance, whether the ICU is at full or partial capacity. Thus, the focus remains on identifying and addressing these persistent issues for the benefit of both current and future patients.

Table 2.

Room 109 ICU Daytime and Nighttime Lighting Within Optimal Range for Sleep.

Admission	Percentage daytime light >1,000 lx	Percentage nighttime light <10 lx
1	2.6	70.8
2	10.9	97.2
3	0	NA
4	2.0	66.6

Note. ICU = intensive care unit.

Baseline Assessment of Noise, Temperature, and Light Conditions

The research conducted a baseline audio test, sound logging, temperature, and light assessment. The locations of the data loggers were determined in consultation with the Nurse Manager to ensure they did not disrupt normal day-to-day clinical operations and were in approximate alignment with the patient's pillow in the north–south axis.

The case study (Room 109) is a single-occupancy ICU room with a floor area of 25 m², operating 24 h a day, intended for one patient requiring intensive medical treatment, one visitor, and six to eight staff members. The artificial lighting in the ICU comprises overhead panels and bedside spotlights. While the case study lacks a standardized sleep-protected time policy the research established: daytime (7 a.m. to 10 p.m.), and nighttime (10 p.m. to 7 a.m.) parameters. Recognizing the importance of light for both patient well-being and staff alertness during long shifts, this research aimed to understand how fluctuating light levels might influence clinical performance and patient recovery.

The variable nature of overhead lighting and window blind management presented challenges, which were accounted for in the research design to provide a comprehensive understanding of the impact of these environmental factors on the data within the ICU setting. Site visits were conducted to assess the spatial layout and specifications against the Australasian Health Facility Guidelines (AusHFG, 2016).

The noise monitoring equipment, comprising a Cirrus Optimus CR199B Analyser (serial number G061705) and a NATA-calibrated Class 1 sound level meter, was strategically placed in Room 109. The noise monitoring equipment underwent field calibration before and after measurements, demonstrating no calibration drift. The data logger captured readings at one-minute intervals throughout the monitoring period. Postprocessing was performed using proprietary software to obtain noise level data, time profiles, and statistical noise levels. The data were graphed at 15 min intervals in conjunction with the LAmax noise level, representing the highest recorded noise level (peak) within each interval (Jonescu et al., 2024).

The analysis included LAeq and LA90 noise levels, providing insights into average and background noise levels, respectively. The latter might be influenced by constant sources such as ventilators or air-conditioning. Alarm-associated noise levels were measured separately using a NATA-calibrated Bruel and Kjaer 2270 Hand-held analyzer (Serial No. 2644641) at a 1 m distance. It is essential to note that elevated noise levels not only impact patient sleep and recovery but also contribute to clinician stress and reduced communication efficacy during critical care tasks (Jonescu et al., 2024).

A HOBO® MX2202 data logger was employed to gather data on both temperature and light conditions at one-minute intervals for a comprehensive assessment. Simultaneously, an LX 1010 BS Lux Meter was utilized as a cross-verification tool to ensure the accuracy and reliability of the light readings. This dual-method approach aimed to enhance the robustness of the research's environmental assessments, providing a thorough and validated dataset for further analysis. The data logger was situated on a vertical plane at approximately 1.2 m in height. Humidity levels were not measured.

The research involved overlaying the observed data with optimal target ranges for noise, temperature, and light intensity, providing a nuanced understanding of when these environmental factors were within or outside the desired thresholds. By doing so, this methodology allows us to identify critical periods and their potential impact on patient well-being and clinical operations, such as how fluctuations in temperature may affect clinician comfort and efficiency during patient care, ultimately influencing recovery times.

Findings

Lighting Levels During Admission Periods

During the first Admission period on August 15, 2022, a nighttime temperature spike coincided with elevated lux levels, peaking at 649 lx at 20:00 (see Figure 1). The second nighttime spike on August 15, 2022, showed a spike in lux levels to 497 lx. A spike during Discharge (August 17, 2022, 17:45) occurred during daytime hours, reaching 815 lx. An admission spike on August 19, 2022, saw lux levels briefly entering the optimum range for daytime light exposure, reaching 1180 lx. The subsequent discharge (August 20, 2022, 15:30) presented a spike in lux to just over 1000 lx. Lux levels during the final Admission on August 23, 2022, peaked at 1013 lx around discharge time (see Figure 4). Mean daylight lx and standard deviations are as follows: admission (1) 367.3 (345), admission (2) 551.2 (368), admission (3) 208.2 (82), and admission (4) 413.8 (327). Table 3 outlines the percentage of time the daytime and nighttime lighting was within optimal range for sleep.

Figure 1.

Room 109 intensive care unit (ICU) Temperature, light, and acoustic data between August 15, 2022, and August 17, 2022, while a patient was in the room.

Figure 4.

Room 109 intensive care unit (ICU) temperature, light, and acoustic data between August 23, 2022, and August 26, 2022, while a patient was in the room.

Table 3.

Room 109 ICU Sound, Temperature, and Light Levels—Time Within Optimal Range.

Environmental Factor	Percentage Time Within Optimal Range
	Daytime	Nighttime	Overall
Occupied periods
Sound (AverageLAeq)	0.6	5.6	2.3
Temperature (C)	45.5	61.5	51.1
Light (lux)	5.7	73.6	29.5
Vacant periods
Sound (LAeq)	16.9	48.1	28.8
Temperature (C)	84.5	100	91.1
Light (lux)	5.5	94.1	41.0

Note. ICU = intensive care unit.

Lux recordings, in general, frequently fell below the optimum range for daytime light exposure recommended for daytime exposure to support circadian rhythm. While this lux level is generally sufficient for clinicians to perform their activities prolonged exposure to suboptimal lighting may lead to decreased alertness during long shifts, potentially impacting the clinicians’ focus, decision-making, and overall well-being. Conversely, nighttime lux levels often exceed the recommended threshold of 30 lx, which can disrupt patients’ circadian rhythms and hinder their ability to achieve restorative sleep. Poor sleep quality among patients is linked to prolonged recovery times, as it can negatively affect physiological healing processes and overall well-being. Thus, the suboptimal lighting conditions observed in the ICU create a dual challenge, detrimentally affecting both clinician performance and patient recovery experiences.

Standard lux levels for various rooms/settings, offering a comparative reference to contextualize the lux levels detected in the ICU against established benchmarks are provided in Table 4 (see Discussion section).

Table 4.

Compiled Using Data From Alzubaidi & Soori (2012), Outlines Standard Lux Levels for Various Rooms/Settings, Offering a Comparative Reference to Contextualize the Lux Levels Detected in the ICU Against Established Benchmarks.

Area	Illuminance standard (lx)
Corridors: at night	50
General lighting	100
Waiting rooms/corridors: during the day	200
Staff rooms/reading lighting	300
Simple examinations	300
Staff office	500
Examination and treatment wards	1,000
Overcast daylight	1,000 to 5,000
Ambient daylight	10,000 to 25,000

Note. ICU = intensive care unit.

Temperature Fluctuations During Admission Periods

The temperature spiked during the first admission period on August 15, 2022, reaching 24.19°C, with an average temperature of 24.05°C. A second nighttime spike on August 15, 2022, saw the room temperature unaffected, averaging 23.46°C. During discharge (August 17, 2022, 17:45), a spike occurred, reaching 23.12°C. An admission spike on August 19, 2022, saw temperature reaching a high of 23.29°C. The subsequent discharge (August 20, 2022, 15:30) presented negligible impact on temperature, remaining at approximately 22.86°C (see Figure 2). The final admission on August 23, 2022, showed no significant change in temperature. Diurnal temperature range ranged from: admission (1) 0.0°C, admission (2) 0.4°C, admission (3) N/A, and admission (4) 0.5°C. The findings revealed that temperature conditions in the ICU frequently deviated from the recommended optimal range for sleep during nighttime hours. During critical admission and discharge periods, temperature spikes were observed, which not only compromised patient comfort but also posed challenges for clinicians. Elevated temperatures can lead to increased physical discomfort for staff, potentially affecting their concentration and overall performance during critical care situations.

Figure 2.

Room 109 intensive care unit (ICU) temperature, light, and acoustic data between August 19, 2022, and August 20, 2022, while a patient was in the room.

For patients, unstable thermal conditions hinder their ability to achieve restful sleep, a vital component of the recovery process. Inadequate thermal regulation can result in heightened physiological stress responses, negatively impacting healing times and recovery outcomes. Therefore, suboptimal temperature settings in the ICU adversely affect both the working conditions of healthcare professionals and patient recovery, underscoring the necessity for improved thermal management strategies.

Noise Spikes During Admission and Discharge Periods

During the first Admission period on August 15, 2022, an LAeq spike of 71.2 dB and LAFmax of 108.9 dB was detected. A discharge spike on August 17, 2022, showed an LAeq of 57 dB and LAFmax of 84.3 dB. An admission spike on August 19, 2022, saw an LAeq spike of 60 dB and LAFmax of 88.3 dB. The subsequent Discharge (August 20, 2022, 15:30) presented an LAeq spike of 60.9 dB and LAFmax of 94.7 dB. No significant spikes in data were detected during the final Admission on August 23, 2022 (see Figure 3). The acoustic analysis indicated that noise levels within the ICU consistently exceeded recommended thresholds, with recorded levels ranging between 60 and 90 dB(A) and a mean of 74 dB(A). These elevated noise levels can significantly impact clinician performance and patient outcomes. For healthcare professionals, prolonged exposure to high noise levels can lead to increased stress and fatigue, which may impair cognitive function and decision-making abilities during critical care situations. This stress can further disrupt effective communication among the healthcare team, potentially compromising patient safety and care quality (Jonescu et al., 2024).

Figure 3.

Room 109 intensive care unit (ICU) temperature, light, and acoustic data on August 23, 2022, while a patient was in the room.

Moreover, for patients, the high noise levels can interfere with sleep patterns, which are crucial for recovery. Disrupted sleep can exacerbate feelings of anxiety and discomfort, hindering the body's natural healing processes. The cumulative effect of noise disturbances during key moments of patient care, such as during admissions or procedure transitions, may not only affect individual recovery but also prolong hospital stays. Thus, the significant presence of disruptive noise in the ICU underscores the urgent need for design interventions aimed at mitigating acoustic disturbances, fostering a healing environment for patients, and optimizing working conditions for healthcare professionals.

Overall Trends

Table 3 provides an overview of the percentage of time the ICU sound, temperature, and light levels are within optimal range.

Discussion

This section analyses how noise levels, thermal conditions, and lighting intensity impact clinicians’ working conditions and patients’ recovery in the ICU, offering design-based recommendations for optimizing performance.

The temporal dynamics of these environmental factors reveal a complex interplay that affects patient comfort and recovery. Rather than treating these factors in isolation, acknowledging their collective influence provides a more comprehensive understanding of their effects. These elements fluctuate throughout the day, influenced by ICU activities and external conditions, underscoring the importance of performance-based analysis in healthcare design.

Thermal Conditions and Lighting

Temperature consistently remained outside of the optimum range for sleep at night, and the lack of diurnal variation is not optimal for circadian rhythm regulation. Daytime lux levels reached the recommended 1000—2000 lx range, necessary for maintaining circadian rhythm. During the research period, lux recordings entered the optimum range for daytime light exposure levels <10% of the time.

Though our research did not collect light wavelength data, it is essential to note that “white” light-emitting diodes (LEDs), often fail to replicate sunlight's 480 nm output which is critical for circadian alignment. Future research should explore spectral data to better understand its influence on ICU environments. In line with existing standards such as the well standard, selecting LEDs that mimic sunlight across the melanopic spectrum is crucial for patient well-being.

Noise Levels

The acoustic analysis revealed that noise levels during patient occupancy ranged from 60 to 90 dB(A), with a mean of 74 dB(A) exceeding the sleep disruption threshold of 50–55 dB(A).

Overall, daytime Leq averaged 53.6 dB(A), and nighttime Leq averaged 48.5 dB(A). During occupancy, daytime Leq averaged 55.8 dB(A) and 50.4 dB(A) at night. These findings exceed the criteria set by AS/NZS 2016: 2017 and WHO guidelines, but are somewhat lower than those recorded in other Australian ICUs (Elliott et al., 2010). Additionally, Lmax frequently ranged between 60 and 90 dB(A) when patients were present, with a mean of 74 dB(A), significantly surpassing the recommended limits for sleep disruption of the WHO Guidelines for Community Noise (1999) which advise a Leq of 30 dB(A) and Lmax(F) of 40 dB(A) at night (Darbyshire & Young, 2013; Jonescu et al., 2024).

Notably, these findings align with previous research on ICU noise levels, which highlighted that excessive noise impedes both clinical care and patient recovery (Jonescu et al., 2024). Our research echoes staff perceptions from earlier surveys that high noise levels, especially during critical care periods, increase stress and reduce communication efficacy. Noise spikes during medical procedures, such as the nighttime LAeq spike of 71.2 dB(A) and LAFmax of 108.9 dB, could lead to clinician stress levels, impact communication effectiveness, and hinder patient recovery, reinforcing the importance of noise mitigation in ICU design.

Design Recommendations

Noise and Integrated Services

Noise, temperature, and lighting conditions in the ICU significantly affect both clinicians and patients, necessitating a holistic approach for optimal care. High environmental stressors, particularly during admission periods, demand closer attention. The following design recommendations aim to advance patient-centered care and improve working conditions for healthcare staff.

Noise Control

As highlighted by Jonescu et al. (2024), noise not only disrupts patients but also affects clinicians’ ability to provide care, intensifying stress and reducing communication effectiveness. To address this: (1) integrate building management systems for real-time environmental monitoring and adjustments; (2) implement automated systems to adjust conditions based on sensor inputs; (3) ensure regular maintenance of heating, ventilation, and air- conditioning (HVAC), lighting, and acoustic systems; (4) foster interdisciplinary collaboration between architects, engineers, and healthcare professionals to create holistic, outcomes-driven spaces; (5) select medical and HVAC equipment that generate lower operational noise; and (6) implement sound masking systems to mitigate disruptive sounds.

Temperature Control

Thermal comfort, often underprioritized, adapts to external factors such as occupancy detection and climate control system settings. The recommended ICU temperature range (21–24 °C) was frequently not achieved, especially during key periods such as admissions and discharges (Saran et al., 2020). Temperature spikes during admission and discharge periods, notably at 19:45 on August 15, 22, and at night on August 19, 22, raise concerns for both clinician performance and patient comfort. Design recommendations include: (1) installing HVAC systems capable of precise temperature and humidity control; and (2) employing smart thermostats with occupancy sensors to maintain optimal conditions conducive to sleep.

Light Level Control

Daytime light levels in the ICU should reach 1000 to 2000 lx to support circadian rhythms, while nighttime levels should remain below 30 lx. The research data from August 19, 2022, indicate lux level spikes that were disruptive during both admission and discharge periods. Table 4, compiled from Alzubaidi & Soori (2012), contextualizes standard lux levels for various room settings.

Design recommendations include: (1) where feasible, maximize natural light through windows and light shelves deeper into the building; (2) install energy-efficient LEDs that adjust color temperature and intensity to mimic natural daylight; (3) provide adjustable task lighting at workstations and patient beds; and (4) use automated blinds or shades to manage glare and daylight exposure.

Conclusion

This extensive research of ICU environmental factors’ temporal dynamics shows how noise, temperature conditions, and lighting levels interact. Recognizing the cumulative impact of these elements enhances knowledge of their capacity to substantially impact clinicians’ working conditions and patients’ recovery experiences.

The periodic fluctuations observed throughout numerous admission and discharge periods show that these environmental components respond to varied activities and external factors. These strategies enrich the scientific narrative and highlight healthcare's linked dynamics. Through performance-based analysis in the complex ICU temporal fabric, such insights advance healthcare design.

Acoustic research showed noise levels above prescribed thresholds, potentially affecting physicians’ stress and communication. Noise at vital moments might interrupt sleep habits and slow recovery for patients.

The thermal environment had a temporal rhythm, with temperature increases at entry and discharge. Clinicians and patients needed optimal and stable temperature conditions for medical care and recuperation.

Lighting levels, both day and night, posed issues for medical staff and patients. Balanced visibility during patient care with patient well-being, especially during transitions, showed the paradoxical nature of workplace lighting against appropriate ICU illumination.

During patient occupancy, the combined effects of noise, temperature, and lighting spikes illustrate the difficulty of regulating several environmental conditions underlining the necessity for comprehensive healthcare design.

In conclusion, the research highlights environmental dynamics and informs healthcare design. Noise, temperature, and lighting levels should be considered in healthcare design, according to the research. This strategy is essential for patient-centered care, healthcare worker well-being, and ICU quality. With these findings, future research and treatments might improve hospital settings, encouraging healing, comfort, and well-being.