Milieu Enhancement Strategies for the ICU

By Linda L. Chlan, RN, PhD, Dean’s Distinguished Professor of Symptom Management Research, The Ohio State University, College of Nursing, is Associate Editor for Critical Care Alert.

Dr. Chlan reports that she receives grant/research support from the National Institutes of Health.

The modern-day intensive care unit (ICU) is a cacophony of noise from beeps, buzzers, loud conversations, and harsh lighting. Stimuli overload has been documented to be detrimental to critically ill patients.1 It is a wonder that patients actually recover from their critical illness in this type of environment that is extremely harsh! While high-tech interventions and care need to be available 24/7, the clinician is reminded to consider the impact of the physical environment when providing care to these complex patients. This special feature will focus broadly on the milieu of the ICU and suggest strategies and interventions to promote a more therapeutic, healing environment for patients and their family members.

Definition of Milieu

Milieu is defined by the Merriam-Webster dictionary2 as the physical or social setting in which something occurs or develops; its environment. The word milieu is of French origin with the first known use in 1854. Words related to milieu include: ambient, atmosphere, climate, clime, context, contexture, environs, medium, environment, mise-en-scène, setting, surround, surroundings, and terrain.2 From a medical perspective, milieu is simply defined as environment.

Florence Nightingale, nursing’s pioneering founder, described the importance of placing the patient in the best environment for healing.3 Nightingale believed that the first goal of a hospital was to do the sick no harm. In her era, there was no ICU with mechanical ventilation, antibiotics, or other technological treatment modalities. Her care interventions consisted of reducing noise and harsh lights, with a focus on fresh air and room cleanliness, all to promote a healing environment. It is time to revisit some of Nightingale’s principles of care to meet the goal of doing no harm to patients by promoting a healing environment in the ICU. One area to consider in meeting this goal of doing no harm to ICU patients is the topic of milieu enhancement.

Importance of Milieu Enhancement in the ICU

In the critical care unit, why are milieu consideration and the implementation of environmental enhancement strategies important? Noise alone is a major issue and source of stress for patients. In fact, the ICU has been documented as one of the noisiest health care environments.4 Elevated noise levels increase stress, which can affect the body’s ability to heal.4 An environment of constant noise and light stimulates the sympathetic nervous system with increased levels of catecholamines and leads to increased heart rate and vasoconstriction.5 While the World Health Organization recommends that noise levels not exceed 35 dB(A) during the day and 30dB (A) at night, ICUs noise levels typically are around 55-65 dB(A).6 Noise also interrupts the sleep-wake cycle of critically ill patients. In addition, harsh overhead fluorescent lighting can contribute to sleep disruptions.4 Further, reports from as early as 1993 have documented increased agitation in patients exposed to increased stimuli and noise.7

One study reported that the greatest amount of light exposure during the nighttime was for obtaining laboratory blood samples.8 The second most recorded activity with lights on in a patient room was noted to be “none,” suggesting that the room lights were left on during the night for no apparent specific reason.8 In addition to overhead lights being left on, another study documented on average 42.6 patient care interactions that occurred during the night, with bathing occurring for a majority of patients between 9 p.m. and 6 a.m.1

Strategies and Interventions to Enhance the ICU Milieu

There are a number of both common-sense strategies and evidence-based interventions that can be implemented to enhance the ICU milieu environment for patients. Some of these interventions are more appropriate for daytime hours while others are more suited for the night-time.

Common-Sense Strategies

The first step to enhance the ICU milieu is to perform an environmental scan to determine existing sources of noise and nuisance lighting evident in the ICU that might be amenable to intervention. The direct measurement of sound/noise levels can be accomplished with a decibel meter while light levels can be obtained with a lux meter. Further, staff can query patients and family members about bothersome sources of noise or light. If noisy door closures are verbalized as a source of irritation, contact hospital maintenance to determine if a buffering device can be added to muffle the door closure. Special compact disks, sources for “white noise,” or other noise-masking devices can be effective strategies to reduce some level of noxious noise in the ICU.

For patients with lengthy ICU stays, family members can be asked to bring in comforting items from home to personalize the environment. These items may include some favorite music, a favorite pillow or blanket, or a sleep mask if a patient uses one at home to facilitate rest and relaxation.

While newer ICUs require that patients have access to windows and natural light, older ICUs may not meet these requirements. One strategy would be to ensure that patients who are alert and awake have a room that contains a window. Open the blinds during the day and close them at night to mimic as closely as possible a normal day-night cycle.

Alarms from ICU equipment and monitors are significant sources of noise. False alarms and irrelevant alarms most frequently occur during routine nursing care, with up to 70% of these alarms identified as unnecessary.9 ICU staff are reminded to temporarily disable or minimize alarms while turning or suctioning a patient to prevent any unnecessary audible tone from sounding. Staff are reminded to carefully assess the need for monitoring equipment at least once per shift and and reset the ranges for alarms to ensure they are set to appropriately match the patient’s status. Monitoring equipment that sounds an audible alarm can be discontinued as soon as it is no longer needed.

Other common-sense strategies for enhancing the ICU milieu include a number of interventions that are specifically warranted for reducing noise during the nighttime. One of the first common-sense strategies is simply to turn down harsh overhead lights and turn down the telephones. Similarly, limit patients’ exposure to nighttime light and interruptions to promote rest and sleep. Exposure to bright, harsh light can alert the body to “wake up” when in fact it is the middle of the night. To safely carry out any necessary nighttime care interventions, the use of nighttime lighting and flashlights should be a priority for ICU staff. Whenever possible, any lighting directly above a patient’s bed should be dimmed to avoid bright light in the patient’s eyes. In addition, eye masks or sleep masks may be used to reduce light exposure in those patients who are more sensitive to or bothered by light. Further, any direct care interventions should be avoided if a patient is stable and does not need to physically be disturbed. Since ICU patients are continuously monitored, direct care interventions for stable patients should be clustered together so patients are not disturbed frequently and unnecessarily during the night.

Administrative support may be needed to reschedule routine nursing care activities that may be delegated to the night shift, such as bathing, routine radiology and laboratory blood draws, and linen changes at 3:00 a.m. These care activities should be rescheduled to daylight hours to foster uninterrupted nighttime periods of rest and sleep for ICU patients.

Evidence-Based Interventions

There have been a few studies testing interventions to reduce noise and enhance the ICU environment. One of these simple interventions is the use of ear plugs during the night. In a study by Van Rompaey and colleagues,10 earplugs used early in the ICU stay were found to significantly improve perceived nighttime sleep quality and reduce the risk for confusion in patients. Providing patients with preferred, relaxing music through headphones is one evidence-based intervention that can reduce anxiety and promote rest in the ICU.11

The implementation of quiet-time protocols is another strategy to enhance the ICU milieu, based on research evidence.5 The purpose of quiet-time protocols is to reduce noise and light levels as well as other environmental stimuli to promote rest and sleep. These protocols are implemented during both the day and night shifts. Quiet time can consist of turning down the lights, turning down the phones and alarm levels, and restricting interactions in the patient rooms, including unnecessary staff care interventions and visitation. Typically, quiet time is designated twice daily: during the mid-afternoon (2-4 p.m.) and during the night (1-3 a.m.). These times are specifically selected to mirror the natural circadian body rhythms to promote rest and sleep. ICU staff can utilize this evidence to design a quiet-time protocol that meets the needs of the patients on their respective ICUs.

Concerted efforts to minimize nocturnal nursing interventions are needed.12 All members of the health care team need to decide which care interactions can be safely omitted during the night or during designated quiet times to provide patients with uninterrupted rest periods.

A major source of noise irritation for patients is sounds from the many alarms on equipment and monitors found in the ICU. Gorges and colleagues9 suggested a number of strategies for safely minimizing false alarms associated with nursing care interventions. These include the design of smarter alarm systems that detect patient care information like suctioning, positioning, oral care, etc. that could validate a device alarm before it is sounded.9

Desired Outcomes of Milieu Enhancement in the ICU

Once goals and protocols for specific milieu enhancement strategies are designed, outcomes should be measured to determine whether the goals are being met. One basic goal could be assessing once per shift each patient’s perceptions of noise, rest, and relaxation. Any number of the suggested milieu enhancement strategies can be implemented to promote patient rest and relaxation. This in turn may improve patient and family satisfaction ratings, which are very important metrics in today’s health care environment. Milieu enhancement protocols can be used for quality improvement projects on individual ICUs.

A multidisciplinary approach is needed to implement the suggested common-sense and evidence-based milieu enhancement strategies. Staff champions are needed to design and implement protocols tailored for individual units; efforts are needed to sustain these efforts. The interventions to improve the ICU milieu will enhance the patient experience and promote a healing environment, leading to the achievement of the goal to do patients no harm.


  1. Tamburri LM, et al. Nocturnal care interactions with patients in critical care units. Am J Crit Care 2004;13:102-115.
  2. Merriam Webster Dictionary. Accessed January 8, 2013.
  3. Nightingale F. Notes on Nursing: What it is and what it is not. New York: Dover Publications; 1860, 1969.
  4. Tracy MF, Chlan L. Nonpharmacological interventions to manage common symptoms in patients receiving mechanical ventilation. Crit Care Nurs 2011;31:19-29.
  5. Dennis CM, et al. Benefits of quiet time for neuro-intensive care patients. J Neurosci Nurs 2010;42:217-224.
  6. Freedman NS, et al. Abnormal sleep/wake cycles and the effect of environmental noise on sleep disruption in the intensive care unit. Am J Respir Crit Care Med 2001;163:451-457.
  7. Grumlet GW. Pandemonium in the modern hospital. N Engl J Med 1993;328:433-437.
  8. Dunn H, et al. Nighttime lighting in intensive care units. Crit Care Nurs 2010;30:31-37.
  9. Gorges M, et al. Improving alarm performance in the medical intensive care unit using delays and clinical context. Anesth Analg 2009;108:1546-1552.
  10. Van Rompaey B, et al. The effect of earplugs during the night on the onset of delirium and sleep perception: A randomized controlled trial in intensive care patients. Critical Care 2012;16:R73.
  11. Heiderscheit A, et al. Instituting a music listening intervention for critically ill patients receiving mechanical ventilation: Exemplars from two patient cases. Music Med 2011;3:239-245.
  12. Le A, et al. Sleep disruptions and nocturnal nursing interactions in the intensive care unit. J Surg Res 2012;177:310-314.