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

Danielson, Samantha J.; Rappaport, Charles A.; Loher, Michael K.; Gehlbach, Brian K.

doi:10.1016/j.iccn.2017.12.006

Cited by 35 publications

(27 citation statements)

References 54 publications

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“…Intensive care units are particularly noisy areas of hospitals . Neonatal units have average sound pressure levels of 48–61 dB for up to 95% of the time , paediatric units average 53–73 dB and adult units are 53–59 dB . The unit at the John Radcliffe Hospital when measured in 2012 had daytime averages of 58 dB at the desk and 60 dB adjacent to the patient .…”

Section: Discussionmentioning

confidence: 99%

Mapping sources of noise in an intensive care unit

et al. 2019

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Summary Excessive noise in hospitals adversely affects patients’ sleep and recovery, causes stress and fatigue in staff and hampers communication. The World Health Organization suggests sound levels should be limited to 35 decibels. This is probably unachievable in intensive care units, but some reduction from current levels should be possible. A preliminary step would be to identify principal sources of noise. As part of a larger project investigating techniques to reduce environmental noise, we installed a microphone array system in one with four beds in an adult general intensive care unit. This continuously measured locations and sound pressure levels of noise sources. This report summarises results recorded over one year. Data were collected between 7 April 2017 and 16 April 2018 inclusive. Data for a whole day were available for 248 days. The sound location system revealed that the majority of loud sounds originated from extremely limited areas, very close to patients’ ears. This proximity maximises the adverse effects of high environmental noise levels for patients. Some of this was likely to be appropriate communication between the patient, their caring staff and visitors. However, a significant proportion of loud sounds may originate from equipment alarms which are sited at the bedside. A redesign of the intensive care unit environment to move alarm sounds away from the bed‐side might significantly reduce the environmental noise burden to patients.

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Section: Discussionmentioning

confidence: 99%

Mapping sources of noise in an intensive care unit

et al. 2019

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“…Though study limitations prevent us from reporting on light levels in study participants' rooms, it is worth commenting on since light is a strong synchronizer of the circadian system. Interestingly, some groups have observed a lack of bright light levels as well as a lack of 24-h variation in light levels in ICU patient rooms, which may contribute to circadian rhythm disruption in patients ( 16 , 17 , 44 ). Protocols to enforce strict light-dark cycles with sufficient brightness in ICU patient rooms during the day should be standard-of-care to help synchronize patient circadian rhythms.…”

Section: Discussionmentioning

confidence: 99%

Metabolomics Pilot Study Identifies Desynchronization of 24-H Rhythms and Distinct Intra-patient Variability Patterns in Critical Illness: A Preliminary Report

et al. 2020

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Background: Synchronized circadian rhythms play a key role in coordinating physiologic health. Desynchronized circadian rhythms may predispose individuals to disease or be indicative of underlying disease. Intensive care unit (ICU) patients likely experience desynchronized circadian rhythms due to disruptive environmental conditions in the ICU and underlying pathophysiology. This observational pilot study was undertaken to determine if 24-h rhythms are altered in ICU patients relative to healthy controls by profiling 24-h rhythms in vital signs and plasma metabolites. Methods: We monitored daily rhythms in 5 healthy controls and 5 ICU patients for 24 h. Heart rate and blood pressure were measured every 30 min, temperature was measured every hour, and blood was sampled for mass spectrometry-based plasma metabolomics every 4 h. Bedside sound levels were measured every minute. Twenty-four hours rhythms were evaluated in vitals and putatively identified plasma metabolites individually and in each group using the cosinor method. Results: ICU patient rooms were significantly louder than healthy controls' rooms and average noise levels were above EPA recommendations. Healthy controls generally had significant 24-h rhythms individually and as a group. While a few ICU patients had significant 24-h rhythms in isolated variables, no significant rhythms were identified in ICU patients as a group, except in cortisol. This indicates a lack of coherence in phases and amplitudes among ICU patients. Finally, principal component analysis of metabolic profiles showed surprising patterns in plasma sample clustering. Each ICU patient's samples were clearly discernable in individual clusters, separate from a single cluster of healthy controls. Conclusions: In this pilot study, ICU patients' 24-h rhythms show significant desynchronization compared to healthy controls. Clustering of plasma metabolic profiles suggests that metabolomics could be used to track individual patients' clinical courses longitudinally. Our results show global disordering of metabolism and the circadian system in ICU patients which should be characterized further in order to determine implications for patient care.

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“…34 Similarly, a study of light and sound measurements in a medical ICU showed that both were nearly completely disconnected from solar time. 5 As stated above, sleep is an important zeitgeber. In the ICU, sleep is of short duration and is predominantly light sleep with almost a complete absence of REM or slow wave components.…”

Section: Abnormal Zeitgebers In the Intensive Care Unitmentioning

confidence: 98%

“…Patients are most commonly shifted to either an advanced or delayed phase. 5 In addition, there are likely to be more complex circadian disruptions present in ICU patients. These disruptions may include loss of circadian amplitude, misalignment amongst peripheral clocks, and/or misalignment between the peripheral and master clocks.…”

Section: Master Clocks and Entrainmentmentioning

confidence: 99%

Circadian Biology and Its Importance to Intensive Care Unit Care and Outcomes

Gao

Knauert

2019

Semin Respir Crit Care Med

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Circadian rhythms are an integral part of life on earth. Circadian rhythms play a fundamental role in homeostasis as they ensure coordination between the environment and an organism's behavior and physiology. This coordination is called entrainment. Entrainment depends on environmental cues known as zeitgebers. Human zeitgebers include light (primary zeitgeber), sleep, eating, exercise, and activity. Circadian rhythms are disrupted in critically-ill patients due to both critical illness and current intensive care unit (ICU) practices. Disruptions in circadian rhythms are tightly linked with ICU sleep disruption. Together these entities potentiate numerous adverse outcomes including delirium, metabolic derangements, cardiovascular instability, and immune compromise. Herein, we will highlight potential areas for care improvement via chronobundles. We suggest bright light during the day, maintaining darkness, and protecting sleep at night, intermittent rather than continuous feeds, and activity via mobilization during the day. Optimizing circadian rhythms is a low-risk intervention that is underutilized in current ICU practice. This optimization could be a powerful tool in helping to improve outcomes in the critically-ill patient.

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

Abstract: 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.

Cited by 35 publications

References 54 publications

Mapping sources of noise in an intensive care unit

Mapping sources of noise in an intensive care unit

Metabolomics Pilot Study Identifies Desynchronization of 24-H Rhythms and Distinct Intra-patient Variability Patterns in Critical Illness: A Preliminary Report

Circadian Biology and Its Importance to Intensive Care Unit Care and Outcomes

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