Circadian Hygiene in the ICU Environment (CHIE) study.

Area of Science:

• Critical Care Medicine
• Sleep Science
• Environmental Health

Background:

• Intensive care units (ICUs) present unique environmental challenges that may impact patient recovery.
• Disruption of circadian rhythms, including core body temperature (CBT), is common in critically ill patients.
• Understanding the ICU environment's role in circadian disruption is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate the relationship between the ICU environment (light, sound, temperature, humidity) and nursing care interventions with patient circadian temperature disruption.
• To assess the impact of specific care activities on patient sleep and circadian rhythmicity.

Main Methods:

• A 30-day prospective period prevalence study was conducted in a 27-bed tertiary ICU.
• Data collected included ICU environmental factors (light, sound, temperature, humidity), nursing interventions (Therapeutic Intervention Scoring System-28), and patient core body temperature.
• 28 patients expected to stay at least 24 hours were included, with 71% on mechanical ventilation.

Main Results:

• ICU light intensity was low, peaking at 165 lux at 07:00 and troughing at 15 lux at 23:00, often below 100 lux overnight.
• Noise levels frequently reached 62.55 dB, comparable to conversational speech, with significant overnight presence.
• Care activities like linen changes and bathing disturbed overnight sleep in over 50% of patients; however, disrupted CBT rhythmicity was not clearly associated with environmental factors or nursing interventions.

Conclusions:

• The ICU environment is characterized by low light, suboptimal temperature and humidity for circadian alignment, and noise levels similar to conversation.
• Patient care procedures frequently interrupt overnight sleep.
• The direct contribution of these environmental factors and care activities to disrupted core body temperature rhythmicity in ICU patients remains unclear.