Trial to Evaluate the Effects of Sound Modulation on Critically Ill Patients (SMART)

Prospective Randomized Controlled Trial to Compare and Analyze the Effects of Sound Masking and Reduction Techniques on Heart Rate and Blood Pressure Variability in Critically Ill Patients

The goal of the project is to determine the effects of noise masking and noise reduction on stress related physiological parameters in critically ill patients admitted to the intensive care unit.

Study Overview

• Status: Completed
• Conditions: Delirium; Critical Illness; Sleep Deprivation; Physiological Stress
• Intervention / Treatment: Device: Sound reduction; Device: Sound masking

Detailed Description

Sleep deprivation is common in critically ill patients in the intensive care unit (ICU) and may impair recovery. While noise is widely cited as the most common cause of sleep disruption in the ICU setting, its contribution to sympathetic activity in critically ill patients is not known. This is an important knowledge gap, because noise initiates a sequence of physiological changes including vasoconstriction, raised diastolic blood pressure, pupil dilatation and muscle tension. Furthermore, noise is implicated in sympathetic arousals, resulting in a release of adrenaline which prevents relaxation and consequently prevents the patient from falling asleep.

The investigators plan to study the effect of noise masking and noise reduction on stress related physiological parameters in critically ill patients admitted to the ICU. Subjects will be randomized into 3 separate groups: control, noise reduction, and noise masking. The investigators will compare the heart rate and blood pressure variability between and within the groups to determine the effects of treatment assignment on these variables. Non-invasive measurements obtained from the bedside monitor will be collected using physiological data acquisition software.

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • University of Iowa Hospitals and Clinics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Subjects aged 18-99 years who are expected to receive care on an adult critical care unit for at least 24 hours

Exclusion Criteria:

• Admission for drug overdose or with a known substance abuse disorder
• Untreated sleep apnea disorder, narcolepsy, REM sleep behavior disorder, parasomnia, restless leg syndrome or other sleep disorder
• Use of hearing aids, or known significant conductive or sensory hearing loss
• Ventilator support via an endotracheal tube
• Use of vasopressors
• Unresponsive or delirious
• Subjects with known Dementia, Parkinson's disease, or other neurodegenerative disorder
• Subjects with a pacemaker or who have received cardiac transplant

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Usual Care; Usual care will be provided.
Active Comparator: Sound reduction; Use of noise reduction headphones. Pro For Sho safety ear muffs with a noise reduction rate of 34dB will be used.	Device: Sound reduction; Subjects will wear noise reduction headphones between the hours of 8:00 pm and 8:00 am.
Active Comparator: Sound masking; Use of headphones and relaxing music. Sennheiser HD 280 pro headphones will be used for sound masking.	Device: Sound masking; Subjects will wear wear headphones playing relaxing music between the hours of 8:00 pm and 8:00 am.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nocturnal LF/HF ratio (a.u.)	The effect of group assignment on nocturnal (8pm to 8am) low frequency/high frequency (LF/HF) ratio will be determined.	Day 1 of study

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nocturnal heart rate (bpm)	The effect of group assignment on nocturnal (8pm to 8am) heart rate will be determined.	Day 1 of study
Nocturnal RMSSD (ms)	The effect of group assignment on nocturnal (8pm to 8am) root mean square of sequential differences of RR intervals (RMSSD) will be determined.	Day 1 of study
Nocturnal blood pressure (mm Hg)	The effect of group assignment on nocturnal (8pm to 8am) blood pressure (mean arterial pressure) will be determined.	Day 1 of study
Incidence of ICU delirium	The effect of group assignment on the incidence of ICU delirium as assessed by the CAM-ICU will be determined.	Assessed at the time of ICU discharge up to a maximum of 28 days after enrollment, and averaging 4 days after enrollment
Hospital length of stay (days)	The effect of group assignment on hospital length of stay will be assessed.	Assessed at the time of hospital discharge up to a maximum of 28 days after enrollment, and averaging 6 days after enrollment.
ICU length of stay (days)	The effect of group assignment on ICU length of stay will be assessed.	Assessed at the time of ICU discharge up to a maximum of 28 days after enrollment, and averaging 4 days after enrollment.
Hospital mortality (%)	The effect of group assignment on in-hospital mortality will be assessed.	Assessed at the time of hospital discharge up to a maximum of 28 days after enrollment, and averaging 6 days after enrollment.
Discharged home (%, versus discharge to another health care facility or died)	The effect of group assignment on being discharged directly to home (versus to another skilled care facility or died) from the hospital will be assessed.	Assessed at the time of hospital discharge up to a maximum of 28 days after enrollment, and averaging 6 days after enrollment.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intra-individual nocturnal LF/HF ratio (a.u.)	For each subject, the effect of treatment assignment on nocturnal (8pm to 8am) low frequency/high frequency (LF/HF) ratio will be determined by comparing the LF/HF ratio on Day 1 (intervention) with that on Day 2.	Days 1 and 2 of study

Collaborators and Investigators

• Sponsor: Brian Gehlbach
• Investigators: Principal Investigator: Brian K Gehlbach, MD, Faculty

Study record dates

Study Major Dates

• Study Start: December 1, 2016
• Primary Completion (Actual): December 31, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: December 19, 2016
• First Submitted That Met QC Criteria: January 10, 2017
• First Posted (Estimated): January 12, 2017

Study Record Updates

• Last Update Posted (Actual): April 6, 2025
• Last Update Submitted That Met QC Criteria: April 3, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: Heart rate; Blood pressure variability
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Pathologic Processes; Disease Attributes; Sleep Wake Disorders; Dyssomnias; Critical Illness; Sleep Deprivation
• Other Study ID Numbers: 201609843

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: As this is a pilot study, there are no definite plans for sharing individual participant data at this time.

Study Data/Documents

1. Informed Consent Form
   Information identifier: 201609843

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No