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.

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.

Use of noise reduction headphones. Pro For Sho safety ear muffs with a noise reduction rate of 34dB will be used.

Use of headphones and relaxing music. Sennheiser HD 280 pro headphones will be used for sound masking.

The effect of group assignment on nocturnal (8pm to 8am) low frequency/high frequency (LF/HF) ratio will be determined.

The effect of group assignment on nocturnal (8pm to 8am) root mean square of sequential differences of RR intervals (RMSSD) will be determined.

The effect of group assignment on nocturnal (8pm to 8am) blood pressure (mean arterial pressure) will be determined.

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

Assessed at the time of hospital discharge up to a maximum of 28 days after enrollment, and averaging 6 days after enrollment.

Assessed at the time of ICU discharge up to a maximum of 28 days after enrollment, and averaging 4 days after enrollment.

Assessed at the time of hospital discharge up to a maximum of 28 days after enrollment, and averaging 6 days after enrollment.

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.

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.

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

As this is a pilot study, there are no definite plans for sharing individual participant data at this time.