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

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.