Noise levels in a burn intensive care unit

Introduction: Increased noise levels in hospitals, critical care units, and peri-operative areas have been associated with higher levels of sleep deprivation and patient stress. The World Health Organization (WHO) guidelines stipulate a limit of 35 decibels (dB(A)) equivalent continuous sound level (LEq) during the day and 30 dB(A) LEq at night in patients' rooms. To date, no quantitative studies of noise levels have been performed in burn units. The objective of this study was to quantify noise levels in a burn critical care unit to ascertain compliance with guidelines in order to minimize this potential insult.

Methods: An A-weighted sound pressure level meter was used to measure the ambient noise levels in a burn intensive care unit. Maximum and minimum sound pressure levels were measured at 30-min intervals on 10 days over a 1 month period. Measurements were obtained during shift changes and random times during the day and night-time. Descriptive statistical analyses were performed, to calculate means and standard deviations. Noise measurements at specified times were compared using analysis of variance (ANOVA).

Results: Mean dB(A) LEq values for shift changes, day, and night-time were 65.9 ± 2.8, 65.7 ± 2.6, and 60.9 ± 5.2 dB(A), respectively. There was no significant difference in dB(A)(max) or dB(A)(min) between shift changes, day or night-time (p>0.05). However, night-time minimum values were consistently lower. There was no significant difference between sound pressure level (SPL) inside and outside patients' rooms (p>0.05) at any time.

Conclusions: Irrespective of time or location, the mean dB(A) LEq in the burn unit was significantly greater than World Health Organization (WHO), National Institute for Occupational Safety and Health (NIOSH), and the Environmental Protection Agency (EPA) recommendations. Guidelines for decreasing noise exposure are necessary to reduce potential negative effects on patients, visitors, and staff.