Evaluation of Noise Levels in Intensive Care Units in Two Large Teaching Hospitals – A Prospective Observational Study

Abstract

Critically ill patients do not sleep well. One of the major environmental factors influencing sleep is noise. We prospectively measured noise levels and their relation to the time of day and location in different parts of two separate intensive care units (ICUs). Maximum, minimum and average noise levels were collected over 24 hour periods on five random days in both ICUs using digital sound meters, measured by the A-weighted decibel scale (dB (A)). The World Health Organisation (WHO) recommends that the average background noise in hospitals should not exceed 35 dB (A), and that peaks during the night should be less than 40 dB (A). The measured noise levels in both ICUs were well above the WHO standards. We recommend that various aspects, including staff education and modification of ICU design, must be carefully considered to provide an optimum environment for critically ill patients.