Background noise in Iranian hospital intensive care units

Abstract

The genesis of noise criterion (NC) and preferred noise criterion (PNC) curves was the development of a method for evaluating of continuous indoor background noise in order to control goals. The aim of this study was to evaluate background noise to which patients in intensive care unit (ICU) are typically exposed, by NC and PNC curves. This cross-sectional study was conducted at ICU in a governmental hospital in Iran in 2015. In order to evaluate background noise by noise criterion curves (PNC and NC), background noise exposure levels in patient auditory zone in ICU were studied over a 24-hour period. Cel 450 sound level meter was used for noise measurement. Data were analyzed by Excel and SPSS 16 software. The average equivalent sound level (Leq) during the morning, afternoon and evening shifts was 62.5, 60.5 and 59 dBA, respectively. There is no significant relationship between Leq in three shifts, but, between Lmax and Lmin, a significant relationship in three shifts was found. PNC and NC curves for equivalent sound level during the 24-hour period were greater than PNC = 60 and NC = 55, respectively. According to the results, sound level, PNC and NC curves in ICU exceeded all national and international recommended standards for hospital environments. Results revealed that the low frequencies (?63 Hz) had high sound levels, whereas high frequencies (>1000 Hz) had low sound levels and frequencies between 63 and 1000 Hz had medium sound levels in ICU. To reduce the noise levels in ICU, financial and applicable measures such as environmental changes, constituting a “culture of quiet” and “masking or muting sources of noise” had been recommended.