The effect of noise in the emergency department

It is hypothesized that high ambient noise in the emergency department (ED) adversely affects the ability of the examiner to hear heart and lung sounds.

To determine the ability of various examiners to hear heart tones and lung sounds at the high end of loudness typically found in the ED setting.

The study was divided into two parts. First, sound levels in the ED were measured over various times during the months of January through June 2001, using a sound level monitor. The second part of the study was the determination of the ability to hear heart and lung sounds on a young healthy volunteer using the same Littmann lightweight stethoscope at a predetermined ambient noise level of 90 dB. The results were entered into a database and analyzed using SPSS version 10 (Chicago, IL). Descriptive statistics, analysis of variance, frequencies, and correlation were calculated using this program.

Two hundred five sound measurements were taken in the ED during the study period in three locations at various hours. The mean noise level at the nursing station was 57.60 dB, with a minimum of 45.00 dB and a maximum of 70.00 dB. Four of the 104 test subjects (3.8%) were unable to hear the heart tones, and nine of the 104 (8.7%) were unable to hear the lung sounds. Fifty percent (27 of 54) of the test subjects reported diminished lung sounds and eight of 15 (53.3%) reported diminished heart sounds. No significant difference was found between hearing heart sounds and years of experience, age, professional position, and quality of the sound. Significant differences were found between hearing lung sounds and years of experience and professional position, but not with age, gender, and sound quality.

This study demonstrated that most of the tested examiners have the ability to hear heart and lung sounds at the extreme of loudness found in one ED.