Noise in an inpatient hospital ward in New Zealand

This article describes an investigation into the noise levels which patients are exposed to in a general inpatient hospital ward in New Zealand. An initial noise survey was conducted over a period of nine consecutive days in order to establish the noise levels in the ward. It was identified that noise levels increased dramatically between 4:00 a.m. and 7:00 a.m. In order to identify the sources of noise during this period, three noise surveys were undertaken between 4:30 a.m. and 7:00 a.m. on typical weekdays using a microphone placed inside a shared bedroom. During the noise survey, an observer identified the noise sources and their locations for significant noise events. Noise sources were then categorised into three main groups based on the character of the source (machine, staff or patient). Staff noise was found to account for 64% of the total duration of significant noise events (29% of the number of events) which occurred during the observations compared with 20% from patients (43% of the number of events) and 16% from machines (28% of the number of events). It was found that many staff and machine noise events could be mitigated or eliminated. Methods for mitigating noise are suggested and an experimental method was used to estimate the likely reduction in noise which could be attained by moving a staff conversation from the corridor outside the observed bedroom to other locations on the ward.