Measured Levels of Hospital Noise Before, During, and After Renovation of a Hospital Wing, and a Survey of Resulting Patient Perception 1
Cassandra H. H Wiese Lily M. Wang, PhD, PE 2011 ASHRAE Winter Conference, Las Vegas, NV
Architectural Engineering Program Durham School of Architectural Engineering and Construction University of Nebraska-Lincoln
Special p Thanks to the staff and patients of the collaborating medical facility! Partially supported by ASHRAE Graduate Grant-in-Aid
Learning Objectives for this Session • Describe how sound levels have changed over the last 50 years. g y • Describe how patients and staff subjectively rank various noise sources in the hospital, including noise from HVAC systems. • Plan for how occupancy impacts hospital background noise levels. • Learn how to characterize hospital background noise by using detailed acoustic Learn how to characterize hospital background noise by using detailed acoustic measurements. • Define current acoustic guidelines for hospitals and describe how well they are met in current facilities. • Explain how peak and ambient noise levels in a hospital may be affected differently by material, environmental and/or staff behavioral changes. ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA members. Certificates of Completion for non‐AIA members are available on request. This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Hospital Noise Guidelines 3
y Noise impacts patients’ patients physical and psychological health {
Sleep deprivation
{
Stress levels (perhaps leading to increased pain medication, length of hospital stay stay, and wound healing times)
y World Health Organizations(WHO) guidelines {
35 dBA max in i patient i rooms - day d
{
30 dBA max in patient rooms - night
{
LAmax sound events not exceed 40 dBA at night
y Recent survey found average levels of 72 dBA during day, 60 dBA at
night (Busch-Vishniac et al 2005)
Previous Work 4
y How do changes g to hospital p environment affect
sound levels and patient perception of noise? {
Acoustical material treatment more likely to impact ambient noise levels
{
Environmental controls (like dimmed lights, visual alarms, behavioral changes g byy staff or p patients)) more likelyy to impact p peak levels
{
Some research indicating improved patient satisfaction …due d to acoustical i l materials i l (M (MacLeod L d et all 2005)) Ù …due to environmental controls (Taylor-Ford et al 2008, Overman Dube et al 2008) Ù
Goals of Study 5
y Objectively measure if sound levels changed before, during, and after
renovation i off a h hospital i l wing i y Determine if the patients’ perception of care was impacted by the
improvements y Use results to make further improvements p and suggestions gg
6
Black dots indicate location of sound level meters
Hospital floor plan
Nurses’ Station 7
Before
After
Patient Room 8
Before
After
Hallway 9
Before
After
Sound Level Meter Measurements Procedure 10
y Sound level meter (SLM) measurements: { {
Three locations: nurses’ station, a patient room, and hallway Three time periods: Ù Ù Ù
{
before renovations (December 2009) during renovations (March 2010) after renovations (May 2010)
Logged gg everyy 10 seconds continuouslyy over a four-dayy p period from Monday through Thursday
y Data analyzed: { {
Hourly A-weighted equivalent sound levels (Leq) Various exceedence levels (Ln) Ù Ù
L10 = level L l l off sound d exceeded d d 10% % off the th time ti period i d (~peak) ( k) L90 = level of sound exceeded 90% of the time period (~ambient)
Patient Survey Procedure 11
y Patients survey criteria: { { {
{
at least 19 years old able to read English able to cognitively g y understand the surveyy as determined byy the distributing staff stayed at least one night in the hospital unit between February and June 2010
y Patients that met the criteria were asked to fill out the survey and
return it { No patient identifiers were collected y Due D tto d delay l iin receiving i i approval, l th the survey was only l di distributed t ib t d
during and after renovations
12
Data Evaluation/Analysis 13
y Leq, L10, and L90 values were compiled in Excel for each location
b f before, during, d i and d after f the h renovation i
y Statistical Package for the Social Sciences 18 (SPSS) used to analyze the
survey data y Non-parametric p tests: { { {
Chi-square Kruskal Willis Mann Whitney
SLM Measurement Results 14
Before Renovation 70 65 60 LAeq (dBA)
63
62
59 60
55
57 51
57
59
53
Nurses' Station Patient Room Hallway
50 45 40 35 Ave Day Ave.
Ave Night Ave.
Overall LAeq
SLM Measurement Results 15
During Renovation 70 65 60
59 58
57
55 LA (dBA) LAeq
57 57 56 52 53 51 5
50 45 40 35 Ave. Day
Ave. Night Overall LAeq
Nurses' Station Patient Room Hallway
SLM Measurement Results 16
After Renovation 70 65 60 55 LA (dBA) LAeq
59 58 55
57 57
55 51
52 5
54
50 45 40 35 Ave. Day
Ave. Night Overall LAeq
Nurses' Station Patient Room Hallway
SLM Measurement Results 17
Before Renovation 70 65 60 dBA
60
58
55
52
50 45
47 43
45
40 4 35 Nurses' Station
Patient Room Locations
Hallway
L10 L90
SLM Measurement Results 18
During Renovation 70 65 60 dBA
60
60 57
55 50 45
45
44
43
40 4 35 Nurses' Station
Patient Room Locations
Hallway
L10 L90
SLM Measurement Results 19
After Renovation 70 65 60 dBA
60
60 57
55 50 45
44
42
42
40 4 35 Nurses' Station
Patient Room Locations
Hallway
L10 L90
Patient Survey Results 20
y 158 out of 210 eligible patients participated (75%) { {
108 during renovation 50 after renovation
y Age and gender not statistically related to any responses y Over 80% of respondents p were not annoyed y or onlyy slightly g y annoyed y byy
noise in day (72% at night) (Q#1 and #2) y Few (only 9%) indicated having hard time hearing what was said to
them (Q#4) y Greater concern expressed (33%) about being able to overhear private
conversations (Q#5)
Patient Survey Results 21
y 24% of respondents reported being sensitive to noise (Q#6) {
Significant correlation to those that reported being severely annoyed by noise during day (p=0.001) and night (p