NOISE IN HOSPITALS: EFFECTS AND CURES

NOISE IN HOSPITALS:NOISE IN HOSPITALS:EFFECTS AND CURES EFFECTS AND CURES

By James E. West By James E. West Johns Hopkins University Baltimore MDJohns Hopkins University Baltimore MD

[email protected]@jhu.edu2008 2008 GegenheimerGegenheimer Lecture Series in Lecture Series in

InnovationInnovationMotivation for current studies at JHHMotivation for current studies at JHHWhy are hospitals noisy?Why are hospitals noisy?What we found in the literatureWhat we found in the literatureNoise measurements at JHHNoise measurements at JHHSome solutionsSome solutions

Florence Nightingale (1859)Florence Nightingale (1859)

““Unnecessary noise, then, is the most cruel Unnecessary noise, then, is the most cruel absence of care which can be inflicted either absence of care which can be inflicted either on sick or wellon sick or well””

Open Literature on Hospital Open Literature on Hospital NoiseNoise

Intensive care units, Operating rooms, and Intensive care units, Operating rooms, and Nurseries Nurseries Hospital tools (orthopedics)Hospital tools (orthopedics)Control of hospital noise limited to Control of hospital noise limited to administrative control measuresadministrative control measuresStudies conducted mainly by physicians and Studies conducted mainly by physicians and nurses and reported in medical literaturenurses and reported in medical literature

Open Literature on Hospital Noise and itsOpen Literature on Hospital Noise and its’’ effect effect on peopleon people

Contribute to stress in hospital staffContribute to stress in hospital staffNoise negatively affects speed of wound Noise negatively affects speed of wound healinghealingCataract surgery patients required longer Cataract surgery patients required longer stay during exposure to construction noisestay during exposure to construction noiseAdditional medication required surgical Additional medication required surgical patients when SPL >60dBpatients when SPL >60dBNoise effects on performance ?????Noise effects on performance ?????

Existing Hospital Noise GuidelinesExisting Hospital Noise GuidelinesWorld Health OrganizationWorld Health Organization–– Lmax(ALmax(A) no more than ) no more than 4040 dB(AdB(A))–– LeqLeq of of 3030 dB(AdB(A) in rooms) in roomsANSI Standard S12.2ANSI Standard S12.2--19951995–– RC(N) values of RC(N) values of 2525--4040 depending on type of roomdepending on type of room–– NCB values of NCB values of 2525--4343US EPA US EPA ““LevelsLevels”” DocumentDocument–– LdnLdn of no more than of no more than 4545 dB(AdB(A))

Our Project on Hospital NoiseOur Project on Hospital NoiseFully characterize noise in JHH.Fully characterize noise in JHH.–– As a function of time of dayAs a function of time of day–– Different locationsDifferent locations–– Octave bandsOctave bands–– Source identificationSource identification

Work on noise control issues.Work on noise control issues.–– Architectural designArchitectural design–– New materialsNew materials–– Active and passive noise controlActive and passive noise control

Special IssuesSpecial Issues–– PrivacyPrivacy–– Speech communication errorsSpeech communication errors

Sound pressure levels measured in hospitals Sound pressure levels measured in hospitals as a function of the year of publicationas a function of the year of publication

WHO Upper Limit

20

30

40

50

60

70

80

90

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Leq

in d

B(A

)

Sound pressure levels in octave bands at Johns Sound pressure levels in octave bands at Johns Hopkins Hospital and in a typical buildingHopkins Hospital and in a typical building

Sound Pressure Levels at Johns Hopkins Hospital

20

30

40

50

60

70

16 32 64 125 250 500 1000 2000 4000 8000 16000

Octave Band Center Frequency (Hz)

Leq

in d

B

JHHtypical building

telephone bandwidth

Average sound levels for surgeries Average sound levels for surgeries by category by category

Maximum Maximum L(peakL(peak) for each ) for each surgery monitoredsurgery monitored

Maximum Lpeak

70

80

90

100

110

120

130

cardiology gastrointestinal neurosurgery orthopedics otolaryngology plastic, pediatric thorasic urology

Division

Leve

l in

dB

QUIETING WEINBERG 5CQUIETING WEINBERG 5C

Weinberg 5CWeinberg 5C

InstallationInstallation

InstallationInstallation

Results: Reverberation TimesResults: Reverberation Times

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

250

315

400

500

630

800

1000

1250

1600

2000

2500

3150

4000

5000

6300

8000

1000

012

500

1600

020

000

Third Octave Band Center Frequency (Hz)

Seco

nds

before

after

Subjective Results Subjective Results -- PatientsPatients

68

40

10

20

30

40

50

60

70

80

Percentage of Patients Reporting Noiseas a Problem

BeforeAfter

Subjective Results Subjective Results --NursesNurses

98

4250

83.3

0

20

40

60

80

100

Communication Hearing Rounds CheckingChemotherapy

Stressful

BeforeAfter

Comparison of Comparison of FFTsFFTsT5C hall (1015.00-1035.00 s).FFT vs. Time (4096,50.0%,HAN). f /Hz

20

50

100

200

500

1k

2k

5k

10k

20k

t/s1017.5 1020 1022.5 1027.5 1030 1032.5L/dB[SPL]10 20 30 40 60 70 80 90

Left

T5D hall (1030.00-1050.00 s).FFT vs. Time (4096,50.0%,HAN). f /Hz

20

50

100

200

500

1k

2k

5k

10k

20k

t/s1032.5 1035 1037.5 1042.5 1045 1047.5L/dB[SPL]10 20 30 40 60 70 80 90

Left

T5B hall (395.00-415.00 s ).FFT vs. Time (4096,50.0%,HAN). f /Hz

20

50

100

200

500

1k

2k

5k

10k

20k

t/s397.5 400 402.5 407.5 410 412.5L/dB[SPL]10 20 30 40 60 70 80 90

Left

W5C W5D

W5B

SII SII

Described in ANSI S3.5 Described in ANSI S3.5 –– 19971997We used the octave band approach.We used the octave band approach.

Results in a number between 0 and 1 .Results in a number between 0 and 1 .0 is clearly awful, and 1 is clearly great.0 is clearly awful, and 1 is clearly great.The quality between 0 and 1 is NOT well The quality between 0 and 1 is NOT well defined!defined!

Speech Intelligibility Index vs. TimeSpeech Intelligibility Index vs. TimeT5C hall (1015.00-1035.00 s).Speech Intelligibility Index vs. Time (3rd octave, 300.0ms). SII/%

10

20

30

40

50

60

70

80

90

100

t/s1015 1017.5 1020 1022.5 1027.5 1030 1032.5 1035

LeftRight

T5D hall (1030.00-1050.00 s).Speech Intelligibility Index vs. Time (3rd octave, 300.0ms). SII/%

0

20

40

60

80

100

t/s1030 1032.5 1035 1037.5 1042.5 1045 1047.5 1050

Lef tRight

T5B hall (395.00-415.00 s ).Speech Intelligibility Index vs. Time (3rd octave, 300.0ms). SII/%

0

20

40

60

80

100

t/s395 397.5 400 402.5 407.5 410 412.5 415

LeftRight

W5C: SII= 0.8 W5D: SII=0.5

W5B: SII=0.35

Research NeededResearch Needed

1.1. What acoustical measures best What acoustical measures best correlate with patient and staff correlate with patient and staff outcomes? outcomes? ►► Is it level alone that predicts outcomes or Is it level alone that predicts outcomes or

spectral content or variations in these?spectral content or variations in these?►► Which medical outcomes should we monitor Which medical outcomes should we monitor ––

hospital stay length, need for pain medication, hospital stay length, need for pain medication, need for sleep meds?need for sleep meds?

► Ideally, we would like to determine a causal relationship.

More ResearchMore Research2.2. What changes in acoustical What changes in acoustical

measures are produced from a measures are produced from a variety of noise interventions? variety of noise interventions? ►► Interventions could include better doors for Interventions could include better doors for

patient rooms, earplugs for patients, masking patient rooms, earplugs for patients, masking noise, absorption on walls, noise, absorption on walls, ……

Results from 1 and 2 could let us determine which noise interventions are most likely to produce positive medical outcomes.

More ResearchMore Research3.3. To what extent do medical errors in To what extent do medical errors in

hospitals correlate with noise? hospitals correlate with noise? ►► There is significant work in this area There is significant work in this area

ongoing for pharmaceutical confusion. ongoing for pharmaceutical confusion. What about other kinds of errors?What about other kinds of errors?

►► Can we establish a causal effect?Can we establish a causal effect?

Frequency and Neighborhood Effects on Auditory Frequency and Neighborhood Effects on Auditory

Perception of Drug Names in Noise (Lambert )Perception of Drug Names in Noise (Lambert )

3.9 million 3.9 million ““wrong drugwrong drug”” errors in errors in US retail pharmacies each year US retail pharmacies each year (e.g., (e.g., Zyrtec/ZyprexaZyrtec/Zyprexa, , Celebrex/Celebrex/CelexaCelexa, , Toradol/TapazoleToradol/Tapazole), many due to ), many due to confusion between similar namesconfusion between similar namesAuditory perceptual identification Auditory perceptual identification task (noise)task (noise)Data collection ongoing, Data collection ongoing, preliminary resultspreliminary results

More ResearchMore Research4.4. What is the best way to design What is the best way to design

hospital units to reduce noise while hospital units to reduce noise while preserving efficiency and preserving efficiency and effectiveness of operation?effectiveness of operation?►► A report by Ulrich, et al. showed that A report by Ulrich, et al. showed that

the single most important factor in the single most important factor in reducing hospital noise is single reducing hospital noise is single patient rooms.patient rooms.

►► How do we balance staff convenience How do we balance staff convenience with designs that reduce noise? with designs that reduce noise?

5.5. How might hospitals cope with How might hospitals cope with requirements for speech privacy? requirements for speech privacy? ►► Masking is NOT a possibility in most Masking is NOT a possibility in most

cases.cases.

6.6. Given the desire to move to a more Given the desire to move to a more digital hospital, what level of noise digital hospital, what level of noise mitigation is needed for accurate mitigation is needed for accurate speech recognition? speech recognition? ►► How do we achieve BOTH privacy and How do we achieve BOTH privacy and

accurate speech recognition?accurate speech recognition?►► Can we improve speech recognition in Can we improve speech recognition in

noise?noise?

Research ContinuedResearch Continued7.7. As operating rooms shrink in size As operating rooms shrink in size

and theaters disappear, how do we and theaters disappear, how do we create a means for students to create a means for students to experience surgery from a experience surgery from a distance? distance? ►► Simulations to date donSimulations to date don’’t include t include

realistic operating room audiorealistic operating room audio►► Remote viewing rooms donRemote viewing rooms don’’t take t take

advantage of multiadvantage of multi--channel audio to channel audio to produce realistic sounds.produce realistic sounds.

Research ContinuedResearch Continued

8.8. What is the relationship between What is the relationship between noise and performance for a variety noise and performance for a variety of important tasks in hospitals? of important tasks in hospitals? ►► The literature on the influence of noise The literature on the influence of noise

on surgical tasks is not conclusive.on surgical tasks is not conclusive.►► What noise measures correlate with What noise measures correlate with

degradation of task performance degradation of task performance quality?quality?

►► Which tasks are most susceptible to Which tasks are most susceptible to noise influence?noise influence?

Still More ResearchStill More Research

10.10.Can we manufacture quiet medical Can we manufacture quiet medical equipment?equipment?

Which equipment contributes the most Which equipment contributes the most to annoyance or negative outcomes?to annoyance or negative outcomes?Why are those darn carts so noisy?!?!Why are those darn carts so noisy?!?!

FinallyFinally11.11.How can we communicate in How can we communicate in

hospitals without overhead paging?hospitals without overhead paging?There is one system available for There is one system available for handshands--free communication. Is it free communication. Is it optimal?optimal?How can a handsHow can a hands--free system be free system be squared with privacy?squared with privacy?

What will it include at Johns Hopkins Digital Hospital

Digital imaging and data integrationMulti-modal interactive devices (televisions, monitors, video phones)Wireless communications; pervasive and ubiquitousVoice Recognition and Speech recognitionWearable communication devices