Running head: EFFECTS OF NOISE ON PATIENT SAFETY
Effects of Noise on Patient Safety in the Operating Room
Jacqueline E. Bertucci, CRNA MSN and Cassie M. Ishmael, CRNA MSN
Major Peter Strube CRNA MSNA APNP ARNP
Rosalind Franklin University of Medicine and Science
1
EFFECTS OF NOISE ON PATIENT SAFETY
2
Abstract
Noise is unavoidable in the operating room environment. Hospitalized patients are more
susceptible to the effects of noise because of their diminished capacity to cope during
stressful situations. The World Health Organization (WHO) recommends that operating
room noise levels should not exceed 30 dB (A). Elevated noise levels in the operating room
are correlated with negative physiological changes, hearing loss, tinnitus, patient anxiety
and distraction. Noise reduction measures are essential to ensure an optimal surgical
environment.
Keywords: operating room, noise, sound, physiologic effects, anesthetic needs,
hazards
EFFECTS OF NOISE ON PATIENT SAFETY
Objectives
1. Describe the physiologic effects of noise
2. Explain the effects of noise on anesthetic need
3. Define the hazardous effects of noise
4. Identify acceptable amounts of noise in operating room suites
5. Outline operating room noise reduction measures
3
EFFECTS OF NOISE ON PATIENT SAFETY
4
Effects of Noise on Patient Safety in the Operating Room
Introduction
Noise comes from the Latin word nausea and is defined as any undesirable sound or
interference with the process of hearing (Merriam Webster, 2013). The importance of
noise in healthcare has been recognized for years, and had been described by Florence
Nightingale in 1859 as, “Unnecessary noise, then, is the cruelest absence of care which can
be inflicted either on sick or well” (Busch-Vishniac et al., 2005, p. 3629). Noise pollution
was identified as the third pollution in the operating room after air and water pollution by
Shapiro and Berland (1972). Noise poses several threats to the operating room
environment, including negative physiologic changes resulting in increased cortisol levels,
hearing loss, patient anxiety, and distraction.
The World Health Organization (WHO) describes that hospitalized patients are
more susceptible to the effects of noise because of their diminished capacity to cope during
stressful situations (WHO, 1999). Decibel (dB) is a unit used to express the magnitude of
change in sound frequency (Soucy, Ko, Denstedt, & Razvi, 2008). A weighted scale, dB (A) is
used in clinical practice due to its ability to closely resemble the human ear in the
frequency spectrum (Fritsch, Chacko, & Patterson, 2010). Considerable discrepancy
remains in regards to recommended noise levels in the operating room (OR) by national
regulation agencies. WHO (1999) recommend that OR noise levels should not exceed 30 dB
(A). The Occupations Safety and Health Administration (OSHA) recommend that noise
levels should not exceed 90 dB for an eight-hour time period (OSHA, 1974). The National
Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and
EFFECTS OF NOISE ON PATIENT SAFETY
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Prevention recommend noise exposure should not exceed 85 dB for an eight-hour time
period (NIOSH, 1970).
Documented noise levels in the operating room range from 55 to 86 dB, depending
upon the surgical procedure performed (Kim, Kil, & White, 2001). Comparison of baseline
noise levels; 20 dB is associated with a quiet environment, 50 dB with normal conversation
and 70 dB is comparable to street traffic (Kurmann et al., 2011). Advancing technology and
enhancements in anesthetic safety have increased the number of auditory alarms,
contributing to growing noise levels amongst operating rooms (Kim, Kil, & White, 2001).
Noise levels in the operating room interfere with the anesthesia provider’s ability to
provide optimal levels of anesthetic care. Elevated noise levels in the OR present as a
hazard and are associated with patient related physiologic responses and alter patient
anesthetic need.
Review of Literature
A literature search was conducted in May 2012. The search for primary research
articles written in English was performed in Medical Literature Online (Medline),
Cumulative Index to Nursing (CINAHL) and Academic Search Premier (ASP) databases
using the following search terms: operating room, noise, sound, physiologic effects,
anesthetic needs and hazards. Abstracts were reviewed for suitable articles and the
reference list of each article was examined for additional sources.
Physiologic Effects of Noise
Noise levels in the operating room have been correlated with patient related
physiologic responses. Studies demonstrate that auditory processing functions remain
intact during anesthesia (Tsuchiya et al., 2003). Manipulation of auditory input the patient
EFFECTS OF NOISE ON PATIENT SAFETY
6
receives during anesthesia may modify their response to surgical stress. Subconscious
memories, with auditory input, during general anesthesia may exist postoperatively. Vivid
memories of noise under propofol anesthesia have been reported. Inhibitory properties of
anesthetics cause the effects of noise to be blunted during the maintenance phase of
general anesthesia.
Physiologic responses originate from the stress response which stimulates the
sympathetic nervous system (Kam, Kam, & Thompson, 1994). Researchers have identified
negative effects of intraoperative noise exposure including tachycardia, hypertension, an
elevation in stress cortisol response and psychological effects (Fritsch, Chacko, & Patterson,
2010). Sympathetic responses also include peripheral vasoconstriction and dilation of the
pupils (Shapiro & Berland, 1972). Elevated noise levels have been identified and remain a
significant concern hospital-wide.
Morrison et al. (2003) studied the effects of elevated noise levels in the intensive
care unit setting. Researchers identified excessive noise levels correlate with patient
annoyance, prolonged length of stay, abnormal sleep patterns, intensive care “psychosis”
and delayed wound healing. Cardiovascular measurements including blood pressure, heart
rate, ectopy frequency, variability and ST segment changes have been evaluated in stress
studies. Researchers have displayed variable results in studies with animals. In human
studies, acute changes in heart rate were noted to be greatest with uncontrollable noise
and specific personality types.
A significant association has been identified between intraoperative noise levels and
the development of surgical site infection (Kurmann et al., 2011). Researchers noted the
median noise levels above baseline were considerably higher in patients that developed a
EFFECTS OF NOISE ON PATIENT SAFETY
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postoperative surgical site infection. The greater elevation of peak noise levels above the
median in those who developed surgical site infection may have been the result of noise
from various sources. Sources that attribute to the elevation in noise levels include
conversation between individuals, background noise, monitors, alarms, suction devices and
surgical instruments. Intraoperative noise levels may enhance factors including surgical
difficulty, lack of concentration, lack of discipline or stress among the OR leading to surgical
site infection.
Studies have also evaluated the association of noise levels on salivary hormone
release. The measurements of salivary biomarkers have been evaluated in studies as stress
biomarkers (Arai et al., 2008). Levels of salivary alpha-amylase have been associated with
autonomic nervous system changes and are utilized as an index for psychological stress.
The study results identified that intraoperative natural sounds significantly reduce salivary
amylase activity in patients under epidural anesthesia.
Hazardous Effects of Noise
Elevated operating room noise levels increase the risk of hazardous effects on
surgical patients. Operating room sources of noise can be categorized into two primary
groups: sources related to surgical and anesthesia equipment and sources related to
operating room staff conduct (Fritsch, Chacko, & Patterson, 2010). Equipment including
metal tools, suction and anesthesia monitors produce significant noise levels with routine
use. Otolaryngology, orthopedics and neurosurgery commonly use devices that regularly
surpass noise level recommendations. Exposure to elevated noise levels may lead to
hearing loss, tinnitus and noise related physiologic stresses (Love, 2003). Causes of noise
induced hearing loss (NIHL) are related to sound level, frequency, duration and exposure
EFFECTS OF NOISE ON PATIENT SAFETY
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pattern. Factors that predispose patients to hearing loss include elderly age, comorbid
conditions, medications, substance addiction and previous cumulative exposures. Noise
induced hearing loss remains the most common cause of acquired hearing loss. Nott and
West (2003) identified peak noise levels of 100 dB (A) during orthopedic surgery. Multiple
orthopedic surgeries place the surgical patient at the greatest risk.
Music is frequently played in the OR to provide a comfortable environment for the
patient, to placate the surgeon, and to maintain a pleasurable work environment for the
surgical staff. Music can be a distraction, cause communication breaks and can affect
surgical outcomes. Sanderson et al. (2005) reported that most participants of simulated
anesthesia indicated that monitoring was enhanced without the presence of music and
reported reduced concentration with music.
The ability to communicate effectively in the OR is essential to safely perform
patient care. For speech to be easily understood it needs to be 10-15 dB above the ambient
noise level (Stringer, Haines, & Oudyk, 2008). Operating room noise can quickly rise above
recommended levels and impair communication. This study measured average and peak
noise levels in operating rooms as well as operating room nurse perceptions on speech
interference in a variety of surgical specialties. Results revealed that effective
communication is more difficult to accomplish during times of increased noise levels.
Increased noise levels can also cause the Lombard effect, where speech levels are increased
in order to counteract the background noise (Kam, Kam, & Thompson, 1994).
Effects of Noise on Anesthetic Need
Non-pharmacological interventions such as music, meditation and guided imagery
have all been shown to have a positive impact on patient surgical experience. The use of
EFFECTS OF NOISE ON PATIENT SAFETY
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peaceful sounds has proven beneficial, while others have speculated the effect may be due
to the suppression of ambient operating room noise. Bispectral index scores (BIS) have
been utilized to determine depth of anesthesia as it demonstrates correlation with the
Observer’s Assessment of Anesthesia Sedation (OAA/S) score in anesthesia with propofol.
The suppression of ambient operating room noise resulted in reduced BIS scores under
combined spinal-epidural and propofol infusion during total knee replacement surgery
(Kang, Lee, Kim, Kim, Kim, Hahm, & Lee, 2008). Ganidagli et al. (2005) noted that reduction
in sedative requirements may be related to elimination of ambient operating room noise.
Hemisync sounds represent a modern approach to the application of sound to assist
in relaxation, meditation, stress reduction, pain management and sleep (Dabu-Bondoc et
al., 2010). Both Kliempt, Ruta, Ogston, Landeck, and Martay (1999) and Lewis, Osborn, and
Roth (2004) reported patients required significantly less intraoperative fentanyl while they
received Hemisync sounds under general anesthesia. Lewis et al. (2004) evaluated the
effects of Hemisync sounds on participants that received bariatric or lumbar surgery under
general anesthesia. The study reported bariatric participants required less fentanyl, while
the lumbar participants required the same amount of fentanyl.
Conclusion
Noise in the operating room is a major challenge that presents as a hazard and is
associated with patient related physiologic responses and affects anesthetic need.
Advancing technology and enhancements in anesthetic safety have increased the number
of auditory alarms that contribute to rising noise levels among the operating room.
Operating room noise levels continue to be measured above recommended guidelines. It is
imperative to acknowledge that noise levels continue to increase in the operating room
EFFECTS OF NOISE ON PATIENT SAFETY
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environment and implementation of noise reduction protocols are essential to ensure an
optimal surgical environment.
Discussion
Studies have consistently identified the negative effects of elevated noise level
exposure. With the growth of a modern technological age, concerns of noise pollution
continue to arise. Average daytime noise levels have grown from 57 dB, during the 1960’s,
to 72 dB by 2005 in acute care hospitals (AORN, 2009). Noise reduction interventions have
been suggested due to the growing concerns of the hazardous effects of noise.
Recommendations have included the use of soft-soled shoes for staff, elimination of
multiple occupancy patient rooms as well as the introduction of quieter alarms (Morrison,
Haas, Shaffner, Garrett, & Fackler, 2003). It is also suggested that staff set pagers to vibrate,
reduce the amount of overhead pages and limit the amount of unnecessary conversation.
The Association of Perioperative Registered Nurses (AORN) position statement
acknowledges that noise is unavoidable in the perioperative environment and supports
noise reduction measures (AORN, 2009). Identifiable contributing factors of noise include
beepers, cell phones, overhead pages, alarms, electronic music devices, medical devices and
equipment, pneumatic tube systems and communication. AORN suggests that noise
reduction measures in the following domains of administrative, engineering/facilities and
behavioral interventions should be considered when developing an action plan.
Administrative interventions involve promoting a team effort in brainstorming
strategies for noise reduction, evaluating communication methods, muting all nonessential
communication devices, limiting the type of music and specifying a volume level during
procedures (AORN, 2009). Engineering interventions include measuring noise levels,
EFFECTS OF NOISE ON PATIENT SAFETY
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setting trigger points appropriately on devices, replacing noisy metal carts, using trash and
linen bins that use a damping system to slowly close the lid and investigating less
distracting ringtones. Recommended behavioral interventions consist of assessing one’s
own voice tone and volume, expecting all team members to be personally responsible for
managing the noise they generate, limiting telephone conversations, minimizing the
number of people during the procedure and number of door openings and instituting
specific times when noise levels should be reduced, particularly during induction and
emergence of general anesthesia.
Intraoperative noise is an unavoidable distraction that disrupts patient care and
potentially increases the risk of error (AORN, 2009). Measures can be taken to minimize
the undesirable effects of intraoperative noise. Team development of hospital-wide
protocols is an essential step in noise reduction measures. With the development and
implementation of hospital-wide protocols, excessive operating room noise can be
eradicated.
EFFECTS OF NOISE ON PATIENT SAFETY
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CE Questions
1.
In 1972, Shapiro and Berland identified three pollutants in the operating room:
a. Air
b. Exhaust
c. Water
d. Noise
2.
Physiological effects of noise exposure include all of the following EXCEPT:
a. Hypertension
b. Tachycardia
c. Pupil constriction
d. Peripheral vasoconstriction
3.
The hazardous effects associated with noise include all of the following EXCEPT:
a. Diminished capacity to cope with stress
b. Emergence delirium
c. Tinnitus
d. Hearing loss
4.
According to the Occupational Safety and Health Administration (OSHA), what is the
acceptable amount of noise in operating room suites in an eight-hour period?
a. 70 dB
b. 80 dB
c. 90 dB
d. 100 dB
EFFECTS OF NOISE ON PATIENT SAFETY
5.
Patients exposed to music intraoperatively experience a ______________
17
_______________
in the use of propofol.
a. significant reduction
b. significant increase
c. moderate reduction
d. moderate increase
6.
Which item is a predisposing factor for hearing loss:
a. Male gender
b. Cardiac conditions
c. Substance addiction
d. Previous exposure to asbestos
7.
For speech to be easily understood it needs to be_________ above the ambient noise
level:
a. 5-10 dB
b. 10-15 MHz
c. 10-15 dB
d. 15-20 MHz
8.
Which three subspecialties most commonly use instruments that regularly exceed
noise level recommendations?
a. Otolaryngology
b. Neurosurgery
c. Ophthalmology
d. Orthopedics
EFFECTS OF NOISE ON PATIENT SAFETY
9.
A phenomenon called _____________
18
____________occurs when speech levels are
increased in order to counteract background noise.
a. Geneva result
b. Johnson product
c. William’s outcome
d. Lombard effect
10.
The effects of Hemisync sounds represent a modern approach to assist in (select 3):
a. Relaxation
b. Alcohol dependence
c. Stress reduction
d. Pain management
11.
Studies have demonstrated that auditory processing functions remain intact during
anesthesia:
a. True
b. False
12.
Street traffic sound levels have been measured at _______ dB:
a. 70
b. 90
c. 110
d. 130
13.
Advances in technology assist in the reduction of operating room sound levels:
a. True
b. False
EFFECTS OF NOISE ON PATIENT SAFETY
14.
The inhibitory properties of anesthetics most effectively blunt the physiologic
effects of sound levels during _______________________________:
a. monitored anesthesia care
b. induction of anesthesia
c. maintenance of anesthesia
d. emergence of anesthesia
15.
Since the mid-1900’s sound levels in operating rooms have?
a. Decreased
b. Remained consistent
c. Increased
16.
An administrative intervention in the promotion of effective sound level reducing
measures would include (select 2):
a. Muting all non-essential communication devices during the procedure
b. Measuring sound levels
c. Institute specific times when noise levels should be reduced
d. Promoting a team effort in brainstorming strategies for noise control
17.
Recommended engineering interventions in the promotion of sound reduction
consist of _________________:
a. use of trash and linen bins that use a damping system to slowly close the lid
b. evaluating communication methods
c. limiting the type of music and specify a volume level
d. minimize the number of people during the procedure
18.
Behavioral interventions that support sound level reduction include (select 2):
a. Setting trigger points appropriately on devices
b. Replacing noisy metal carts
c. Assessing one’s own voice tone and volume
d. Limiting telephone conversations
19
EFFECTS OF NOISE ON PATIENT SAFETY
19.
Increased levels of __________________ salivary secretions have been associated with
autonomic nervous system changes as a result of psychological stress.
a. polytene chromosomes
b. amylase chromosomes
c. alpha-amylase
d. beta-amylase
20.
A negative effect of intraoperative noise exposure includes an elevated cortisol
response.
a. True
b. False
20
EFFECTS OF NOISE ON PATIENT SAFETY
1. a, c, d
2. c
3. b
4. c
5. a
6. c
7. c
8. a, b ,d
9. d
10. a, c, d
11. a
12. a
13. b
14. c
15. c
16. a, d
17. a
18. c, d
19. c
20. a
CE Answers
21