Effects of Noise on Patient Safety in the Operating Room

EFFECTS OF NOISE ON PATIENT SAFETY 1

Effects of Noise on Patient Safety in the Operating Room

Jacqueline E. Bertucci, CRNA MSNand Cassie M. Ishmael, CRNA MSN

Major Peter Strube CRNA MSNA APNP ARNP

Rosalind Franklin University of Medicine and Science

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 physiologicalchanges, hearing loss, tinnitus, patient anxiety and distraction. Noise reduction measures are essential to ensure anoptimal surgical environment.

Keywords: operating room, noise, sound, physiologic effects, anesthetic needs,hazards

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

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 identifiedas 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 Prevention recommend noise exposure should not exceed 85dB 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 haveincreased 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 ORpresent 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 demonstratethat auditory processing functions remain intact during anesthesia (Tsuchiya et al., 2003). Manipulation of auditory input the patient 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 noiseto 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 alsoinclude 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 inthe 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 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 attributeto the elevation in noise levels includeconversation 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 increasethe 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 roomstaff conduct (Fritsch, Chacko, & Patterson, 2010). Equipment including metal tools, suctionand 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 pattern. Factors that predispose patients tohearing 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 apleasurablework 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 10-15dB above the ambient noise level (Stringer, Haines, & Oudyk, 2008). Operating room noise can quickly rise above recommended levels and impaircommunication. 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 peaceful sounds has proven beneficial, while others have speculatedthe 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 managementand 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 amongthe 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 roomenvironment and implementation of noise reduction protocols are essential to ensure an optimal surgical environment.

Discussion

Studies have consistently identified the negative effects of elevated noiselevel 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 2005in 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 levelduring procedures (AORN, 2009). Engineering interventions include measuring noise levels, 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 riskof 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.

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CE Questions

1.In 1972, Shapiro and Berland identifiedthree 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. 70dB

b. 80dB