The impact of noise in the operating theatre: a review of the evidence

Abstract

Introduction

Noise has been recognised to have a negative impact on performance and wellbeing in many settings. Average noise levels have been found to range between 51dB and 79dB in operating theatres. Despite these levels of noise, there is little research investigating their effect on surgical team functioning.

Methods

A literature review to look at the impact of noise in the operating theatre was performed on MEDLINE, which included the search terms ‘noise’ OR ‘distraction’ AND ‘technical skill’ OR ‘Surgical skill’ OR ‘Operating Room’. Only 10 of 307 articles identified were deemed relevant.

Findings

Eight of ten studies found noise to be detrimental to communication and surgical performance, particularly regarding total errors and time to task completion. No studies found noise to be beneficial. Two studies found case-irrelevant verbal communication to be a frequent form of noise pollution in operating theatres; this is both perceived by surgeons to be distracting and delays patient care.

Conclusion

Noise and irrelevant verbal communications were both found to be harmful to surgical performance, surgeon experience and team functioning.

Introduction

Noise or ‘unwanted sound’ is recognised to negatively impact productivity and wellbeing in a wide variety of settings including healthcare.^1–3 Across the globe, operating theatres are known to have high levels of noise; average noise levels ranged between 51dB and 79dB in a review of 16 studies.⁴ The World Health Organization advises noise levels to remain below 35dB in operating theatres to facilitate a peaceful environment for patients.⁵ There has been increased recognition by healthcare workers that noise is linked to distraction, poor task performance and increased error and that it should be minimised whenever possible.⁶ Noise in the operating theatre is largely generated by machinery or environment moderating systems; this non-verbal noise in theatre has been classed as ‘background’ noise for the purpose of this review.

Loud noise generated by machinery or equipment has been shown to affect the accuracy of the information transmitted between a speaker and listener.⁷ Noise has a detrimental effect on attention by distraction of focus which leads to a cognitive interruption in relaying information; this interruption leaves the flow of communication vulnerable to omissions.⁸ The effect of potential error is exacerbated where the content of the relayed information is unpredictable, technical and complex in nature.^9–11

Despite the knowledge that noise can be disruptive and that it is present in high volumes within the operating theatre, there is limited information regarding its impact on surgical performance in this environment. This review explores the effect of background noise, verbal sound and music on surgical performance and surgeon wellbeing.

Method

A literature search was performed on MEDLINE using the search terms ‘noise’ OR ‘sound’ OR ‘distraction’ AND ‘technical skill’ OR ‘surgical skill’ OR ‘operating room’ from 2000 to 2020. Some 304 articles were returned and 10 were deemed appropriate to the objective of the study, determining the effect of noise on theatre staff performance in the workplace.

Results

Effective verbal communication

Effective communication is the cornerstone of patient and professional safety during any procedure within the operating theatre. This is well documented in the literature most notably through the success of the World Health Organization checklist over the last decade.^10,12–14 Failure of such an important function has been linked to technical errors and is thus regarded as a common cause of adverse events in surgery.^12,15

Despite evidence that miscommunication is a prevalent factor resulting in medical errors;¹¹ there is a relative sparsity of research directly investigating the effect of unnecessary or inappropriate verbal communication on surgical performance.^9,16

Background noise

Noise peaks of sudden and high-level sounds have been shown to hamper surgical team communication by reducing case-relevant communication that is integral to efficient workflow; this effect was observed to be more prominent in junior surgical trainees.⁹ High volumes of background noise did not deter case-irrelevant communication.⁹ There was a direct correlation between noise peaks and impairment of case-relevant communication and thus dividing attention.⁹ In a further study, noise levels in 110 open abdominal surgeries were recorded and surgeons of varying grades were asked to self-report distraction by the level of noise.¹⁷ Surgeons of junior grades reported being more distracted by lower volumes of background noise and all surgeons reported feeling more distracted during critical times of the procedure.¹⁷ Noise is therefore felt to be detrimental to the cognitive efficacy of the surgeon by causing distraction and applying an unnecessary stressor.

Although conducted in a single hospital, one study found a direct link between noise in theatre and surgical site infections at follow-up at 30 days.¹⁸ The study acknowledges a small sample but advocates for reduction in noise in theatre, particularly during closure, in order to reduce surgical site infections.

Speaking volume in theatre

It has been determined that for an auditory signal to be understood with an accuracy of 90%, it has to be 10–15dBHL louder than the background noise.¹⁹ The average noise level in the operating room is 65dB, thus theatre stuff must speak at a volume of 75–80dB for 90% accuracy in understanding to be achieved.^11,20 To compensate, individuals will abbreviate or minimise their communication,²¹ such interference with effective communication can potentially degrade patient safety.¹¹

Increased error

Prerecorded theatre noise at 80–85dB was used in a study to assess the effect of noise on performance of 13 trainee surgeons completing a simulated laparoscopic task.²² Noise exposure was found to increase error and impair dexterity. The authors repeated the study in 2004 with experienced surgeons and found no such effect.²³ The hypothesis was supported that surgeons may acclimatise to theatre noise over time and consequently produce fewer errors.

Common distractions during surgery

Persoon et al performed an observational study using qualitative interviews from 78 surgeons who had experienced distractions while performing endourological procedures.²⁴ The most common and frequently occurring distraction reported was equipment difficulties, followed by verbal interruptions. Interviewees reported patient-irrelevant and medically irrelevant communication to be the most distracting and all agreed that the timing of such distraction was also crucial in that at moments of intense concentration, these were most unwelcome. Interviewees perceived these unwanted sounds (and equipment difficulties) to impair their efficacy and personal experience but not impact patient outcome.²⁴

Small talk: verbal disruptions

Another study recorded intraoperative communications in 48 surgical procedures and found that around half of case-irrelevant communications were ‘small talk’.¹⁶ One-third of the case-irrelevant communications were made by the operating surgeon and around two-thirds were received by them. Case-irrelevant verbal communication is distracting and harmfully impacts the quality of care delivered as well as the experience of the surgeon.^16,24

In a study examining distractions and their impact on surgical performance, 18 surgical trainees were exposed to realistic distractions while performing laparoscopic cholecystectomies in a stimulated environment.²⁵ Verbal interruption was found to be the most disruptive, followed by non-verbal noise. Verbal disruption in the form of a question, resulting in a requisite answer, elicited the most error.²⁵

Simulated distraction

Pluyter et al conducted a similar study of 12 novice surgeons performing laparoscopic cholecystectomy while being distracted.²⁶ Performance outcome was measured by an overall task score, task errors and operating time. Distractions included both technological (improper laparoscope navigation) and noise (music and case-irrelevant conversation). Case-irrelevant conversation was played simultaneously with music to represent ‘social distraction’. Although unable to distinguish the effect of conversation from music, the exposure to both caused a decline in all outcome measures.²⁶ This study interestingly identified a trait that may be protective against the impact of noise on surgical performance, ‘cognitive absorption’. This term describes an individual that focuses intently on the task and is seemingly impervious to distraction.

Table 1 summarises the studies exploring the effects of both ambient or background noise and verbal communication on surgical performance in various aspects. Table 2 shows the observational studies exploring noise and its impact in the operating theatre.

Table 1 .

Simulation studies of noise and its effect on specific performance measures

Study	Noise exposure				Performance measure or impact
	Pre-recorded theatre noise	Ringing phone	Verbal communication	Dropped instrument tray	Questionnaire	Script concordance test	Task errors	Time to completion	Tip trajectory	EMG	Average speed.	Economy of movement
Moorthy et al (2003)22	−						✓		✓			✓
Moorthy et al (2004)23	•							✓	✓		✓	✓
Pluyter et al (2010)26			−				✓	✓				✓
Suh et al (2010)30	•							✓	✓		✓
Feuerbacher et al (2012)25		−	−	−	✓		✓
Siu et al (2010)28	−							✓	✓	✓
Suh et al (2016)30	−				✓			✓	✓		✓

− Denotes a negative effect on the outcome measure

• Denotes a neutral or statistically insignificant effect on the outcome measure

✓ Denotes the outcome measure used

Table 2 .

Observational studies on noise and its implications for surgeons and patient outcomes

Study	Study design	Effect of noise
Keller et al (2016)9	Observational study where noise levels and communications were recorded in 109 surgeries.	Higher levels of background noise deterred case relevant communication but not case irrelevant communication.
Keller et al (2018)17	Observational study of 110 open abdominal surgeries where noise levels were measured.	Increased noise levels were associated with increased self-reported distraction; most amplified at critical moments of the procedure.
Persoon et al (2011)24	Interviews of 78 surgeons performing endourological procedures.	All reported verbal communication, specifically case-irrelevant communication, to be highly distracting.
Sevdalis et al (2007)16	Observational study of 48 surgical procedures.	Case-irrelevant communication is frequent in the operating theatre. It interferes with workflow and degrades the surgeons’ experiences.
Dholakia et al (2015)18	Prospective study where noise levels were recorded and correlated with surgical site infections at 30 days follow-up.	Cases performed in noisy environments were more highly associated with surgical site infections at 30 days follow-up.
Wiegmann et al (2007)31	Observational study of 31 cardiac operations.	Verbal interruptions had a strong relationship with delay and an inclination towards error.

Discussion

This review examined studies describing the effects of a range of sound on surgical efficacy. The evidence for background noise and case-irrelevant communication is strongly suggestive that these are both harmful to surgical performance across an array of measures. Both have also been identified as stressful to the operating surgeon and should therefore be minimised wherever possible.

The advance of simulation and expansion of surgical training should provide the ideal circumstances for such research. Studies from even the earliest included years of this review conclude with significance that unwanted sound, in a variety of forms, has a detrimental effect on attention which represents a threat to optimal surgical training. The perception of noise being distracting and detrimental to successful outcomes is a burden most strongly felt by trainees rather than experts or consultants.²⁴ It is also demonstrated to inflict error from trainees at a much higher rate than it affects more senior surgeons.^22,25 The protection of surgical trainees’ learning environments should be of paramount importance to future programmes by limiting noise as is described in these studies. However, the effect of doing so must be studied against its impact on the other members of the theatre team before any changes can be made in real-life settings. Training could be modified in simulated environments in the meantime, to improve surgical skill and accuracy and develop the automation demonstrated by senior surgeons before trainees are exposed to auditory distraction which could potentially result in harmful error. However, as demonstrated by Miskovic in 2012, surgeons learned to compensate over repeated trials and became more accurate despite distraction with practice;²⁷ it is arguable that this has manifested in senior surgeons becoming less affected by noise. Perhaps the question arises over the level of error we are willing to accept for the sake of training resilient surgeons in a timely manner.

Pluyter et al identify cognitive absorption as a protective trait in surgeons when faced with distraction from noise such as music and irrelevant conversation.²⁶ Such trait had been identified in their study sample through an information technology-specific assessment. These individuals exhibited less severe physiological responses to noise and self-reported less annoyance. The study suggests similar psychometric testing could be used in the future to select surgical training candidates. Before this could be considered, it is important to recognise the entire role of a surgeon and not merely their ability to perform one specific laparoscopic task under distraction. Further research is needed into how this trait may translate into performance in other areas of professional necessity (eg communication skills, organisation, teaching and training).

Conclusions

Sound encompasses a variety of stimuli and can be particularly evocative for the human mind. It is clear that background non-verbal noise is prevalent in the operating theatre and has a definite detrimental effect on surgical performance and on staff wellbeing.^22,28

Verbal communication is also highly distracting and although it affects cognitive and emotional function, it does not always appear to inflict surgical error.²⁵ Some disparity in the effect on error is observed between surgeons of different expertise; this is likely to represent the difference in cognitive demand where a trainee is developing skill and using more of their working memory.^26,29 Case-irrelevant verbal communications were found to be more distracting when compared with case-relevant verbal communication, more critically those delivered by external staff entering theatre were more distracting than from the theatre team. The potential for rectifying these seems most achievable and beneficial as an initial measure.

Although surgeons do not perceive noise to have a harmful effect on patient outcome,²⁴ some evidence exists to support the hypothesis that increased noise in theatre leads to higher complications such increased incidence of surgical site infections.¹⁸