Years ago, I had the pleasure of working with several individuals who were interpreting in the operating room for a surgical resident with hearing loss. While the sign language interpreters had normal hearing, they had difficulty hearing the surgeon clearly because of operating room noise, the noise from a small fan in the surgeon's headgear, and the surgeon's use of a clear plastic face shield, which changed the acoustic signal the interpreters had to hear and translate for the resident. This situation gave me an opportunity to learn about the audiological challenges that the operating room presents, even for those who have normal hearing.
The importance of accurate communication in the operating room cannot be understated. Noise increases the chance of miscommunication, and small errors in the discrimination of speech or sounds can have a significant negative impact on the patient and staff.
In addition, the demands of performing complicated tasks in the operating room increase the cognitive effort required for their successful completion. The presence of typical operating room noise can increase the cognitive burden of the surgical team, who have to multitask as they perform, assist, or monitor procedures.
The usual sources of noise in the operating room include moving equipment, doors opening and closing, metal tools, suction devices, monitors and alarms, air-handling systems, and conversation among staff in the room and via intercom devices. When noise levels rise, conversation also gets louder as speakers try to hear their own voices and make themselves heard over the noise—a phenomenon called the Lombard effect—increasing the overall noise level.
Music is another frequent contributor to noise in the operating room. It has been suggested that music provides a soothing background, reducing staff member stress and patient anxiety. However, music that is pleasant and relaxing to one listener may be unpleasant and agitating to another.
POORER PERFORMANCE IN NOISE
Since the early 1970s, a number of studies have investigated noise levels in the operating room (see bibliography). Most of these studies quantified noise levels and their sources, and some measured the effects on surgical-team performance and patients’ perception of noise.
Effect of Noise on Auditory Processing in the Operating Room
Way TJ, Long A, et al J Am Coll Surg 2013;216(5):933-938
Adding to the literature is this recently published investigation into the effect of noise, particularly music, on auditory processing in the operating room. The study tested 15 surgeons who had varying lengths of surgical experience, averaging six years, and normal hearing sensitivity, with pure-tone thresholds less than 25 dB at 500, 1,000, 2,000 and 4,000 Hz in each ear.
Speech testing was completed in a “simulated” operating room using low- and high-predictability sentences from the Speech Perception in Noise Test–Revised (SPIN–R) in four conditions: SPIN-R in quiet, SPIN-R filtered (to simulate the filter effect of a surgical mask), SPIN-R filtered plus OR noise, and SPIN-R filtered plus OR noise plus music.
Prior to this analysis, speech, noise, and music levels were measured in a variety of operating rooms to determine average values, which were then used in the study. In the filtered speech plus noise condition, the OR noise level was 65 dB SPL, while in the noise plus music condition, which added classic rock music to the mix, the level was 74.2 dB SPL.
The surgeons were seated in a double-walled booth, with speech and filtered speech presented at 70 dB SPL from speakers placed at ±45 degrees azimuth. They were asked to repeat the last word they heard in both an un-tasked and tasked state.
In the tasked state, the surgeons completed a manual dexterity task while responding to the speech test. Using the Ethicon Endo-Surgery Train Anywhere Skill Kit and a computer plus webcam, they moved pegs from one container to another with two Maryland graspers.
Task, predictability of sentence, and noise were found to be statistically significant factors in the study. Performance was poorer in the tasked compared with the un-tasked state, in the low-predictability than the high-predictability condition, and in the noise than in the quiet condition.
In the tasked state, scores were poorer in noise and poorer yet in noise plus music. There was no statistically significant difference in the unfiltered versus filtered condition, and the addition of music was significant in the tasked condition only.
ROLE OF THE AUDIOLOGIST
Staff should be educated about the “dangers” of noise in the operating room, the authors concluded. They suggested that institutions determine a means to provide accurate communication and safety for staff and patients in the operating room while allowing music.
The authors made several recommendations for future studies, including to use a more realistic complex task in order to investigate the effects of noise and task complexity on hearing, to evaluate the influence of surgeon experience level on communication ability in the operating room, and to determine the effects of noise on other operating room personnel—i.e., anesthesiology staff and nurses. They also suggested that an exploration of the effects of noise on surgeons and other operating room staff who have hearing loss or are nonnative English speakers is warranted.
Audiologists can play several important roles in overcoming some of the potentially negative effects of noise in the operating room. One role is to educate operating room personnel about the influence of noise and music on communication and how to overcome these effects. Another is working with planning teams on possible ways to reduce noise through the physical aspects of new or remodeled operating rooms, including reduction of reverberation. Audiologists should also be prepared to offer those with and without hearing loss solutions for improved communication in the noisy operating room environment.
As for the difficulty our sign language interpreters were experiencing in the operating room, we came up with a solution that worked for them. We clipped an FM microphone under the surgeon's face shield—it took a few attempts using different microphone styles, microphone placements, and clips—and the interpreters wore behind-the-ear FM receivers with custom vented earmolds.
The FM system reduced the effects of operating room noise on the interpreters’ ability to hear the surgeon's communications, improving the accuracy of the interpretation for the resident.
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* Ginsberg SH, Pantin E, Kraidin J, Solina A, Panjwani S, Yang G. Noise levels in modern operating rooms during surgery. J Cardiothorac Vasc Anesth 2013;27(3):528-530.
* Hasfeldt D, Laerkner E, Birkelund R. Noise in the operating room—what do we know? A review of the literature. J Perianesth Nurs 2010;25(6):380-386.
* Kurmann A, Peter M, Tschan F, Mühlemann K, Candinas D, Beldi G. Adverse effect of noise in the operating theater on surgical-site infection. Br J Surg 2011;98(7):1021-1025.
* Wahr JA, Abernathy JH 3rd. Environmental hygiene in the operating room: cleanliness, godliness, and reality. Int Anesthesiol Clin 2013;51(1):93-104.