key: cord-0746430-cw51g3ci
authors: Malin, A.; Dooley, A.; Garvey, G.
title: Quantifying the effect of personal protective equipment on speech understanding
date: 2021-08-18
journal: Br J Anaesth
DOI: 10.1016/j.bja.2021.08.005
sha: ada9465f70c3b9a650b2db3fe623537e6b27fcc6
doc_id: 746430
cord_uid: cw51g3ci

nan

The authors set out to assess this issue using a commonly used audiology tool called the AzBio sentence list test 5 . This tool is a collection of non-contextual spoken word sentences that generate a score based on how many words the listener can correctly repeat back to the investigator in a quiet environment. It is a highly sensitive measure of a subjects 'real world' hearing performance in a quiet or noisy environment 6 . Using this test, a study was designed with the primary outcome to quantify and compare the deterioration in understanding of verbal communication whilst wearing different levels of PPE. The secondary outcome was to compare the understanding of verbal communication at two different distances to represent the space normally maintained in a functioning operating theatre between the anaesthetist and an operating department practitioner (1 m) , and between the anaesthetist and a theatre circulator (2.5 m).

Following Health Research Authority approval, five videos were recorded using a laptop with an inbuilt microphone, each consisting of 20 different AzBio sentences (with this number significantly reducing inter-video variability 6 ) read aloud. Recorded videos were used to ensure that speech characteristics and nonverbal facial cues were consistently reproduced for each study participant. Each video included an author wearing either no PPE or one of three different forms of PPE including a fluid resistant surgical mask, a disposable FFP3 mask and protective goggles, and a disposable FFP3 mask and a visor. The fifth video included the same equipment as the fourth (FFP3 and visor) however was designed for the participant to also wear a visor to examine the effects of the speaker and listener both wearing one. A second set of five videos (creating a total of 10 videos) were recorded using the same increments of PPE to allow repeated assessment at a 2.5 m distance. A sample of convenience of 20 participants was chosen for this study due to clinical pressures. Inclusion criteria included aged ≥ 18 yr and previous training to don PPE to ensure familiarity with J o u r n a l P r e -p r o o f the subject matter. Exclusion criteria included consent refusal and complete hearing/visual impairment. Demographics for each participant were also recorded.

Each participant sat in an unoccupied theatre (to reduce sound variability) facing a computer 1 m away from them, with only the sound from the theatre air circulation in the background. The maximum background noise level was recorded using a sound meter to account for any variations in this level during analysis. Each sentence was played at the same volume as the speaker's live voice during recording, with a pause after each, and the participant asked to repeat it aloud. Each correctly repeated word was given a score of 1, with the total score for each video allowing a percentage understanding for each PPE level to be calculated. Once the first five videos had been shown, the participant was repositioned 2.5 m away from the screen with the second set of five videos administered. This gave a total of 10 sets of results to represent the relative comprehension of speech through each level of PPE and distance. Data were statistically analysed using a one-way repeated-measure ANOVA for both primary and secondary outcomes using SPSS Statistics (IBM, location).

The summarised results for each video are shown in figure 1 consisting of obstetric, general practice and anaesthetic trainees and consultants, theatre staff and midwife participants. Analysis showed that at 1 m with no PPE, mean understanding was 96 (4.5) % but this dramatically reduced to 25 (11.0) % when an FFP3 mask and visor were used at 2.5 m. Increases in both PPE level and distance were negatively correlated with participant understanding. Each consecutive PPE level for each distance showed a significant difference (p=<0.05) apart from when the participant also donned a visor (p=0.317 at 1 m and p=0.85 at 2.5 m). The mean reduction in speech comprehension between each consecutive PPE level increase where a significant difference existed was 11 (15.2) % with the exception of donning a visor at 2.5 m which led to a mean 41 (6.7) % reduction. The secondary outcome measure showed that when participants sat at 2.5 m from the speaker they could understand a mean of 10 (11.6) % less than when sitting at 1 m. The exception to this was after a visor was donned which led to a mean 35 (9.9) % reduction.

This study, although underpowered due to its sample of convenience, is the largest of its kind using evidence-based audiological tests, and has confirmed conventional thinking 7 that increasing levels of PPE and distance can diminish communication between members of a clinical team or with patients. It has also quantified how significant this deterioration is, especially due to visors, even in optimal conditions. Due to a frequent reliance by humans on the unconscious assumption of unheard words 8 , clear verbal communication is integral for clinicians, especially during high stakes situations 9 . As a result, its deterioration can create a substantial opportunity for error in patient care or adverse long-term health effects for staff 10 . In light of these findings, we would like to highlight the need for institutions to conduct larger scale investigations into both this issue and methods to circumvent these barriers to communication in order to protect the safety of both patients and staff during this and any subsequent disease pandemics. J o u r n a l P r e -p r o o f

World Health Organisation. Personal protective equipment for use in a filovirus disease outbreak: Rapid advice guideline. World Health Organisation

Speech understanding using surgical masks: A problem in health care?

Evaluation of Human Performance While Wearing Respirators. Federal Aviation Administration

The negative impact of wearing personal protective equipment on communication during coronavirus disease 2019

Performance of Subjects Fit with the Advanced Bionics CII and Nucleus 3G Cochlear Implant Devices

Development and validation of the azbio sentence lists

Human factor considerations in using personal protective equipment in the COVID-19 pandemic context: Binational survey study

Increasing the intelligibility of speech through multiple phonemic restorations

Human factors in preventing complications in anaesthesia: a systematic review

Impact of enhanced personal protective equipment on the physical and mental well-being of healthcare workers during COVID-19

The authors declare no conflicts of interest.

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