Discussion

The operating theatre as a learning environment is unique in that it is a high-risk environment and shaped heavily by human factors. Modern surgical training curriculums often incorporate skills laboratory and simulations to navigate this. However, non-technical skills such as team work, leadership and situation awareness are difficult to address in a simulated environment.^{Reference Moorthy, Munz, Adams, Pandey and Darzi12} Compounded by the lack of suitable analogous surgical models for the simulation of procedures, the operating theatre remains the predominant learning environment for trainees to acquire both technical and non-technical skills, despite recent technological advances. Therefore, it is imperative that the operating theatre learning environment is evaluated regularly to address its deficiencies, as perceived by trainees themselves, in order to enhance learner performance.

In our study, items were taken from the widely used Surgical Theatre Educational Environment Measure and discussed in a focus group of higher surgical trainees. Cassar's instrument has been adapted and validated in various studies aimed at different populations.^{Reference Mahoney, Crowe and Harris13–Reference Clapham, Wall and Batchelor15} In these studies, the subscale structure of the instrument was largely preserved in the factor analyses; hence, it is not surprising that the participants in our focus group agreed on the three existing subscales as being the main constructs in the operating theatre learning environment. Similarly, as in the aforementioned studies, population- and discipline-specific factors precipitated the collapse of items in our version of the instrument, which was aimed at higher surgical trainees. ‘I am too busy doing other work to go to theatre’ was removed, as trainees felt the item was not applicable to them because higher surgical trainees will have protected operating theatre sessions incorporated into their job plan. ‘I am so stressed in theatre that I do not learn as much as I could’ was removed, as trainees felt that this statement did not identify any elements in the learning environment as the source of stress, and could be interpreted as trainees not coping with the programme.

The content validity index and Cronbach's α both indicate that our instrument has high content validity and internal consistency. Two items were excluded from the instrument because they did not reach a critical content validity index after being reviewed by the panel of higher surgical trainees. It is surprising that item ‘The theatre staff are friendly’ did not reach the critical content validity index, as operating theatre staff personalities have been found to be a consistent theme in influencing the operating theatre atmosphere and, hence, the learning environment.^{Reference Holt and Roff8,Reference Nagraj, Wall and Jones14} This could be because the item was perceived to be redundant, as there are already other items addressing operating theatre nursing staff and anaesthetists in the instrument. The friendliness of operating theatre staff was also accessed by item ‘I feel part of a team in theatre’; therefore, the removed item was not assessing a unique element and, hence, would not reduce the overall scope of the instrument. Item ‘I can comfortably express my preference if music is played in theatre’ had the lowest content validity index of 0.43 in both the higher surgical trainee panel and the consultant trainer panel. Interestingly, this was an extra item added upon discussion with the focus group in the initial stage of the study. Participants felt that music improves the calmness and atmosphere of the operating theatre. Current literature supports this view, but has suggested that music can also be distracting and cause impaired communications.^{Reference Moris and Linos16} Studies have also shown that surgeons are the most empowered group amongst operating theatre staff when it comes to choosing music.^{Reference Narayanan and Gray17} However, the importance of this was not recognised by either panel in our study.

Cronbach's α of the final 27-item instrument was 0.89. This is comparable to similar established instruments, such as the Surgical Theatre Educational Environment Measure (Cronbach's α = 0.877)^{Reference Cassar9} and the Postgraduate Hospital Educational Environment Measure (Cronbach's α = 0.899).^{Reference Vieira18} When looking at individual Cronbach's α values in the three subscales, these values are also in the same range as studies that broke down the Postgraduate Hospital Educational Environment Measure into individual subscales.^{Reference Koutsogiannou, Dimoliatis, Mavridis, Bellos, Karathanos and Jelastopulu19}

Although our study aimed to develop and validate a feedback instrument, the initial responses from higher surgical trainees were also analysed in order to provide a current view of the operating theatre learning environment. The mean score of our study population (77.2 per cent) was similar to the mean score of the Surgical Theatre Educational Environment Measure (74.4 per cent).^{Reference Cassar9} Similarly, operating opportunities had the lowest subscale score compared with the other subscales. This may reflect that providing opportunities for trainees to operate is the most challenging aspect to optimise in the learning environment, as this is dependent on multiple factors, such as variety of cases and time pressure.

A conducive learning environment has been shown to be associated with improved learner performances and can help develop trainees’ surgical confidence.^{Reference Lees, Zheng, Daniels and White20} By regularly evaluating how trainees perceive their training experiences in the operating theatre, programmes can identify areas that need to be improved in order to ensure successful training. The limitation of our instrument lies within the validation process, as only local higher surgical trainees were involved, and this could incur a selection bias. Factors and items perceived to be important could be population-specific, making the instrument only applicable to surgical training programmes with similar curriculum structure and work culture. This is particularly relevant in the UK with the introduction of the revised curriculum in August 2021, as surgical training across subspecialties has been largely unified with Generic Professional Capabilities and Capabilities in Practice.^{Reference Lund21} Nonetheless, the transparent development and validation process depicted in our study can be easily adapted by other institutions or specialty training programmes, thereby creating a feedback instrument that is targeted at clinical learners at different levels and the wider clinical learning environment.