Operating rooms (ORs) are high-risk areas for preventable patient harm [16–18]. Besides wrong-site surgery and medication or instrument-related incidents, surgical site infection (SSI) has been reported to be one of its major categories [16, 17, 19–21]. For example, bacterial air and fomite contamination are generally accepted as the main causal risk factor of SSIs [19, 20, 22, 23]. Proper ventilation in and near the OR coupled with rigorous hand hygiene is key in establishing an environment that stops the spread of infection [24, 25]. Since Lidwell et al. in 1982 demonstrated a correlation between airborne bacteria contamination levels and the incidence of postoperative wound infections, the use of ultraclean ORs with laminar air flow (LAF) ventilation has been recommended for many types of surgery [19, 20, 22]. With LAF, cold, clean air is blown into the OR from a ceiling system and contaminated air is sucked out through ventilation grids in the walls. Different studies have shown the effects of LAF ventilation on the number of contaminations of samples in different OR areas [19, 20, 22].

In the past 30 years, much attention has been given to the proper installation of LAF systems as well as details about its size, position, concentration, efficiency, degree of filter, temperature, and other technicalities [26]. The actual effect of the clean air, however, is largely dependent on the correct positioning of the surgical table and instruments in its flow as well as staff traffic behaviour and patterns (e.g. number of people standing within the flow or against wall vents) [22, 23, 25–28]. Energy from movement of devices and staff decreases the volume of clean air and both hinder air flow [25, 28].

In most literature on hygiene and infection studies, the focus is on teaching, training, and changing staff behaviour , e.g. appropriate OR dress or hand hygiene discipline [16, 17, 19, 22, 25, 27]). Adhering to infection prevention recommendations like correct positioning of devices within the clean air flow is rarely emphasized, despite infection prevalence being dependent on design characteristics of the OR.

Most safety improvements in high-risk industries first focus on work area design—here defined as ‘creating and developing concepts and specifications that optimize the function value and appearance of products and systems for the mutual benefit of both user and manufacturer’ [29]—before attempting to change behaviour. Many studies performed in industry have concluded that it is hard to change behaviour; changing design is probably easier [30–34]. On offshore oil vessels, for example, the position of all materials on decks is marked to support safe behaviour [35], as are the positions of airplanes and all surrounding equipment on the airport tarmac [36].

Human factor engineering, concerned with the understanding of interactions among humans and other elements of a system, can help in ‘mistake proofing’ by changing designs to make processes more reliable and effective [21, 37]. Influencing users’ behaviour is challenging and smart design can potentially shape behaviour towards sustainable practices and improve teamwork dynamics and situational awareness [38, 39]. Teamwork has been defined as ‘skills for working in a group context, in any role, to ensure effective joint task completion and team member satisfaction’ [40]. Situational awareness has been defined for this context as ‘developing and maintaining a dynamic awareness of the situation in theatre based on assembling data from the environment, understanding what they mean and thinking ahead what might happen next’ [41]. Behaviour steering could be used as a strategy that could be integrated into product design [33, 42], encouraging users to behave in ways prescribed by the designer through embedded affordances and constraints. In operating rooms, human factor engineering and design thinking therefore plays an important role in safety and efficiency improvement. An unacceptable number of avoidable patient safety incidents result from the widening disparity between surgical innovation and the environment in which it is applied [43, 44]. Design that aims to minimize the increasing problem of patient safety must consider the behaviour of staff and patients as well as the complex interrelationships between culture; technology; and achieving reliable, high-quality surgical outcomes [44]. While OR floor marking is increasingly applied in the design of ORs, little is known about its effects on clean air compliance .

The application of OR floor marking at the Rotterdam Eye Hospital, The Netherlands (REH) was part of a safety learning programme between surgical staff at the hospital and terminal operators at Amsterdam’s Schiphol Airport. While the direct purposes of floor marking are obviously different for airside and OR (prevention of collisions and logistic support in a dynamic environment versus infection prevention and proximity for ease of use in a relatively static environment), the main goal of doing the right things on the right spot is similar. The hospital used a laminar flow system with an inflow of 0.27 m/s, from a ceiling rectangle area of 160 × 220 cm, and with a total content of 124.5 m³ per OR (See also Fig. 24.1a). The relative humidity was 55 % and the temperature was 19.5 °C. The ventilation rate was calculated at 20.5 per hour. An OR workspace analysis was performed, indicating 42 different items on various positions. The following equipment was routinely used during ophthalmic operations: surgical table, one (mostly) or two (e.g. for more extensive retina surgery) instrument tables, Mayo instrument stand (e.g. for retina surgery and cataracts with general anaesthesia), surgical lamp (for oculoplastic and strabismus surgery), chair for surgeon, chair for assistant (resident or surgical nurse), medicine and disposable material trolley, anaesthesia instrument, chair for anaesthesiologist, phacoemulsification and vitrectomy machinery for cataract, respectively, vitreoretinal surgery (See Fig. 24.1b).

The REH is a major referral centre, handling approximately 140,000 outpatient visits and 14,000 surgical cases annually. According to Dutch infection prevention guidelines, the ORs of virtually all ophthalmic surgeries are required to have an LAF [46]. We studied the potential relationships between equipment position and endophthalmitis (an internal inflammation of the eye), the most common infection in intraocular surgery, particularly cataract surgery, which can result in loss of vision or the eye itself [47]. A mixed methods study was done including interviewing providers and doing a detailed time series analysis to measure compliance (the position of devices within the clean air flow) 5 months before marking (T0, n = 180 surgeries), and at 1 month (T1, n = 194 marked, n = 86 not marked), 6 months (T2, n = 166 marked), and 20 months (T3, n = 199 marked). The positions of devices, mobile OR table, instrument table, Mayo stand, and surgical lamp were determined by four circulating nurses (Fig. 24.1a).