“First-person view” of pathogen transmission and hand hygiene – use of a new head-mounted video capture and coding tool

We opted for a mobile, head-mounted action camera (GoPro® Hero 4 Black edition, GoPro Inc., San Mateo, CA) worn by HCW during patient care. The camera was positioned on the forehead of the HCW by means of a head-strap and was oriented facing slightly downwards. With the help of an iPad mini (Apple, Cupertino, CA) the researcher could control the optimal orientation of the camera through a Wi-Fi connection. The camera was oriented to keep the participant’s hands in its visual field. In a first round, we tested and adjusted the camera in the medical high-fidelity simulator of our institution. After resolving all technical issues, we proceeded to videotape real-life care activity in three intensive care units (ICUs) specialized in trauma, cardiology, and visceral surgery at the University Hospital Zurich (USZ), Switzerland. The USZ is a 900-bed university-affiliated tertiary care center with a well-established infection prevention and control (IPC) group, weekly IPC rounds, and a designated IPC nurse consultant for each hospital ward.

A convenience sample of 10 participants was recruited among ICU nurses and physicians. Each participant wore the head-mounted camera during his/her morning shift for about 70 min. Morning shifts were chosen purposefully to guarantee that patient care activity took place. Subsequently, HCW continued their care activity without further interruptions by the researcher, who left the area.

The videos were exported from the camera and stored on a secured server. Episodes of ~30 min direct patient care were purposefully selected from each of the 10 videos for further processing. Within each of these video episodes, the occurrence, duration, and type of every HSE was systematically coded by a trained coder (MS) and supervised by a second person (LC) using the behavioral observation software INTERACT® (Mangold international, Arnstorf, Germany) together with a structured, hierarchical coding system (Fig. 1).

The observation and coding system aimed to capture the duration and nature of all HSE, defined as contact between the observed healthcare worker’s hand and any other surface. The hierarchical coding system consisted of 4 levels, of which the first two indicate the nature of the hand (gloved vs. bare and right vs. left), and the latter two indicate the nature of the surface (location relative to patient zone and type of surface) involved in the hand-to-surface exposure (Fig. 1). In line with the WHO patient zone concept [10] and observation method [15] the third coding level distinguished between surfaces “inside patient zone”, “outside patient zone”, and “critical sites”. “Inside patient zone” was defined as the patient him−/herself and all items in the immediate environment likely to be colonized with patient flora [10]. The “outside patient zone” contained other patients with their respective zones, the HCW’s own body and professional apparel (“HCW Self”), and all the other areas and surfaces outside the patient zone [10]. “Critical sites” included clean sites such as medical devices or patient’s body parts that have to be protected against microbial colonization in order to avoid infections [10]. Hand hygiene actions were registered as specific events and coded as either “hand washing” or “hand disinfection” with alcohol-based handrub. Patient zones were established a-priori for each ICU setting to ensure accurate and consistent coding (Fig. 2).

To assess the utility of the observation and coding system, we performed a descriptive analysis of frequency and duration of HSE. Coded event data were exported as comma separate values (.cvs) files, merged and edited in Excel (Microsoft, Redmond, WA) and analyzed in STATA special edition 12.0 (StataCorp, College Station, TX). Sequential analysis was additionally conducted to identify HSE sequences of particular relevance to infectious risks, as informed by the WHO ‘Five Moments for Hand Hygiene’ [10]. We defined sequences of touching a surface outside the patient zone followed by touching any surface inside a patient zone as a ‘colonization event’ and a sequence of touching any surface, except a critical site, followed by touching a critical site as an ‘infection event’ (Table 1). A colonization event would correspond to a modified WHO “Five Moments” concept’s Moment 1 “Before touching a patient” but include touching any surface inside the patient zone and not only the patient. This modification of Moment 1 was made to capture more precisely colonization risk of the patient by hospital flora that is brought into the immediate vicinity of the patient and from there to the patient. An infection event would correspond to WHO “Five Moments” concept’s Moment 2 “Before clean/aseptic procedure”. According to Sax et al., “Critical sites for infectious risks” included breaks in the patient’s intact skin such as wounds and catheter insertion sites, any patient mucous membrane, invasive devices in-situ if the lumen was accessed such as vascular or urinary catheters, and semi-critical or critical medical devices ready to be used on the patient [10].