Distributed Prospective Memory in Critical Care: Resuming interrupted tasks and remembering future intentions

An important cognitive function in everyday life is the formation of an intention and the execution of this intention at an appropriate time in the future – a function also known as prospective memory. In safety-critical domains such as healthcare, failure to remember future intentions can have severe consequences. Healthcare researchers and memory researchers have recognised the prospective memory challenges that healthcare staff face, such as remembering routine tasks or resuming interrupted tasks. However, healthcare researchers have not fully considered the cognitive processes involved in prospective memory, and experimental memory researchers have not fully considered the rich and supportive environment in which healthcare staff work. This thesis combines theories about prospective memory drawn from basic research with the approach of distributed cognition to investigate the prospective memory performance of intensive care nurses. A particular focus of the thesis is the resumption of interrupted healthcare tasks. The healthcare literature on interruptions is motivated by the possibly disruptive effects of interruptions on memory, but this potential outcome has seldom been investigated directly. In a retrospective analysis of a full-scale simulation study with anaesthesiologists (Study 1), we showed that whether anesthesiologists remember or forget an interrupted blood transfusion bedside check depends on how they handle the interruption. Only anaesthesiologists who engaged fully with the interruption forgot the check. The study shows that interruptions can lead to forgetting of tasks. The results highlight the fact that interruption management needs to be considered when investigating interruptions in healthcare, a factor that we considered in Study 2. Laboratory research has shown how demanding prospective memory tasks such as resuming interrupted tasks can be. In a theoretically-motivated prospective observation using a mobile eye tracker (Study 2), we investigated which characteristics of an interruption influence the resumption lag, which is the time from the end of the interruption to the recall of the interrupted primary task. The resumption lag served as an indicator of how effortful task resumption was. Furthermore, we investigated how nurses managed prospective memory demands caused by interruptions and how interruption management affected the initial prospective memory demand. The results of a series of multiple regression models show that longer interruptions and a context change due to the interruption make the resumption of interrupted tasks more effortful. Nurses managed prospective memory demands by, for example, holding task artifacts while attending an interruption. This lowers the cognitive demands for an individual nurse because the artefact indicates the task that needs to be resumed and when. Using such ideas we extended the “individual model” of interruption and resumption processes to a “distributed model” to accommodate the behaviour we observed in the field. The next study addressed the role of external support in a controlled setting. To test the influence of the reminders, we controlled the presence and absence of reminders in different prospective memory situations (Study 3). To achieve the necessary control but still allow nurses to use their experience to manage memory demands, we used a full-scale simulator and a scenario representative of professional practice. The results showed that only reminders designed to cue a specific action, or reminders that are essential for the action, improved prospective memory performance. In addition, reminders affected prospective memory processes and strategies for managing prospective memory demands. The final study of the thesis was designed to apply the knowledge gained by implementing a cognitive aid to help nurses remember intentions (Study 4). We tested whether introducing an emergency equipment drawer divider with pictorial representations of emergency equipment items at the appropriate locations would increase how completely the drawers would be stocked. The introduction of the divider resulted in a small but significant increase in equipment completeness, it increased the standardisation between different patient bays, and it eased the safety check for staff with less local intensive care experience. In summary, this research program presents a first step towards investigating prospective memory demands in critical care settings using different methods. The results indicate factors that impede or support remembering of future intentions and highlight how nurses distribute and manage prospective memory challenges. The approach of a distributed prospective memory was suggested for studying and improving prospective memory performance in complex socio-technical domains. However, remembering future intentions in socio-technical settings such as healthcare is a complex task. Future research is discussed that could advance our understanding further, and so potentially increase patient safety.