Intensive Care Unit (ICU) nurses are under constant influx of information generated by patient monitoring systems in the form of audio-visual alarms. Alarms are designed to attract attention and induce action in nurses. However, patient monitoring systems generate alarms regardless of the nurses’ capacity to receive and act on them. Excessive number and continuous inflow of alarms overwhelm the sensory and cognitive capacities of nurses, leading to ‘alarm fatigue’ (Cvach, 2012; Lewandowska et al., 2020; Sendelbach & Funk, 2013). Nurses become desensitised to alarms, resulting in inappropriate or lack of response to alarms, increased stress in nurses and threats on patient safety (Kristensen et al., 2015; Ruskin & Hüske-Kraus, 2015). The problem has been on the radar of the healthcare industry and academic community for several decades; yet no sustained improvements have been achieved so far (Özcan et al., 2018). We argue a mismatch exists between the interaction possibilities offered by patient monitoring systems and the capabilities of nurses. This mismatch results in burdened workload, stress, and fatigue, all of which can be mitigated by system design improvements (Nuamah & Mehta, 2020). Aligning system interaction possibilities with nurse capabilities necessitates an in-depth understanding of ICU nurses as system users. To gain deeper understanding of ICU nurses, this study scrutinizes individual characteristics of nurses to reveal distinct user groups. We identify four primary types of ICU nurses with the objective of informing future studies aimed at enhancing patient monitoring interactions. By doing so, we aim to reduce the mismatch between the systems and their users, and a take step towards symbiotic efficient collaboration (Grootjen et al., 2010).
In the field of human factors, recent efforts to mitigate the alarm problem have brought the focus onto nurses. Strategies involve optimizing the way medical information is presented to nurses so that the burden on cognitive load is minimized (Garot et al., 2020; Koomen et al., 2021). However, system functionalities that facilitate the interaction might vary among different types of users. Efforts so far have often targeted a generic ICU nurse. We propose this one-size-fits-all approach fails to capture the variation among different users and their interaction styles with the system. People appraise events and respond differently based on their individual backgrounds, memories, associations, and characteristics (Scherer et al., 2001). Recent studies point to this variation among nurses and suggest nursing styles differ based on personal differences (Ruppel et al., 2019). We argue that capturing this variation in nurses is valuable as it allows designing for distinct user groups in a more targeted manner. Patient monitoring systems currently in use offer the same interaction possibilities to all users without room for customization. However, nurses may have different natural tendencies in system use based on individual differences. Addressing the individual differences through improved design has the potential to reduce the additional workload and stress induced by use of patient monitoring systems.
Innovation and design efforts for healthcare is rapidly introducing novel products and systems at nurses’ disposal. It is critical that these novel approaches are well-adjusted to nurses’ needs so that their acceptability is increased, and adoption process is shortened. End-user involvement in the design process has been put forward as one of the five major requirements for information technology adoption in healthcare (Bernstein et al., 2007). Consideration of the well-being of healthcare providers is one of the elements for optimizing ICU care delivery (Bueno & La Calle, 2020). By considering the needs and preferences of nurses through a user-centred design approach, we take a step towards humanizing intensive care.
In this paper, our aim is to understand latent nurse needs that might be relevant in nurse-system interactions. We believe this will offer new tools for designers who aim to facilitate nurses’ willingness to interact with novel products and systems. We describe the processes involved in the cognitive processing of patient monitoring alarms and explore how individual differences (e.g., personality, vulnerability to stress, sensory sensitivity, musicality, and risk tolerance) play roles throughout the perception-action trajectory.
Cognitive Processing of Alarms
Alarms are audio-visual signals intended to communicate information to nurses. Audio-visual information requires cognitive processing to decode its meaning and induce action. An understanding of information processing via the widely accepted Human Information Processing Model helps illuminate the significance of individual differences (Wickens, 2002). Within this framework, information processing involves three main stages: perception, cognition, and response (Fig. 1). Perception involves the bottom-up reception of the sensory signal and transformation into neural signal for further processing. Perceptual processing of alarms has been thoroughly investigated by previous studies, and generated extensive inventory of knowledge in making alarm sounds more readily informative and pleasant in the acoustic complexity of the ICU (Bennett et al., 2019; J. Edworthy & Hellier, 2005; J. R. Edworthy et al., 2017; Foley et al., 2020; Pereira et al., 2021; Sreetharan et al., 2021). Nevertheless, previous work indicates that simply improving sensory quality of alarms is not sufficient (Andrade-Méndez et al., 2020; Sanz-Segura et al., 2022). Nurses are cognitively overwhelmed by the sheer number of alarms (Bostan et al., 2022; Cvach, 2012).
The stage of cognition involves attributing meaning to perceptual elements through processes such as attention and decision-making. This process is modulated by long- and short-term memory (Fig. 1). We focus on the individual differences in this modulator as indicated by the darker box in the figure. Individual differences in one’s memory, associations, and habits influence what meanings are attributed to perceptual elements. In the field of noise annoyance, personal differences in noise-sensitivity and attitudes towards sound source are predictors of level of annoyance by sounds (Crichton et al., 2015; Haac et al., 2019; Janssen et al., 2011; Paunović et al., 2009). This applies to ICU nurses, where it was shown that nurses with musical training identify and respond to audible alarms faster (Yue et al., 2017). This demonstrates individual differences in cognitive processing influence nurse responses to patient monitoring alarms.
Final stage of the HIP model involves response and lastly a feedback loop. Response is the stage where user acts on the stimulus. Alarm fatigue is often associated with inappropriate, or lack of, response, such as seeming to ignore an alarm (Sendelbach & Funk, 2013). Personality and other individual differences have been shown to influence alarm responsivity (Claudio et al., 2021; Deb & Claudio, 2015). Feedback loop can also be influenced by individual differences. A nurse annoyed by the loud environment can customize system settings to generate fewer alarms or can turn up the volume to increase chances of hearing. The action upon the patient monitoring system is therefore based on this personal appraisal of the environment.
We argue certain individual factors affect how nurses process alarms, resulting in differences in how they interact with the patient monitoring systems. In the following section, we explore which factors we consider to be relevant.
Factors that Influence Cognitive Processing of Alarms
In efforts to improve the alarm responsivity of nurses, one seldom asks the question of who the ICU nurse actually is. Studies in human factors and training/intervention programs often target a generic nurse. Moreover, studies in this field often target the observable interaction, yielding measures such as reaction times or usability scales. However, growing evidence indicates a diverse range of nursing styles with regards to how they manage alarms (Ruppel et al., 2019). Recent studies suggest that what is ‘user friendly’ may depend on individual needs of nurses (Sanz-Segura et al., 2022). We argue that latent individual properties underlie and modulate the cognitive processes related to interacting with the system, and that their potential has yet not been explored from the human factors engineering perspective. To explain this further, we refer to Fig. 2. In the figure, observable behaviour and attitudes constitute the tip of the interaction iceberg. This is the portion of the interaction that has been brought to the surface and made visible by human factors research up to date. Revealing more of the iceberg requires bringing the latent portion closer to the visible surface. Shifting our focus from observable, explicit interaction behaviour to latent individual properties can offer new insights into addressing the needs of nurses. By understanding what drives the actions of the user, we can determine the most effective cognitive cues to optimize the interaction with the system.
We argue that several factors modulate the way alarms are cognitively processed and appraised. Level of noise annoyance hinges upon several individual factors (Crichton et al., 2015; Haac et al., 2019; Janssen et al., 2011; Paunović et al., 2009). In the ICU, nurses who feel more annoyed by alarms might be more inclined to decrease the number of alarms generated by the patient monitoring system by customizing system settings. Nurses vary in how they customize alarm settings (Özcan & Gommers, 2020; Ruppel et al., 2018). To capture this variation, we list several factors that we consider influential in how nurses process alarms and interact with the patient monitoring system.
Nursing Experience
The first relevant factor that influences nurse-system interactions is the level of nursing experience. Several studies have suggested experience level to be a main factor in determining how nurses set their alarms (Özcan & Gommers, 2020; Ruppel et al., 2018; Wung & Schatz, 2018). Nurses report their response to alarms is influenced by their prior experience since experience and expertise enables them to anticipate future events more accurately (Gazarian et al., 2015). This allows more confidence and freedom in customizing alarm settings. Customizing the alarm limits of a vital parameter to be wider yields fewer alarms, while narrow bounds generate more alarms. Nurses with more experience tend to feel more confident in their judgement and set the bandwidth of limits wider (Ruppel et al., 2019; Wung & Schatz, 2018). Inexperienced nurses use alarms as a form of distant monitoring of patient status and tend to set narrower bandwidths, increasing the number of audible alarms. Consequently, the number of alarms is partially determined by the user’s actions, even before the alarm-generating medical condition occurs.
Personality
A second relevant factor is nurse personality. Deb and Claudio have shown ‘nurse individuality’ measured as personality type is one of the predictors of alarm fatigue (Deb & Claudio, 2015b). Nurses with different personality traits attach different meanings to alarms, have different affective responses to them, and are influenced by the negative effects of alarm fatigue differently. Similarly, Ruppel et al. have shown that nurse ‘expertise, education, knowledge, and style’ are factors in nurses’ clinical reasoning about alarm customization (Ruppel et al., 2019). Even though the term ‘style’ remains relatively vague, their discussion suggests that this attribute is related to personal values and personality. Previous investigations from our research group indicate that nurse personality plays a role in how and why they set their alarm limits (Özcan et al., 2018; Schokkin, 2019). Taken together, these studies suggest clear differences in nurse-system interactions based on personality; yet efforts to mitigate alarm fatigue fail to capture this variation.
Operationalizing personality is challenging since factors such as context and culture are highly influential. A widely accepted approach has been the Big Five Personality Inventory (BFI) (John & Srivastava, 1999). In this approach, personality varies among five distinct dimensions: Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness. People lie within the range between two extremes for these five dimensions. Extraversion is related to sociability and emotional expressiveness. Higher scores are associated with outgoing, lively character while lower scores indicate more introspective and reflective character. Agreeableness relates to interest in others and prosocial behaviour. Higher agreeableness is marked by considerate, nurturing, warm demeanour whereas lower scores suggest assertive, independent, direct disposition. Conscientiousness encompasses level of organization and goal-directed behaviour. Greater scores relate to disciplined, methodological, and responsible character while lower scores indicate more spontaneous and easy-going personality. Neuroticism relates to emotional stability. Higher scores are associated with more emotional and temperamental nature whereas lower scores reflect a calmer, resilient and stable demeanour. Finally, openness is related to creativity and novelty. Higher scores indicate a curious, imaginative, and inventive mindset whereas lower levels are distinguished by a preference for practicality, conventionality, and a realistic approach. In the context of ICU, the importance of certain personality traits is highlighted. For example, an ICU nurse would be expected to be a highly conscientious person so that they are diligent about the details of their work and are able to perform clinical actions in an organised manner. A rather spontaneous nurse might pay less attention to how the patient monitor alarms are set, while an organized nurse might have higher regard for such details. In the case of neuroticism, a nurse who is often carried away by their emotions might have stronger negative reactions to alarm fatigue (Claudio et al., 2021b). Considering such influences, we posit personality as operationalized by the BFI is important to investigate in understanding nurse-system interactions. In this study, we used the validated translation of the BFI in Dutch language (Denissen et al., 2008).
Other traits that influence alarm processing
There are several other factors that we suggest play roles in nurse-system interactions. One of these is one’s inherent vulnerability to stress. Noise in ICUs in general (Morrison et al., 2003), and monitoring alarms in particular cause stress in nurses (Ruskin & Hüske-Kraus, 2015; Wung & Schatz, 2018). People differ in how well they are equipped with coping mechanisms against stress. These mechanisms may be in the form of lifestyle choices, in the form of psychological resilience, and in the form of neurobiological resilience (Connor et al., 2007; Pfau & Russo, 2015). Although nurses are trained and well-equipped for dealing with high stress, ultimately, they are not invulnerable. We argue their level of vulnerability to stress might influence how they process and respond to alarms as a stressor. In this study, we operationalize stress via the Vulnerability to Stress Scale (SVS) (Miller & Smith, 1985). This validated questionnaire measures vulnerability to and ability in dealing with stressful events of daily life. Items are related to lifestyle choices and personal attitudes, such that healthier choices in diet, exercise, and social life leads to higher resilience to stress, whereas engaging in bad habits such as smoking leads to higher vulnerability to stress. Higher scores in SVS indicate higher vulnerability to stress.
Another factor we consider to be influential is sensitivity to physical stimuli. People vary in their subjective ratings of how annoying they find the same sound based solely on differences in individual noise sensitivity (Haac et al., 2019; Paunović et al., 2009). Noise sensitivity has been shown to be a predictor of noise-related stress (Topf, 1989) and is associated with higher levels of annoyance in nurses (Aletta et al., 2018). We argue sensitivity to stimuli might determine how nurses evaluate alarms, and consequently modulate their responses. As in the example above, nurses who are more sensitive to noise in the environment may be more likely to reduce the noise. To measure sensitivity, we use an adjusted version of the Highly Sensitive Person Scale (HSPS). This validated scale measures sensitivity to physical, emotional, and social stimuli (Aron & Aron, 1997). Only the physical sensitivity dimension is relevant for our research. We used this subset of items to measure sensitivity to sensory stimulation. This gives an indication with regards to an individual’s sensitivity to strong stimuli such as loud noises and bright lights. Higher scores indicate higher sensitivity.
An additional factor that might play a role is musicality. A systematic review reveals that nurses who have a musical background (e.g., music theory, singing, playing an instrument) differ in how they respond to alarms (Yue et al., 2017). Musically trained nurses have faster response times to alarms (Lacherez et al., 2007). Such nurses identify alarms more accurately and find the task to be subjectively easier (Wee & Sanderson, 2008). Experience with music influences how sensitive one’s ear is to musical tones. Consequently, we believe nurses’ ability to process alarm sounds may be influenced by their musical background. To gauge musical background, we used the validated Goldsmiths Musical Sophistication Index (MSI). MSI measures musical involvement, ability, and knowledge of non-musicians on several dimensions (Müllensiefen et al., 2014). We used a subset of MSI to include the relevant items along the dimension of ‘perceptual ability’. This dimension evaluates of one’s abilities in perceiving musical and sound related attributes. Higher scores indicate higher perceptual ability for music.
A final factor that might be influential is risk tolerance. Risk assessment is one of the key roles of nurses (Henneman et al., 2012). Nurses need to make risk-assessment calculations frequently in deciding the course of action (Despins, 2017). For example, ignoring or silencing an alarm without tending to the patient requires taking a well-calculated risk (Schokkin, 2019). People vary in how risk-tolerant they are (Dohmen et al., 2011). Therefore, we argue that the level of risk tolerance could play a role in how nurses process and act on alarms. Recent literature on risk tolerance suggests simply asking people to rate their risk-taking attitudes prompts them to consider several relevant domains of life and yields valid and reliable results (Mata et al., 2018). Consequently, we included a single item to inquire how risk-taking participants perceived themselves to be. Higher scores indicate higher risk-taking tendency.
Unit Differences
A final set of differences that can lead to variations in alarm processing is differences in alarm culture within the unit. Nurses report their customization of alarm settings are influenced by factors such as how alarms are managed within the unit, whether the unit is already noisy or relatively quiet, and some broader factors such as leadership styles and staffing (Ruppel et al., 2019). Another observation study supports this notion, suggesting that ‘sound cultures’ within units compel nurses to adopt particular alarm customization habits (Schokkin, 2019).
Physical attributes of the unit may further influence how alarms are processed. Some units are open layout with all patients in one large room; meanwhile some units consist of individual chambers for each patient. Physical layout of the unit directly influences where the patient monitoring systems are located and how sound is dispersed within the environment. This creates differences in the soundscape and influences how nurses hear the alarms. Another difference might lie in the protocols regarding family visits. While some units only allow for visitation during particular hours, some units allow family to be around more often. The number of people around the patient and concerned questions from the family following each alarm might force the nurses to be more considerate of their alarm settings. Finally, characteristics of the patients also differ between units. Some units accommodate adults, while others accommodate children or even neonates. Some units involve patients around planned surgeries, while other units have patients following unplanned acute trauma (e.g., after car accident). The type of patient influences the type of alarms generated. Therefore, we argue unit related differences also play role in how nurses interact with patient monitoring systems.
To explore the relevance of above-mentioned individual characteristics, we conducted a survey study as the first step of the investigation of our hypothesis. This step involved acquiring information on the relevant individual characteristics listed above. Our future studies will investigate how individual characteristics influence nurse-system interactions in the form of alarm settings.