Actual and potential applications of our conclusions include a reorientation of workload modeling in complex work systems to capture the dynamic and adaptive nature of the operator's work. Models based around workload regulation may be more useful in helping management organizations adapt to future control regimens in complex work systems.

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Interruptions are frequent in many work domains. Researchers in health care have started to study interruptions extensively, but their studies usually do not use a theoretically guided approach. Conversely, researchers conducting theoretically rich laboratory studies on interruptions have not usually investigated how effectively their findings account for humans working in complex systems such as intensive care units. In the current study, we use the memory for goals theory and prospective memory theory to investigate which properties of an interruption influence how long it takes nurses to resume interrupted critical care tasks. We collected data with a mobile eye tracker in an intensive care unit and developed multiple regression models to predict resumption times. In 55.8% of all interruptions there was a finite-and therefore analyzable-resumption lag. For these cases, the main regression model explained 30.9% (adjusted R 2 ) of the variance. Longer interruptions (␤ ϭ .36, p Ͻ .001) and changes in physical location due to interruptions (␤ ϭ .40, p Ͻ .001) lengthened the resumption lag. We also calculated regression models on subsets of the data to investigate the generality of the above findings across different situations. In a further 37.6% of all interruptions, nurses used behavioral strategies that greatly diminished or eliminated individual prospective memory demands caused by interruptions, resulting in no analyzable resumption lag. We introduce a descriptive model that accounts for how nurses' behaviors affect the cognitive demand of resuming an interrupted task. Finally, we discuss how the disruptive effects of interruptions in the intensive care unit could be diminished or prevented.Keywords: interruptions, prospective memory, memory for goals, distributed cognition, intensive careIn the present study, we use theoretical models of interruptions and prospective memory to investigate factors that might make it easier or harder for people to return to an interrupted task. The potentially disruptive effects of interruptions on cognition are well recognized. Interruptions have been examined in aviation (e.g., Dismukes, Young, & Sumwalt, 1998), driving (e.g., Strayer & Johnston, 2001), human-computer interaction (e.g., Iqbal & Horvitz, 2007;McFarlane, 2002), and health care (e.g., Chisholm, Collison, Nelson, & Cordell, 2000;Coiera & Tombs, 1998;Parker & Coiera, 2000). In safety-critical domains, interruptions might contribute to errors and accidents. For example, Westbrook, Woods, Rob, Dunsmuir, and Day (2010b) showed that interruptions increase the chance of medication administration errors.Although studies have investigated interruptions in applied settings, most studies are descriptive. In contrast, in the present study we have aimed for a theoretically motivated causal account. To our knowledge, in health care only one empirical paper on interruptions appears to have used a theoretically motivated approach (for reviews see Biron, Loiselle, & Lavoie-Tremblay, 2009;. In a retrospective analysis of findi...

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Summary Melodic alarms proposed in the IEC 60601‐1‐8 standard for medical electrical equipment were tested for learnability and discriminability. Thirty‐three non‐anaesthetist participants learned the alarms over two sessions of practice, with or without mnemonics suggested in the standard. Fewer than 30% of participants could identify the alarms with 100% accuracy at the end of practice. Confusions persisted between pairs of alarms, especially if mnemonics were used during learning (p = 0.011). Participants responded faster (p < 0.00001) and more accurately (p = 0.002) to medium priority alarms than to high priority alarms, even though they rated the high priority alarms as sounding more urgent (p < 0.00001). Participants with at least 1 year of formal musical training identified the alarms more accurately (p = 0.0002) than musically untrained participants, and found the task easier overall (p < 0.00001). More intensive studies of the IEC 60601‐1‐8 alarms are needed for their effectiveness to be determined.

The HMD helped anesthesiologists detect events when physically constrained, but not when physically unconstrained. Although there was no conclusive evidence of worsened inattentional blindness, found in aviation, the perceptual properties of the HMD display appear to influence whether events are detected. Anesthesiologists wearing HMDs should self-adjust the focus to minimize eyestrain and should be aware that some changes may not attract their attention. Future areas of research include developing principles for the design of HMDs, evaluating other types of HMDs, and evaluating the HMD in clinical contexts.

The slow rate of learning and persistent confusions suggest that the IEC 60601-1-8 melodic alarms should be redesigned before they are adopted for clinical practice.

Actual or potential uses of this research include the implementation of IEC 60601-1-8 alarms in medical electrical equipment.