The concept of vigilance is central to anesthesiology and had served as the original motto of ASA.1 Vigilance is the ability to concentrate on, or attend to, a situation for an extended period of time to detect a signal or critical event.2 In anesthesiology, vigilance can be considered a state of awareness in which dangerous conditions are anticipated and recognized.3 These conditions may initially present as subtle signals that appear at unspecified intervals.4 The understanding of how vigilance leads to safe, effective performance has been enhanced though the theory of situational awareness (SA), which describes the perception of elements in the environment, the comprehension of their meaning, and the projection of their state in the near future.5 This can guide both an understanding of and solutions to the causes of patient harm.6,7 

In a relatively unchanging environment, and without directed cognitive effort, vigilance decrement typically occurs after about 20 minutes of visual monitoring, although this may vary depending on different stressors, such as fatigue or task difficulty.3,8 The Yerkes-Dodson law provides a useful conceptual (though not empirical) model for this observation (Figure). Generally speaking, optimal performance lies at the peak between arousal that is too low (boredom) and arousal that is too high (stress and anxiety). The extremes of the horizonal axis on the graph in the Figure correspond with the causal theories for vigilance decrement. The substantial mental burden imposed by prolonged attention on a specific task, as well as the need to remain alert and to combat boredom over sustained periods of time, degrades vigilance9 and can lead to daydreaming as a way to maintain arousal by providing varied internal stimuli.10,11 Some theorists postulate that attention is withdrawn because the task is unstimulating12, though it may simply be that attention becomes directed elsewhere.

Figure: The relation of strength of stimulus to rapidity of habit-formation. Adapted from Journal of Comparative Neurology and Psychology 1908;18(5):459-82.

Figure: The relation of strength of stimulus to rapidity of habit-formation. Adapted from Journal of Comparative Neurology and Psychology 1908;18(5):459-82.

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Anesthesiologists spend the majority of patient care time either directly observing the patient or the hemodynamic monitors.13 Monitoring is, in essence, a vigilance task.3 Approximately 85% of the time associated with anesthesia tasks is devoted to the maintenance phase of anesthesia.14 In addition to induction and emergence, there are several periods of high cognitive load during the management of an anesthetic, such as the management of the difficult airway, surgical complications, equipment failure, and the interpretation of alarms. When there is more information to monitor that is rapidly changing, this produces a greater mental burden, leading to fatigue and a need to avoid distraction.15 In one study, clinicians were delayed in recognizing monitor signals when observing or adjusting a transesophageal (TEE) probe, compared to less demanding tasks such as record-keeping.16 

Knowing what is important to attend to is a component of vigilance. Anesthesiology trainees are slower to detect monitor alarms compared to more experienced practitioners, and this was more pronounced during the higher workload of induction.17 Several studies have examined the increased heart rate among anesthesiologists during periods of high stress, including induction and emergence.18 These increases persisted but diminished in magnitude with the experience of the practitioner. Shift patterns (transitioning from day to night or vice versa), shift length, and number of consecutive days working have all been reported to affect fatigue and vigilance.2,19 Age also affects vigilance, with both younger and older individuals tending to score lower on signal detection than those in-between.20 Other sources of distress also impair vigilance, including those that originate in the anesthesiologist's personal life and interpersonal conflict at work.3 

As in other domains of patient safety, every human failure (in this case, deficit in vigilance) has a systems component. Since a decline in vigilance begins approximately 20 minutes into a monitoring task, a vigilance decrement will occur during nearly every anesthetic. Hypervigilance focused on one aspect of a situation can lead to an overall loss of situational awareness, with possible catastrophic consequences.21,22 This can take the form of inattentional blindness, where focusing attention on one task means that other signals, even gross environmental signals, are ignored. A classic example of this phenomenon is the invisible gorilla experiment conducted by Chabris and Simons, which should be viewed at theinvisiblegorilla.com/videos.html before reading ahead.23 About half of the subjects watching a video and attempting to count the number of basketball passes between members of one of two teams are oblivious to an actor wearing a full-body gorilla suit walking through the scene and stopping briefly to thump on her chest. Indeed, in adverse events in which a lack of vigilance is identified as a causative factor, it is often because attention was misdirected, for example through distractions or task interruptions that divert vigilance away from critical monitoring.

Fatigue is impossible to ameliorate completely, but mitigation strategies exist, such as introducing evening shifts in advance of a shift transition.19 Breaks are a critical component of restoring attentional capacity and should probably occur, at minimum, every four hours.3,24 Even brief breaks in which attention is switched away from what is being monitored have been shown to be beneficial.25,26. The working environment also influences the vigilance of the anesthesiologist occupied within it. Noise3,20, temperature20, lighting27, humidity, and space constraints can all modify vigilance, positively or negatively, with guidance on workspace design now available. In an OR, examples of how workspace design can enhance vigilance include locating critical tasks and displays within the primary field of vision, minimizing equipment clutter, and optimizing task lighting.28 

Strategies to address fatigue have historically focused on trainees but have begun to include anesthesiologists in practice as well.29 For both groups, an adequate volume and variety of cases can mitigate the stress response that can impede vigilance. Sufficient time off for both physical and mental concerns should be ensured to avoid “presenteeism” – the act of being at work but not fully functioning.30 Targeting an individual with either a reward or a punishment has produced positive effects on sustaining attention, but these experimental situations may not be relevant to the complex monitoring task of the anesthesiologist.31,32.

There has been considerable debate on whether reading in the OR is acceptable. The literature supports that self-initiated distractions are rarely associated with loss of vigilance and nonroutine events, and most anesthesiology professionals use discretion when engaging in them (during periods of low cognitive load).33,34 Just culture principles can also help with the design of better systems.35 For instance, there may be greater individual culpability if an anesthesiologist's vigilance was impaired by silencing monitor alarms to watch a streaming movie on a cell phone than if the anesthesiologist was adjusting a TEE probe. Of course, the optics and medicolegal impact of reading in the OR are separate issues for consideration.

The importance of teamwork as a strategy to mitigate vigilance loss cannot be understated. Fatigued individuals make more errors, but if they were part of a team that had worked together for several days, the group compensates for their error. Established teams can outperform teams composed of well-rested individuals who had not previously worked together.36 Anesthesiologists' training in nontechnical skills should include focus on identifying task fixation and cognitive overload and when help should be sought to maintain situational awareness. Creating an environment of psychological safety will allow team members to voice their concerns when these circumstances occur.

“Fatigue is impossible to ameliorate completely, but mitigation strategies exist, such as introducing evening shifts in advance of a shift transition. Breaks are a critical component of restoring attentional capacity and should probably occur, at minimum, every four hours. Even brief breaks in which attention is switched away from what is being monitored have been shown to be beneficial.”

Finally, vigilance can be supported through the application of human factors design principles, and embedding human factors experts into health care is long overdue.2,37 By supporting anesthesiologist performance and eliminating hazards, human factors expertise can enhance vigilance in a complex monitoring environment.38 Experts are developing novel alarms to allow faster detection of signal aberration, better alarm recognition, and use of tactile features to overcome ambient noise that may mask an audible alarm.39 In the OR, artificial intelligence (AI) systems are being created that assist in tasks such as regulating anesthetic delivery, interpreting processed electroencephalogram signals, and managing blood pressure.40 While AI has the promise to augment vigilance, human factors expertise is critical to ensure that automation is designed to support rather than supplant anesthesiologist oversight and does not paradoxically result in skill and vigilance decrement.41 

Admonitions directed at anesthesiologists to “pay closer attention” or “remain more alert” will not achieve an improvement in vigilance. Methods of affecting change in patient safety are more effective when they are focused on the systems level, rather than the individual.42 As we seek to improve the vigilance of anesthesiologists, a similar approach should be applied. Vigilance must be considered not only as a property of individuals, but also of the tasks they are performing and the context and environment in which the work is being conducted. To this end, strategies that seek to mitigate fatigue, focus on improving teamwork, and help develop the nontechnical skills of anesthesiologists are all beneficial. Finally, human factors experts working in conjunction with anesthesiologists are essential to the design of workspaces, equipment, and workflow that support vigilance.

Jonathan B. Cohen, MD, MS, CPPS, FASA, ASA Committee on Patient Safety and Education, ASA Patient Safety Editorial Board, and Vice Chair, Safety and Quality, Moffitt Cancer Center, Tampa, Florida.

Jonathan B. Cohen, MD, MS, CPPS, FASA, ASA Committee on Patient Safety and Education, ASA Patient Safety Editorial Board, and Vice Chair, Safety and Quality, Moffitt Cancer Center, Tampa, Florida.

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Della M. Lin, MS, MD, FASA, ASA Committee on Patient Safety and Education, ASA Committee on Physician Well-Being, APSF Board of Directors, APSF Executive Officer, Secretary, Ariadne Labs and John A. Burns School of Medicine, Honolulu, Hawaii. @dellalinMD

Della M. Lin, MS, MD, FASA, ASA Committee on Patient Safety and Education, ASA Committee on Physician Well-Being, APSF Board of Directors, APSF Executive Officer, Secretary, Ariadne Labs and John A. Burns School of Medicine, Honolulu, Hawaii. @dellalinMD

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Lilibeth Fermin, MD, MBA, ASA Committee on Patient Safety and Education, ASA Committee on Problem-Based Learning Discussions, Society of Cardiovascular Anesthesiologists Quality, Safety and Value Committee, Clinical Associate Professor of Anesthesiology, Cleveland Clinic Lerner College of Medicine, and Cardiothoracic Anesthesiologist and Intensivist, Cleveland Clinic, Weston, Florida.

Lilibeth Fermin, MD, MBA, ASA Committee on Patient Safety and Education, ASA Committee on Problem-Based Learning Discussions, Society of Cardiovascular Anesthesiologists Quality, Safety and Value Committee, Clinical Associate Professor of Anesthesiology, Cleveland Clinic Lerner College of Medicine, and Cardiothoracic Anesthesiologist and Intensivist, Cleveland Clinic, Weston, Florida.

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Kenneth R. Catchpole, PhD, Endowed Chair in Clinical Practice and Human Factors, Medical University of South Carolina, Charleston, South Carolina.

Kenneth R. Catchpole, PhD, Endowed Chair in Clinical Practice and Human Factors, Medical University of South Carolina, Charleston, South Carolina.

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