Common Behaviors and Faults When Doffing Personal Protective Equipment for Patients With Serious Communicable Diseases.

BACKGROUND: The safe removal of personal protective equipment (PPE) can limit transmission of serious communicable diseases, but this process poses challenges to healthcare workers (HCWs). METHODS: We observed 41 HCWs across 4 Ebola treatment centers in Georgia doffing PPE for simulated patients with serious communicable diseases. Using human factors methodologies, we obtained the details, sequences, and durations of doffing steps; identified the ways each step can fail (failure modes [FMs]); quantified the riskiness of FMs; and characterized the workload of doffing steps. RESULTS: Eight doffing steps were common to all hospitals-removal of boot covers, gloves (outer and inner pairs), the outermost garment, the powered air purifying respirator (PAPR) hood, and the PAPR helmet assembly; repeated hand hygiene (eg, with hand sanitizer); and a final handwashing with soap and water. Across hospitals, we identified 256 FMs during the common doffing steps, 61 of which comprised 19 common FMs. Most of these common FMs were above average in their riskiness at each hospital. At all hospitals, hand hygiene, removal of the outermost garment, and removal of boot covers were above average in their overall riskiness. Measurements of workload revealed that doffing steps were often mentally demanding, and this facet of workload correlated most strongly with the effortfulness of a doffing step. CONCLUSIONS: We systematically identified common points of concern in protocols for doffing high-level PPE. Addressing FMs related to hand hygiene and the removal of the outermost garment, boot covers, and PAPR hood could improve HCW safety when doffing high-level PPE.We identified ways that doffing protocols for high-level personal protective equipment may fail to protect healthcare workers. Hand hygiene, removing the outermost garment, boot covers, and respirator hood harbored the greatest risk and failed in similar ways across different hospitals.

Variability in the Duration and Thoroughness of Hand Hygiene.

We observed 354 hand hygiene instances across 41 healthcare workers doffing personal protective equipment at 4 hospital-based biocontainment units. We measured the duration and thoroughness of each hand hygiene instance. Both parameters varied substantially, with systematic differences between hospitals and differences between healthcare workers accounting for much of the variance.

Design Strategies for Biocontainment Units to Reduce Risk During Doffing of High-level Personal Protective Equipment.

BACKGROUND: Few data exist to guide the physical design of biocontainment units, particularly the doffing area. This can impact the contamination risk of healthcare workers (HCWs) during doffing of personal protective equipment (PPE). METHODS: In phase I of our study, we analyzed simulations of a standard patient care task with 56 trained HCWs focusing on doffing of high-level PPE. In phase II, using a rapid cycle improvement approach, we tested different balance aids and redesigned doffing area layouts with 38 students. In phase III, we tested 1 redesigned layout with an additional 10 trained HCWs. We assessed the effectiveness of design changes on improving the HCW performance (measured by occurrence and number of risky behaviors) and reducing the physical and cognitive load by comparing the results from phase I and phase III. RESULTS: The physical load was highest when participants were removing their shoe covers without any balance aid; the use of a chair required the lowest physical effort, followed by horizontal and vertical grab bars. In the revised design (phase III), the overall performance of participants improved. There was a significant decrease in the number of HCW risky behaviors (P = .004); 5 risky behaviors were eliminated and 2 others increased. There was a significant decrease in physical load when removing disposable shoe covers (P = .04), and participants reported a similar workload in the redesigned doffing layout (P = .43). CONCLUSIONS: Through optimizing the design and layout of the doffing space, we reduced risky behaviors of HCWs during doffing of high-level PPE.

Human Factors Risk Analyses of a Doffing Protocol for Ebola-Level Personal Protective Equipment: Mapping Errors to Contamination.

Background: Doffing protocols for personal protective equipment (PPE) are critical for keeping healthcare workers (HCWs) safe during care of patients with Ebola virus disease. We assessed the relationship between errors and self-contamination during doffing. Methods: Eleven HCWs experienced with doffing Ebola-level PPE participated in simulations in which HCWs donned PPE marked with surrogate viruses (ɸ6 and MS2), completed a clinical task, and were assessed for contamination after doffing. Simulations were video recorded, and a failure modes and effects analysis and fault tree analyses were performed to identify errors during doffing, quantify their risk (risk index), and predict contamination data. Results: Fifty-one types of errors were identified, many having the potential to spread contamination. Hand hygiene and removing the powered air purifying respirator (PAPR) hood had the highest total risk indexes (111 and 70, respectively) and number of types of errors (9 and 13, respectively). ɸ6 was detected on 10% of scrubs and the fault tree predicted a 10.4% contamination rate, likely occurring when the PAPR hood inadvertently contacted scrubs during removal. MS2 was detected on 10% of hands, 20% of scrubs, and 70% of inner gloves and the predicted rates were 7.3%, 19.4%, 73.4%, respectively. Fault trees for MS2 and ɸ6 contamination suggested similar pathways. Conclusions: Ebola-level PPE can both protect and put HCWs at risk for self-contamination throughout the doffing process, even among experienced HCWs doffing with a trained observer. Human factors methodologies can identify error-prone steps, delineate the relationship between errors and self-contamination, and suggest remediation strategies.

Assessing Viral Transfer During Doffing of Ebola-Level Personal Protective Equipment in a Biocontainment Unit.

Background: Personal protective equipment (PPE) protects healthcare workers (HCWs) caring for patients with Ebola virus disease (EVD), and PPE doffing is a critical point for preventing viral self-contamination. We assessed contamination of skin, gloves, and scrubs after doffing Ebola-level PPE contaminated with surrogate viruses: bacteriophages MS2 and Φ6. Methods: In a medical biocontainment unit, HCWs (n = 10) experienced in EVD care donned and doffed PPE following unit protocols that incorporate trained observer guidance and alcohol-based hand rub (ABHR). A mixture of Φ6 (enveloped), MS2 (nonenveloped), and fluorescent marker was applied to 4 PPE sites, approximating body fluid viral load (Φ6, 105; MS2, 106). They performed a patient care task, then doffed. Inner gloves, face, hands, and scrubs were sampled for virus, as were environmental sites with visible fluorescent marker. Results: Among 10 HCWs there was no Φ6 transfer to inner gloves, hands, or face; 1 participant had Φ6 on scrubs at low levels (1.4 × 102). MS2 transfer (range, 101-106) was observed to scrubs (n = 2), hands (n = 1), and inner gloves (n = 7), where it was highest. Most (n = 8) had only 1 positive site. Environmental samples with visible fluorescent marker (n = 21) were negative. Conclusions: Among experienced HCWs, structured, observed doffing using ABHR protected against hand contamination with enveloped virus. Nonenveloped virus was infrequent on hands and scrubs but common on inner gloves, suggesting that inner gloves, but not necessarily ABHR, protect against hand contamination. Optimizing doffing protocols to protect against all types of viruses may require reinforcing careful handling of scrubs and good glove/hand hygiene with effective agents.

Preventing healthcare-associated infections through human factors engineering.

PURPOSE OF REVIEW: Human factors engineering (HFE) approaches are increasingly being used in healthcare, but have been applied in relatively limited ways to infection prevention and control (IPC). Previous studies have focused on using selected HFE tools, but newer literature supports a system-based HFE approach to IPC. RECENT FINDINGS: Cross-contamination and the existence of workarounds suggest that healthcare workers need better support to reduce and simplify steps in delivering care. Simplifying workflow can lead to better understanding of why a process fails and allow for improvements to reduce errors and increase efficiency. Hand hygiene can be improved using visual cues and nudges based on room layout. Using personal protective equipment appropriately appears simple, but exists in a complex interaction with workload, behavior, emotion, and environmental variables including product placement. HFE can help prevent the pathogen transmission through improving environmental cleaning and appropriate use of medical devices. SUMMARY: Emerging evidence suggests that HFE can be applied in IPC to reduce healthcare-associated infections. HFE and IPC collaboration can help improve many of the basic best practices including use of hand hygiene and personal protective equipment by healthcare workers during patient care.

Bag Valve Mask Ventilation as a Perceptual-Cognitive Skill.

Objective This study used a high-fidelity infant mannequin to examine the relationship between the quality of bag valve mask ventilation (BVMV) and how providers of varying levels of experience use visual feedback (e.g., electronic vital signs) to guide their performance. Background BVMV is a common and critical procedure for managing pediatric respiratory emergencies. However, providers do not consistently deliver effective BVMV. Efforts to improve BVMV have ignored the question of how providers effectively use feedback often available during BVMV. Method Six expert and six novice respiratory therapists completed two simulations of an infant requiring BVMV. In one, the technology failed to display SpO2, an important but somewhat redundant visual cue. Eye movements, verbal reports, and ventilation rate (in breaths per minute) were measured in each simulation. Results Regardless of SpO2 availability, eye movements and verbal reports suggested that novices depended strongly on electronic vital signs and when SpO2 was absent ventilated at a faster rate (exceeding the recommended range of ventilation rates) than when SpO2 was present. Experts' ventilation rates were comparable and within the recommended range in both conditions. When SpO2 was absent, experts emphasized information from direct observation of the patient that novices neglected. Conclusion Individual differences in the use of feedback during BVMV contribute to the quality of BVMV. This work bears on the theoretical discussions involving the use of automation and nontechnological cues to guide performance. Application These results have the potential to expand the current understanding of factors underlying effective BVMV with implications for training novice providers.

Improving the communication of hand hygiene procedures: Controlled observation, redesign, and randomized group comparisons.

OBJECTIVE: To assess the clarity and efficacy of the World Health Organization (WHO) hand-rub diagram, develop a modified version, and compare the 2 diagrams. DESIGN: Randomized group design preceded by controlled observation and iterative product redesigns. SETTING: The Cognitive Ergonomics Lab in the School of Psychology at the Georgia Institute of Technology. PARTICIPANTS: We included participants who were unfamiliar with the WHO hand-rub diagram (convenience sampling) to ensure that performance was based on the diagram and not, for example, on prior experience. METHODS: We iterated through the steps of a human factors design procedure: (1) Participants simulated hand hygiene using ultraviolet (UV) absorbent lotion and a hand-rub technique diagram (ie, WHO or a redesign). (2) Coverage, confusion judgments, and behavioral videos informed potentially improved diagrams. And (3) the redesigned diagrams were compared with the WHO version in a randomized group design. Coverage was assessed across 72 hand areas from multiple UV photographs. RESULTS: The WHO diagram led to multiple omissions in hand-surface coverage, including inadequate coverage by up to 75% of participants for the ulnar edge. The redesigns improved coverage significantly overall and often substantially. CONCLUSIONS: Human factors modification to the WHO diagram reduced inadequate coverage for naïve users. Implementation of an improved diagram should help in the prevention of healthcare-associated infections.

Design strategies to improve healthcare worker safety in biocontainment units: learning from ebola preparedness.

OBJECTIVE: To identify ways that the built environment may support or disrupt safe doffing of personal protective equipment (PPE) in biocontainment units (BCU). DESIGN: We observed interactions between healthcare workers (HCWs) and the built environment during 41 simulated PPE donning and doffing exercises. SETTING: The BCUs of 4 Ebola treatment facilities and 1 high-fidelity BCU mockup.ParticipantsA total of 64 HCWs (41 doffing HCWs and 15 trained observers) participated in this study. RESULTS: In each facility, we observed how the physical environment influences risky behaviors by the HCW. The environmental design impeded communication between trained observers (TOs) and HCWs because of limited window size or visual obstructions with louvers, which allowed unobserved errors. The size and configuration of the doffing area impacted HCW adherence to protocol, and lack of clear demarcation of zones resulted in HCWs inadvertently leaving the doffing area and stepping back into the contaminated areas. Lack of standard location for items resulted in equipment and supplies frequently shifting positions. Finally, different solutions for maintaining balance while removing shoe covers (ie, chair, hand grips, and step stool) had variable success. We identified the 5 key requirements that doffing areas must achieve to support safe doffing of PPE, and we developed a matrix of proposed design strategies that can be implemented to meet those requirements. CONCLUSIONS: Simple, low-cost environmental design interventions can provide structure to support and improve HCW safety in BCUs. These interventions should be implemented in both current and future BCUs.

Vigilance in a dynamic environment.

Advances in technology have led to increasing levels of automation in modern work environments, moving people to the position of a passive monitor. When persons are in passive monitoring states, they are often subject to overall deficits in performance that become worse as time on task increases (i.e., vigilance decrements). Although many factors have been shown to influence whether or not a vigilance decrement will occur in a monitoring task (e.g., event rate), it is not clear how laboratory experiments translate to operational environments (Hancock, 2013). Four experiments were conducted that examined the effects of signal rate, event rate, cognitive load, training, and the presence of a dual task on performance during an air traffic control (ATC) automation failure detection task. Both failure detection and detection time were analyzed. Results from a meta-analysis revealed that cognitive load placed on participants through the use of task-relevant complex instructions produced a reliable vigilance decrement. However, other types of cognitive load did not produce any reliable vigilance decrements. The relationship of the cognitive load to the vigilance task may be an important factor in determining if the cognitive load will produce a vigilance decrement in a dynamic operational environment like air traffic control.

A Behavioral Intervention for Reducing Postcompletion Errors in a Safety-Critical System.

OBJECTIVE: We investigated the effectiveness of a theoretically motivated intervention at reducing procedural errors in train yard operations, where making these errors could be costly or life-threatening. BACKGROUND: A widespread and persistent memory error that people commit on a daily basis is the postcompletion error (PCE), that is, forgetting to complete the final step of a procedural task in which the final step occurs after completion of the task goal. PCEs occur in the railroad industry when a locomotive conductor changes the direction of a rail switch but fails to report this change. This particular error could contribute to unsafe conditions as another train traveling on the same track could derail. Although training can help reduce some of the factors leading to unsafe conditions on the rail, research has demonstrated that PCEs are different from other errors of omission in that they cannot be eliminated through training, which makes them a difficult problem to address. METHOD: Twenty-eight undergraduates completed train yard tasks within a mid-fidelity simulator used in commercial rail operations for training. Each participant received the behavioral intervention in one block and no intervention in another. Specifically, participants were required to perform an additional task designed to remind participants of the postcompletion step. RESULTS: Our intervention significantly reduced PCE rates in the context of train yard operations, on average by 65%. CONCLUSION: We discuss implications of the effectiveness of our intervention at reducing train yard accidents and how this outcome can contribute to the literature on the cause of PCEs. APPLICATION: In cases such as the railroad industry, where redesigning technology is prohibitive, our behavioral intervention is an effective alternative for significantly reducing PCEs.

The Threat-Strategy Interview.

Operators in dynamic work environments use strategies to manage threats in order to achieve task goals. We introduce a structured interview method, the Threat-Strategy Interview (TSI), and an accompanying qualitative analysis to induce operator-level threats, strategies, and the cues that give rise to them. The TSI can be used to elicit knowledge from operators who are on the front line of managing threats to provide an understanding of strategic thinking, which in turn can be applied toward a variety of problems.

Individual differences in the calibration of trust in automation.

OBJECTIVE: The objective was to determine whether operators with an expectancy that automation is trustworthy are better at calibrating their trust to changes in the capabilities of automation, and if so, why. BACKGROUND: Studies suggest that individual differences in automation expectancy may be able to account for why changes in the capabilities of automation lead to a substantial change in trust for some, yet only a small change for others. METHOD: In a baggage screening task, 225 participants searched for weapons in 200 X-ray images of luggage. Participants were assisted by an automated decision aid exhibiting different levels of reliability. Measures of expectancy that automation is trustworthy were used in conjunction with subjective measures of trust and perceived reliability to identify individual differences in trust calibration. RESULTS: Operators with high expectancy that automation is trustworthy were more sensitive to changes (both increases and decreases) in automation reliability. This difference was eliminated by manipulating the causal attribution of automation errors. CONCLUSION: Attributing the cause of automation errors to factors external to the automation fosters an understanding of tasks and situations in which automation differs in reliability and may lead to more appropriate trust. APPLICATION: The development of interventions can lead to calibrated trust in automation.

Strategic threat management: an exploration of nursing strategies in the pediatric intensive care unit.

Part of the work of a critical care nurse is to manage the threats that arise that could impede efficient and effective job performance. Nurses manage threats by employing various strategies to keep performance high and workload manageable. We investigated strategic threat management by using the Threat-Strategy Interview. Threats frequently involved technology, staff, or organizational components. The threats were managed by a toolbox of multifaceted strategies, the most frequent of which involved staff-, treatment- (patient + technology), examination- (patient + clinician), and patient-oriented strategies. The profile of strategies for a particular threat often leveraged work facets similar to the work facet that characterized the threat. In such cases, the nurse's strategy was directed at eliminating the threat (not working around it). A description at both a domain invariant level - useful for understanding strategic threat management generally - and a description at an operational, specific level - useful for guiding interventions-- are presented. A structural description of the relationship among threats, strategies, and the cues that trigger them is presented in the form of an evidence accumulation framework of strategic threat management.

Situation awareness measures for simulated submarine track management.

OBJECTIVE: The aim of this study was to examine whether the Situation Present Assessment Method (SPAM) and the Situation Awareness Global Assessment Technique (SAGAT) predict incremental variance in performance on a simulated submarine track management task and to measure the potential disruptive effect of these situation awareness (SA) measures. BACKGROUND: Submarine track managers use various displays to localize and track contacts detected by own-ship sensors. The measurement of SA is crucial for designing effective submarine display interfaces and training programs. METHOD: Participants monitored a tactical display and sonar bearing-history display to track the cumulative behaviors of contacts in relationship to own-ship position and landmarks. SPAM (or SAGAT) and the Air Traffic Workload Input Technique (ATWIT) were administered during each scenario, and the NASA Task Load Index (NASA-TLX) and Situation Awareness Rating Technique were administered postscenario. RESULTS: SPAM and SAGAT predicted variance in performance after controlling for subjective measures of SA and workload, and SA for past information was a stronger predictor than SA for current/future information. The NASA-TLX predicted performance on some tasks. Only SAGAT predicted variance in performance on all three tasks but marginally increased subjective workload. CONCLUSION: SPAM, SAGAT, and the NASA-TLX can predict unique variance in submarine track management performance. SAGAT marginally increased subjective workload, but this increase did not lead to any performance decrement. APPLICATION: Defense researchers have identified SPAM as an alternative to SAGAT because it would not require field exercises involving submarines to be paused. SPAM was not disruptive, but it is potentially problematic that SPAM did not predict variance in all three performance tasks.

Exploring relationships of human-automation interaction consequences on pilots: uncovering subsystems.

OBJECTIVE: We attempted to understand the latent structure underlying the systems pilots use to operate in situations involving human-automation interaction (HAI). BACKGROUND: HAI is an important characteristic of many modern work situations. Of course, the cognitive subsystems are not immediately apparent by observing a functioning system, but correlations between variables may reveal important relations. METHOD: The current report examined pilot judgments of 11 HAI dimensions (e.g., Workload, Task Management, Stress/Nervousness, Monitoring Automation, and Cross-Checking Automation) across 48 scenarios that required airline pilots to interact with automation on the flight deck. RESULTS: We found three major clusters of the dimensions identifying subsystems on the flight deck: a workload subsystem, a management subsystem, and an awareness subsystem. DISCUSSION: Relationships characterized by simple correlations cohered in ways that suggested underlying subsystems consistent with those that had previously been theorized. APPLICATION: Understanding the relationship among dimensions affecting HAI is an important aspect in determining how a new piece of automation designed to affect one dimension will affect other dimensions as well.

Individual differences in working memory capacity predict visual attention allocation.

To the extent that individual differences in working memory capacity (WMC) reflect differences in attention (Baddeley, 1993; Engle, Kane, & Tuholski, 1999), differences in WMC should predict performance on visual attention tasks. Individuals who scored in the upper and lower quartiles on the OSPAN working memory test performed a modification of Egly and Homa's (1984) selective attention task. In this task, the participants identified a central letter and localized a displaced letter flashed somewhere on one of three concentric rings. When the displaced letter occurred closer to fixation than the cue implied, high-WMC, but not low-WMC, individuals showed a cost in the letter localization task. This suggests that low-WMC participants allocated attention as a spotlight, whereas those with high WMC showed flexible allocation.

The role of number of tasks in determining the relevance of information.

OBJECTIVE: Our objective was to explore the value of considering the number of tasks that use a piece of information when calculating the relevance information has to an operator. BACKGROUND: Whereas frequency and criticality of information are often identified as information attributes, the number of tasks that use the information is rarely considered. METHOD: We calculated the relevance of pieces of information in air traffic control using criticality and frequency, and compared it to a formula that also considered the number of tasks. RESULTS: Including number of tasks resulted in information ranking that better accounted for aircraft relevant information, and better supported the information needs of air traffic controllers as determined by judgments of controllers. CONCLUSION: The attribute of number of tasks is valuable in calculating the relevance of information. Application: Interface designers should consider the number of tasks that use a particular piece of information when determining the placement of information within a display.

Detecting confusion using facial electromyography.

OBJECTIVE: The ability to detect confusion using facial electromyography (EMG) was evaluated. BACKGROUND: Facial EMG has been useful in detecting various emotional states. Another state potentially detectable from facial musculature is confusion. Confusion reflects a loss of understanding or, in a dynamic environment, a loss of situation understanding or situation awareness. METHOD: For this study, 24 participants listened to a confusing and a neutral audio passage while they were monitored with EMG. Electrical activity of the right and left corrugator supercilii, the right zygomaticus major, and right depressor anguli oris was recorded. Participants also reported whether they felt confused during the experimental passage. Finally, they were asked to pose facial expressions. Two raters assessed responses in the graphed EMG data for evidence of activation near a confusing sentence in the passage. RESULTS: EMG revealed confusion in 21 of 24 (87.5%) participants, even in some participants who did not admit confusion. Posed expressions of confusion differed somewhat from spontaneous expressions elicited during the experimental passage. CONCLUSION: EMG was effective in detecting confusion, regardless of operator self-report. Not all muscles in the face were important for the detection of confusion: The zygomaticus major led to a large number of false positives. APPLICATION: EMG can be an effective addition to a sensor suite designed to monitor the cognitive state of operators of systems.