Infection Control & Hospital Epidemiology
modes and effects analysis (FMEA)13 to identify self- contamination risks during PPE doffing, to prioritize areas of risk, investigate contributing factors and consequences, and to develop strategies to mitigate risks. This methodology engages key stakeholders to identify system-level factors that jeopardize safety and performance.14,15
In this study, we aimed to conduct an HF-informed failure Methods
The HF-informed FMEA involved 5 steps: (1) conducting a hierarchical task analysis (HTA) of the PPE doffing process, (2) identifying failure modes (ie, different ways a subtask can fail to accomplish its purpose), (3) prioritizing each failure mode based on a composite score of its severity, probability and detectability, (4) identifying contributing factors and potential consequences of the prioritized failure modes, and (5) designing solutions to eliminate or mitigate risks.13,16–18 The Systems Engineering Initiative for Patient Safety (SEIPS) model19 was the conceptual framework guiding the FMEA. The SEIPS is an HF model pre- viously used for other IP improvement initiatives20–23 to identify safety risks and to develop effective mitigation strategies. SEIPS examines 5 elements of the work system (ie, people, tasks, tools and technologies, physical environment, and organization) and their interactions with each other to improve processes and outcomes. Self-contamination risks during PPE doffing emerge because of characteristics of any of the 5 work-system elements or interactions between them. The Johns Hopkins University School of Medicine Institutional Review Board approved this study.
Participants and setting
Five IP experts at the Johns Hopkins Hospital in Baltimore, Maryland, all certified by the Board of Infection Control and Epidemiology, participated in 6 focus-group FMEA sessions, each ~2 hours. In addition, 3 IP experts (2 physicians board certified in infectious diseases and 1 nurse certified by the Board of Infection Control and Epidemiology), who were not part of the initial FMEA sessions, participated in a seventh focus-group FMEA validation session.
Procedure
First, 2 HF experts conducted an HTA of the PPE doffing pro- cess.24,25 Hierarchical task analysis is an HF methodology used to provide a detailed understanding of tasks an actor needs to complete to achieve a certain goal. In this study, we used HTA to describe the PPE doffing task in terms of the individual steps, the sequence of these steps, and the tools used to complete each step.25 The HF experts conducted the HTA by reviewing the CDC
guidelines and web-based training for the powered air purifying respirator (PAPR) and gown PPE combination26 and by obser- ving 7 simulated doffing sessions. Next, findings were displayed in tabular and graphical formats and were used to facilitate discus- sion during the focus groups. An HF expert (A.D.) was the facilitator in focus group ses-
sions, and 2 others (A.P.G., L.B.) assisted and recorded data in the FMEA worksheet (Table 1). Also, 5 IP subject-matter experts viewed the documented data and asked for any corrections in real time. Based on a semistructured discussion guide, participants completed the following 5 steps:
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(1) Reviewed the HTA for accuracy and completeness. (2) Identified failure mode(s) for each doffing step. (3) Rated each failure mode using a 10-point scale based on its severity (none to catastrophic), probability (remote to very high), and detectability (almost certain to absolutely uncertain) using a consensus approach. These 3 scores were multiplied to obtain a risk priority number (RPN) using a modified version of the scale developed by Department of Defense (Table 2).27
(4) Identified contributing factors and potential consequences for each prioritized failure mode.
(5) Identified potential solutions to mitigate the effects of the contributing factors.
A seventh focus group session with 3 IP experts not involved
in the previous sessions was conducted for review and validation of the FMEA worksheet data, and any gaps or inaccuracies were corrected. We analyzed 4 newly identified failure modes using the process outlined above.
Results Flowchart representation of the hierarchical task analysis
Figure 1 provides an overview of the 19 main PPE doffing tasks. A full graphical depiction of the HTA, including 82 subtasks, is available in Appendix 1 (online).
Failure modes and risk priority numbers
Appendix 2 (online) provides a complete listing of the 103 failure modes identified and the corresponding RPNs, contributing fac- tors, potential consequences, and proposed risk mitigation strate- gies. The IP experts identified at least 1 failure mode for all, but 10 of the 82 subtasks, with RPNs ranging from6 to 630 (mean, 115.28; median, 90; mode, 144). A failure mode with an RPN of 84 or greater was considered high priority and was further investigated. Table 3 depicts the failure modes with the 5 highest RPN values. The highest RPN (630) was associated with the DA or TO moving between clean and potentially contaminated areas. Other high- priority failure modes were associated with glove removal, apron removal, and self-inspection while preparing to doff.
Contributing factors
Further investigation was conducted to explore why the identified failure modes occur and to inform the development of risk mitigation strategies. Here, we briefly describe contributing fac- tors associated with the high-priority failure modes; Appendix 2 includes a complete list. Contributing factors were classified based on the work-system
elements of the SEIPS model. Identified person (ie, HCW) factors included anthropometric and physiological characteristics, tech- nical and teamwork-related competencies, and psycho- physiological responses of HCWs. For example, it is more diffi- cult for HCWs with shorter arms to keep contaminated PPE away from their body during removal. Conversely, larger HCWs have a greater surface area to inspect, increasing the probability of missing a breach or contamination. The flexibility and dexterity of HCWs can impact risk when doffing PPE (eg, removing boot covers without contamination). Healthcare workers need not only technical competency but also spatial awareness of where they are
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