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. 2018 Mar 5;66(6):950-958.
doi: 10.1093/cid/cix957.

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

Joel M Mumma  1 , Francis T Durso  1 , Ashley N Ferguson  1 , Christina L Gipson  1 , Lisa Casanova  2 , Kimberly Erukunuakpor  2 , Colleen S Kraft  3   4 , Victoria L Walsh  3 , Craig Zimring  5 , Jennifer DuBose  5 , Jesse T Jacob  3 ; Centers for Disease Control and Prevention Epicenters Program, Division of Healthcare Quality Promotion
Affiliations

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

Joel M Mumma et al. Clin Infect Dis. .

Abstract

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.

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Figures

Figure 1.
Figure 1.
Box plots of the duration of each major doffing step during simulations with Ebola-level personal protective equipment. For each step, the maximum (top whisker), 75th percentile (top line), median (dark line), 25th percentile (bottom line), and minimum (bottom whisker) values are shown. Asterisks represent the mean. Abbreviation: PAPR, powered air purifying respirator.
Figure 2.
Figure 2.
Box plots of the duration of hand hygiene after each major step of doffing during simulations with Ebola-level personal protective equipment. For each step, the maximum (top whisker), 75th percentile (top line), median (dark line), 25th percentile (bottom line), and minimum (bottom whisker) values are shown. Asterisks represent the mean. Abbreviations: PAPR, powered air purifying respirator; TO, trained observer.
Figure 3.
Figure 3.
Fault tree analysis of 10 healthcare workers during doffing of Ebola-level personal protective equipment for Φ6 self-contamination of scrubs (highlighted in red). Events highlighted in yellow did not involve PPE contaminated in the simulation and did not contribute to the probability of the top event. Abbreviations: FTA, fault tree analysis; IG, inner gloves; PAPR, powered air purifying respirator; PPE, personal protective equipment.
Figure 4.
Figure 4.
Fault tree analysis of 10 healthcare workers during doffing of Ebola-level personal protective equipment for Φ6 self-contamination of hands and inner gloves (highlighted in red). Gates highlighted in green are decomposed in Supplementary Figure 1. Abbreviations: FTA, fault tree analysis; IG, inner glove; PAPR, powered air purifying respirator; PPE, personal protective equipment.
Figure 5.
Figure 5.
Fault tree analysis of 10 healthcare workers during doffing of Ebola-level personal protective equipment for MS2 self-contamination of scrubs (highlighted in red). Events highlighted in yellow did not involve PPE contaminated in the simulation and did not contribute to the probability of the top event. Abbreviations: FTA, fault tree analysis; IG, inner gloves; PAPR, powered air purifying respirator; PPE, personal protective equipment.
Figure 6
Figure 6
Fault tree analysis of 10 healthcare workers during doffing of Ebola-level personal protective equipment for MS2 self-contamination of hands and inner gloves (highlighted in red). Gates highlighted in green are decomposed in Supplementary Figure 2. Abbreviations: FTA, fault tree analysis; IG, inner gloves; PPE, personal protective equipment.
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