Ensuring the safety of health care workers (HCWs) is the aim of all work health and safety (WHS) principles regardless of which country the health setting is located.
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For an infection with a high case fatality rate, it is paramount that WHS principles for HCWs are fail-safe because failure to protect HCWs from contamination during the doffing (removal) of contaminated personal protective equipment (PPE) may be fatal.2
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During the 2014-2015 Ebola virus disease (EVD) epidemic, unexplained occupational acquisition of EVD by HCWs and the contribution made by breaches in doffing protocol was debated.3
In the absence of firm evidence of the degree that faulty doffing contributed to occupational acquisition of EVD, the doffing sequence must be designed to reduce potential exposure to contaminated PPE to zero. This is especially the case given EVD has a low infective dose, between just 1 and 10 viral particles.4
Doffing PPE after caring for wet (bleeding, vomiting, and diarrhea) EVD patients means the margin of error for transmission during doffing PPE must be zero. Regardless of whether the EVD patient receives care in a high or low resourced health care setting, the high viral load found in explosive vomitus and diarrhea of wet EVD patients contributes to the risk of occupational acquisition.3
The basic reproductive number of EVD (R0) in Africa has been estimated to be 2, and the mortality rate of EVD is estimated at 70%.5
The last global outbreak with life-threatening implications for HCWs was sudden acute respiratory syndrome (SARS) in 2003, which had an estimated R0 of 1.2-3.6 and a mortality rate of approximately 10%.6
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Regardless of the country where HCWs are at risk of acquiring SARS or EVD from their patients, both diseases have mortality rates that are orders of magnitude higher than pandemic influenza or other infections we are trained to deal with. For example, the highest estimated case fatality of the 2009 pandemic influenza virus was 0.18%.9
We reviewed video guidelines and guidelines considered to lead infection control globally,
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and a modified Centers for Disease Control and Prevention (CDC) video13
and a local video from the New South Wales Ministry of Health.14
Each video was reviewed with the intent of identifying exemplary doffing for the principle that no used PPE surface should come into contact with mucous membranes, face, or hair. Our review identified a lack of consensus for 3 critical areas: sequence, assistance, and environment (Table 1). Exemplary practices from each video that would assist in reducing the risk of occupationally acquired EVD are listed in Table 2.Table 1Doffing sequences observed in videos
| Critical Areas | CDC PAPR | CDC N95 + hood + face shield | North Carolina 13 N95 + hood + face shield | CEC 14 N95 + hood + face shield | MSF 11 N95 + hood + face shield, heavy duty apron | |
|---|---|---|---|---|---|---|
| Gown/coverall | Gown | Coverall | Coverall | Gown | Coverall | |
| Doffing under supervision | ||||||
| Active assistance inside doffing area | Yes | Yes, with specific items | Yes, with specific items | Mostly passive at 1 m from HCW, may wipe down visible contaminants on PPE | Passive only | Passive, but may actively decontaminate PPE |
| Wears gown or coverall, face shield, double gloving, shoe cover | Yes | Yes | Yes | Yes | No PPE | Yes, apron and N95, goggle instead of face shield |
| Doffing environment | ||||||
| Dirty and clean zones demarcated by visible line | No | No | No | Yes | No | Yes |
| Clean chair/stool for disinfecting washable shoe surfaces/boot covers and floor mat | Yes, no mat | Yes, no mat | Yes, no mat | Predoffing area 0.5% chlorine bath, absorbent walk-off mat | No | No |
| Dirty chair/stool for removal covers/boots; impervious stool cover and floor mat | Yes; no | No | No | No | Yes; yes | No |
| Hands-free ABHR delivery system for disinfection of gloves and hands | Yes | Yes | Yes | Hands-free soap and water wash, except ABHR for final hand hygiene | ABHR not hands-free; soap and water or ABHR for final hand hygiene | Bleach solution, clean water for face wash |
| Shower, clean scrubs | No | No | No | Yes | Yes | |
| Doffing sequences | ||||||
| Predoffing boot decontamination | No | No | No | Yes, predoffing 1 min 0.5% chlorine bath with walk-off mat; yes, soap and water wash, after inspecting PPE for visible contamination; yes | No | Yes, sprayed with chlorine |
| Predoffing glove disinfected and tear check | Yes | Yes | Yes | Yes | Yes | |
| Disinfects outer gloves | Yes, no drying time | Yes | Yes | Yes, using water wash, no drying time | Yes, air dry gloves | Yes, discards; disinfects inner gloves |
| Apron removal | Yes, with assistance to untie | Yes. | Yes | No | Yes | Yes |
| Disinfects and discard outer gloves | Yes | Yes, does not discard | Yes | No | Disinfects outer gloves, air dried, not discard | Does not disinfect inner gloves |
| Remove boot covers/shoe covers on mat | Yes, may have assistance | Yes | No; Yes, no drying time, discards only if contaminated or torn | Yes, impervious floor and stool mats; yes | No | |
| Disinfects and discard inner gloves | Yes, only discard if gloves contaminated or torn | Yes, outer gloves and discards | ||||
| Remove and discards PAPR, face shield, hood, or N95 and tilts head forward | Yes, assistant detached hose from hood, PAPR turns off system; HCW unhook belt, assistant holds and removes system, HCW removes hood | Yes, face shield | Yes, face shield; removes surgical hood | No, removed later | Yes, face shield, disinfects and replaces gloves, removes surgical hood | Yes, goggles, remove hood. |
| Disinfect inner gloves | Yes | Yes, no drying time | Yes, no drying time | Yes, air dried | Disinfects inner gloves | |
| Undo gown ties, removes by pulling down arms and away from body roll inside out; if coverall used, tilt head back to unzip then roll down inside out; disinfect inner gloves | Yes, may require assistant to unfasten | Yes | Yes, coverall and used feet to stand on and remove; outside of coverall seen to make contact with floor | Yes, coverall used feet to stand on and remove; outside of coverall seen to make contact with floor | No | Assistant decontaminates coverall, HCW unzips coverall, remove coverall down arms, down to feet, using feet to stand on it |
| Yes | Yes, then changes inner gloves | Yes, no drying time | Yes, no drying time | |||
| Remove face shield/N95, surgical hood by tilting head forward and discard; disinfect inner gloves | N95 removed | Yes, face shield, then hood | Face shield and surgical hood removed earlier | Yes | ||
| Yes, no drying time | Yes | |||||
| Disinfect surface washable shoes/remove boot; disinfect inner glove | Disinfect surface washable shoes; yes, replaced with new gloves | Yes; yes | Yes, boot covers; yes, between each boot covers, no drying time; discards and dons new gloves | Disinfect surface washable shoes; yes, no drying time | Yes with assistance/HCW removes one boot at a time after disinfects boot soles; yes | |
| Remove and discard N95; disinfects gloves, no drying time; disinfect shoes; disinfects and discards gloves; hand hygiene HCW seen in same scrubs as worn in patient zone | Discard gloves; hand hygiene, no drying time; new pair gloves; remove and discard N95 with eyes closed and discard; disinfects and discards gloves; hand hygiene with soap and water, no drying time; HCW boots inside dirty zone and on removal with bare hands a foot is placed inside clean area; hand hygiene with ABHR; instructed to shower and change scrubs | Discards gown; disinfects and discards gloves; disinfects hands, air dry; don new gloves, air dry; remove and discards N95; disinfect gloves, air dry; disinfect boots; disinfects and discards gloves; hand hygiene up to elbows; instructed to show with soap if long shift or at the end of a shift; if remaining on duty replace scrubs | Wash face and rinse twice | |||
ABHR, alcohol based hand rub; CDC, Centers for Disease Control and Prevention; CEC, clinical excellence commission; HCW, health care worker; MSF, Médecins Sans Frontières; PAPR, powered air purifying respirator; PPE, personal protective equipment.
Table 2Examples of exemplary doffing practices
| Practices | Examples (reference) |
|---|---|
| Environmental protection from decontamination for shoes | Health care worker stands in chlorine water solution footbath for 1 min before entering doffing area. 13 Impervious mat provided on entry to doffing area.14 Demarcation between dirty and clean doffing areas using overt red line. Health care workers place feet only over line into clean zone once shoes are removed.13 Shoe removed prior to leaving doffing zone13 , 14 ; however, socks must also be removed.Two stools provided for different stages of doffing; one in the dirty zone and one in the clean zone. |
| Sequence to protect skin, hair, and mucous membranes from PPE during doffing | Mask as last PPE to be removed 13 protects mucous membranes, skin, and hair from aerosolized contamination during doffing of other PPE. Early removal of outer gloves prior to removal of apron or coverall. 11 , 13 Adding new pair of gloves after this step could be considered. |
| Additional steps | Removal of visible decontaminants at various stages by active assistant 11 to protect skin, hair, and mucous membranes from PPE during doffing.Passive assistant is provided with gown or coverall, full face shield, 2 pairs of gloves, shoe covers. If an active assistant removes coverall or hood of health care worker then assistant should be provided with respiratory protection. |
PPE, personal protective equipment.
Outbreak response requires adapting to situations and new knowledge as these unfold,
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regardless of health care setting. We know face-touching is a common unconscious practice in the community,16
and in HCWs this may increase with heat and the discomfort generated from wearing plastic aprons, gloves, shoes covers, hair cover or cap, water-resistant mask, and face shield.17
After 2 occupationally acquired cases of EVD, recommendations in the United States moved away from surgical masks to wearing disposable N95/P2 masks together with a face shield and to powered air purifying respirators (PAPRs) to improve comfort, tolerability, and safety, 17
that remove the risk of HCWs face-touching with contaminated gloved hands. The ramping up of PPE by the CDC18
with a surgical hood, coverall, and PAPR is understandable for wet EVD patients given viral load is high in the excreted body fluids. Regardless of whether PAPRs or N95/P2 masks are used, there is a high likelihood that HCWs caring for wet EVD patients will have their PPE contaminated with explosive vomitus and diarrhea high in viral load especially around the torso. However, the gains in risk reduction with the introduction of PAPR may be offset by risk for occupational acquisition through the exposure of vulnerable facial mucous membranes to microscopic sprays from highly contaminated apron and coveralls. The Médecins Sans Frontières video illustrates spraying the heavy duty apron with bleach, but later sequencing of the removal of the facial protection would improve the margin of error. For the removal of boots, that have already been decontaminated in a 0.5% chlorine footbath but that may have become recontaminated during doffing of coveralls, the North Carolina video13
instructs the HCW to keep boots within the doffing zone while turning to sit on a chair that is located inside the clean zone. This modification to the CDC video includes an excellent additional step that prevents the environment outside the doffing area from becoming contaminated. This video also demonstrates the HCW standing in a basin of bleach for 1 minute before stepping onto a mat that is in accordance with the MSF guideline11
used in Ebola treatment units. The CDC did not show a mat designated for contaminated shoes in the doffing area, and theoretically the floor may have become contaminated on entry to the doffing area. After the removal of shoe covers, the bottom of shoes may have become recontaminated, and these same shoes are worn into hallways according to the CDC and CEC (Clinical Excellence Commission).14
This is an avoidable breach. Other breaches in doffing observed in the CDC and CEC14
videos that may even in the absence of evidence undermine zero risk efforts that we believe require modification include the following:- •Hands-free alcohol based hand rub (ABHR) delivered directly into the HCWs' palm keeping the dispenser uncontaminated. If the use of elbows to turn on the water faucets for the final medicated soap and water wash is important, then it is logical that the ABHR dispenser inside the doffing zone should also remain free of viral particles during the entire doffing procedure. If hands-free delivery of ABHR is unavailable then the ABHR dispensers must be decontaminated using disinfection wipes between doffing steps.
- •Decontaminating gloves with ABHR must include coverage of the entire surfaces of each hand, including the dorsal side.19HCWs should be instructed to continue to rub gloved hands to increase coverage and decrease drying time.
- •When removing gloves the HCWs' outstretched thumb must not touch the surface of the contaminated glove that is being removed, which was observed to occur twice in the CEC video.14
- •In accordance with North Carolina instructions,13the removal of the apron is safer when the apron is unfastened easily, the upper unfastened half of the apron is lowered onto the outside faces of the lower half of the apron. The apron is moved away from the body and folded onto itself to avoid contaminating other PPE, then immediately discarded into a waste receptacle.
- •Mucous membranes of the assistants must be protected at all times from even the most inconsequential spray with face shield and mask. To be further prepared for situations where the HCW needs help to doff their coverall or hood, the assistant should also routinely wear apron, gloves, and shoe covers. The steps for removal of PPE after actively assisting a HCW would be ABHR of outer gloves and apron; removal of outer gloves and face shield; ABHR of outer gloves, followed by removal of apron, outer gloves then faceshield; ABHR of inner gloves followed by removal of mask, and shoe covers; followed by removal of inner gloves and hand hygiene.
With the potential for high viral load on gloves, aprons, and coveralls, after caring for wet EVD patients, a doffing sequence that is near enough to zero risk is not yet safe enough. When a HCW occupationally acquires an infection as serious as EVD, it is imperative to openly disclose breaches during doffing potentially responsible for infection so that doffing recommendations can move toward zero risk. Even with a deficiency of evidence about the risk of transmission, it is then our duty of care to develop a highly precautionary doffing sequence to remove even a remote risk of occupational infection associated with doffing.
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In addition to smart design and equipment principles for doffing spaces, and the use of assistants for doffing, a single principle should underpin doffing guidelines: PPE items with the highest risk of contamination should be removed early and HCW's mucous membranes should be protected to the last sequence in doffing to achieve zero risk.Our recommendations for doffing may also be applicable to doffing after dry EVD patients, in the early stages of illness, who are considered to pose less risk of transmission.
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Our precautionary sequencing has one critical doffing sequence (sequencing the removal of facial protective equipment last) and several potentially important sequences (the early removal of outer gloves, early decontamination of shoes, keeping the environment free from recontamination and removal of boots prior to leaving the doffing area). It is essential we do not trivialize our responsibility to provide the best WHS conditions during doffing procedures for HCWs, especially after they have cared for wet Ebola patients. The current sequencing was most likely designed around overcoming any obstruction from the facial protection equipment that could prevent the HCW from removing the apron or coverall without an assistant. We recommend that frontline HCWs be trained and routinely accredited to correctly don and doff PPE. To protect assistants from contamination through direct or microscopic sprays from the PPE the assistant should be, at a minimum, attired with a face shield, mask, apron, and gloves.References
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Article info
Publication history
Published online: February 17, 2016
Footnotes
Conflicts of Interest: None to report.
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Copyright
Crown Copyright © 2016 Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc. All rights reserved.
