Saturday, January 3, 2015

Up-coming: Protecting Critical Care Workers in the Hotzone

Draft version

One of the highest risk activities health care workers perform is the doffing of personal protective equipment. As it is standard protocol that health care workers are allowed to be in high risk zones for the maximum of one hour, doffing and a few times a day, increases the risk of exposure to EBV. According to the World Health Organization: "A total of 678 health-care workers (HCWs) are known to have been infected with EVD up to the end of 28 December 2014, 382 of whom have died (table 6). The total case count includes 2 HCWs in Mali, 11 HCWs infected in Nigeria, 1 HCW infected in Spain while treating an EVD-positive patient, 1 HCW in the UK who became infected in Sierra Leone, and 3 HCWs in the USA (including 1 HCW infected in Guinea, and 2 HCWs infected during the care of a patient in Texas). Two HCW infections were reported in the week to 28 December: 1 in Montserrado in Liberia, and 1 in Keroune in Guinea." Source:

In September, 2014, Johns Hopkins published an article entitled: For Ebola Health Care Workers How Protective Gear is Removed Poses Risk of Deadly Exposure Experts Caution." The article notes: 

"A team of American infectious disease and critical care experts is alerting colleagues caring for Ebola patients that how they remove their personal protective gear can be just as crucial as wearing it to prevent exposure to the deadly virus. In a commentary published online on Aug. 26 in the Annals of Internal Medicine, the physician-specialists from Johns Hopkins and the University of North Carolina say rigorous steps exist — and must be taken — to avoid “inadvertent” contact of frontline caregivers’ exposed skin and mucous membranes to infected body fluids.
Personal protective equipment, including goggles or face shields, gloves and gowns, are effectively decreasing West African caregivers’ exposure to infected bodily fluids, but workers are still at risk “if removal of protective clothing that is contaminated with infectious bodily fluids is not done in a manner that prevents exposure,” say the authors, who include Trish M. Perl, M.D., M.Sc., and Noreen Hynes, M.D., M.P.H., two Johns Hopkins infectious disease experts. Perl is senior epidemiologist for the Johns Hopkins Health System and a consultant to the Johns Hopkins Office of Critical Event Preparedness and Response (CEPAR), which is overseeing and coordinating Johns Hopkins’ readiness for any potential Ebola patient. Hynes is the director of the Geographic Medicine Center in the Division of Infectious Diseases. William Fischer II, M.D., of the University of North Carolina School of Medicine also co-authored the commentary.
The physical exhaustion and emotional fatigue that come with caring for patients infected with Ebola may further increase the chance of an inadvertent exposure to bodily fluids on the outside of the personal protective equipment, leading to unwanted contact when the gear is removed,” the authors say. “The impulse to wipe away sweat in the ever-present hot, humid environment during personal protective equipment removal may lead to inadvertent inoculation of mucous membranes” in and on the nose, mouth and eyes." Source:
How do we reduce the risk and what technologies could mediate exposure at the time of doffing perhaps in addition to chlorine solution which is sprayed and repeatedly used in hand washing during the doffing process? Technologies which not only protect health care workers but that which can increase time spent inside high risk zones and reduce exposure from doffing would certainly benefit health care workers in theatre."The treatment sites administered by Médecins Sans Frontières have addressed this critical need by creating both a structure and a systematic, measured process to mitigate the risks associated with removal of PPE. First, a separate exit, physically removed from the entrance, is created to ensure that persons donning PPE do not come into contact with PPE from exiting health care workers that may be contaminated with bodily fluids. Second, and more important, a dedicated person is stationed at the exit with the sole focus of guiding the health care provider through each step of PPE removal, regardless of how many times the provider has been through the process. This standard of operations ensures that the process becomes ritualized, thereby protecting and reassuring the health care worker." Source:

In the process of considering which technologies might reduce exposure to health workers I came across a rather concise list of activities for which a number of pipeline technologies would seem highly relevant. The list was posted on this site  With a number of solutions offered here: : 

Donning (~15mins) 
1. Caretaker suits up in front a mirror, typically starting out in scrubs. 
2. Second person observing to do body checks 
3. Put on Boot made of rubber that reach above the ankles 
4. Put on thin latex gloves  
5. Put on Hazmat suit 
6. Put on Surgical Mask - blocks microbes from entering and exiting the resporatory system 
7. Put on Hood goes over the head with built in mask. 
8. Put on Water proof apron 
9. Put on Goggles, sprayed with antifogging agent 
10. Put on Second set of gloves, thick rubber ones. 
11. (Optional) Decontamination Sprayer  

(First gut reaction: Why are there so many layers? Can we minimize the layers into one body suit (I'm thinking something like Fire Retardant Clothing (FRC) with sewed on gloves) 

Hot Zone - ready to treat patients (Limited to only one hour due to heat -- through out the day this means they go through this process a lot!) 
Activities include 
- Getting patients from the truck 
- Lifting patients to a crowded room - or putting them two toa bed 
- Lifting workers from bed to give them water. Screwing off the water top 
- Flies might enter the goggles - tempting user to adjust, opening a risk 
- Itching, which also may expose caretakers 
- IV needles, if puncture suit is of great risk.. "placing an IV, you get nervous... then get fogged up and you could start pulling at your equipment" 

Doffing/taking it off - Many articles point to this as the most risk 
1. Burn all books/articles/notebooks 
2. Workers wash glove covered hands in clorine solution (used every time below when 'wash') and walk through a clorine foot bath - interesting to note, looks like they do some sort of assembly line 
3. Apron and suit get sprayed front at back (almost like a car wash!) 
4. Outer gloves are dosed or thrown away 
5. Off come the goggles 
6. Latex gloves are disinfected 
7. Head cover is thrown away 
8. Remove heavy overalls, which are thrown away 
9. Latex gloves are washed again 
10. Gloves come off, bare hands are washed again 
11. Boots come off to dry, usually upside down on stick in the ground 
12. Looks like they are then doused with water to cool off. 
(Why is a second person not mentioned here for taking it off?) 

I believe we should consider not only suits which are comprised of materials impregnated with antimicrobial agents but also suits with fewer disposable layers and or one piece with PARP. Additionally, cooling systems developed for the military and work mainly in Afghanistan may also reduce the number of times in one day workers must doff. There are a number of personal cooling systems designed to be worn under combat uniforms which may, with modifications be adapted to caregivers to enable longer periods in high risk zones. "Thermal management is an increasingly important issue for soldiers on the battlefield." (Source: Just like soldiers on the battlefield, health care workers in West Africa battling EBV face extreme conditions which ultimately may contribute to secondary exposure.

Army notes in an article entitled: Thermal Control in the Heat of Battle," (Source:, that, "Various programmes are underway to address these concerns. In Europe, EADS Defence & Security is f on developing its IdZ (Infanterist der Zukunft) future soldier systems for the German army. In the UK, the programme is"; Future Infantry Soldier Technology"; (FIST), the Italian army has"; Soldato Futuro,"; and the French army has"; FÉLIN."; In the US, the military has the Future Force Warrior (FFW) concept. These programmes include developing materials and are even exploring nanotechnology to optimise thermal management.RINI Technologies of the USA is also looking at measures to keep soldiers cool. The company specialises in advanced Evaporative Spray Cooling (ESC), Thermal Energy Storage (TES) solutions and Miniature Refrigeration Systems for application to high-power lasers, power electronics, and personal cooling devices. Its soldier cooling system, or Micro Climate Cooling System (MCCS), is the smallest, lightest, and most efficient personal cooling system yet developed, says RINI.
The MCCS mitigates heat stress and health risk concerns by managing core body temperature and decreasing the risk of dehydration. As a result, soldiers are able to maintain cognitive skills, enhancing mission performance and duration. MCCS harnesses patented miniaturisation refrigeration and electronics technologies to provide heat stress relief, improve operational performance, and reduce water consumption for soldiers working under hazardous conditions." (Source:

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.