How to decontaminate in case of chemical contact?

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How to decontaminate in case of chemical contact?

Reminder: Immediate or emergency decontamination is the process that consists in eliminating as quickly as possible the chemical, biological or radiological agents that have contaminated a person, in order to avoid the propagation of pathogenic effects, in particular on the skin, and the transfer of contamination.

This is not the first time that we have discussed this subject, but the publication of a number of scientific articles on this subject over the last two years has encouraged us to take stock of the situation by analysing some recent publications.

1°) In the publication “Chemical Decontamination”, the author reminds us of the main principles of decontamination: exposure to chemical products, and the resulting tissue damage or dysfunction of organic systems, depend on both dose and time. Chemical exposures, in general, cause injury more rapidly than with radiological or biological agents. Given the relationship between time of exposure and degree of injury, immediate decontamination is essential to limit absorption into the skin and also to reduce potential contamination of caregivers (secondary contamination).

It is preferable to initiate decontamination before arrival at the medical treatment facility, but this is not always possible

Experts agree that, when possible, chemical decontamination should occur within one minute of exposure.

A hands-on, practical approach to decontamination will protect the patient, caregivers and the treatment space.

– Step One: Put on personal protective equipment (PPE);

– Step Two: Remove the victim’s clothing as soon as possible;

Clothing is a reservoir for chemical contaminants, especially liquids for which decontamination effectiveness decreases rapidly over time. Any attempt to decontaminate a clothed patient may result in further introduction of chemicals into the deep tissues.

This undressing step would result in an 80-90% reduction in chemical contamination.

– Step Three: Remove/Inactivate Contaminant;

Once the patient has been undressed any solid or particulate material should be removed, as some dry chemicals can be exothermic and cause further damage to the patient when exposed to water. Remove these particles with a brush or soft cloth or, if possible, a battery-operated hand-held vacuum cleaner. After removing all clothing and particles, perform dry or water-based decontamination. Dry decontamination can be performed using an adsorbent material such as Foulon’s earth, activated charcoal, talcum powder, or absorbent materials such as paper towels or baby diapers to reduce skin exposure before wet decontamination.

Wet decontamination with water is essential to reduce contamination and toxicity, but some liquid-soluble chemicals, particularly organophosphates and similar insecticides, are not easily removed with water alone. The addition of a detergent (1% mild soap) improves the removal of fat-soluble chemicals, such as organophosphates, and results in decreased toxicity and improved survival.

Paradoxically, prolonged exposure to water can promote the systemic absorption of certain chemicals, the so-called “wash-in effect”.

Research from the European Union’s ORCHIDS (Optimisation through Research of Chemical Incident Decontamination Systems) project reveals that the optimal wash-in time is 90 seconds and that the additional use of a soft cloth to thoroughly clean all skin surfaces can improve decontamination rates by an additional 20%.

The 3 steps, dry decontamination, wet decontamination, technical decontamination (washcloths, towels…) form the most effective trilogy.

If open wounds are present, these areas must also be carefully irrigated.

A more specific product such as RSDL can also be used.

2°) Skin decontamination is addressed in the paper “Effect of superabsorbent polymers (SAP) and metal organic frameworks (MOF) wiping sandwich patch on human skin decontamination and detoxification in vitro.”

They designed a patch combining superabsorbent polymers (SAP) and/or a skin decontamination gel (DDGel) and UiO-66 MOFs. With pre-wetting, SAP/MOF wipe, and DDGel applications, maximum efficacy was observed during early and/or prolonged skin exposure, and no wash-in effect was observed.

3°) In the study “In vitro human skin decontamination efficacy of MOF-808 in decontamination lotion following exposure to the nerve agent VX” seven zirconium-based MOFs were evaluated for their ability to degrade VX and then tested in vitro for VX decontamination on human skin.

In the skin decontamination experiments, MOF-808 improved the efficiency compared to the carrier alone, primarily through better absorption of the agent. The addition of MOF-808 to RSDL did not improve its already high efficiency.

4°) “Efficacy of Different Hair and Skin Decontamination Strategies with Identification of Associated Hazards to First Responders”. This paper shows that the introduction of dry decontamination prior to wet forms of decontamination offers a simple strategy to begin treatment at a much earlier time, with a corresponding improvement in clinical outcomes and a substantial reduction in secondary risks associated with operational processes.

5°) ” Skin Decontamination “. This excellent review by Annick Roul, gives an overview of undressing, primary decontamination (immediate decontamination) carried out as quickly as possible to avoid the spread of the pathological effects of the products and secondary contamination of the caregivers, then secondary decontamination (use of water and/or technical decontamination).

Then, the author draws up an exhaustive list of the different decontamination and neutralization products for toxic products; powders, gloves, wipes, etc., followed by neutralizing products such as nanoparticles of oxides, gels, enzymes, etc.

In the case of decontamination of individuals involved in a chemical exposure, physical removal, compared to neutralization, is by far easier to implement. Beginning with the removal of clothing and protective equipment from personnel, the goal is to eliminate overall contamination and remove patient clothing in an efficient and timely manner. Dry decontamination, based on powders, adsorbent gloves, and wiping systems, should be considered first for chemicals to ensure effective decontamination, manage the emergency response, and ensure immediate first aid and medical countermeasures.

Wet decontamination, by washing with or without detergent, is a universal method but has some constraints in organization when there is massive exposure.

Conversely, neutralization can only be considered after the chemical has been identified. Some constraints limit neutralization as a first decontamination, such as the time it takes, the dependence on volume, and the risks it presents.

6°) ” Dry decontamination of chemical and biological simulants “. The neutralization of the product can sometimes be done inside the decontamination device itself.

The emergency decontamination wipe – DEC’POL ABS

Ouvry® has developed a decontamination wipe used for emergency decontamination (dry decontamination). It decontaminates by transferring chemical and biological agents and traps them in order to avoid their spreading.

The 20×10 cm wipe is able to absorb 40 mL of oily product (NF T 90-301 standard).

According to AEP 58 – STANAG 4653 standards, the wipe absorbs 99.6% of HD and VX, on glass, raw steel and textile coupons.

According to STANAG 4653, less than 0.3% of VX and HD are re-calibrated on a blank surface.

Skin decontamination on HD is more than 99.5% effective according to STANAG 4625 (pigskin test).

References

1°) G. M. Johnston, B. K. Wills. Chemical Decontamination.  NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021.

2°) Y. Caoa , X. Huia , H. I. Maibacha. Effect of superabsorbent polymers (SAP) and metal organic frameworks (MOF) wiping sandwich patch on human skin decontamination and detoxification in vitro. Toxicology Letters, 2021, 337, 7-17.

3°) A. Larsson, J. Qvarnström, S. Lindberg, E. Wigenstam, L. Öberg, R. A.Sander, S. Johansson, A. Bucht, L. Thors. In vitro human skin decontamination efficacy of MOF-808 in decontamination lotion following exposure to the nerve agent VX. Toxicology Letters, 2021, 339, 32-38.

4°) J. Larner , A. Durrant , P. Hughes , D. Mahalingam , S. Rivers , H. Matar. Efficacy of Different Hair and Skin Decontamination Strategies with Identification of Associated Hazards to First Responders. Prehospital Emergency Care, 2020, 24, Issue 3.

5°) A. Roul, H.H.I Maibach, Skin Decontamination, Emergency Medicine Investigations, DOI: 10.29011/2475-5605.010105

6°) M.B Espina-Benitez, E. Denet, M.A. Bolzinger, V. Rodriguez Nava, T. Pollet, I. Pitault, D. Blaha, S. Briançon. Décontamination sèche de simulants chimiques et biologiques / Chemical and biological dry decontamination.(Revue SFMC)

Without forgetting the articles already published in the Ouvry blog

Les nouveaux protocoles de décontamination en réponse à une attaque nrbc

La décontamination pédiatrique

Ouvry et bbi detection lance decpol® : le gant de décontamination

La décontamination des EPI avant déshabillage,

La décontamination immédiate ou d’urgence

 

 

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