Volunteer trials of a novel improvised dry decontamination protocol for use during mass casualty incidents as part of the UK'S Initial Operational Response (IOR)

Immediate dry decontamination using efficient absorbent materials is beneficial following skin exposure to low-volatile toxic chemicals

In a chemical mass casualty incident requiring skin decontamination, dry removal using absorbent materials may be beneficial to enable immediate decontamination. The efficacy of absorbent materials has therefore been evaluated, alone or procedures including both dry and wet decontamination, following skin exposure to two low volatile toxic chemicals using an in vitro human skin penetration model. Additionally, removal using active carbon wipes was evaluated with or without the Dahlgren Decon solution. All dry decontamination procedures resulted in a significantly decreased skin penetration rate of the industrial chemical 2-butoxyethanol compared to the control without decontamination. Wet decontamination following dry absorption significantly improved the efficacy compared to dry removal alone. Dry decontamination post-exposure to the chemical warfare nerve agent VX showed no decontamination efficacy. However, dry and wet decontamination resulted in a decreased agent skin penetration rate during the last hour of the experiment. At -15°C, significantly reduced VX skin penetration rates were demonstrated for both dry decontamination alone and the dry and wet decontamination procedure. The Dahlgren Decon solution significantly reduced the amount of VX penetrating the skin, but the active carbon wipe alone did not impact the skin penetration rate. In conclusion, absorbent materials are beneficial for the removal of low-volatile chemicals from the skin, but the degree of efficacy varies between chemicals. Despite the variability, immediate dry decontamination using available absorbent materials prior to wet decontamination is recommended as a general procedure for skin decontamination. The procedure should also be prioritized in cold-weather conditions to prevent patient hypothermia.

Managing CBRN mass casualty incidents at hospitals-Find a simple solution for a complex problem: A pilot study

OBJECTIVE

Chemical, biological, radiological, and nuclear (CBRN) incidents are a major challenge for emergency medical services and the involved hospitals, especially if decontamination needs to be performed nearby or even within the hospital campus. The University Hospital Wuerzburg has developed a comprehensive and alternative CBRN response plan. The focus of this study was to proof the practicability of the concept, the duration of the decontamination process, and the temperature management.

METHODS

The entire decontamination area can be deployed 24/7 by the hospitals technical staff. Fire and rescue services are responsible for the decontamination process itself. This study was designed as full-scale exercise with 30 participants.

RESULTS

The decontamination area was ready for operation within 30 minutes. The decontamination of the four simulated patients took 5.5 ± 0.6 minutes (mean ± SD). At the end of the decontamination process, the temperature of the undressed upper body of the training patients was 27.25 ± 1°C (81.05 ± 2°F) (mean ± SD) and the water in the shower was about 35°C (95°F).

CONCLUSION

The presented concept is comprehensive and simple for a best possible care during CBRN incidents at hospitals. It ensures wet decontamination by Special Forces, while the technical requirements are created by the hospital.

Advancing the scientific study of prehospital mass casualty response through a Translational Science process: the T1 scoping literature review stage

PURPOSE

The European Union Horizon 2020 research and innovation funding program awarded the NIGHTINGALE grant to develop a toolkit to support first responders engaged in prehospital (PH) mass casualty incident (MCI) response. To reach the projects' objectives, the NIGHTINGALE consortium used a Translational Science (TS) process. The present work is the first TS stage (T1) aimed to extract data relevant for the subsequent modified Delphi study (T2) statements.

METHODS

The authors were divided into three work groups (WGs) MCI Triage, PH Life Support and Damage Control (PHLSDC), and PH Processes (PHP). Each WG conducted simultaneous literature searches following the PRISMA extension for scoping reviews. Relevant data were extracted from the included articles and indexed using pre-identified PH MCI response themes and subthemes.

RESULTS

The initial search yielded 925 total references to be considered for title and abstract review (MCI Triage 311, PHLSDC 329, PHP 285), then 483 articles for full reference review (MCI Triage 111, PHLSDC 216, PHP 156), and finally 152 articles for the database extraction process (MCI Triage 27, PHLSDC 37, PHP 88). Most frequent subthemes and novel concepts have been identified as a basis for the elaboration of draft statements for the T2 modified Delphi study.

CONCLUSION

The three simultaneous scoping reviews allowed the extraction of relevant PH MCI subthemes and novel concepts that will enable the NIGHTINGALE consortium to create scientifically anchored statements in the T2 modified Delphi study.

Comparison of skin decontamination strategies in the initial operational response following chemical exposures

In mass casualty incidents including hazardous chemical skin exposure, decontamination is the primary intervention to avoid systemic uptake of the toxic compound. The protocol needs to be both simple and efficient to enable a rapid response and avoid delay of patient management. In the present study, decontamination strategies included in the initial operational response were evaluated following human skin exposure in vitro to four different contaminants. Results demonstrated that the efficacy of selected decontamination procedures was highly dependent on the chemical contaminant used. Dry removal of the sulfur mustard simulant methyl salicylate prior to wet decontamination was found beneficial compared to wet decontamination alone. Rapidly initiated wet decontamination was more efficient compared to dry and wet removal of the industrial chemical 2-butoxyethanol and the nerve agent tabun. Following VX-exposure, all wet decontamination procedures resulted in increased agent penetration compared to the control. In conclusion, challenges in establishing simple and efficient decontamination procedures for a broad-spectrum of chemicals have been demonstrated. The impact of including a dry removal step during decontamination was evidently agent specific. Despite the variation in efficacy, immediately initiated dry removal may facilitate patient management until wet decontamination resources are available and to reduce the risk of secondary contamination.

A Review of the Efficacy of Easily Accessible Dry Decontaminants for Human Chemical Contamination

Soap and water are often considered the gold standard for dermal decontamination. However, recent systematic reviews have shown that these methods often result in incomplete decontamination and may even induce contaminant absorption due to the "wash-in" effect. Therefore, it is important to gain insight on other decontamination methods. A literature search was done using PubMed to find experimental studies relating to dry decontamination performed with readily available items. Seven studies met eligibility criteria, and the study model, dry decontaminant, method of dry decontamination, method of analyzing decontamination, and main conclusions from each study were extracted, summarized and compared. Important conclusions include that all studies investigated found that dry decontamination yielded decreases in contamination. In addition, it was shown by multiple studies that not only the decontaminant, but the manner in which it is used (method used (blotting, rubbing, etc.), amount used, and whether decontamination instructions are provided to exposed individuals) is vital to success. Finally, in all four studies that investigated wet and dry decontamination combination protocols, combinations were more efficacious than dry decontamination alone. However, this means that dry improvised decontamination can be performed while waiting for the deployment and arrival of further formal decontaminants. These conclusions deserve consideration in the event that universal decontamination guidelines are designed. However, more studies are required in order to draw definitive conclusions regarding the important topic of dermal decontamination.

Do cold weather temperatures affect the efficacy of skin decontamination?

Skin decontamination in cold weather temperatures might be challenging due to the aggravating circumstances. However, no information is available on the efficacy of commonly used procedures in winter conditions. Therefore, the efficacy of the reactive skin decontamination lotion (RSDL) and soapy water decontamination following skin exposure to the nerve agent VX was evaluated at three ambient air temperatures (-5°C, -15°C and room temperature). Experiments were performed in vitro using human dermatomed skin. The ability of RSDL to degrade VX at the three different air temperatures was separately evaluated. The ambient air temperature in experiments without decontamination did not influence the penetration rate of VX through skin. RSDL decontamination was highly efficient in removing VX from skin when performed in all three ambient temperatures, despite the slower agent degradation rate of VX at the lower temperatures. Decontamination with soapy water at RT resulted in an increased skin penetration of VX compared with the control without decontamination; however, in colder temperatures the VX skin penetration was similar to the corresponding control without decontamination. At RT, dry removal prior to washing with soapy water did not improve decontamination of VX compared with washing solely with soapy water. This study demonstrated high efficacy of RSDL decontamination following skin exposure to VX also at cold temperatures. The previously reported 'wash-in' effect of soapy water on VX skin penetration was reduced at cold temperatures. Altogether, this study found a scientific basis to establish guidelines for skin decontamination of chemical casualties at cold weather temperatures.

Efficacy of water-only or soap and water skin decontamination of chemical warfare agents or simulants using in vitro human models: A systematic review

Water-only or water and soap are widely recommended as preferred solutions for dermal decontamination. However, limited efficacy data exist. We summarized experimental studies evaluating in vitro efficacy of water-only or soap and water in decontaminating chemical warfare agents (CWA) or their simulants from human skin models. Embase, Covidence®, MEDLINE, PubMed, Web of Science, and Google Scholar were searched for articles using water-only or soap and water decontamination methods for removal of CWA/CWA simulants in in vitro human skin models. Data extraction was completed from seven studies, yielding seven contaminants. Water-only decontamination led to partial decontamination in all skin samples (100%, n = 81/81). Soap and water decontamination led to partial decontamination in all skin samples (100%, n = 143/143). Four studies found decontamination to either paradoxically enhance absorption of contaminants or their penetration rates, known as the "wash-in" effect. Despite recommendations, water-only or water and soap decontamination were found to yield partial decontamination of CWA or their simulants in all human in vitro studies. Thus, more effective decontaminating agents are needed. Some studies demonstrated increased or faster penetration of chemicals following decontamination, which could prove deadly for agents such as VX, although these findings require in vivo validation. Heterogeneity in experimental setups limits interstudy comparison, and it remains unclear when water-only or water and soap are ideal decontaminants, which requires more studies. Pending manuscripts will summarize in vivo human and animal efficacy data. International harmonized efficacy protocol should enable more efficient public health decisions for evidence-based public health decisions.

Identification of Novel Simulants for Toxic Industrial Chemicals and Chemical Warfare Agents for Human Decontamination Studies: A Systematic Review and Categorisation of Physicochemical Characteristics

Chemical simulants have long been used in human trials of mass decontamination to determine the efficacy of decontamination interventions against more toxic agents. Until now, reliance has mostly been on individual chemicals as surrogates to specific agents (e.g., methyl salicylate for sulphur mustard). A literature review was conducted to identify chemicals that had been previously tested on human volunteers and that represent diverse physicochemical characteristics in order to create a repository for chemical simulants. Of the 171 unique chemicals identified, 78 were discounted for the risk they could pose to human volunteers, 39 were deemed suitable for use, and a further 54 were considered to be possible simulants but would require further research. Suitable simulants included both solid and liquid chemicals spanning a wide range of physicochemical properties including molecular weight, octanol/water partition coefficient, vapour pressure, and solubility. This review identifies an array of potential simulants suitable for use in human volunteer decontamination studies and is of relevance to future studies on systemic absorption and surface decontamination.

Evaluating the impact of decontamination interventions performed in sequence for mass casualty chemical incidents

The Initial Operational Response (IOR) to chemical incidents is a suite of rapid strategies including evacuation, disrobe and improvised and interim decontamination. IOR and Specialist Operational Response (SOR) decontamination protocols involving mass decontamination units would be conducted in sequence by UK emergency services following a chemical incident, to allow for safe onward transfer of casualties. As part of a series of human volunteer studies, we examined for the first time, the effectiveness of UK IOR and SOR decontamination procedures alone and in sequence. Specifically, we evaluated the additional contribution of SOR, when following improvised and interim decontamination. Two simulants, methyl salicylate (MeS) with vegetable oil and benzyl salicylate (BeS), were applied to participants’ skin. Participants underwent improvised dry, improvised wet, interim wet, specialist decontamination and a no decontamination control. Skin analysis and UV photography indicated significantly lower levels of both simulants remaining following decontamination compared to controls. There were no significant differences in MeS levels recovered between decontamination conditions. Analysis of BeS, a more persistent simulant than MeS, showed that recovery from skin was significantly reduced following combined IOR with SOR than IOR alone. These results show modest additional benefits of decontamination interventions conducted in sequence, particularly for persistent chemicals, supporting current UK operational procedures.

Skin decontamination procedures against potential hazards substances exposure

Decontamination of unprotected skin areas is crucial to prevent excessive penetration of chemical contaminants after criminal or accidental release. A review of literature studies was performed to identify the available decontamination methods adopted to treat skin contamination after chemical, radiological and metal exposures. In this bibliographic review, an overview of the old and recent works on decontamination procedures followed in case of potential hazards substances contaminations with a comparison between these systems are provided. Almost all data from our 95 selected studies conducted in vitro and in vivo revealed that a rapid skin decontamination process is the most efficient way to reduce the risk of intoxication. The commonly-used or recommended conventional procedures are simple rinsing with water only or soapy water. However, this approach has some limitations because an easy removal by flushing may not be sufficient to decontaminate all chemical deposited on the skin, and skin absorption can be enhanced by the wash-in effect. Other liquid solutions or systems as adsorbent powders, mobilizing agents, chelation therapy are also applied as decontaminants, but till nowadays does not exist a decontamination method which can be adopted in all situations. Therefore, there is an urgent need to develop more efficient and successful decontaminating formulations.

Mass Casualty Decontamination for Chemical Incidents: Research Outcomes and Future Priorities

Planning for major incidents involving the release of hazardous chemicals has been informed by a multi-disciplinary research agenda which has sought to inform all aspects of emergency response, but with a focus in recent years on mass casualty decontamination. In vitro and human volunteer studies have established the relative effectiveness of different decontamination protocols for a range of chemical agents. In parallel, a programme of research has focused on communicating with and managing large numbers of contaminated casualties at the scene of an incident. We present an accessible overview of the evidence underpinning current casualty decontamination strategies. We highlight where research outcomes can directly inform response planning, including the critical importance of beginning the decontamination process as soon as possible, the benefits of early removal of contaminated clothing, the evidence under-pinning dry and wet decontamination and how effective communication is essential to any decontamination response. We identify a range of priority areas for future research including establishing the significance of the 'wash-in' effect and developing effective strategies for the decontamination of hair. We also highlight several areas of future methodological development, such as the need for novel chemical simulants. Whilst considerable progress has been made towards incorporating research outcomes into operational policy and practice, we outline how this developing evidence-base might be used to inform future iterations of mass casualty decontamination guidance.

Human volunteer study of the decontamination of chemically contaminated hair and the consequences for systemic exposure

The decontamination of exposed persons is a priority following the release of toxic chemicals. Efficacious decontamination reduces the risk of harm to those directly affected and prevents the uncontrolled spread of contamination. Human studies examining the effectiveness of emergency decontamination procedures have primarily focused on decontaminating skin, with few examining the decontamination of hair and scalp. We report the outcome of two studies designed to evaluate the efficacy of current United Kingdom (UK) improvised, interim and specialist mass casualty decontamination protocols when conducted in sequence. Decontamination efficacy was evaluated using two chemical simulants, methyl salicylate (MeS) and benzyl salicylate (BeS) applied to and recovered from the hair of volunteers. Twenty-four-hour urinary MeS and BeS were measured as a surrogate for systemic bioavailability. Current UK decontamination methods performed in sequence were partially effective at removing MeS and BeS from hair and underlying scalp. BeS and MeS levels in urine indicated that decontamination had no significant effect on systemic exposure raising important considerations with respect to the speed of decontamination. The decontamination of hair may therefore be challenging for first responders, requiring careful management of exposed persons following decontamination. Further work to extend these studies is required with a broader range of chemical simulants, a larger group of volunteers and at different intervention times.

A controlled cross-over study to evaluate the efficacy of improvised dry and wet emergency decontamination protocols for chemical incidents

The UK Initial Operational Response (IOR) to chemical incidents includes improvised decontamination procedures, which use readily available materials to rapidly reduce risk to potentially exposed persons. A controlled, cross-over human volunteer study was conducted to investigate the effectiveness of improvised dry and wet decontamination procedures on skin, both alone, and in sequence. A simulant contaminant, methyl salicylate (MeS) in vegetable oil with a fluorophore was applied to three locations (shoulder, leg, arm). Participants then received no decontamination (control) or attempted to remove the simulant using one of three improvised protocols (dry decontamination; wet decontamination; combined dry and wet decontamination). Simulant remaining on the skin following decontamination was quantified using both Gas Chromatography Tandem Mass Spectrometry (GC-MSMS) for analysis of MeS and UV imaging to detect fluorophores. Additionally, urine samples were collected for 24 hours following application for analysis of MeS. Significantly less simulant was recovered from skin following each improvised decontamination protocol, compared to the no decontamination control. Further, combined dry and wet decontamination resulted in lower recovery of simulant when compared to either dry or wet decontamination alone. Irrespective of decontamination protocol, significantly more simulant remained on the shoulders compared to either the arms or legs, suggesting that improvised decontamination procedures are less effective for difficult to reach areas of the body. There was no effect of decontamination on excreted MeS in urine over 24 hours. Overall, findings indicate that improvised decontamination is an effective means of rapidly removing contaminants from skin, and combinations of improvised approaches can increase effectiveness in the early stages of decontamination and in the absence of specialist resources at an incident scene. However, the variable control and consistency of improvised decontamination techniques means that further intervention is likely to be needed, particularly for less accessible areas of the body.

Analysis of Chemical Simulants in Urine: A Useful Tool for Assessing Emergency Decontamination Efficacy in Human Volunteer Studies

INTRODUCTION

To date, all human studies of mass-casualty decontamination for chemical incidents have relied on the collection and analysis of external samples, including skin and hair, to determine decontamination efficacy. The removal of a simulant contaminant from the surface of the body with the assumption that this translates to reduced systemic exposure and reduced risk of secondary contamination has been the main outcome measure of these studies. Some studies have investigated systemic exposure through urinary levels of simulant metabolites. The data obtained in these studies were confounded by high background concentrations from dietary sources. The unmetabolized simulants have never been analyzed in urine for the purposes of decontamination efficacy assessment.

STUDY OBJECTIVE

Urinary simulant analysis could obviate the need to collect skin or hair samples during decontamination trials and provide a better estimate of both decontamination efficacy and systemic exposure. The study objective therefore was to determine whether gross skin contamination as part of a decontamination study would yield urine levels of simulants sufficient to evaluate systemic availability free from dietary confounders.

METHODS

In this study, a gas chromatography-tandem mass spectrometry method was developed for the analysis of two chemical simulants, methyl salicylate (MeS) and benzyl salicylate (BeS), in urine. An extraction and sample clean-up method was validated, enabling quantitation of these simulants in urine. The method was then applied to urine collected over a 24-hour period following simulant application to the skin of volunteers.

RESULTS

Both MeS and BeS were present in all urine samples and were significantly increased in all post-application samples. The MeS levels peaked one hour after skin application. The remaining urinary levels were variable, possibly due to additional MeS exposures such as inhalation. In contrast, the urinary excretion pattern for BeS was more typical for urinary excretion curves, increasing clearly above baseline from four hours post-dose and peaking between 12.5 and 21 hours, a pattern consistent with dermal absorption and rapid excretion.

CONCLUSION

The authors propose BeS is a useful simulant for use in decontamination studies and that its measurement in urine can be used to model systemic exposures following skin application and therefore likely health consequences.

Efficacy of Different Hair and Skin Decontamination Strategies with Identification of Associated Hazards to First Responders

Background: Established procedures for mass casualty decontamination involve the deployment of equipment for showering with water (such as the ladder pipe system [LPS] and technical decontamination [TD]). This necessarily introduces a short, but critical delay. The incorporation of dry decontamination to the incident response process offers the potential to establish a more rapid and timely intervention. Objectives: To investigate the effectiveness of various dry (DD) and wet decontamination strategies for removing a chemical warfare simulant (methyl salicylate; MS) from the hair and skin of human volunteers. Methods: The simulant was applied to volunteers via whole body exposure to an aerosol. Three decontamination protocols (dry, LPS and technical decontamination) were applied, singly and in various combinations. The efficacy of the protocols was evaluated by fluorescent photography and analysis of residual MS from skin/hair swabs, decontamination materials and air samples. Results: Dry decontamination was effective, with the greatest reduction in skin and hair contamination arising from the "Triple Protocol" (DD+LPS+TD). Secondary hazards associated with contaminated individuals and equipment decreased as the number of decontamination procedures increased. In particular, dry decontamination reduced the potential contact and inhalation hazard arising from used washcloths, towels and vapor within the TD units. Discussion: The introduction of dry decontamination prior to wet forms of decontamination offers a simple strategy to initiate treatment at a much earlier opportunity, with a corresponding improvement in clinical outcomes and substantial reduction of secondary hazards associated with operational processes.

GC-MS/MS quantification of benzyl salicylate on skin and hair: A novel chemical simulant for human decontamination studies

Human studies investigating the efficacy of emergency decontamination protocols for chemical incidents require the use of non-hazardous chemical simulants. Methyl salicylate (MeS) has almost exclusively been used for this purpose. Whilst MeS is a simulant of the chemical warfare agent (CWA) sulphur mustard, it is not an ideal simulant for many other chemical threats with greater persistence and lower volatility. Benzyl salicylate (BeS) has been investigated here as a low toxicity simulant for lower volatility, persistent chemical threat agents and toxic industrial chemicals (TICs). To evaluate the suitability of BeS as a simulant for human decontamination studies a gas chromatography-triple quadrupole mass spectrometry method was designed, optimised and validated, for the analysis of human skin and hair. Quantification was achieved using isotope-dilution, EI and collision-induced dissociation and multiple reaction monitoring for both qualifier and quantifier ion transitions. The mass transitions were m/z 285 → 91 and m/z 210 → 181, respectively for the quantifier and qualifier ions of BeS, and m/z 289 → 91 and m/z 214 → 185 for the quantifier and qualifier ions for the BeS-d4 internal standard, respectively. The method exhibited excellent coefficients of determination (R² = 0.9992-0.9999) with LOD and LOQ values at 0.023 ng/ml and 0.23 ng/ml. Across three Quality Controls (QCs), 11.5 ng/ml, 115 ng/ml and 1150 ng/ml) average accuracy (intra-day 95.6-100.3%, inter-day 98.5-104.91%) and precision (intra-day RSD (%) 2-13.7%, inter-day RSD (%) 3.3-8.8%) were determined. The validated method was applied in a proof of principle volunteer study for the determination of total BeS recovered from skin and hair. The average total BeS recovery after 70 min was 37.9% from skin and there was a significant increase between baseline and post-intervention levels for hair. These data demonstrate that BeS is an appropriate simulant for persistent chemicals and that the analytical method employed here is suitable for BeS analysis in human studies.

Decontamination and management of contaminated hair following a CBRN incident

This in vitro study evaluated the "triple protocol" of dry decontamination, the ladder pipe system, a method for gross decontamination, and technical decontamination in the decontamination of hair following chemical contamination. First, we assessed the efficacy of the three protocols, alone or in combination, on excised porcine skin and human hair contaminated with either methyl salicylate (MS), phorate (PHR), sodium fluoroacetate (SFA) or potassium cyanide (KCN). A second experiment investigated the residual hair contamination following decontamination with the triple protocol at different intervals post exposure. In a third experiment, hair decontaminated after exposure to MS or PHR was evaluated for off-gassing. Though skin decontamination was highly effective, a substantial proportion (20-40%) of the lipophilic compounds (MS and PHR) remained within the hair. The more water-soluble contaminants (SFA and KCN) tended to form much smaller reservoirs within the hair. Interestingly, substantial off-gassing of MS, a medium volatility chemical, was detectable from triple-decontaminated hair up to five days post exposure. Overall, the decontamination strategies investigated were effective for the decontamination of skin, but less so for hair. These findings highlight the importance of contaminated hair serving as a source of potential secondary contamination by contact or inhalation. Therefore, consideration should be given to the management of contaminated hair following exposure to toxic chemicals.

Optimisation and validation of a GC-MS/MS method for the analysis of methyl salicylate in hair and skin samples for use in human-volunteer decontamination studies

Methyl salicylate has a long history of use as a chemical warfare agent simulant for volatile lipophilic compounds such as sulphur mustard. An improved isotope dilution GC-MS/MS method was developed, optimised and validated for the analysis of methyl salicylate in human skin and hair samples, for use in emergency decontamination volunteer studies. Following derivatisation, quantification was measured on a triple quadrupole mass spectrometer, set to EI mode and conducting multiple reaction monitoring of target ions. The mass transitions were 209 → 179 and 213 → 161 for quantitation of methyl salicylate and methyl salicylate D4, respectively whereas qualifier ion transitions used to verify identity were 209 → 169 and 213 → 89. The method achieved excellent coefficient of determination (R² > 0.9968 to 0.9999) over the range of 0.5-5000 ng/ml and the LOD and LOQ were 0.05 ng/ml and 0.5 ng/ml. The method was further validated for accuracy (intra-day and inter-day average 100.28% to 102.03% and 99.48% to 102.33%, respectively) and precision (intra-day RSD 1.43% to 2.35%, inter-day RSD 1.91% to 2.97%) at three concentrations (25, 250 and 2500 ng/ml). The validated method was successfully used to identify methyl salicylate in samples of human skin generated during volunteer studies of emergency decontamination systems and in hair of staff conducting these studies.

UK's initial operational response and specialist operational response to CBRN and HazMat incidents: a primer on decontamination protocols for healthcare professionals

The UK is currently in the process of implementing a modified response to chemical, biological, radiological and nuclear and hazardous material incidents that combines an initial operational response with a revision of the existing specialist operational response for ambulant casualties. The process is based on scientific evidence and focuses on the needs of casualties rather than the availability of specialist resources such as personal protective equipment, detection and monitoring instruments and bespoke showering (mass casualty decontamination) facilities. Two main features of the revised process are: (1) the introduction of an emergency disrobe and dry decontamination step prior to the arrival of specialist resources and (2) a revised protocol for mass casualty (wet) decontamination that has the potential to double the throughput of casualties and improve the removal of contaminants from the skin surface. Optimised methods for performing dry and wet decontamination are presented that may be of relevance to hospitals, as well as first responders at the scene of a chemical incident.

Hybrid in vitro diffusion cell for simultaneous evaluation of hair and skin decontamination: temporal distribution of chemical contaminants

Most casualty or personnel decontamination studies have focused on removing contaminants from the skin. However, scalp hair and underlying skin are the most likely areas of contamination following airborne exposure to chemicals. The aim of this study was to investigate the interactions of contaminants with scalp hair and underlying skin using a hybrid in vitro diffusion cell model. The in vitro hybrid test system comprised “curtains” of human hair mounted onto sections of excised porcine skin within a modified diffusion cell. The results demonstrated that hair substantially reduced underlying scalp skin contamination and that hair may provide a limited decontamination effect by removing contaminants from the skin surface. This hybrid test system may have application in the development of improved chemical incident response processes through the evaluation of various hair and skin decontamination strategies.

Further studies of the efficacy of military, commercial and novel skin decontaminants against the chemical warfare agents sulphur Mustard, Soman and VX

BACKGROUND/AIMS

Following an incident involving toxic chemicals, deployment of countermeasures before the arrival of specialised services at the scene may provide a "therapeutic" window in which to mitigate skin absorption.

METHODS

Five potential candidates (itaconic acid, N,N'-methylenebisacrylamide, 2-trifluoromethylacrylic acid, fuller's earth and Fast-Act®) previously found effective against a simulant (methyl salicylate) were evaluated against a 10 μL droplet of ¹⁴C-sulphur mustard (HD), soman (GD) or VX applied to the surface of porcine skin mounted on static skin diffusion cells.

RESULTS

All the decontaminants applied to the skin 5 min post exposure achieved a marked reduction in the amount of ¹⁴C contaminant remaining within the skin at 24 h. Itaconic acid significantly (p < .05) reduced the amount of ¹⁴C-HD, GD and VX remaining in the skin at 24 h. Additionally, 2-trifluoromethylacrylic acid significantly reduced the amount of ¹⁴C-HD, whilst fuller's earth significantly reduced the amounts of ¹⁴C-HD and VX recovered within the skin at 24 h.

CONCLUSION

All of the products evaluated in this study performed well in reducing the dermal absorption of all the chemical warfare agents tested.

Optimization of Nonambulant Mass Casualty Decontamination Protocols as Part of an Initial or Specialist Operational Response to Chemical Incidents

Objective: The UK's Initial Operational Response (IOR) is a new process for improving the survival of multiple casualties following a chemical, biological, radiological or nuclear incident. Whilst the introduction of IOR represents a patient-focused response for ambulant casualties, there is currently no provision for disrobe and dry decontamination of nonambulant casualties. Moreover, the current specialist operational response (SOR) protocol for nonambulant casualty decontamination (also referred to as "clinical decontamination") has not been subject to rigorous evaluation or development. Therefore, the aim of this study was to confirm the effectiveness of putatively optimized dry (IOR) and wet (SOR) protocols for nonambulant decontamination in human volunteers. Methods: Dry and wet decontamination protocols were objectively evaluated using human volunteers. Decontamination effectiveness was quantified by liquid chromatography-mass spectrometry analysis of the recovery of a chemical warfare agent simulant (methylsalicylate) from skin and hair of volunteers, with whole-body fluorescence imaging to quantify the skin distribution of residual simulant. Results: Both the dry and wet decontamination processes were rapid (3 and 4 min, respectively) and were effective in removing simulant from the hair and skin of volunteers, with no observable adverse effects related to skin surface spreading of contaminant. Conclusions: Further studies are required to assess the combined effectiveness of dry and wet decontamination under more realistic conditions and to develop appropriate operational procedures that ensure the safety of first responders.

Public perceptions of emergency decontamination: Effects of intervention type and responder management strategy during a focus group study

In the event of an incident involving the release of a hazardous chemical, first responders may decide to initiate emergency decontamination in order to remove any contaminant from affected casualties. Recent initiatives such as the UK Home Office-led Initial Operational Response Programme have introduced new evidence-based decontamination protocols that reduce the time taken to initiate the decontamination process, including an increased emphasis on rapidly removing contaminated clothing (disrobe), and the use of improvised dry decontamination methods. The current study used a series of focus groups to examine public perceptions of different decontamination interventions and responder management strategies. Results revealed that a decontamination shower was perceived to be more effective than dry decontamination methods and that a management strategy that included effective responder communication resulted in increased willingness to comply with the need for decontamination. This study demonstrates that public understanding and acceptance of novel decontamination methods such as dry decontamination may present additional challenges for first responders. Increased emphasis on effective communication during decontamination is needed. Furthermore, provision of information during the focus group study resulted in an increase in participants’ knowledge and confidence in taking recommended decontamination actions, which was maintained three months after the study. The longitudinal nature of these effects suggest that it may be possible to increase public awareness about actions to take during chemical incidents by developing pre-incident public education; however, further research is needed to examine this more fully.