Aims and issues of decontamination in case of chemical exposure
PREVOR laboratory is a specialist in the field of Chemical Risk.
It has a double mission:
- to help companies decrease the frequency of accidents,
- to develop products which are able to minimize the consequences of chemical projections in the event of an accident.
It is on the basis of this double objective that research has been undertaken to understand the mechanism of chemical burns, to improve on existing rinsing solutions (water, saline solution) and to propose medical devices to be used in case of emergency, irrespective of the surface and size of the affected area, and of the nature and the concentration of the chemical involved.
There are more than 25,000 chemicals likely to cause cutaneous or ocular lesions and burns (after a single or repeated contact), such as acids, bases, oxidizers, reducing agents, and solvents.
The Benefits and the Limitations of Rinsing with Water
After receiving a chemical splash, the victim must be undressed and the affected tissues must be rinsed as quickly as possible. Rinsing with water was the first protocol used for chemical decontamination and this dogma persists on the basis of arguments which are more practical than scientific, because of its general-purpose and non-toxic character, and of its availability. It allows the chemical agent at the surface of the affected tissues to be carried away by a mechanical effect, independent of its nature and concentration.
However, there are limits to water rinsings:
- it does not act on the potentially irritating or corrosive nature of the chemical agent,
- there is no rapid return to a physiological state (the effect of carrying the chemical agent away is limited to the surface tissue and has no in-depth effect),
- water favors the chemical agent's penetration of the tissue (Professor Schrage) (link with the publication Schrage, Klin Monastbl Augenheilkd, 2004),
- in order to obtain optimal results, it is necessary to intervene very quickly (10 seconds according to the ANSI standard) after the splash. However, there is sometimes only partial effectiveness, in particular on major corrosive agents.
- Observations of significant after-effects, secondary care and surgical interventions resulting in permanent disability, and even fatalities are regularly reported in the scientific literature2,3.
- Recently, comparative studies have shown the possibility of improving on rinsing with water4.
Increasing the Chances of Being Saved
Improving on rinsing with water consists of finding other solutions without these limitations in order to increase the chances of the victim both being saved and experiencing a minimum of after-effects.
In order to accomplish this, the DIPHOTERINE® solution, an aqueous solution that contains an amphoteric and chelating molecule was introduced. The aim of the resulting solution is to prevent chemical burns or to lessen their seriousness.
The improvements brought by the DIPHOTERINE® solution to chemical decontamination are as follows
- it stops the irritating and corrosive agents actions on the eye and skin, thanks to its amphoteric and chelating properties,
- it stops the chemical agent penetration of the tissues and carries the chemical away from the interior to the exterior of the tissue, thanks to its hypertonicity,
- it allows a rapid return to a pH level between 5.5 et 9, without any danger of a burn,
- it has a prolonged intervention time compared to water (in the minute following the chemical splash) with improved rinsing effectiveness: absence of after-effects, no or little need for secondary care, and no or little loss of work.
The DIPHOTERINE® solution has been classified as a medical device according to the 93/42 CEE. Directive. It claims to act on the chemical agent in order to stop or to minimize the development of chemical burns. It is classified IIa because it can be used on injured skin.(Dr Cavallini) (link with the publications: Cavallini, Annals of Burns and Fire disasters 2004, vol XVII-2, 84-87 and Cavallini, European Journal of Anaesthesiology 2004, 21, 389-392).
Since the DIPHOTERINE® solution does not act on the human organism and its action on the chemical agent is not obtained neither by pharmaceutical, immunological or by metabolism means, it has not been classified as a drug.
Analysis of the Scientific Data
The analysis of the clinical and experimental data of chemical decontamination with the DIPHOTERINE® solution is based on three levels of scientific evidence.
Convergent clinical data
In spite of the difficulties of performing studies on first aid in the workplace and the inevitable limitations related to the interpretation of the results, much of the data collected on human subjects provides convergent elements.
Many accounts of the DIPHOTERINE® solution use (Hall Vet Hum Toxicol 2002, 44, 4, 228-231) have been provided by companies. Generally transmitted by occupational health doctors, the reports can be criticized one by one, either for a problem of methodology or interpretation, but when all of these several hundreds cases of the DIPHOTERINE® solution uses are combined, the coherence of the whole reveals some certainties about its effectivenes:
- no noxious effects,
- lessens pain,
- no after-effects,
- absence of or only a small amount of secondary care,
- absence of or a few days of work loss.
The INRS (National Institute of Research and Safety) decided to independently verify the effectiveness of the various chemical splash decontamination methods, including the DIPHOTERINE® solution. For that purpose, an investigation was carried out with the help of occupaitonal health doctors (link with the paper: Falcy, DMT 53, 1er quarter 1993) in France. 73 companies and more than 60 accidents were taken into consideration. This study shows the action of the DIPHOTERINE® solution on a varied sample of chemicals, and indicates that the DIPHOTERINE® solution, when used according to the recommended protocol, is always at least as effective as water. The continuation of this investigation (link with the publication Falcy DMT 70, 2nd quarter 1997) showed that the results, for a total of 145 chemical splash cases studied, were superior on concentrated bases. This was confirmed by the study carried out by Martinswerk (link with the publication: Hall Vet Hum Toxicol 2002, 44, 4, 228-231), which made it possible to confirm the superiority of the rinsing with the DIPHOTERINE® solution on bases, both in terms of effectiveness and rinsing safety, despite the small size of the statistical series:
|Rinsing solution||The DIPHOTERINE® solution||Acetic Acid||Water|
|No secondary care||100 % +/- 15 %||0 % +/- 15 %||0 % +/- 15 %|
|Simple secondary care||0 % +/- 15 %||80 % +/- 15 %||25 % +/- 15 %|
|Medicalized secondary care||0 % +/- 15 %||20 % +/- 15 %||75 % +/- 15 %|
|Number of days of work loss||0.18 +/- 0.4||2.91 +/- 4.3||8 +/- 8.12|
For isolated reported cases, the examples are also very significant. Take the case of 2 large cutaneous splashes of concentrated sulfuric acid with equal concentrations (95%): the one rinsed with water lead to serious after-effects, and six months of work loss, and the other rinsed with the DIPHOTERINE® solution resulted in neither after-effects nor work loss. (link with the letter from Quinoléine. Translation into English).
Experimental data in vivo which confirm the clinical results
When the chemical burn does occur, its development is determined by two phenomena:
- the cleaning phase (inflammation, destruction), which is increased in cases of chemical burns,
- the reparing phase (healing), which is decreased.
The in vivo experiments have confirmed that when the development of the chemical burn is stopped, the healing of the injured tissues is carried out in optimal conditions. Dr Cavallini (lien Cavallini European Journal of Anaesthesiology, 2004, 21, 389-392) compared the effectiveness of rinsing with the DIPHOTERINE® solution to rinsing with saline solution on a concentrated cutaneous hydrochloric acid burn in rats. Concentrated DIPHOTERINE® solution stopped the development of the chemical burn, which had the following consequences:
- better healing of the skin (size of the lesion at 7 days : DIPHOTERINE® solution 4 mm versus saline solution 6 mm), see also another publication by the same (link with Cavallini Annals of Burns and Fire Disasters, vol XVII, 2004)
- a significant reduction of pain (Substance P in the first 48 hours, p < 0.05 ; beta-endorphine after 7 days, p < 0.05),
- a reduction of inflammation (IL-6 to 48h, p < 0.01 ; at 7 days, p < 0.05).
Doctor Gérard studied a 15.3% amonia occular burn in rabbits (link with the study J Fr Ophtalmol 1999;22, 10, 1047-1053). This study has allowed an understanding of the chemical burn mechanism and has showed the relevance of delayed treatment of such a burn. This experimental burn model was then tested in order to compare the effectiveness of the DIPHOTERINE® solution versus saline solution.(link with Gérard, J Fr Ophtalmol, 2000, 23,5,449-458).
After rinsing with the DIPHOTERINE® solution there is:
- an absence of a stromal edema, while it has been observed after rinsing with saline solution or when there is no rinsing,
- an inflexion of the pH, which has not been observed after rinsing with saline solution or when there is no rinsing.
The presence of a stromal edema, resulting from inflammation due to the burn and the hypotonic effect of rinsing, is known to be an aggravating factor in the development of chemical burns5.
Experimental data ex vivo/in vitro which explain the clinical results
These studies have allowed us to understand and confirm the clinical results obtained. Professor Schrage (link with Klin Monatsbl Augenheilkd, 2004) compares the effectiveness of different rinsing solutions by dosage of 5ml of 0.5 M caustic soda or hydrochloric acid and shows the limitations of water rinsing on corrosives. Despite adding an amount of water which represented 50 times the amount of caustic soda or of hydrochloric acid contamination, water did not bring the pH level back to physiological values:
|chemical||Added water (250 ml)||Added DIPHOTERINE® solution (PREVIN solution) (100ml)|
|0.5M Caustic Soda||11.8||<9|
|0.5M Hydrochloric Acid||2||6.3|
Physiological Zone (no burn): 5.5 < pH < 9
An experiment on enucleated pig eyes measured the effect of rinsing on the development of the intra-ocular pH according to whether it was early or delayed: only rinsing with the DIPHOTERINE® solution showed an improvement of the intra-ocular pH, even if the rinsing was delayed.
In this same publication, the physical limits of water rinsing on fibroblast cultures is shown. Water is hypotonic. When there is a chemical burn, the osmotic pressure of the cornea increases up to 1280 mosmoles/kg. Rinsing with a hypotonic solution (such as water) can cause an osmotic shock and a cellular cytolysis (destruction of cells after swelling). See also the following publication (link with Kompa, Graefe’s Arch Clin Exp Ophthalmol, 2002) on the direct effect of a rinsing solution’s osmolarity on the cornea’s osmolarity.
The following table clearly shows the advantages of using the DIPHOTERINE® solution
|WATER||the DIPHOTERINE® solution|
|Chemical agent at the surface of the affected tissues carried away||Chemical agent at the surface of the affected tissues carried away|
Theoretical effectiveness proven on major chemical groups
Should be verified case by case for specific chemical agents
Favors a part of the chemical agent’s penetration of the tissue, especially in eyes
Stops the chemical agent’s penetration of the tissue and carries the chemical away from the interior to the exterior of the tissue
|No action on corrosives or irritants
Development of the chemical burn
|“Neutralizing” action on the potentially irritating or corrosive nature of the chemical agent
Stops the development of the burn
Allows a rapid return to a physiological pH
|Intervention time: the first 10 seconds||Intervention time: the first minute|
|Possibility of serious physical after-effects, which may even be fatal||Decrease or absence of after-effects
Prevents chemical burns
|In certain cases, complex secondary treatment with reconstructive surge||Decrease or absence of secondary treatments
Prevents chemical burns
|A medical consultation is necessary in every case|
|Decreases in work loss|
|Non toxique||Non toxic, sterile||Expiration date must be observed|
The latest study published by Dr. Merle (link with publication Burns 31 (2005) 205-211) shows the importance of using the DIPHOTERINE® solution in the first hours following an accident. The study compares, for the equivalent stages of burns, the differences which occur after rinsing with the DIPHOTERINE® solution versus rinsing with water before treatment of a basic burn . This study shows a significant reduction in the amount of time needed for the reepithelialisation of the eye.
|Reepithelialisation time in days||the DIPHOTERINE® solution||Sérum physiologique||Value of p|
|Stade I||1.9 +/- 1||11.1 +/- 1.4||p <10-7|
|Stade II||5.6 +/- 4.9||10 +/- 9.2||p <0.02|
|Stade III||20 +/- 14.1||45.2 +/- 23||0.21 NS|
Absence of ocular Stage IV with the DIPHOTERINE® solution
Dr Max Gérard has published a case of a severe ocular chemical burn (stage IV) which shows the advantages of delayed rinsing with the DIPHOTERINE® solution and describes the associated secondary treatment, principally aimed at reducing inflammation, as well as infection and pain. No surgical act was necessary in this case.
What is important to remember
First-aid rinsing with water was the first decisive improvement in the decontamination of chemical splashes; But water rinsing has limits that have been improved on with the DIPHOTERINE® solution.
The DIPHOTERINE® solution can be used according to two protocols
- Either as a first-aid treatment in emergency situations, in the workplace, (at the scene of the accident), in order to avoid any after-effects when used in the first minute after the splash has occurred,
- Or with a delayed usage, in the case of treatment before or after hospitalization, where the DIPHOTERINE® solution stops the develpment of chemical burns and allows a rapid return to a physiological state. It is a treatment adapted to the seriousness of the burn which can then be applied in optimal conditions.
If the chemical is corrosive, or if there is a risk that the splash will not be handled in the first seconds, the water protocol represents a missed opportunity when compared to the DIPHOTERINE® solution protocol.
- The DIPHOTERINE® solution is an active molecule which permits the rapid and effective rinsing of chemical agents.
- Its effectiveness has been proved on more than 600 chemical agents representing the majority of major chemical groups.
- The DIPHOTERINE® solution, thanks to its amphoteric characteristics can never be dangerous.
- The DIPHOTERINE® solution, even if it has no chemical activity on a compound, is always more effective when compared to an isotonic solution, and even more when compared to water.
- If their is any doubt regarding new chemicals, the effectiveness of the DIPHOTERINE® solution must always be evaluated.
We remain at you disposition to perform this evaluation.
- 1 Liao CC, Rossignol AM Landmarks in burn prevention. Burns 2000 ; 26 : 422-434
- 2 Sykes RA, Mani MM, Hiebert JH Chemical burns : retrospective review. J Burn Care Rehabil 1986 ; 7 : 343-347
- 3 Bromberg BE, Song IC, Walden RH : Hydrotherapy of chemical burns. Plastic Reconstr Surg 1965 ; 35 : 85-95
- 4 Andrews K, Mowlavi A, Milner S The treatment of alkaline burns of the skin by neutralization. Plastic Reconstr Surg 2003 ; 111 : 1918-1921
- 5 Kubota M, Fagerholm P. Corneal alkali burn in the rabbit. Water-balance, healing and transparency. Acta Ophthalmol Scand 1991 ; 69 : 635-640