Development of haemostatic decontaminants for the treatment of wounds contaminated with chemical warfare agents. 1: Evaluation of in vitro clotting efficacy in the presence of certain contaminants

Abstract

The treatment of penetrating, haemorrhaging injuries sustained within a hazardous environment may be complicated by contamination with toxic chemicals. There are currently no specific medical countermeasures for such injuries. Haemostats with an absorbent mechanism of action have the potential to simultaneously stop bleeding and decontaminate wounds. However, a primary requirement of a 'haemostatic decontaminant' is the retention of clotting function in the presence of chemical contaminants. Thus, the aim of this study was to investigate the haemostatic efficacy of seven commercially available haemostats in the presence of toxic chemicals (soman, VX, sulphur mustard, petrol, aviation fuel and motor oil). Clot viscosity was assessed ex vivo using thrombelastography following treatment of pig blood with: (i) toxic chemical; (ii) haemostat; or (iii) haemostat in combination with toxic chemical. Several contaminants (VX, petrol and GD) were found to be pro-haemostatic and none had an adverse effect on the rate with which the test products attained haemostasis. However, the total clot strength for blood treated with certain haemostats in the presence of sulphur mustard, soman and petrol was significantly decreased. Three test products failed to demonstrate haemostatic function in this ex vivo (thrombelastography) model; this was tentatively ascribed to the products achieving haemostasis through a tamponade mechanism of action, which can only be replicated using in vivo models. Overall, this study has identified a number of commercial products that may have potential as haemostatic decontaminants and warrant further investigation to establish their decontaminant efficacy.

Development of haemostatic decontaminants for treatment of wounds contaminated with chemical warfare agents. 3: Evaluation of in vitro topical decontamination efficacy using damaged skin

“…Haemostatic products (based on an absorptive mechanism of action) also have potential clinical application in sequestering toxic materials from within wounds. Previous studies have demonstrated that a number of products retain their clotting function in the presence of toxic chemicals (Hall et al, ) and that, following topical application to undamaged skin, certain haemostats are highly effective in preventing the dermal absorption of chemical warfare (CW) agents (Dalton et al, ). While normal skin can provide some protection against the ingress of xenobiotics, damage resulting from trauma associated with penetrating injury or any other insult that may compromise the stratum corneum (such as abrasions, excoriations or burns) could lead to enhanced local and systemic absorption (Chilcott et al, ; Wu et al, ).…”

The percutaneous toxicokinetics of Sulphur mustard in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant

“…Previous studies have demonstrated that WoundStat™, a granular haemostat, has comparable efficacy to in‐service military decontaminants (fuller's earth and M291) in the decontamination of both undamaged and damaged skin (Dalton et al ., , Lydon et al ., ). Additionally, WoundStat™ maintains its haemostatic capability in the presence of toxic chemicals, including SM, in vitro (Hall et al ., ).…”

The percutaneous absorption of soman in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant

“…Previous in vitro studies have demonstrated that haemostatic products may retain the ability to clot blood in the presence of CWAs and that certain products (based on absorptive powders) are able to effectively decontaminate CWAs from normal and superficiallydamaged skin (11)(12)(13). One product, WoundStat™, was identified as being particularly effective in terms of its ability to decontaminate CWAs from undamaged or superficiallydamaged skin.…”