Medical Aspects of Chemical Warfare (2008) - The Black Vault

Toxic Inhalational Injury and Toxic Industrial ChemicalsInhalation of chlorine gasCl 2 + H 2 O 2HCl + [Or]Cl 2 + H 2 O HOCl + HClHydrochloric and hypochlorious acids as well as nascent oxygenToxic to the mucosa from the upper respiratory tract to the alveoliIrritation of the airway mucosa leads to local oedema,perhaps direct stimulation of the smooth muscleof the bronchioles with resulting contractionDirect injury to the epithelialand endothelial membranesRelease of mediatorsProinflammatorycytokines,(TNFα, IL-1β, IL-6)SystemicinflammatoryresponseIncreasedright heartworkEndothelinsHypoxaemiaHypoxicpulmonaryVasoconstrictionvasoconstrictionPulmonaryhypertensionImbalancein V/QmatchingAirwayobstructionIncreasedexpiratoryresistanceAir trappinghyperinflationDecreasedlungcomplianceGrossshuntingof bloodFloodingof alveoliIncreasedtransport of fluidand protein intothe alveolusPulmonaryoedemaIncreasedpermeability ofthe pulmonarycapillary wallsSieving ofplasma to theinterstitiumRight heart failureIncreased interstitial hydrationHaemoconcentrationFig. 10–1. General mechanisms of toxic gas exposure.IL: interleukinTNF: tumor necrosis factorV/Q: ventilation profusion ratioReproduced with permission from: Wang J. Pathophysiology and Treatment of Chlorine Gas-Induced Lung Injury: An ExperimentalStudy in Pigs [dissertation]. Linköping, Sweden: Linköping University; 2004: 36.inhaled compounds affect basic life processes.It should be kept in mind that the effects of an inhalationalevent are related to the chemical reactivity of thetoxicant, its concentration, and the duration of exposure.In accidental exposure scenarios, there is generally poorquantifiable information on concentration and exposureduration; in some cases the identity of the agent may beuncertain. Also, the possibility of multiple simultaneouschemical exposures, which can occur in a chemical plantexplosion, must be considered. In Bhopal, India, an accidentalrelease of methylisocyanate used in the productionof the pesticide carbaryl was responsible for over60,000 casualties and nearly 5,000 deaths in December1984. 35 Inhalation of the toxic gas resulted in a range ofpulmonary symptoms that included irritation and coughing.Pulmonary edema and atelectasis were the eventualcauses of death. Long-term survivors were diagnosedwith lung inflammation, fibrosis, and compromised lungfunction. Survivors continue to have health issues relatedto catastrophe event after nearly 25 years. 36Physiological ResponsesMany studies have shown that the adverse effects347