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

Medical Aspects of Chemical Warfarelonged periods. Ventilatory support may be necessaryto assist oxygenation and adequate carbon dioxideclearance. The use of certain antibiotic skin creams(such as mafenide acetate) to treat skin lesions maycomplicate the acid–base status of the individual byinducing a metabolic acidosis.Initially, bronchitis resulting from mustard exposureis nonbacterial. White blood cell elevation, fever,pulmonary infiltrates on chest radiograph, and coloredsputum may all be present. Careful assessmentof sputum by Gram stain and culture demonstratesthat bacterial superinfection typically is not presentduring the first 3 to 4 days. Antibiotic therapy shouldbe withheld until the identity of a specific organismbecomes available. Of particular importance is thepatient’s immune status, which may be compromisedby a progressive leukopenia beginning about day 4or 5. The development of leukopenia signals severeimmune system dysfunction; intensive medical supportmay become necessary for these patients. In theseinstances, sepsis typically becomes a complicatingfactor.Casualties with evidence of deteriorating pulmonarystatus should be intubated early, before laryngealspasm makes it difficult or impossible. Intubationassists in ventilation and also allows suction of necroticand inflammatory debris. Bronchoscopy maybe necessary to remove intact pseudomembranes orfragments of pseudomembranes (one of the Iraniancasualties treated in western European hospitals duringthe Iran-Iraq War died of tracheal obstruction bya pseudomembrane, as did World War I casualties).Early use of positive end-expiratory pressure or continuouspositive airway pressure may be beneficial.The need for continuous ventilatory support suggestsa poor prognosis; of the Iranian casualties treated inEuropean hospitals who required assisted ventilation,87% died. 17An especially devastating pulmonary complication,severe and progressive stenosis of the tracheobronchialtree (Figure 8-14), developed in about 10% of the Iraniancasualties treated in European hospitals. With theIranian casualties, bronchoscopy was of value whenused both for diagnosis and for therapeutic dilation. 236(This complication was possibly not recognized inWorld War I mustard casualties because the degree ofexposure required to cause severe tracheobronchialinjury resulted in early death from pneumonia.)Gastrointestinal TractInitial nausea and vomiting are rarely severe andcan usually be relieved with atropine or common antiemetics.Prolonged vomiting and diarrhea beyond24 hours are usually indicative of systemic toxicityrequiring intensive care.Bone MarrowSuppression of hemopoietic elements cannot bepredicted from the extent of skin lesions (eg, the lesionsmight be from vapor and therefore superficial,but significant amounts of mustard may have beenabsorbed through inhalation). Frequent counts of theformed blood elements must be performed on casualtieswith significant skin lesions or airway damage.Mustard destroys the precursor cells, and cell elementsin the blood are depressed. Because white blood cellshave the shortest life span, their numbers decreasefirst; red blood cells and thrombocytes soon follow.Typically, leukopenia begins at day 3 through day 5after exposure, and reaches a nadir in 7 to 21 days.Leukopenia with a cell count lower than 200 cells/mm 3usually signifies a poor prognosis, as does a rapid dropin the cell count; for example, from 30,000 to 15,000cells/mm 3 in a day. 17,61Medical personnel should institute therapy withnonabsorbable antibiotics that sterilize the gut at theonset of leukopenia. 17 Cellular replacement may alsobe successful (see also the comments on granulocytecolony stimulating factor below).Eye. Research at USAMRICD with rabbits exposedto sulfur mustard showed remarkable results usingsteroids and antibiotic eye combinations. In the study,the treatments were given both by injection and topicallyin the form of solutions and ointments. Eyes thatwould have been nearly destroyed appeared almostnormal when these combinations were applied earlyand frequently. Based on this research, USAMRICDrecommended that commercially available ophthalmologicsteroid/antibiotic solutions or ointments beadded to field medical sets. Recommended use is assoon as possible for even the mildest mustard eyeinjury. Frequency of use is every 1 to 2 hours untilthe full extent of the developing mustard injury becomesknown. Treatment should then be modifiedaccordingly, with consultation and examination byan ophthalmologist. This initial treatment would beapplied only in the absence of a penetrating injury tothe eye or in the case of obvious secondary bacterialinfection. Eye pain can be severe enough to requirenarcotic analgesia. 237Lung. No specific antidotes for the mustard injuryto the lung exist. However, a tremendous amount ofsupportive care is available for all pulmonary injuries.Mustard lung injuries in the trachea and bronchi havea high rate of secondary bacterial infection starting asearly as 3 days and developing as late as 2 to 3 weeks288