Page 27 - JSOM Winter 2018

Vital signs at that time were heart rate, 140/min; blood pres- Zinc chloride readily combines with water in the atmosphere
sure, 100/60mmHg; respiratory rate, 40/min; temperature, and in the respiratory tract to create hydrochloric acid and
103.6°F (39.8°C), and pulse oximetry, 55% on room air. He zinc oxychloride. Because of the small particle size, it can pen-
was awake and alert, visibly in severe respiratory distress, with etrate deep into the respiratory tract and cause severe irrita-
crepitus over the anterior chest and neck. Cardiac examina- tion and pulmonary epithelial necrosis within the alveoli. For
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tion revealed tachycardia without murmurs, rubs, or gallops. zinc chloride, the threshold limit value and immediately dan-
Pulmonary auscultation demonstrated coarse breath sounds gerous to life and health value are 1mg/mm and 50mg/mm ,
3
3
with loud bilateral crackles. The remainder of his physical ex- respectively, and animal studies have demonstrated pulmonary
amination was without abnormal findings. edema, alveolar hemorrhage, localized bulbous emphysema,
and alveolar cell carcinoma with exposure. 9
The patient was intubated for respiratory failure. His chest
radiograph and computed tomography imaging exhibited Hexachlorethane is also a potentially toxic chemical, reported
bilateral, diffuse interstitial infiltrates consistent with acute to be a cause of hepatic failure. The patient presented in this
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respiratory distress syndrome, pneumomediastinum, and pne- case did not experience this adverse effect.
umothorax with subcutaneous emphysema (Figure 1), which
required bilateral tube thoracotomies. Echocardiogram re- Conclusion
vealed no cardiac abnormalities. A bronchoscopy with sputum
samples was significant for numerous neutrophils. All cultures This case highlights the dangers of these smoke-bomb chemi-
(i.e., blood, urine, and bronchoalveolar lavage) were negative cals in partially open environments, which may be erroneously
for bacterial, viral, fungal, pneumocystis, and legionella infec- considered safe, as well as the potential delay of severe symp-
tions. A screen for human immunodeficiency virus was also tomatology and respiratory distress. Previous cases have only
negative. described significant morbidity after enclosed exposure, and
so a mild presentation after semi-open exposure may cause a
The patient ultimately required mechanical ventilation for 42 practitioner to erroneously assume a nonconsequential inci-
days and a percutaneous tracheostomy tube was placed on day dent. However, because significant lung injury can be delayed
21. The patient was discharged 56 days after admission with days to weeks after the initial exposure, the patient may be
persistent dyspnea and bilateral pulmonary infiltrates consistent put at considerable risk if they are too soon without adequate
with early pulmonary fibrosis. Outpatient follow-up 3 weeks follow-up instruction. Medical providers and medics should
after discharge revealed residual shortness of breath and pul- consider close observation of patients with mild symptoms
monary function tests with 30% of his lung capacity remaining. during the first days after exposure and issue clear return pre-
cautions to the patient for any worsening symptoms. Finally,
military leadership, operational medical providers, and team
Discussion
medics should all be aware of the potential hazards of the
The civilian C3 and military M18 smoke bombs both use M18 and similar devices when planning training exercises,
hexachlorethane and zinc oxide, and differ only in packag- because they have the potential to cause significant morbidity
ing and source of ignition. When ignited, calcium silicide re- even in semi-open environments.
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duces zinc oxide, which, in turn, reacts with hexachlorethane,
forming zinc chloride, calcium carbonate, free carbons, and Disclaimer
silica. Additional minor products of combustion include small The view(s) expressed herein are those of the authors and do
amounts of phosgene, tetrachloroethane, carbon tetrachlo- not reflect the official policy or position of the US Army Med-
ride, and carbon monoxide. ical Department, the US Army Office of the Surgeon General,

FIGURE 1 (A) Computed tomography scan of the thorax showing bilateral diffuse infiltrates, pneumomediastinum, and subcutaneous
emphysema. (B) Chest radiograph showing pneumomediastinum and bilateral pulmonary infiltrates.

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