Abstract
Objective. To evaluate bronchial challenges using three different stimuli as screening tools for bronchial hyper-responsiveness in sulfur mustard gas-induced asthma. Design. Randomized, cross-over clinical study. Setting. University hospital. Patients. Eighteen veterans with mustard gas-induced asthma and 18 normal veterans as the control group. Intervention. Pulmonary function tests and inhalation challenges with ultrasonically nebulized distilled water (UNDW), methacholine, and ultrasonically nebulized cold water (UNDCW) were performed on all patients and subjects. Results. Six mustard gas-induced asthmatic veterans did not respond to a 20% in FEV1 after distilled water (13.3%), and two of them (11.11%) did not respond with distilled cold water; all responded with methacholine. Only one healthy subject developed a PC20 FEV1 after methacholine but did not with both distilled water and distilled cold water challenges. The asthmatic patients were sensitive to distilled water with a median PD20 of 7.24 ± 3.83 ml (range 2.54 ml to 15.83 ml), and sensitive to cold water with a median PD20 of 6.42 ± 6.24 ml (range 1.92 ml to 25.15 ml). The median PC20 methacholine was 1.90 ± 1.88 mg/ml (range 0.14 mg/ml to 6.20 mg/ml). In patients with a positive response to the distilled water challenge test, no significant correlation was found between PC20 of methacholine and PD20 of distilled water (Rho = −0.34, p = 0.25), whereas in patients whose responses to distilled cold water (DCW) were positive, PD20 of distilled cold water (DCW) correlated well with PC20 of methacholine (Rho = −0.69, p = 0.006). Conclusion. Overall, the methacholine challenge test is the best method to distinguish these asthmatic patients from normal subjects in this study. When compared to the methacholine challenge, although the airway response to ultrasonically nebulized distilled cold water test was somewhat less sensitive, it may be used as a simple, fast, inexpensive, and relatively reliable method to predict the absence of asthma in sulfur mustard gas-induced asthma.
Highlights
Sulfur mustard gas is used as a vesicant chemical warfare agent [1]
Since there are no reports on the behavior response of airway hyper-reactivity to a variety of stimuli in asthmatic veterans who have been exposed to an acute and heavy exposure of sulfur mustard gas, this study was carried out to define its pattern
In patients with a positive response to the distilled water challenge test, no significant correlation was found between PC20 of methacholine and PD20 of distilled water (Rho = −0.34, p = 0.25) (Fig. 1).I In patients whose responses to distilled cold water (UNDCW) were positive, PD20 of distilled cold water (UNDCW) correlated well with PC20 of methacholine (Rho = −0.69, p = 0.006) (Fig. 2)
Summary
Sulfur mustard gas is used as a vesicant chemical warfare agent [1]. This chemical gas is an alkylating agent that is acutely toxic to the skin, eyes, and respiratory system [2,3,4]. The diversity of the effects of sulfur mustard gas inhalation upon the respiratory system has been investigated following a single and heavy exposure in Iranian veterans [2]. Nonpharmacological challenge tests involve provocation with cold air, exercise, and inhalation of isotonic and nonisotonic aerosols [24,26,29]. These methods provide a high specificity but somewhat less sensitivity. Since there are no reports on the behavior response of airway hyper-reactivity to a variety of stimuli in asthmatic veterans who have been exposed to an acute and heavy exposure of sulfur mustard gas, this study was carried out to define its pattern. The purpose of the current investigation was to investigate and compare the responses to inhaled methacholine, ultrasonically
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