Acute health effects after exposure to chlorine gas released after a train derailment

A Pyrazine-Based Chromophore Photophysical Properties and its Detection for Hydrazine and Acid Vapors

Designed and synthesized linear pyrazine-based D-π-A-π-A probe is investigated to study the colorimetric and emission properties with different polarity index solvents. Their molar extinction coefficients were estimated for each solvent. This TLP probe was investigated in THF/water binary solution aggregates, and a redshifted AIE was observed reaching a water fraction of 70%. Also, this TLP probe was applied to the multifunctional, rapid, sensitive and selective detection of acid-base (TFA/TEA) and hydrazine (N2H4) in colorimetric and fluorimetric sensors. The pyrazine unit probe demonstrated an acidochromic effect and explored the acid-sensing behavior. The TLP probe containing malononitrile functional groups has extensively detected hazardous hydrazine species due to nucleophilic attack of hydrazine at the α-position of dicyano. This TLP probe allowed the quick and fast-sensitive detection of hydrazine hydride with a low detection limit of 1.08 nM. According to the results, the mechanism was confirmed by UV-Vis, PL, NMR and MS spectra for the detection of hydrazine, and further evidence of the protonation-deprotonation process in added TFA/TEA was made by titration studies by 1H NMR. Therefore, this work can be used for test strip kits for multifunction applications.

Hemopexin reverses activation of lung eIF2α and decreases mitochondrial injury in chlorine-exposed mice

We assessed the mechanisms by which nonencapsulated heme, released in the plasma of mice after exposure to chlorine (Cl2) gas, resulted in the initiation and propagation of acute lung injury. We exposed adult male and female C57BL/6 mice to Cl2 (500 ppm for 30 min), returned them to room air, and injected them intramuscularly with either human hemopexin (hHPX; 5 µg/g BW in 50-µL saline) or vehicle at 1 h post-exposure. Upon return to room air, Cl2-exposed mice, injected with vehicle, developed respiratory acidosis, increased concentrations of plasma proteins in the alveolar space, lung mitochondrial DNA injury, increased levels of free plasma heme, and major alterations of their lung proteome. hHPX injection mice mitigated the onset and development of lung and mitochondrial injury and the increase of plasma heme, reversed the Cl2-induced changes in 83 of 237 proteins in the lung proteome at 24 h post-exposure, and improved survival at 15 days post-exposure. Systems biology analysis of the lung global proteomics data showed that hHPX reversed changes in a number of key pathways including elF2 signaling, verified by Western blotting measurements. Recombinant human hemopexin, generated in tobacco plants, injected at 1 h post-Cl2 exposure, was equally effective in reversing acute lung and mtDNA injury. The results of this study offer new insights as to the mechanisms by which exposure to Cl2 results in acute lung injury and the therapeutic effects of hemopexin.NEW & NOTEWORTHY Herein, we demonstrate that exposure of mice to chlorine gas causes significant changes in the lung proteome 24 h post-exposure. Systems biology analysis of the proteomic data is consistent with damage to mitochondria and activation of eIF2, the master regulator of transcription and protein translation. Post-exposure injection of hemopexin, which scavenges free heme, attenuated mtDNA injury, eIF2α phosphorylation, decreased lung injury, and increased survival.

Recapitulation of human pathophysiology and identification of forensic biomarkers in a translational model of chlorine inhalation injury

Chlorine gas (Cl2) has been repeatedly used as a chemical weapon, first in World War I and most recently in Syria. Life-threatening Cl2 exposures frequently occur in domestic and occupational environments, and in transportation accidents. Modeling the human etiology of Cl2-induced acute lung injury (ALI), forensic biomarkers, and targeted countermeasures development have been hampered by inadequate large animal models. The objective of this study was to develop a translational model of Cl2-induced ALI in swine to understand toxico-pathophysiology and evaluate whether it is suitable for screening potential medical countermeasures and to identify biomarkers useful for forensic analysis. Specific pathogen-free Yorkshire swine (30-40 kg) of either sex were exposed to Cl2 (≤240 ppm for 1 h) or filtered air under anesthesia and controlled mechanical ventilation. Exposure to Cl2 resulted in severe hypoxia and hypoxemia, increased airway resistance and peak inspiratory pressure, and decreased dynamic lung compliance. Cl2 exposure resulted in increased total leucocyte and neutrophil counts in bronchoalveolar lavage fluid, vascular leakage, and pulmonary edema compared with the air-exposed group. The model recapitulated all three key histopathological features of human ALI, such as neutrophilic alveolitis, deposition of hyaline membranes, and formation of microthrombi. Free and lipid-bound 2-chlorofatty acids and chlorotyrosine-modified proteins (3-chloro-l-tyrosine and 3,5-dichloro-l-tyrosine) were detected in plasma and lung tissue after Cl2 exposure. In this study, we developed a translational swine model that recapitulates key features of human Cl2 inhalation injury and is suitable for testing medical countermeasures, and validated chlorinated fatty acids and protein adducts as biomarkers of Cl2 inhalation.NEW & NOTEWORTHY We established a swine model of chlorine gas-induced acute lung injury that exhibits several features of human acute lung injury and is suitable for screening potential medical countermeasures. We validated chlorinated fatty acids and protein adducts in plasma and lung samples as forensic biomarkers of chlorine inhalation.

Ophthalmic Manifestations of Chlorine Gas Exposure: What Do We Know So Far?

Chlorine gas is a hazardous substance that can cause severe health effects when inhaled or exposed to the skin. It is an odorless, colorless gas in many industrial and manufacturing settings and conflict areas. While exposure to chlorine gas is generally limited to the workplace and public areas, there are instances in which people may be exposed to high levels of chlorine gas for a short period of time due to spills, mishaps on the road or railroads, or other tragedies. In addition to the general health effects of chlorine gas, this essay will focus on the effects of chlorine gas on the eyes. The eyes are particularly sensitive to chlorine gas, and exposure can cause various symptoms, ranging from mild irritation to severe damage. Symptoms of chlorine gas exposure to the eyes include redness, burning, tearing, and blurred vision. In more serious cases, exposure to chlorine gas can cause permanent damage to the eyes, including corneal ulcers, scarring, and blindness. It is important to be aware of the signs and symptoms of chlorine gas exposure and the potential long-term effects to take the necessary steps to protect oneself. In addition to the potential health effects, it is important to understand the properties of chlorine gas. Chlorine gas is heavier than air and tends to settle in low-lying areas. It is highly reactive and can react with other substances to form hazardous compounds. As such, it is important to be aware of the potential for chlorine gas to react with other environmental substances and accumulate in certain areas. Finally, it is important to understand the background of chlorine gas use in various conflict areas. Chlorine gas has been used as a chemical weapon for centuries, and its use in modern warfare has been documented in various conflicts. As such, it is important to be aware of the potential for chlorine gas to be used in war zones and to take the necessary precautions to protect oneself. In conclusion, chlorine gas is a hazardous substance that can cause severe health effects when inhaled or exposed to the skin. The eyes are particularly sensitive to chlorine gas, and exposure can cause various symptoms, ranging from mild irritation to severe damage. It is important to be aware of the signs and symptoms of chlorine gas exposure and the potential long-term effects to take the necessary steps to protect oneself. Additionally, it is important to understand chlorine gas's properties and its background use in various conflict areas.

[The role of the pulmonologist in an armed conflict]

INTRODUCTION

Recent news points to the eventuality of an armed conflict on the national territory.

STATE OF THE ART

In this situation, pulmonologists will in all likelihood have a major role to assume in caring for the injured, especially insofar as chest damage is a major cause of patient death.

PERSPECTIVES

The main injuries that pulmonologists may be called upon to treat stem not only from explosions, but also from chemical, biological and nuclear hazards. In this article, relevant organizational and pedagogical aspects are addressed. Since exhaustiveness on this subject is unattainable, we are proposing training on specific subjects for interested practitioners.

CONCLUSION

The resilience of the French health system in a situation of armed conflict depends on the active participation of all concerned parties. With this in mind, it is of prime importance that the pneumological community be sensitized to the potential predictable severity of war-related injuries.

Human chlorine gas exposition and its management - an umbrella review on human data

Even though exposure to chlorine gas has been quite frequent in the past few decades, no specific antidotes exist. This umbrella review aimed to investigate possible recommendations for treatment after a chlorine gas exposure. A published systematic review protocol that adapted the existing Navigation Guide methodology was used for including studies without comparator. Using PubMed, Web of Science, Google scholar for all potentially relevant systematic reviews, two authors independently included papers and extracted data. The risk of bias and quality of evidence was assessed by two independent review teams blinded to each other. A qualitative summary of the study findings was conducted for this overview. There were a total of 31 studies, from 4 systematic reviews, that met the inclusion criteria, comprising 3567 reported cases, with only two studies with comparators. Six studies reported pre-hospital management of patients after exposure to chlorine gas. With respect to the treatment, the most used were oxygen therapy, endotracheal intubation, β2-agonists, and corticosteroids. This review found a high quality of evidence for the effectiveness of pre-hospital management (i.e. exposure cessation) on survival at hospital discharge after exposure to chlorine gas. Oxygen administration was effective with moderate quality of evidence, as well as other types of treatment (e.g. β2, corticosteroids), but with a low level of evidence. This umbrella review highlighted the low level of evidence for existing treatments of chlorine gas poisoning. This project was supported by the French Pays de la Loire region and Angers Loire Métropole (TEC-TOP project). There is no award/grant number. The review protocol was registered on PROSPERO under the registration number CRD42021231524.

Clinical Features and Outcomes of Acute Chlorine Gas Inhalation; a Brief Report

Introduction

On March 6^th,2020, chlorine gas leak was reported at Engro Polymer & Chemicals Plant in Karachi City, Pakistan. This study aimed to evaluate the clinical features and outcomes of patients who presented to emergency department (ED) following this event.

Methods

This retrospective cross-sectional study, evaluated the clinical features and outcomes (length of hospital stay, complications, and mechanical ventilation requirement) of patients presenting to ED of Aga Khan University Hospital, Karachi, Pakistan, with history of chlorine gas exposure at the Engro Plant from 6^th March to 14^th March 2020.

Results

38 patients with mean age of 33.1 ± 8.1 years presented to ED with history of chlorine gas exposure (100% male). 4 (10.5%) cases had comorbid diseases. Most common presenting symptom was dyspnea, observed in 33 (86.8%) cases, followed by cough, seen in 27 (71.1%) subjects. 13.2% (5/38) patients had infiltration on chest x-ray and 33 (86.8 %) required hospitalization. 6 (15.8%) patients had repeat presentation requiring hospitalization or ED visit. 18 (47.4%) were managed with high flow oxygen therapy, 9 (23.7%) required non-invasive ventilation and one patient was intubated due to development of pneumo-mediastinum. Mean length of stay was 1.55 ± 1.58 days and no patients died. Presence of tachycardia was the only finding significantly associated with need for oxygen (p = 0.033) and non-invasive ventilation (p = 0.012).

Conclusion

The majority of patients presenting with acute chlorine gas exposure showed good clinical outcomes and rapid recovery, however, a high index of suspicion and vigilance should be maintained for complications such as pneumomediastinum and acute respiratory distress syndrome in these patients.

Safety and toxicology assessment of sodium nitrite administered by intramuscular injection

Intramuscular (IM) injection of nitrite (1-10 mg/kg) confers survival benefit and protects against lung injury after exposure to chlorine gas in preclinical models. Herein, we evaluated safety/toxicity parameters after single, and repeated (once daily for 7 days) IM injection of nitrite in male and female Sprague Dawley rats and Beagle dogs. The repeat dose studies were performed in compliance with the Federal Drug Administration's (FDA) Good Laboratory Practices Code of Federal Regulations (21 CFR Part 58). Parameters evaluated consisted of survival, clinical observations, body weights, clinical pathology, plasma drug levels, methemoglobin and macroscopic and microscopic pathology. In rats and dogs, single doses of ≥100 mg/kg and 60 mg/kg resulted in death and moribundity, while repeated administration of ≤30 or ≤ 10 mg/kg/day, respectively, was well tolerated. Therefore, the maximum tolerated dose following repeated administration in rats and dogs were determined to be 30 mg/kg/day and 10 mg/kg/day, respectively. Effects at doses below the maximum tolerated dose (MTD) were limited to emesis (in dogs only) and methemoglobinemia (in both species) with clinical signs (e.g. blue discoloration of lips) being dose-dependent, transient and reversible. These signs were not considered adverse, therefore the No Observed Adverse Effect Level (NOAEL) for both rats and dogs was 10 mg/kg/day in males (highest dose tested for dogs), and 3 mg/kg/day in females. Toxicokinetic assessment of plasma nitrite showed no difference between male and females, with Cmax occurring between 5 mins and 0.5 h (rats) or 0.25 h (dogs). In summary, IM nitrite was well tolerated in rats and dogs at doses previously shown to confer protection against chlorine gas toxicity.

Effects of Two Chlorine Gas Attacks on Hospital Admission and Clinical Outcomes in Kafr Zita, Syria

Background In 2014, Hama Governorate was exposed twice to chlorine gas, with 15 patients presenting to Kafr Zita Hospital in Northwest Syria. This study aimed to describe clinical manifestations of chlorine gas exposure to identify factors leading to facility admission and the need for ICU/intubation in conflict-affected areas with limited healthcare infrastructure. Methods We conducted a case-series study, using medical records of suspected chlorine-exposed patients presenting at Kafr Zita Hospital on either 11 April or 22 May 2014. Data on age, sex, initial clinical presentation, therapeutic management, and outcome were compared by hospital admission/non-admission and attack date. All patients provided verbal informed consent. Results Fifteen patients with signs of chlorine gas exposure had detailed medical records. The mean age was 25.7 years (range 2-59), eight were male (53%), and three (20%) were under age 16. At initial presentation, all experienced respiratory distress, due to severe airway inflammation confirmed by nonspecific pulmonary infiltrates on chest x-ray, and similar intestinal, neurological, dermatological, ophthalmological, and psychological signs and symptoms. Acute management consisted of oxygen and bronchodilators for all patients, hydrocortisone (93%), antiemetics (80%), and dexamethasone (13%). Seven (47%) made a rapid symptomatic recovery and were discharged the same day and eight (53%) were admitted for a median of two days (range 1-6 days), one of whom required intubation and later died. The only significant associations found were higher mean pulse rate (i.e. 138 versus 124; p=0.043) and body temperature (37.0 versus 36.5; p=0.019) among admitted patients compared to non-admitted. Conclusion Our results demonstrated that even in low-resource humanitarian settings the survival rate for chlorine gas exposed patients is fair. Despite the small sample, this study provides insight into the clinical presentation, management, and outcomes of weaponized chlorine gas exposure, though further research is required to understand any chronic consequences.

Halogen-Induced Chemical Injury to the Mammalian Cardiopulmonary Systems

The halogens chlorine (Cl₂) and bromine (Br₂) are highly reactive oxidizing elements with widespread industrial applications and a history of development and use as chemical weapons. When inhaled, depending on the dose and duration of exposure, they cause acute and chronic injury to both the lungs and systemic organs that may result in the development of chronic changes (such as fibrosis) and death from cardiopulmonary failure. A number of conditions, such as viral infections, coexposure to other toxic gases, and pregnancy increase susceptibility to halogens significantly. Herein we review their danger to public health, their mechanisms of action, and the development of pharmacological agents that when administered post-exposure decrease morbidity and mortality.

Acute chlorine poisoning caused by an accident at a swimming pool

Chlorine is an irritant gas that is widely used in water purification. Several previous reports had reported accidents of inhalation injuries at swimming pools. However, there have been limited data on the detection of on-site chlorine concentration. This study aims to report a chlorine leakage accident at a swimming pool caused by improper disinfection operations. Calculation using the gas diffusion simulation software showed that the on-site chlorine concentration was 221.45 ppm. When the accident occurred, there were 92 individuals at the swimming pool and the gym, among which 61 were referred to the emergency department of five different hospitals for feeling ill. Among them, 22 patients underwent chest high-resolution computed tomography scans in our hospital. According to the findings, 4 (18.2%) patients had peribronchitis, 3 (13.6%) had tracheobronchitis, 4 (18.2%) had pneumonia, 4 (18.2%) had interstitial pulmonary edema, and 3 (13.6%) had alveolar pulmonary edema. The symptoms of 22 patients who visited our hospital significantly improved after comprehensive treatment. Three months after the accident, 8 of 17 patients presented obstructive ventilation defects or small airway dysfunction. The accidental exposure to chlorine may induce acute poisoning with various respiratory injuries and prolonged lung dysfunction.

Chlorine inhalation induces acute chest syndrome in humanized sickle cell mouse model and ameliorated by postexposure hemopexin

Triggering factors of Acute Chest Syndrome (ACS) is a leading cause of death in patients with Sickle Cell Disease (SCD) and targeted therapies are limited. Chlorine (Cl2) inhalation happens frequently, but its role as a potential trigger of ACS has not been determined. In this study, we hypothesized that Cl2 exposure resembling that in the vicinity of industrial accidents induces acute hemolysis with acute lung injury, reminiscent of ACS in humanized SCD mice. When exposed to Cl2 (500 ppm for 30 min), 64% of SCD mice succumbed within 6 h while none of the control mice expressing normal human hemoglobin died (p<0.01). Surviving SCD mice had evidence of acute hemolysis, respiratory acidosis, acute lung injury, and high concentrations of chlorinated palmitic and stearic acids (p<0.05) in their plasmas and RBCs compared to controls. Treatment with a single intraperitoneal dose of human hemopexin 30 min after Cl2 inhalation reduced mortality to around 15% (p<0.01) with reduced hemolysis (decreased RBCs fragility (p<0.001) and returned plasma heme to normal levels (p<0.0001)), improved oxygenation (p<0.0001) and reduced acute lung injury scores (p<0.0001). RBCs from SCD mice had significant levels of carbonylation (which predisposes RBCs to hemolysis) 6 h post-Cl2 exposure which were absent in RBCs of mice treated with hemopexin. To understand the mechanisms leading to carbonylation, we incubated RBCs from SCD mice with chlorinated lipids and identified sickling and increased hemolysis compared to RBCs obtained from control mice and treated similarly. Our study indicates that Cl2 inhalation induces ACS in SCD mice via induction of acute hemolysis, and that post exposure administration of hemopexin reduces mortality and lung injury. Our data suggest that SCD patients are vulnerable in Cl2 exposure incidents and that hemopexin is a potential therapeutic agent.

Development of an LC-MS/MS method for quantification of 3-chloro-L-tyrosine as a candidate marker of chlorine poisoning

A simple and sensitive liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for the determination of 3-chloro-L-tyrosine (Cl-Tyr) was developed and validated. For sample preparation, 50 μL of the body fluids or tissue extracts were processed by protein precipitation followed by the derivatization with dansyl chloride. The calibration curve was linear over the concentration range of 2.0-200 ng/mL blood or 4.0-400 ng/g tissue. Our method allowed the reproducible and accurate quantification. That is, the intra- and inter-assay coefficients of variation were below 7.73 and 6.94%, respectively in both the blood and lung. We applied the developed method to the analysis of Cl-Tyr in the human autopsy samples, which were suspected of chlorine poisoning, and detected 55.2 ng/mL and 206.6 ng/g Cl-Tyr in left heart blood and lung, respectively. Furthermore, in more than 20 autopsy samples, which were obtained from other causes of death including burn, drowning, hanging, internal disease, trauma and drug poisoning, Cl-Tyr was almost not detected in their both body fluids and organ tissues. In conclusion, the data here reported demonstrate that the LC/ESI-MS/MS method allows the Cl-Tyr in the autopsy samples and that chlorine exposure strongly affects its level, providing a basis for novel identification tool of chlorine poisoning.

Forensic issues arising in the assessment of chlorine-related deaths in a domestic setting

A retrospective review of autopsy files at the Forensic Science South Australia, Australia, was undertaken over a 20-year period from January 2000 to December 2019 for all cases where chlorine had caused or contributed to death. Two cases were identified out of a total of 25,121 autopsies (0.008%): a 53-year-old man who committed suicide in a cellar with granulated chlorine, and a 49-year-old woman with asthma who died of acute bronchospasm due to exposure to chlorine gas while mixing swimming pool chemicals in her kitchen. Chlorine-related deaths are uncommon in domestic situations. However, the absence of biomarkers and non-specific findings at autopsy complicate the diagnosis, particularly as environmental levels are not stable. While accidents with cleaning agents or swimming pool reagents are the most common event in the literature in domestic settings (exclusive of industrial or transportation accidents), suicide may also very rarely occur. Individuals with asthma and chronic respiratory diseases are at higher risk of an adverse outcome upon exposure to chlorine gas, with inattention to proper storage conditions and handling protocols being additional risk factors.

Development of chlorine-induced lung injury in the anesthetized, spontaneously breathing pig

Chlorine is a toxic industrial chemical produced in vast quantities globally, being used in a range of applications such as water purification, sanitation and industrial processes. Its use and transport cannot be restricted; exposure may occur following accidental or deliberate releases. The OPCW recently verified the use of chlorine gas against civilians in both Syria and Iraq. Chlorine inhalation produces damage to the lungs, which may result in the development of an acute lung injury, respiratory failure and death. Treatment remains an intractable problem. Our objective was to develop a clinically relevant pre-clinical model of a moderate to severe lung injury in the pig. This would enable future assessment of therapeutic drugs or interventions to be implemented in the pre-hospital phase after exposure. Due to the irritant nature of chlorine, a number of strategies for exposing terminally anesthetized pigs needed to be investigated. A number of challenges (inconsistent acute changes in respiratory parameters; early deaths), resulted in a moderate to severe lung injury not being achieved. However, most pigs developed a mild lung injury by 12 h. Further investigation is required to optimize the model and enable the assessment of therapeutic candidates. In this paper we describe the exposure strategies used and discuss the challenges encountered in establishing a model of chlorine-induced lung injury. A key aim is to assist researchers navigating the challenges of producing a clinically relevant model of higher dose chlorine exposure where animal welfare is protected by use of terminal anesthesia.

Chronic cardiac structural damage, diastolic and systolic dysfunction following acute myocardial injury due to bromine exposure in rats

Accidental bromine spills are common and its large industrial stores risk potential terrorist attacks. The mechanisms of bromine toxicity and effective therapeutic strategies are unknown. Our studies demonstrate that inhaled bromine causes deleterious cardiac manifestations. In this manuscript we describe mechanisms of delayed cardiac effects in the survivors of a single bromine exposure. Rats were exposed to bromine (600 ppm for 45 min) and the survivors were sacrificed at 14 or 28 days. Echocardiography, hemodynamic analysis, histology, transmission electron microscopy (TEM) and biochemical analysis of cardiac tissue were performed to assess functional, structural and molecular effects. Increases in right ventricular (RV) and left ventricular (LV) end-diastolic pressure and LV end-diastolic wall stress with increased LV fibrosis were observed. TEM images demonstrated myofibrillar loss, cytoskeletal breakdown and mitochondrial damage at both time points. Increases in cardiac troponin I (cTnI) and N-terminal pro brain natriuretic peptide (NT-proBNP) reflected myofibrillar damage and increased LV wall stress. LV shortening decreased as a function of increasing LV end-systolic wall stress and was accompanied by increased sarcoendoplasmic reticulum calcium ATPase (SERCA) inactivation and a striking dephosphorylation of phospholamban. NADPH oxidase 2 and protein phosphatase 1 were also increased. Increased circulating eosinophils and myocardial 4-hydroxynonenal content suggested increased oxidative stress as a key contributing factor to these effects. Thus, a continuous oxidative stress-induced chronic myocardial damage along with phospholamban dephosphorylation are critical for bromine-induced chronic cardiac dysfunction. These findings in our preclinical model will educate clinicians and public health personnel and provide important endpoints to evaluate therapies.

Lessons Learned From a Chlorine Gas Leakage in Dezful City, Iran

Dezful is the capital of Dezful County, a city in Khuzestan Province, Iran. On August 12, 2017, after a chlorine gas leakage in Dezful, more than 475 people were affected by chlorine gas, and they all suffered from respiratory complications. A lot of problems were encountered in the preparation of the relief forces and organization of the blueprint on how to respond to the incident, such as lack of knowledge on establishment of danger zone, lack of warning system, lack of proper triage and absence of decontamination plans, lack of special chemical safety outfit and respiratory equipment for rescuers, lack of instructions for proper handling, lack of knowledge in dealing with this type of disaster, and inappropriate evacuation skills and failure to cordon off and insure the location of the incident. Although the initial measures to arrest this crisis was performed based on the health system's instructions of the country with regard to all the possible risks, lack of a comprehensive inter-organizational program and prevention plans, lack of control plans, lack of adequate preparation and response to chemical poisoning, lack of foresight, lack of a risk plan, and lack of an intervention plan for these incidents were the reasons for the damages and problems encountered after the crisis.

Clinical Presentations and Outcomes of Industrial Chlorine Gas Exposure Incidence in Oman

OBJECTIVE

The main objective was to study different clinical presentations and outcomes of patients after acute industrial chlorine gas exposure in Oman with evaluation of overall incident management to help develop a chemical exposure incident protocol.

METHODS

This was a retrospective observational study of 15 patients exposed to chlorine gas after an accidental chlorine gas leak in a metal melting factory in Oman.

RESULTS

Six (40%) patients were admitted and nine (60%) patients were discharged from the emergency department (ED) after initial management. The important post-chlorine gas exposure clinical symptoms were eye irritation (66.6%), cough (73.3%), shortness of breath (40.0%), chest discomfort (66.6%), rhinorrhea (66.6%), dizziness (40.0%), vomiting (46.6%), sore throat (13.3%), and stridor (53.3%). Important signs included tachycardia (40.0%), tachypnea (40.0%), wheeze (20.0%), and use of accessory muscles for breathing (20.0%). Signs and symptoms of eye irritation, rhinorrhea, tachycardia, tachypnea, wheeze, and use of accessory muscles for breathing have shown significant correlation with outcome (admission) having P value of <.05.

CONCLUSION

In the presented acute chlorine gas exposure incidence, 15 exposed persons were brought to the ED, out of which six were admitted and nine were discharged after symptomatic treatment. Signs and symptoms of eye irritation, rhinorrhea, tachycardia, tachypnea, wheeze, and use of accessory muscles of breathing show significant relation with the outcome of admission.

Disease-modifying treatment of chemical threat agent-induced acute lung injury

Acute respiratory distress syndrome (ARDS) is a highly morbid lung pathology induced by exposure to chemical warfare agents, including vesicants, phosgene, chlorine, and ricin. In this review, we describe the pathology associated with the development of ARDS in humans and experimental models of acute lung injury following animal exposure to these high-priority threat agents. Potential future approaches to disease-modifying treatment used in preclinical animal studies, including antioxidants, anti-inflammatories, biologics, and mesenchymal stem cells, are also described. As respiratory pathologies, including ARDS, are the major cause of morbidity and mortality following exposure to chemical threat agents, understanding mechanisms of disease pathogenesis is key to the development of efficacious therapeutics beyond the primary intervention principle, which remains mechanical ventilation.

Transient receptor potential channels in pulmonary chemical injuries and as countermeasure targets

The lung is highly sensitive to chemical injuries caused by exposure to threat agents in industrial or transportation accidents, occupational exposures, or deliberate use as weapons of mass destruction (WMD). There are no antidotes for the majority of the chemical threat agents and toxic inhalation hazards despite their use as WMDs for more than a century. Among several putative targets, evidence for transient receptor potential (TRP) ion channels as mediators of injury by various inhalational chemical threat agents is emerging. TRP channels are expressed in the respiratory system and are essential for homeostasis. Among TRP channels, the body of literature supporting essential roles for TRPA1, TRPV1, and TRPV4 in pulmonary chemical injuries is abundant. TRP channels mediate their function through sensory neuronal and nonneuronal pathways. TRP channels play a crucial role in complex pulmonary pathophysiologic events including, but not limited to, increased intracellular calcium levels, signal transduction, recruitment of proinflammatory cells, neurogenic inflammatory pathways, cough reflex, hampered mucus clearance, disruption of the integrity of the epithelia, pulmonary edema, and fibrosis. In this review, we summarize the role of TRP channels in chemical threat agents-induced pulmonary injuries and how these channels may serve as medical countermeasure targets for broader indications.

Hyaluronan and halogen-induced airway hyperresponsiveness and lung injury

Chlorine (Cl2 ) and bromine (Br2 ) are produced in large quantities throughout the world and used in the industry and the sanitation of water. These halogens can pose a significant threat to public health when released into the atmosphere during transportation and industrial accidents, or as acts of terrorism. In this review, we discuss the evidence showing that the activity of Cl2 and Br2 , and of products formed by their interaction with biomolecules, fragment high-molecular-weight hyaluronan (HMW-HA), a key component of the interstitial space and present in epithelial cells, to form proinflammatory, low-molecular-weight hyaluronan fragments that increase intracellular calcium (Ca2+ ) and activate RAS homolog family member A (RhoA) in airway smooth muscle and epithelial and microvascular cells. These changes result in airway hyperresponsiveness (AHR) to methacholine and increase epithelial and microvascular permeability. The increase in intracellular Ca2+ is the result of the activation of the calcium-sensing receptor by Cl2 , Br2 , and their by-products. Posthalogen administration of a commercially available form of HMW-HA to mice and to airway cells in vitro reverses the increase of Ca2+ and the activation of RhoA, and restores AHR to near-normal levels of airway function. These data have established the potential of HMW-HA to be a countermeasure against Cl2 and Br2 toxicity.

Histone H4 aggravates inflammatory injury through TLR4 in chlorine gas-induced acute respiratory distress syndrome

Background

Chlorine gas (Cl₂) exposure remains a public health concern in household, occupational, and transportation accidents around the world. The death rate associated with acute respiratory distress syndrome (ARDS) caused by high concentrations of Cl₂ is very high, mainly because the pathogenesis of ARDS remains unclear. Histone H4 has been identified as an important endogenous pro-inflammatory molecule. The present study aimed to examine the pathogenic role of histone H4 in Cl₂-induced ARDS.

Methods

ARDS was induced by Cl₂ exposure in male C57BL/6 mice. Circulating histone H4, blood gas, pulmonary edema, endothelial activation, and neutrophil infiltration were measured during acute lung injury (ALI). Histone H4 or anti-H4 antibody was administered through the tail vein 1 h prior to Cl₂ exposure to study the pathogenic role of histone H4. Toll-like receptor 2 knock-out (Tlr2-KO) and Tlr4-KO mice were used in conjunction with blocking antibody against TLR1, TLR2, TLR4, or TLR6 to explore the mechanism involved in histone H4-mediated injury.

Results

Cl₂ exposure induced a concentration-dependent ALI. The levels of circulating histone H4 were positively correlated with Cl₂ concentrations. Pretreatment with intravenous histone H4 further aggravated lethality rate, blood gas, endothelial activation, and neutrophil infiltration, while anti-H4 antibody showed protective effects. Tlr4 deficiency improved lethality rate, blood gas, and pulmonary edema, and prevented endothelial and neutrophil activation caused by Cl₂ exposure. More importantly, Tlr4 gene deletion greatly diminished the effect of histone H4 or anti-H4 antibody observed in wild-type (WT) mice. The impact of Tlr2 on inflammatory injury was not significant. The role of TLRs was also validated by endothelial activation mediated by histone H4 in vitro.

Conclusions

Circulating histone H4 played a pro-inflammatory role in ARDS caused by Cl₂. TLR4 was closely involved in histone H4-mediated inflammatory injury. Therefore, intervention targeting histone H4 is potentially protective.

Halogen exposure injury in the developing lung

Owing to a high-volume industrial usage of the halogens chlorine (Cl₂ ) and bromine (Br₂ ), they are stored and transported in abundance, creating a risk for accidental or malicious release to human populations. Despite extensive efforts to understand the mechanisms of toxicity upon halogen exposure and to develop specific treatments that could be used to treat exposed individuals or large populations, until recently, there has been little to no effort to determine whether there are specific features and or the mechanisms of halogen exposure injury in newborns or children. We established a model of neonatal halogen exposure and published our initial findings. In this review, we aim to contrast and compare the findings in neonatal mice exposed to Br₂ with the findings published on adult mice exposed to Br₂ and the neonatal murine models of bronchopulmonary dysplasia. Despite remarkable similarities across these models in overall alveolar architecture, there are distinct functional and apparent mechanistic differences that are characteristic of each model. Understanding the mechanistic and functional features that are characteristic of the injury process in neonatal mice exposed to halogens will allow us to develop countermeasures that are appropriate for, and effective in, this unique population.

Alleviation of methyl isocyanate-induced airway obstruction and mortality by tissue plasminogen activator

Methyl isocyanate (MIC, "Bhopal agent") is a highly reactive, toxic industrial chemical. Inhalation of high levels (500-1000 ppm) of MIC vapor is almost uniformly fatal. No therapeutic interventions other than supportive care have been described that can delay the onset of illness or death due to MIC. Recently, we found that inhalation of MIC caused the appearance of activated tissue factor in circulation with subsequent activation of the coagulation cascade. Herein, we report that MIC exposure (500 ppm for 30 min, nose-only) caused deposition of fibrin-rich casts in the conducting airways resulting in respiratory failure and death within 24 h in a rat model (LC_90-100 ). We thus investigated the effect of airway delivery of the fibrinolytic agent tissue plasminogen activator (tPA) on mortality and morbidity in this model. Intratracheal administration of tPA was initiated 11 h post MIC exposure and repeated every 4 h for the duration of the study. Treatment with tPA afforded nearly 60% survival at 24 h post MIC exposure and was associated with decreased airway fibrin casts, stabilization of hypoxemia and respiratory distress, and improved acidosis. This work supports the potential of airway-delivered tPA therapy as a useful countermeasure in stabilizing victims of high-level MIC exposure.

Chemical Disaster Preparedness for Hospitals and Emergency Departments

Preparing to evaluate and treat victims of a chemical exposure incident is one aspect of hospital disaster preparedness. Past chemical disasters, including terrorist attacks and industrial or transit accidents, have highlighted the need for hospital planning, preparation, and training. Emergency department and hospital staff members must be familiar with their facility-specific protocols and be trained for their individual roles during these incidents. This article provides a brief review of the requirements and guidelines related to chemical disaster response from a healthcare perspective. Resources for training and the evaluation of chemically contaminated patients are discussed. Decontamination procedures, including pre-hospital and hospital-based decontamination of ambulatory, non-ambulatory, and at-risk patients are also reviewed. Physicians and clinicians, especially in the emergency department, must be familiar with methods of evaluating chemical exposures, identifying substances, recognizing toxidromes, ensuring appropriate personal protective equipment (PPE) use, performing decontamination, and initiating treatments for life-threatening conditions. By understanding the guidelines and resources available, clinicians will be better equipped to safely evaluate and treat chemically exposed or contaminated patients.

TRPA1 and issues relating to animal model selection for extrapolating toxicity data to humans

The transient receptor potential ankyrin 1 (TRPA1) ion channel is a sensor for irritant chemicals, has ancient lineage, and is distributed across animal species including humans, where it features in many organs. Its activation by a diverse panel of electrophilic molecules (TRPA1 agonists) through electrostatic binding and/or covalent attachment to the protein causes the sensation of pain. This article reviews the species differences between TRPA1 channels and their responses, to assess the suitability of different animals to model the effects of TRPA1-activating electrophiles in humans, referring to common TRPA1 activators (exogenous and endogenous) and possible mechanisms of action relating to their toxicology. It concludes that close matching of in vitro and in vivo models will help optimise the identification of relevant biochemical and physiological responses to benchmark the efficacy of potential therapeutic drugs, including TRPA1 antagonists, to counter the toxic effects of those electrophiles capable of harming humans. The analysis of the species issue provided should aid the development of medical treatments to counter poisoning by such chemicals.

Toxic effects of chlorine gas and potential treatments: a literature review

Chlorine gas is one of the highly produced chemicals in the USA and around the world. Chlorine gas has several uses in water purification, sanitation, and industrial applications; however, it is a toxic inhalation hazard agent. Inhalation of chlorine gas, based on the concentration and duration of the exposure, causes a spectrum of symptoms, including but not limited to lacrimation, rhinorrhea, bronchospasm, cough, dyspnea, acute lung injury, death, and survivors develop signs of pulmonary fibrosis and reactive airway disease. Despite the use of chlorine gas as a chemical warfare agent since World War I and its known potential as an industrial hazard, there is no specific antidote. The resurgence of the use of chlorine gas as a chemical warfare agent in recent years has brought speculation of its use as weapons of mass destruction. Therefore, developing antidotes for chlorine gas-induced lung injuries remains the need of the hour. While some of the pre-clinical studies have made substantial progress in the understanding of chlorine gas-induced pulmonary pathophysiology and identifying potential medical countermeasure(s), yet none of the drug candidates are approved by the U.S. Food and Drug Administration (FDA). In this review, we summarized pathophysiology of chlorine gas-induced pulmonary injuries, pre-clinical animal models, development of a pipeline of potential medical countermeasures under FDA animal rule, and future directions for the development of antidotes for chlorine gas-induced lung injuries.

Chemical pneumonitis in a 9-year-old following chlorine gas exposure

A previously fit and well 9-year-old boy developed shortness of breath and chest pain after playing with friends on a building site where bonfire materials were being collected. Firstline investigations failed to explain his symptoms, which worsened over the next 24 hours, necessitating endotracheal intubation and mechanical ventilation. When public health and the police retraced his steps, they found barrels of sodium hypochlorite and red diesel at the bonfire site, which when mixed had the potential to form chlorine gas leading to the diagnosis of a chemical pneumonitis secondary to chlorine gas inhalation. Supportive care was continued, and he was successfully extubated after 48 hours. At 6-week follow-up, he had no ongoing pulmonary symptoms.

Chemical Agents in Disaster: Care and Management in the Intensive Care Unit

Chemical agents of warfare are divided into lung agents, blood agents, vesicants, and nerve agents. Intensivists must familiarize themselves with the clinical presentation and management principles in the event of a chemical attack. Key principles in management include aggressive supportive care and early administration of specific antidotes, if available. Management includes proper personal protection for critical care providers. Patients may make complete recovery with aggressive supportive care, even if they appear to have a poor prognosis. Hospitals must have an emergency response disaster plan in place to deal with all potential causes of disasters, including illnesses resulting from chemical agents.

Temporal Trends in Cardiovascular Hospital Discharges Following a Mass Chlorine Exposure Event in Graniteville, South Carolina

Background: On January 6, 2005, a train derailed in Graniteville, South Carolina, releasing nearly 60,000 kg of toxic chlorine gas. The disaster left nine people dead and was responsible for hundreds of hospitalizations and outpatient visits in the subsequent weeks. While chlorine gas primarily affects the respiratory tract, a growing body of evidence suggests that acute exposure may also cause vascular injury and cardiac toxicity. Here, we describe the incidence of cardiovascular hospitalizations among residents of the zip codes most affected by the chlorine gas plume, and compare the incidence of cardiovascular discharges in the years leading up to the event (2000–2004) to the incidence in the years following the event (2005–2014).

Methods: De-identified hospital discharge information was collected from the South Carolina Revenue and Fiscal Affairs Office for individuals residing in the selected zip codes for the years 2000 to 2014. A quasi-experimental study design was utilized with a population-level interrupted time series model to examine hospital discharge rates for Graniteville-area residents for three cardiovascular diagnoses: hypertension (HTN), acute myocardial infarction (AMI), and coronary heart disease (CHD). We used linear regression with autoregressive error correction to compare slopes for pre- and post-spill time periods. Data from the 2000 and 2010 censuses were used to calculate rates and to provide information on potential demographic shifts over the course of the study.

Results: A significant increase in hypertension-related hospital discharge rates was observed for the years following the Graniteville chlorine spill (slope 8.2, p < 0.001). Concurrent changes to CHD and AMI hospital discharge rates were in the opposite direction (slopes −3.2 and −0.3, p < 0.01 and 0.14, respectively). Importantly, the observed trend cannot be attributed to an aging population.

Conclusions: An unusual increase in hypertension-related hospital discharge rates in the area affected by the Graniteville chlorine spill contrasts with national and state-level trends. A number of factors related to the spill may be contributing the observation: disaster-induced hypertension, healthcare services access issues, and, possibly, chlorine-induced susceptibility to vascular pathologies. Due to the limitations of our data, we cannot determine whether the individuals who visited the hospital were the ones exposed to chlorine gas, however, the finding warrants additional research. Future studies are needed to determine the etiology of the increase and whether individuals exposed to chlorine are at a heightened risk for hypertensive heart disease.

Emergency management of chlorine gas exposure - a systematic review

INTRODUCTION

Chlorine exposure can lead to pulmonary obstruction, reactive airway dysfunction syndrome, acute respiratory distress syndrome and, rarely, death.

OBJECTIVE

We performed a systematic review of published animal and human data regarding the management of chlorine exposure.

METHODS

Three databases were searched from 2007 to 2017 using the following keywords "("chlorine gas" OR "chlorine-induced" OR" chlorine-exposed") AND ("therapy" OR "treatment" OR "post-exposure")". Forty-five relevant papers were found: 22 animal studies, 6 reviews, 19 case reports and 1 human randomized controlled study. General management: Once the casualty has been removed from the source of exposure and adequately decontaminated, chlorine-exposed patients should receive supportive care. Humidified oxygen: If dyspnea and hypoxemia are present, humidified oxygen should be administered. Inhaled bronchodilators: The use of nebulized or inhaled bronchodilators to counteract bronchoconstriction is standard therapy, and the combination of ipratropium bromide with beta₂-agonists effectively reversed bronchoconstriction, airway irritation and increased airway resistance in experimental studies. Inhaled sodium bicarbonate: In a randomized controlled trial, humidified oxygen, intravenous prednisolone and inhaled salbutamol were compared with nebulized sodium bicarbonate. The only additional benefit of sodium bicarbonate was to increase the forced expiratory volume in one second, 2 and 4 h after administration. Corticosteroids: Dexamethasone 100 mg/kg intraperitoneally (IP) reduced lung edema when given within 1 h of chlorine inhalation and when administered within 6 h significantly decreased (p < 0.01) the leukocyte count in the bronchoalveolar lavage (BAL). As corticosteroids were never given alone in clinical studies, it is impossible to assess whether they had an additional beneficial effect. Antioxidants: An ascorbic acid/deferoxamine combination (equivalent to 100 mg/kg and 15 mg/kg, respectively) was administered intramuscularly 1 h after chlorine exposure, then every 12 h up to 60 h, then as an aerosol, and produced a significant reduction (p < 0.05) in BAL leukocytes and a significant reduction (p < 0.007) in mortality at 72 h. The single clinical case reported was uninterpretable. Sodium nitrite: Sodium nitrite 10 mg/kg intramuscularly (IM), 30 min post-chlorine exposure in mice and rabbits significantly reduced (p < 0.01) the number of leukocytes and the protein concentration in BAL and completely reversed mortality in rabbits and decreased mortality by about 50% in mice. No clinical studies have reported the use of sodium nitrite. Dimethylthiourea: Dimethylthiourea 100 mg/kg IP significantly decreased (p < 0.05) lymphocytes and neutrophils in BAL fluid 24 h after chlorine exposure in experimental studies. No clinical studies have been undertaken. AEOL 10150: Administration of AEOL10150 5 mg/kg IP at 1 h and 9 h post-chlorine exposure reduced significantly the neutrophil (p < 0.001) and macrophage (p < 0.05) bronchoalveolar cell counts. Transient receptor potential vanilloid 4 (TRPV4): IM or IP TRPV4 reduced significantly (p < 0.001) bronchoalveolar neutrophil and macrophage counts to baseline at 24 h. No clinical studies have been performed. Reparixin and triptolide: In experimental studies, triptolide 100-1000 µg/kg IP 1 h post-exposure caused a significant decrease (p < 0.001) in bronchoalveolar neutrophils, whereas reparixin 15 mg/kg IP 1 h post-exposure produced no benefit. Rolipram: Nanoemulsion formulated rolipram administered intramuscularly returned airway resistance to baseline. Rolipram (40%)/poly(lactic-co-glycolic acid) (60%) 0.36 mg/mouse given intramuscularly 1 h post-exposure significantly reduced (p < 0.05) extravascular lung water by 20% at t + 6 h. Prophylactic antibiotics: Studies in patients have failed to demonstrate benefit. Sevoflurane: Sevoflurane has been used in one intubated patient in addition to beta₂-agonists. Although the peak inspiratory pressure was decreased after 60 min, the role of sevofluorine is not known.

CONCLUSIONS

Various therapies seem promising based on animal studies or case reports. However, these recommendations are based on low-level quality data. A systematic list of outcomes to monitor and improve may help to design optimal therapeutic protocols to manage chlorine-exposed patients.

Inhibition of chlorine-induced airway fibrosis by budesonide

Chlorine is a chemical threat agent that can be harmful to humans. Acute inhalation of high levels of chlorine results in the death of airway epithelial cells and can lead to persistent adverse effects on respiratory health, including airway remodeling and hyperreactivity. We previously developed a mouse chlorine exposure model in which animals developed inflammation and fibrosis in large airways. In the present study, examination by laser capture microdissection of developing fibroproliferative lesions in FVB/NJ mice exposed to 240 ppm-h chlorine revealed upregulation of genes related to macrophage function. Treatment of chlorine-exposed mice with the corticosteroid drug budesonide daily for 7 days (30-90 μg/mouse i.m.) starting 1 h after exposure prevented the influx of M2 macrophages and the development of airway fibrosis and hyperreactivity. In chlorine-exposed, budesonide-treated mice 7 days after exposure, large airways lacking fibrosis contained extensive denuded areas indicative of a poorly repaired epithelium. Damaged or poorly repaired epithelium has been considered a trigger for fibrogenesis, but the results of this study suggest that inflammation is the ultimate driver of fibrosis in our model. Examination at later times following 7-day budesonide treatment showed continued absence of fibrosis after cessation of treatment and regrowth of a poorly differentiated airway epithelium by 14 days after exposure. Delay in the start of budesonide treatment for up to 2 days still resulted in inhibition of airway fibrosis. Our results show the therapeutic potential of budesonide as a countermeasure for inhibiting persistent effects of chlorine inhalation and shed light on mechanisms underlying the initial development of fibrosis following airway injury.

Fatal chlorine gas exposure at a metal recycling facility: Case report

At least four workers at a metal recycling facility were hospitalized and one died after exposure to chlorine gas when it was accidentally released from an intact, closed-valved cylinder being processed for scrap metal. This unintentional chlorine gas release marks at least the third such incident at a metal recycling facility in the United States since 2010. We describe the fatal case of the worker whose clinical course was consistent with acute respiratory distress syndrome (ARDS) following exposure to high concentrations of chlorine gas. This case report emphasizes the potential risk of chlorine gas exposure to metal recycling workers by accepting and processing intact, closed-valved containers. The metal recycling industry should take steps to increase awareness of this established risk to prevent future chlorine gas releases. Additionally, public health practitioners and clinicians should be aware that metal recycling workers are at risk for chlorine gas exposure.

Halogen Inhalation-Induced Lung Injury and Acute Respiratory Distress Syndrome

OBJECTIVE

Exposure to halogens, such as chlorine or bromine, results in environmental and occupational hazard to the lung and other organs. Chlorine is highly toxic by inhalation, leading to dyspnea, hypoxemia, airway obstruction, pneumonitis, pulmonary edema, and acute respiratory distress syndrome (ARDS). Although bromine is less reactive and oxidative than chlorine, inhalation also results in bronchospasm, airway hyperresponsiveness, ARDS, and even death. Both halogens have been shown to damage the systemic circulation and result in cardiac injury as well. There is no specific antidote for these injuries since the mechanisms are largely unknown.

DATA SOURCES

This review was based on articles published in PubMed databases up to January, 2018, with the following keywords: "chlorine," "bromine," "lung injury," and "ARDS."

STUDY SELECTION

The original articles and reviews including the topics were the primary references.

RESULTS

Based on animal studies, it is found that inhaled chlorine will form chlorine-derived oxidative products that mediate postexposure toxicity; thus, potential treatments will target the oxidative stress and inflammation induced by chlorine. Antioxidants, cAMP-elevating agents, anti-inflammatory agents, nitric oxide-modulating agents, and high-molecular-weight hyaluronan have shown promising effects in treating acute chlorine injury. Elevated free heme level is involved in acute lung injury caused by bromine inhalation. Hemopexin, a heme-scavenging protein, when administered postexposure, decreases lung injury and improves survival.

CONCLUSIONS

At present, there is an urgent need for additional research to develop specific therapies that target the basic mechanisms by which halogens damage the lungs and systemic organs.

Difficulties in interpretation when assessing prolonged and subacute exposure to the toxic effects of chlorine

The purpose of this study was a toxicological interpretation of exposure to chlorine with unusual course. Medical, clinical and court records, as well as reviews of the literature, served as the basis for this interpretation. The first case of poisoning concerns a 52-year-old man who for a short time (probably several hours), during the industrial cleaning of facilities with sodium hypochlorite, was exposed to chlorine in a presumed high concentration. The man was obese and suffered from hypertension and moderate atherosclerosis, and therefore could be more susceptible to the toxic effects of chlorine. After exposure no pulmonary edema or symptoms typical for acute respiratory distress syndrome were present. The second case concerns the chronic poisoning of a 56-year-old man who worked for eight years, 8 h a day, 5 days a week, in a room which was next to a chlorination room. In this chamber technical sodium hypochlorite was stored and dosed. In both cases, determining a cause and effect relationship between exposure to toxic and allergic agents in the form of active chlorine, and the onset of symptoms may be difficult. The findings described above in the first and second case are particularly important in cases of compensation claims and may have a completely different etiology than previously described in medical literature.

Asthma prevalence and school-related hazardous air pollutants in the US-México border area

BACKGROUND

Asthma is the most common chronic disease in children and has been linked to high levels of ambient air pollution and certain hazardous air pollutants (HAPs). Outdoor pollutants such as benzene, released by car emissions, and organic chemicals found in diesel exhaust, as well as particles and irritant gases, including nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃), contribute to an increased prevalence of respiratory diseases such as asthma.

OBJECTIVES

The objectives of this study were to: 1) conduct a screening survey to identify high risk for asthma among school-age children in Hidalgo County, and, 2) study the potential health impact of school-related exposure to HAPs pertaining to asthma risk.

METHODS

We carried out a quantitative cross-sectional study combining a school-based asthma screening survey across 198 schools in Hidalgo County, Texas, with information on school neighborhood environments, including census tract-level information on hazardous air pollutants (HAPs) and socioeconomic status (SES) in the respective school neighborhoods. HAPs levels were assessed based on the EPA 2011 National-Scale Air Toxics Assessment (NATA) while SES information was assessed using data from the 2010-2014 American Community Survey.

RESULTS

2930 students completed the asthma screening survey and results showed an overall asthma prevalence of 9.4%, slightly higher than the national and state prevalence. Participants in the 14-18 years old age group showed a much higher asthma prevalence of 16.7%. When assessing school-neighborhood characteristics, our results revealed no significant differences in asthma prevalence across census tracts with different SES levels. For HAPs, in the single-pollutant model, chlorine levels showed a significant linear trend for prevalence of asthma (p=0.03) while hydrochloric acid had a marginally significant linear trend (p=0.08). The association with chlorine remained significant in the multi-pollutant model.

CONCLUSIONS

Asthma prevalence among school-age children in Hidalgo County, Texas, is 9.4%, which is slightly higher than the state rate, especially among young adults, ages 14-18 years who had an asthma rate of 16.7%. Results support an association between exposures to school-neighborhood HAPs and risk for pediatric asthma, especially as related to chlorine. No significant effects of school-level SES on asthma risk were observed.

Oxygen Administration Improves Survival but Worsens Cardiopulmonary Functions in Chlorine-exposed Rats

Chlorine is a highly reactive gas that can cause significant injury when inhaled. Unfortunately, its use as a chemical weapon has increased in recent years. Massive chlorine inhalation can cause death within 4 hours of exposure. Survivors usually require hospitalization after massive exposure. No countermeasures are available for massive chlorine exposure and supportive-care measures lack controlled trials. In this work, adult rats were exposed to chlorine gas (LD_58-67) in a whole-body exposure chamber, and given oxygen (0.8 Fi_O2) or air (0.21 Fi_O2) for 6 hours after baseline measurements were obtained. Oxygen saturation, vital signs, respiratory distress and neuromuscular scores, arterial blood gases, and hemodynamic measurements were obtained hourly. Massive chlorine inhalation caused severe acute respiratory failure, hypoxemia, decreased cardiac output, neuromuscular abnormalities (ataxia and hypotonia), and seizures resulting in early death. Oxygen improved survival to 6 hours (87% versus 42%) and prevented observed seizure-related deaths. However, oxygen administration worsened the severity of acute respiratory failure in chlorine-exposed rats compared with controls, with increased respiratory acidosis (pH 6.91 ± 0.04 versus 7.06 ± 0.01 at 2 h) and increased hypercapnia (180.0 ± 19.8 versus 103.2 ± 3.9 mm Hg at 2 h). In addition, oxygen did not improve neuromuscular abnormalities, cardiac output, or respiratory distress associated with chlorine exposure. Massive chlorine inhalation causes severe acute respiratory failure and multiorgan damage. Oxygen administration can improve short-term survival but appears to worsen respiratory failure, with no improvement in cardiac output or neuromuscular dysfunction. Oxygen should be used with caution after massive chlorine inhalation, and the need for early assisted ventilation should be assessed in victims.

Data Capture and Analysis of Signs and Symptoms in a Chemically Exposed Population

This manuscript provides a practical case study to demonstrate data collection from paper-based medical records so that the occurrence of specific signs/symptoms indicative of a chemical exposure can be studied.

Comparison of airway response in naïve and ovalbumin-sensitized mice during short-term inhalation exposure to chlorine

OBJECTIVE

It has been suggested that asthmatics are more susceptible than healthy individuals to airborne irritating chemicals in general. However, there is limited human data available to support this hypothesis due to ethical and practical difficulties. We explored a murine model of ovalbumin (OVA)-induced airway inflammation to study susceptibility during acute exposure to chemicals with chlorine as a model substance.

METHODS

Naïve and OVA sensitized female BALB/c mice were exposed to chlorine at four different concentrations (0, 5, 30 and 80 ppm) for 15 minutes with online recording of the respiratory function by plethysmography. The specific effects on respiratory mechanics, inflammatory cells and inflammatory mediators (cytokines and chemokines) of the airways were measured 24 hours after the chlorine exposure as well as histopathological examination of the lungs.

RESULTS

Similar concentration-dependent reductions in respiratory frequency were seen in the two groups, with a 50% reduction (RD₅₀) slightly above 5 ppm. Decreased body weight 24 hours after exposure to 80 ppm was also observed in both groups. Naïve, but not OVA-sensitized, mice showed increased bronchial reactivity and higher number of neutrophils in bronchoalveolar lavage fluid at 80 ppm.

CONCLUSIONS

The results do not support an increased susceptibility to chlorine among OVA-sensitized mice. This animal model, which represents a phenotype of eosinophilic airway inflammation, seems unsuitable to study susceptibility to inhalation of irritants in relation to asthma.

Montelukast reduces inhaled chlorine triggered airway hyperresponsiveness and airway inflammation in the mouse

BACKGROUND AND PURPOSE

Cysteinyl leukotrienes (CysLTs) are pro-inflammatory lipid mediators that exacerbate disease state in several asthma phenotypes including asthma induced by allergen, virus and exercise. However, the role of CysLTs in irritant-induced airway disease is not well characterized. The purpose of the current study was to investigate the effect of montelukast, a CysLT1 receptor antagonist, on parameters of irritant-induced asthma induced by inhalation of chlorine in the mouse.

EXPERIMENTAL APPROACH

BALB/c mice were exposed to chlorine in air (100 ppm, for 5 min). Montelukast (3 mg·kg-1 ) or the vehicle (1% methylcellulose) was administered 24 and 1 h prior to chlorine exposure and 1 h prior to outcome measurements. Twenty-four hours after exposure, responses to inhaled aerosolized methacholine, cell composition and an array of cytokines/chemokines in bronchoalveolar lavage (BAL) fluid were measured. Neutralizing antibodies against IL-6 and VEGF were administered prior to exposures.

KEY RESULTS

Montelukast reduced chlorine -induced airway hyperresponsiveness (AHR) to methacholine in the peripheral lung compartment as estimated from dynamic elastance, but not in large conducting airways. Montelukast treatment attenuated chlorine-induced macrophage influx, neutrophilia and eosinophilia in BAL fluid. Chlorine exposure increased VEGF, IL-6, the chemokines KC and CCL3 in BAL fluid. Montelukast treatment prevented chlorine-induced increases in VEGF and IL-6. Anti-IL-6 antibody inhibited chlorine-induced neutrophilia and reduced AHR.

CONCLUSIONS AND IMPLICATIONS

Pre-treatment with montelukast attenuated chlorine-induced neutrophilia and AHR in mice. These effects are mediated, in part, via IL-6.

An Official American Thoracic Society Workshop Report: Chemical Inhalational Disasters. Biology of Lung Injury, Development of Novel Therapeutics, and Medical Preparedness

This report is based on the proceedings from the Inhalational Lung Injury Workshop jointly sponsored by the American Thoracic Society (ATS) and the National Institutes of Health (NIH) Countermeasures Against Chemical Threats (CounterACT) program on May 21, 2013, in Philadelphia, Pennsylvania. The CounterACT program facilitates research leading to the development of new and improved medical countermeasures for chemical threat agents. The workshop was initiated by the Terrorism and Inhalational Disasters Section of the Environmental, Occupational, and Population Health Assembly of the ATS. Participants included both domestic and international experts in the field, as well as representatives from U.S. governmental funding agencies. The meeting objectives were to (1) provide a forum to review the evidence supporting current standard medical therapies, (2) present updates on our understanding of the epidemiology and underlying pathophysiology of inhalational lung injuries, (3) discuss innovative investigative approaches to further delineating mechanisms of lung injury and identifying new specific therapeutic targets, (4) present promising novel medical countermeasures, (5) facilitate collaborative research efforts, and (6) identify challenges and future directions in the ongoing development, manufacture, and distribution of effective and specific medical countermeasures. Specific inhalational toxins discussed included irritants/pulmonary toxicants (chlorine gas, bromine, and phosgene), vesicants (sulfur mustard), chemical asphyxiants (cyanide), particulates (World Trade Center dust), and respirable nerve agents.

Knowledge and Attitude of Iranian Red Crescent Society Volunteers in Dealing with Chemical Attacks

OBJECTIVE

To evaluate the knowledge, attitude, and preparedness of Mahabad Red Crescent Society volunteers in dealing with chemical attacks.

METHODS

This prospective cross-sectional study was conducted on 120 Red Crescent Society volunteers in Mahabad City, Iran, during 2014-2015.The knowledge of the volunteers was evaluated and rated using a questionnaire as poor, moderate, and good. Also, the attitude of the volunteers towards the chemical attacks and their preparedness were rated as appropriate and inappropriate using a questionnaire. Data were analyzed using the SPSS software version 21.

RESULTS

From a total of 120 volunteers, 62.5% were males. The mean age of the volunteers was 32.0 ± 8.2 years. None of the volunteers had adequate knowledge regarding management of the consequences of chemical terrorist attacks. Only 10 volunteers (8.3%) had appropriate attitude and 7 (5.8%) stated their preparedness for being sent to the crisis zone. Also, 116 volunteers (96.7%) declared that Mahabad Red Crescent Society has an inappropriate level of preparedness to encounter chemical terrorism attacks and release of chemical agents related to petrochemical industrial chlorine resources into the water and wastewater.

CONCLUSION

The findings of the present study show poor knowledge and inappropriate attitude of Mahabad Red Crescent Society volunteers, and rescuers in encountering probable chemical attacks and industrial accidents. Furthermore, the Red Crescent Society had an inappropriate level of preparedness in the field of chemical terrorism from the viewpoint of the studied volunteers.

Validating Signs and Symptoms From An Actual Mass Casualty Incident to Characterize An Irritant Gas Syndrome Agent (IGSA) Exposure: A First Step in The Development of a Novel IGSA Triage Algorithm

CONTRIBUTION TO EMERGENCY NURSING PRACTICE

• Chemical exposures daily pose a significant threat to life. Rapid assessment by first responders/emergency nurses is required to reduce death and disability. Currently, no informatics tools for Irritant Gas Syndrome Agents (IGSA) exposures exist to process victims efficiently, continuously monitor for latent signs/symptoms, or make triage recommendations. • This study uses actual patient data from a chemical incident to characterize and validate signs/symptoms of an IGSA Syndrome. Validating signs/symptoms is the first step in developing new emergency department informatics tools with the potential to revolutionize the process by which emergency nurses manage triage victims of chemical incidents.

ABSTRACTINTRODUCTION

Chemical exposures can pose a significant threat to life. Rapid assessment by first responders/emergency nurses is required to reduce death and disability. Currently, no informatics tools for irritant gas syndrome agents (IGSA) exposures exist to process victims efficiently, continuously monitor for latent signs/symptoms, or make triage recommendations. This study describes the first step in developing ED informatics tools for chemical incidents: validation of signs/symptoms that characterize an IGSA syndrome.

METHODS

Data abstracted from 146 patients treated for chlorine exposure in one emergency department during a 2005 train derailment and 152 patients not exposed to chlorine (a comparison group) were mapped to 93 possible signs/symptoms within 2 tools (WISER and CHEMM-IST) designed to assist emergency responders/emergency nurses with managing hazardous material exposures. Inferential statistics (χ²/Fisher's exact test) and diagnostics tests were used to examine mapped signs/symptoms of persons who were and were not exposed to chlorine.

RESULTS

Three clusters of signs/symptoms are statistically associated with an IGSA syndrome (P < .01): respiratory (shortness of breath, wheezing, coughing, and choking); chest discomfort (tightness, pain, and burning), and eye, nose and/or throat (pain, irritation, and burning). The syndrome requires the presence of signs/symptoms from at least 2 of these clusters. The latency period must also be considered for exposed/potentially exposed persons.

DISCUSSION

This study uses actual patient data from a chemical incident to characterize and validate signs/symptoms of an IGSA syndrome. Validating signs/symptoms is the first step in developing new ED informatics tools with the potential to revolutionize the process by which emergency nurses manage triage victims of chemical incidents.