Chlorine and its impact on an emergency department

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.

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.

Mass Casualty Incident Involving Pepper Spray Exposure: Impact on the Emergency Department and Management of Casualties

Introduction

Exposure to pepper spray in an urban shopping complex resulted in 13 casualties being treated at a tertiary public hospital emergency department (ED). This report describes the ED's organisation in response to the disaster, and clinical management of those affected.

Results

Thirteen casualties – 11 acute, 2 delayed – presented with symptoms ranging from ocular, respiratory and skin irritation to nausea, vomiting and giddiness. The culprit agent was determined basing on the index patient's history and physical findings. All cases were decontaminated at the ED's on-site Hospital Decontamination Station. Nine adults were monitored overnight in the Emergency Observation Ward under the Toxic Inhalation Protocol and discharged well. The index case was treated symptomatically with improvement, but discharged against medical advice three hours later. No ED re-attendances were recorded.

Conclusions

The effects of pepper spray exposure are brief and self-limiting, but ED management can pose challenges in a mass casualty situation.

Personnel response during an internal emergency-unexpected release of an irritant gas in a hospital

Internal emergencies can occur at any time and location in a hospital. Planning, training, and exercises can prepare personnel to respond effectively to internal emergency situations. All hospital staff should be trained to recognize an internal incident and activate the hospital emergency management system. Maintaining the health and safety of patients, employees, and visitors is paramount. Training and exercises also encourage staff to act with competence and confidence during an untoward incident to mitigate or avert possible catastrophe. This article describes an incident in which 12 hospital employees presented to the emergency department after exposure to a potent pulmonary irritant gas, chlorine, following an unfortunate accident. These cases are used to illustrate how planning, training, and exercises assisted health care personnel in responding to a potentially catastrophic internal emergency.

Personnel Response during an Internal Emergency—Unexpected Release of an Irritant Gas in a Hospital

Internal emergencies can occur at any time and location in a hospital. Planning, training, and exercises can prepare personnel to respond effectively to internal emergency situations. All hospital staff should be trained to recognize an internal incident and activate the hospital emergency management system. Maintaining the health and safety of patients, employees, and visitors is paramount. Training and exercises also encourage staff to act with competence and confidence during an untoward incident to mitigate or avert possible catastrophe. This article describes an incident in which 12 hospital employees presented to the emergency department after exposure to a potent pulmonary irritant gas, chlorine, following an unfortunate accident. These cases are used to illustrate how planning, training, and exercises assisted health care personnel in responding to a potentially catastrophic internal emergency.

Post-exposure antioxidant treatment in rats decreases airway hyperplasia and hyperreactivity due to chlorine inhalation

We assessed the safety and efficacy of combined intravenous and aerosolized antioxidant administration to attenuate chlorine gas-induced airway alterations when administered after exposure. Adult male Sprague-Dawley rats were exposed to air or 400 parts per million (ppm) chlorine (a concentration likely to be encountered in the vicinity of industrial accidents) in environmental chambers for 30 minutes, and returned to room air, and they then received a single intravenous injection of ascorbic acid and deferoxamine or saline. At 1 hour and 15 hours after chlorine exposure, the rats were treated with aerosolized ascorbate and deferoxamine or vehicle. Lung antioxidant profiles, plasma ascorbate concentrations, airway morphology, and airway reactivity were evaluated at 24 hours and 7 days after chlorine exposure. At 24 hours after exposure, chlorine-exposed rats had significantly lower pulmonary ascorbate and reduced glutathione concentrations. Treatment with antioxidants restored depleted ascorbate in lungs and plasma. At 7 days after exposure, in chlorine-exposed, vehicle-treated rats, the thickness of the proximal airways was 60% greater than in control rats, with twice the amount of mucosubstances. Airway resistance in response to methacholine challenge was also significantly elevated. Combined treatment with intravenous and aerosolized antioxidants restored airway morphology, the amount of airway mucosubstances, and airway reactivity to control levels by 7 days after chlorine exposure. Our results demonstrate for the first time, to the best of our knowledge, that severe injury to major airways in rats exposed to chlorine, as characterized by epithelial hyperplasia, mucus accumulation, and airway hyperreactivity, can be reversed in a safe and efficacious manner by the post-exposure administration of ascorbate and deferoxamine.

Elucidating mechanisms of chlorine toxicity: reaction kinetics, thermodynamics, and physiological implications

Industrial and transport accidents, accidental releases during recreational swimming pool water treatment, household accidents due to mixing bleach with acidic cleaners, and, in recent years, usage of chlorine during war and in acts of terror, all contribute to the general and elevated state of alert with regard to chlorine gas. We here describe chemical and physical properties of Cl(2) that are relevant to its chemical reactivity with biological molecules, including water-soluble small-molecular-weight antioxidants, amino acid residues in proteins, and amino-phospholipids such as phosphatidylethanolamine and phosphatidylserine that are present in the lining fluid layers covering the airways and alveolar spaces. We further conduct a Cl(2) penetration analysis to assess how far Cl(2) can penetrate the surface of the lung before it reacts with water or biological substrate molecules. Our results strongly suggest that Cl(2) will predominantly react directly with biological molecules in the lung epithelial lining fluid, such as low-molecular-weight antioxidants, and that the hydrolysis of Cl(2) to HOCl (and HCl) can be important only when these biological molecules have been depleted by direct chemical reaction with Cl(2). The results from this theoretical analysis are then used for the assessment of the potential benefits of adjuvant antioxidant therapy in the mitigation of lung injury due to inhalation of Cl(2) and are compared with recent experimental results.