Inhalation Injury

Hx: A male in his 20’s is working when he mixes lime away and bleach in a bottle. He then breathes some of the resultant gas and becomes short of breath, develops an intractable cough, and his co-workers call EMS. He is given a single albuterol nebulizer treatment on the way to the hospital along with supplemental oxygen by non-rebreather mask. He arrives tachypneic with a cough that is preventing him from speaking in full sentences.

PMHX: none

SocHx: occasional alcohol, no tobacco or drugs

Exam: 

• Vitals: BP 160/90, HR 120, RR 25, sat 100% on NRB mask, temp 98.6 F (37 C)
• HEENT: No trauma; watery eyes; no eyelid edema; normal eye movements and pupil reaction. Pharynx clear. Clear rhinorrhea.
• Neck: Supple
• Resp: Bilateral expiratory wheezes in between frequent coughing, non-productive. No SQ crepitance, equal breath sounds. In moderately severe respiratory distress.
• Cardiovascular: Tachycardia, regular, pulses symmetrical bilaterally.
• Abdomen: Soft, non-tender.
• Extremities: Normal pulses, warm

Differential: 

• Chlorine gas inhalation
• Bronchospasm
• Doubt pneumonia

ED Course: 

• Multiple nebulizer treatments with improvement in cough and distress.
• He becomes comfortable with clear breath sounds
• He maintains a slight hypoxia after 3 hours of observation (88% saturation on room air) with improvement in remainder of vital signs
• Admission for further observation due to persistent hypoxia.
• A single dose of decadron is given IV in the ED
• Initial Chest Xray is shown below:

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Hospital Course: 

• The patient is admitted after a total of 4 hours observation. By hour 6, his hypoxia is worsening, and his work of breathing is increasing.
• Repeat chest X-ray demonstrates pulmonary edema and the patient is placed on BiPAP.

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• He is admitted to the ICU where he remains on BiPAP for 24 hours, narrowly avoiding intubation.
• On hospital day #2, the patient develops pneumo-mediastinum as well as diffuse subcutaneous emphysema. No pneumothorax.

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• On hospital day #3, his work of breathing is improved, and he is off BiPAP and reduced to nasal cannula. Repeat chest X-ray shows improvement in the pneumo-mediastinum and sub-cutaneous air but a focal consolidation developing in the retrocardiac region of the left lung.

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• On hospital day 4, work of breathing is almost normal, and he is reduced to room air. Chest X-ray shows minimal residual fluid in the left lung and infiltrate is improving.
• Eventually his pulmonary edema resolves, and the patient is discharged home in good condition.

Diagnosis: Pulmonary Edema and Respiratory Distress due to Chlorine Gas Inhalation

Discussion:  

Chlorine is a gas that can be pressurized and cooled into a liquid. It is one of the most commonly manufactured chemicals in the US due to its use as a cleaning agent. It is currently used in the sanitation of drinking water, swimming pools, and industrial waste. It is also an ingredient in pesticides and household cleaning products. At room temperature, liquid chlorine dissipates into a gas which is heavier than air. It can result in injury by dermal exposure, mucus membrane exposure, or inhalation.

Chlorine is an irritant which causes an inflammatory response in the tissues that are exposed. In mild cases, simple decontamination of the liquid from the exposed area is sufficient. In the case above, the patient suffered an inhalation injury. The severity of these injuries is dependent on the extent of the inhalation. If exposure is brief and limited to the mucus membranes of the upper airway, symptoms may be brief and transient. If inhalation exposure reaches further into the respiratory tract, direct injury and the subsequent inflammatory reaction can be life threatening. Severe bronchospasm is common. Pulmonary edema and acute respiratory distress syndrome (ARDS) may occur. The onset of these severe lung injuries can be delayed several hours from acute exposure.

Much of what is known regarding the effects of chlorine gas comes from exposure of soldiers in World War I as well as industrial workers. Repetitive occupational exposures or high dose single exposures have been shown to leave lasting lung injuries and persistent airway hyper-reactivity. This is most common in those with severe symptoms from exposure, such as pulmonary edema. Today, those at highest risk are professional cleaners. They are frequently exposed to higher levels of chlorine and are at increased risk of accidental mixture of chemicals resulting in chlorine gas release.

In the case above, the patient combined two over the counter cleaning products, “lime away” and “bleach”. Lime away is sold as a descaling agent and includes differing formulations depending on the specific type purchased. The spray bottles and large surface cleaners contain a less volatile sulfamic acid that does not release chlorine gas when mixed with bleach (sodium hypochlorite). However, the lime away toilet bowl cleaner is composed of hydrochloric acid. Mixing this agent with household bleach results in the release of chlorine gas through this chemical reaction:

NaClO + 2 HCl —> Cl2 + H2O + NaCl

The equation shows sodium hypochlorite (bleach) mixing with hydrochloric acid (lime away) to create chlorine gas, water, and salt.

Once the exposure to chlorine gas occurs, decontamination is critical, followed by supportive care. Inhalation frequently results in bronchospasm and rhinorrhea. Hours later pulmonary edema and ARDS may begin. Non-invasive ventilation may be helpful, as in our case, with intubation and full ventilatory support utilized in the most severe of cases.

This patient also developed pneumomediastinum and sub-cutaneous emphysema. This is a known consequence of severe bronchospasm inducing persistent cough. The repetitive cough results in barotrauma to the tracheal tree which can cause an air leak into the mediastinum. The addition of positive pressure ventilation often worsens the problem. Supplemental oxygen is sufficient if the air remains in the mediastinum and does not extend into the pleural space causing a pneumothorax.

References: 

• CDC: Facts About Chlorine
• Gorguner M, Aslan S, Inandi T, Cakir Z. Reactive airways dysfunction syndrome in housewives due to a bleach-hydrochloric acid mixture. Inhal Toxicol. 2004 Feb;16(2):87-91. doi: 10.1080/08958370490265004. PubMed
• Lime-A-Way Toilet Bowl Cleaner

Last Updated on January 24, 2023