Ammonia Poisoning

Ammonia is a highly water-soluble, colorless and alkaline irritating gas, which strongly stimulates eyes and mucous membranes. It can be used in the manufacture of chemical fertilizers and refrigerants, and also in the production of explosives, dyes, plastics and some drugs. The intense stimulation urges people to leave quickly, thus avoiding serious lung injury. Ammonia gas released by household cleaners generally rarely causes lung injury.

Ammonia is a highly water-soluble, colorless and alkaline irritating gas, which strongly stimulates eyes and mucous membranes. Long-term exposure, especially in areas with high chemical concentration when entering or unconscious, can cause ammonia poisoning.

Ammonia is a kind of easily soluble gas, which has severe mucosal irritation, so the main action site is the upper airway. Accidental inhalation of high concentration ammonia can cause laryngeal edema and suffocation.

Symptoms of upper airway obstruction, such as throat spasm, wheezing, mute, difficulty in speaking, etc. These patients have second-degree to third-degree skin burns, and the mortality rate is about 40%. There are two stages in the clinical process of moderate to severe inhalation. First, within 48-72 hours, the clinical symptoms are improved, and then the respiratory resistance is aggravated, resulting in cyanosis and dyspnea or respiratory failure.

The degree of respiratory tract injury after inhalation of ammonia is directly related to ammonia concentration, contact time and inhalation depth. Acute inhalation of ammonia with low to moderate concentration (150-450 mg/m3) causes a large number of tears, throat irritation and cough, which can lead to pulmonary edema and chemical bronchitis. Exposure to high-concentration ammonia gas (≥450 mg/m3) will cause laryngeal edema, tracheitis, bronchospasm and hypersecretion of mucus, and may lead to noncardiac pulmonary edema and bronchopneumonia, which may cause suffocation and death in a few minutes.

Chest X-ray findings vary according to the severity of inhalation. Slight exposure to chest radiographs is normal, and extensive exposure to chest radiographs shows pulmonary edema shadow.

The prevention of ammonia poisoning is mainly reflected in avoiding direct contact with ammonia. The specific preventive measures are as follows:

1, in the production operation, strengthen the airtight, transportation pipeline should be regular maintenance, prevent accidental rupture of pipeline damage. Moreover, ventilation should be strengthened in the workshop to control the ammonia concentration within a safe range.

2. When storing and transporting ammonia bottles, avoid being affected by sunlight and heat radiation and colliding with each other, so as to avoid explosion due to pressure rise in the bottles.

3. In normal work, employees' first-aid drills for accidents should be strengthened, and the first-aid procedures for ammonia poisoning should be clarified. At the same time, personnel engaged in ammonia operations should be given pre-employment physical examination, and those with respiratory diseases or diseases such as liver, kidney and heart should be prohibited from doing so.

4. In the process of production and use of ammonia, check whether the valves and pipes are closed frequently, and wear a gas mask with copper sulfate or zinc sulfate during maintenance.

The treatment of ammonia poisoning mainly adopts supportive therapy. Patients' throats should be carefully examined for obstruction, mucosal damage and abnormal gas exchange. Patients with pulmonary edema on chest X-ray or arterial blood gas analysis showing an increase in alveolar arterial oxygen partial pressure difference should be hospitalized for observation for at least 24 hours. Treatment includes oxygen inhalation, bronchodilator, airway maintenance and auxiliary ventilation. Antibiotics are helpful to prevent extensive mucosal injury complicated with bacterial infection. There is no evidence that corticosteroids or other anti-inflammatory drugs have definite effect on ammonia inhalation. The mortality of patients with second and third degree burns was 40%.

Ammonia poisoning should be distinguished from acute laryngitis, bronchitis and bronchopneumonia caused by other reasons.

Ammonia poisoning can be complicated with acute pulmonary edema, bronchopneumonia and severe respiratory failure.