Chemical Liquid Aspiration

　　The occurrence of chemical liquid inhalation can be due to accidental aspiration or long-term inhalation at a low concentration. The specific etiology and pathogenesis are described as follows.

　　First, Etiology

　　1, Common

　　Substances that can be inhaled into the lungs, such as diesel, gasoline, mineral oil, animal oil, and vegetable oil.

　　2, Aspiration

　　Another cause is accidental inhalation due to impaired laryngeal protective reflex and glottis closure.

　　3, Other

　　Accidental inhalation due to ignorance.

　　Second, Pathogenesis

　　If a chemical liquid is accidentally inhaled into the airway or inhaled at a low concentration for a long time, the liquid can stimulate the bronchial tubes, causing severe bronchospasm. This is followed by an acute inflammatory reaction of the bronchial epithelium and infiltration of inflammatory cells around the bronchial tubes. The stomach fluid entering the alveoli quickly spreads to the surrounding lung tissue. The alveolar epithelial cells are damaged and denatured, affecting the capillary walls. The permeability of the vascular walls increases and the walls of the alveolar capillaries are damaged, leading to interstitial pulmonary edema and other lesions.

　　The early symptoms of chemical liquid inhalation include a burning sensation in the throat, throat pain, nasal congestion with runny nose, hoarseness, and so on. Chemical liquid inhalation can lead to anaerobic bacterial infections, such as aspiration pneumonia. Inhaling vomit can cause sudden laryngeal reflex spasm and bronchial irritation, resulting in wheezing and severe coughing.

　　The early symptoms of chemical liquid inhalation include a burning sensation in the throat, throat pain, nasal congestion with runny nose, hoarseness, and so on. However, the clinical manifestations may vary depending on the type of chemical liquid inhaled. The specific manifestations are described as follows.

　　1, Diesel

　　The main components of diesel are alkanes and aromatic hydrocarbons, both of which are high-boiling point substances, so the chance of injury caused by vapor is relatively low. Most of the inhalation of diesel occurs in drivers. Symptoms may include fever, chills, coughing, blood-tinged sputum, severe chest pain with chest tightness, and may also include gastrointestinal symptoms such as nausea, vomiting, abdominal pain, and black stools. Lesions are often seen in the right lung, and dry and moist rales may be heard.

　　2, Gasoline

　　The main components of gasoline are C4 to C12 aliphatic hydrocarbons and cyclic hydrocarbons, and it also contains a small amount of aromatic hydrocarbons and sulfides. It is a volatile and flammable liquid, insoluble in water, but easily soluble in fats and organic solvents. Inhaling high concentrations of gasoline vapor can cause acute poisoning, mainly characterized by central nervous system anesthesia. Gasoline inhalation pneumonia is common among drivers, and the clinical manifestations are related to the amount of gasoline inhaled. Symptoms such as coughing up blood, coughing, chest pain, chest tightness, shortness of breath, fever, and a gasoline smell in exhaled air may appear immediately. The lung auscultation may show rough breathing sounds, dry rales, or moist rales. The inhaled gasoline can quickly pass through the blood-brain barrier and damage brain tissue. It can directly cause kidney damage and produce hematuria. After inhalation, gasoline is mainly exhaled from the lungs in its original form, and the rest is excreted in urine.

　　3. Mineral oil

　　Mineral oil is often used as a lubricant and accidental inhalation is more common in patients with constipation and dysphagia. Contrast agents also contain mineral oil. After accidental inhalation, the main manifestation is exogenous lipoid pneumonia, and lipoid pneumonia caused by inhalation of oil mist is rare. Mineral oil has stable chemical properties, so there is usually no cough after accidental inhalation. Most patients are asymptomatic, and only X-ray chest films show abnormalities, with complaints of cough and chest pain. Long-term and repeated inhalation of lipids can produce diffuse fibrosis, eventually leading to pulmonary heart disease. Fat droplets in macrophages in sputum or bronchoalveolar lavage fluid suggest the possibility of the disease. Lung biopsy via bronchoscope can usually confirm the diagnosis.

　　4. Animal oil and vegetable oil

　　Milk, dairy products, and cod liver oil all contain animal oil. Accidental inhalation mainly occurs during feeding of infants and children. Animal fats can be hydrolyzed by pulmonary esterase into fatty acids, causing acute hemorrhagic pneumonia. Vegetable oil inhalation often occurs during eating or vomiting, causing varying degrees of tissue damage. Pulmonary manifestations can be very mild or similar to the clinical manifestations of animal oil inhalation. Chest X-ray findings are varied, including solitary lipid granulomas, tumor-like extensive consolidation, segmental or lobar pneumonia, and diffuse alveolar or interstitial infiltration. Some vegetable oils may not cause any obvious reactions in the lungs and can exist in the alveolar cavity for a long time without fibrosis or obvious inflammatory reactions; while others can cause tissue reactions similar to those of animal oil.

　　When chemical liquid inhalation occurs, take immediate measures to terminate the inhalation of the chemical liquid, such as leaving the scene, changing contaminated items, and washing the skin and mouth.

　　Liquids and solids (including vapors) with extremely strong corrosive properties to the human skin, mucous membranes, eyes, respiratory tract, and objects, such as fuming sulfuric acid, sulfuric acid, fuming nitric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, chlorosulfonic acid, chlorosulfane, monochloroacetic acid, formic acid, acetic anhydride, chlorinated oxygen phosphorus, phosphorus pentoxide, anhydrous aluminum trichloride, bromine, sodium hydroxide, potassium hydroxide, sodium sulfide, phenol, anhydrous hydrazine, and hydrated hydrazine, must be stored in a cool, well-ventilated area and isolated from other medicines. Corrosion-resistant materials, such as acid-resistant cement or acid-resistant ceramic, should be used to make shelves for storing these medicines. The shelves should not be too high, nor should they be placed on shelves, but rather on the ground near the wall to ensure safe storage.

　　Kerosene, gasoline, diesel, mineral oil, animal oil, vegetable oil, furniture polish, and other petroleum solvents should be placed in a higher place where children cannot easily reach them.

　　The examination of chemical liquid inhalation includes laboratory examination and other auxiliary examinations, and the specific examination methods are described as follows.

　　1. Laboratory examination

　　Blood count during the acute stage: white blood cell count up to (3-4) × 10^9/L. Neutrophils are more than 90%.

　　2. Other auxiliary examinations

　　Plain X-ray chest film shows large areas of increased density, indistinct infiltrative shadows, and unclear boundaries.

　　3. Fat droplets in macrophages in sputum or bronchoalveolar lavage fluid suggest the possibility of mineral oil inhalation. Bronchoscope lung biopsy can usually determine the diagnosis.

　　Immediate measures should be taken to stop chemical liquid inhalation when it occurs, such as leaving the scene, changing soiled items, washing the skin and mouth, and performing gastric lavage. Oxygen therapy should be actively carried out for those who need it.

　　If the throat or esophagus is stimulated, the intake of food should be controlled, and a liquid diet should be adopted, mainly including millet congee, milk, and vegetable juice, to avoid stimulating the throat and esophagus as much as possible.

　　Chemical liquid inhalation patients should eat light food; eat easily swallowable food; eat liquid or semi-liquid food. Avoid eating spicy and irritating food; avoid cold and cool food; avoid warm and nourishing food.

　　Emergency treatment for chemical liquid inhalation should be carried out to support therapy, and the specific treatment methods are described as follows.

　　First aid on the scene

　　It mainly includes emesis and detoxification. The purpose of emesis is to try to expel the toxic substances in the stomach, and reduce the absorption of toxic substances. The method of emesis is: hold the child up, tilt the body forward, use hands or convenient objects to stimulate the oropharynx directly, and induce vomiting. Finally, let the child drink water, and then induce vomiting again, repeating this several times until the vomit becomes clear and has no smell. It should be reminded that there should be an interval between each induced vomiting to allow the child to rest a little. Emesis must be carried out as soon as possible, if poisoning exceeds three or four hours, then the toxic substances have entered the intestines, and emesis loses its significance.

　　Second, no specific treatment

　　The main supportive therapy, comprehensive treatment, the principles are described as follows.

　　1. Stop inhaling chemical liquids.

　　2. Oxygen therapy.

　　3. Symptomatic treatment.

　　4. Prevention and control of infection.

　　5. Hormonal therapy.