In some plants such as in pits of apricots, cyanide can be found as glycosides can synthesize cyanide. Smoking cigarettes is a major avenue of exposure. Pulmonary Aspiration Syndromes
Deglutition is the main cause for minute food and fluid to get aspirated into the lungs. Impaired consciousness and esophageal disorders can cause deglutition. Acute Aspiration of Gastric Content (Mendelson Syndrome): pulmonary response to aspirated content depend on the quantity and constituent of aspirated gastric content. Chemical pneumonitis is severe if aspirated content is acidic and aspirated gastric acid – pH less than 2.5 – can inflame bronchial epithelium and cause bronchiolitis, hemorrhagen, and pulmonary edema.Chronic Aspiration of Gastric Contents: disorders of the larynx and the esophagus are major causes of chronic aspiration of gastric content – achalasia, esophageal stricture, systemic sclerosis (scleroderma), esophageal carcinoma, esophagitis, and gastro-esophageal reflux. Pulmonary aspiration can result when the lower intestinal sphincter relax and spill out gastric content into the esophagus.Smoking, consuming alcohol or caffeine, and the drug theophylline used in asthma patients are known to cause lower intestinal sphincter relaxation. Gastro-esophageal reflux and chronic aspiration are associated with few pulmonary disorders: asthma, chronic cough, bronchiectasis, and pulmonary fibrosis.Difficulty swallowing, ageing, dental problems impeding proper chewing, consuming alcohol, and taking sedatives cause café coronary, obstruction of the upper airways by food particles.Retaining an Aspirated Foreign Body: poor clearance of aspirated material out of the tracheobronchial tree can result in acute and chronic conditions including atelectasis, post obstructive hyperinflation, acute and recurrent pneumonia, bronchiectasis, and lung abscesses.
A third of all burn victims admitted to a hospital are affected by pulmonary injury from inhaling smoke and fatality from inhalation injuries is higher than burn injuries - mortality exceeds 50% for burn victims with severe burn and inhalation injury. Tissue oxygenation is significantly affected and thermal injury to the upper airways, lower airways, and lung parenchyma occurs. Poor tissue oxygenation is a life-threatening conditions and results from inhaling carbon monoxide, cyanide, a gas mixtures devoid of  oxygen, or from an imbalance between alveolar ventilation and blood supply. Carbon monoxide is a colorless and odorless gas, which can interfere with and impede respiration. Oxygens tendency to bind with hemoglobin is 250 times less than carbon monoxide, severely reducing the quantity of circulating oxygen and limiting tissue oxygenation in carbon monoxide poisoning. Exposure can be deliberate (suicidal) or accidental and can come from automobile exhaust pipes, inhaling smoke during a fire accident, and poorly vented gas heaters, generators, and other appliances.Cyanide is inhaled into the lungs in gaseous form – as hydrogen cyanide. Cyanide can also be diffused through the skin or ingested. Rapid infusion of high-dose cyanide cause cyanide poisoning. It is produced when nitroprusside is broken down into its constituents. It inhibits cells from properly utilizing oxygen by disrupting cytochrome oxidase, and can be more damaging to the brain and heart.Cyanide is a highly toxic chemical often used in industries and in laboratories. Finger nail glue remover products contain acetonitrile and its metabolic break down produces cyanide.