Toxic Gases Flashcards
What are the sources for Ammonia gas?
Decomposing manure
Burning nylon/plastics
fertilizer
What are the properties of Ammonia?
sharp odor
heavier than air
soluble in water
readily reacts with hydroxyl ions in moist mucous membranes to form ammonium hydroxide which is irritant and caustic
What is ammonia converted to on mucous membranes?
Ammonium hydroxide
How is ammonia absorbed?
Inhalation
What is the mechanism of action of Ammonia toxicosis?
Direct irritation of membranes Increased susceptibility to respiratory infections due to continuous irritation Decreases growth in young animals inhibits the TCA cycle pulmonary edema and lung congestion
What is the cause of death due to in Ammonia toxicosis?
asphyxia
electrolyte and cellular metabolic effects
What are the clinical signs of Ammonia toxicosis?
Red mucous membranes lacrimation coughing sneezing nasal discharge decreased growth decreased egg production dyspnea due to fluid in lungs cyanosis CNS stimulation clonic convulsions
What is the treatment for Ammonia toxicosis?
Removal of source Fresh air soothing ointments to eyes antibiotics for 2ndary infections Diuretics
What is the source of Hydrogen sulfide?
decomposition of urine and feces
coal pits, gas wells, sulphur springs
Liquid manure holding pits
Natural gas and crude oil production
What is the most dangerous sewage gas?
Hydrogen Sulfide
At what level is Hydrogen Sulfide immediately fatal?
400ppm
What levels can poultry withstand of Hydrogen Sulfide?
4000ppm
What is Hydrogen Sulfide converted to in the blood?
Alkali sulfides
Where is Hydrogen Sulfide readily absorbed?
Lungs
GI tract
What is the mechanism of action of Hydrogen Sulfide toxicosis?
Direct irritation of mucous membranes
Inhibition of cellular respiration by inhibiting cytochrome oxidate
Stimulation of chemoreceptors of the carotid body interfering with respiratory drive
What are the clinical signs of Hydrogen Sulfide toxicosis?
sudden collapse cyanosis dyspnea anoxic convulsions rapid death irritation to ocular, respiratory mucosa and lungs
What are the lesions associated with Hydrogen Sulfide toxicosis?
Dark blood that may not clot
Tissues may be dark or greenish purple
Carcass may have H2S odor
GI contents may be black or dark gray with sewage odor
What does Hydrogen Sulfide react with?
Silver
Iron
Lead
How do you treat Hydrogen Sulfide toxicosis?
Removal of source Sodium Nitrate IV Oxygen therapy ventilation supportive treatment
What are the sources of Carbon Monoxide?
Fires
Propane
Automobile exhaust
What are the properties of Carbon Monoxide?
Odorless
Colorless
What is important to remember about Carbon Monoxide?
Smaller animals have faster breathing rate and smaller Vd so may show toxicity before humans
“Canary in the coal mine”
What is the mechanism of action of Carbon Monoxide?
CO combines with hemoglobin to form carboxyhemoglobin which cannot carry O2
Carboxyhemoglobin interferes with normal release of O2 carried by normal hemoglobin
competes with oxygen for binding on myoglobin
leads to free radical formation and attraction of leuocytes
What are the clinical signs of Carbon Monoxide Poisoning?
Sudden death Hypoxia drowsiness incoordination dyspnea lethargy coma
What are moderate concentrations of carbon monoxide associated with in swine and sheep?
stillborn fetuses
What lesions are associated with Carbon Monoxide Poisoning?
Bright red blood and pink mucous membranes
What lesions do you see in chronic cases of Carbon Monoxide Poisoning?
brain edema
hemorrhage
necrosis
deafness in dogs and cats
What do you measure for laboratory findings associated with Carbon Monoxide Poisoning?
Percentage of carboxyhemoglobin
What is the treatment for Carbon Monoxide Poisoning?
Oxygen
Blood transfusion
Fluids for acidosis
What are the two forms of Nitrogen Oxide?
Nitrogen dioxide
Nitrogen tetraoxide
What is the name for the disease caused by Nitrogen Oxide Poisoning?
“Silo filler’s disease”
What is a source of Nitrogen Oxide Poisoning?
Silo fermentation
What are properties of Nitrogen Oxide?
NO2 - reddish brown
N2O4 - colorless
NO2 is heavier than air
irritating chlorine-like odor
What does Nitrogen Oxide form in water?
HNO3 - Nitric acid
NO - Nitric oxide
What does smog convert Nitrogen Oxide to?
NO2
O3 (Ozone)
What is more toxic, acute exposure at high levels or chronic exposure at low concentrations of Nitrogen Oxide?
Acute exposure to high concentrations
What does NO2 adn N2O4 form on contact with mucous membranes?
Nitric acid
What does Nitric acid cause in the lungs?
cellular damage in the lungs
What is the mechanism of action of Nitrogen Oxide Poisoning?
Direct irritation of the mucous membranes
Lung damage
What is the cause of Death with Nitrogen Oxide Poisoning?
Hypoxia
What are the clinical signs of Nitrogen Oxide Poisoning?
Irritation of the mucous membranes Pulmonary edema hemorrhage emphysema inflammation of the bronchioles cyanosis methemoglobinemia necrosis of skeletal muscles
What is the treatment for Nitrogen Oxide Poisoning?
Supportive treatment: Fresh air, oxygen, diuretics, antioxidants
Methylene Blue IB for methemoglobinemia
Ointments for mucous membranes
What is the prognosis for Nitrogen Oxide Poisoning?
Low if acutely exposed
Higher if chronically exposed
What are the forms of Sulfur Oxide?
Sulfur Dioxide
Sulfure trioxide
What is the source of Sulfur Oxide?
Fossil fuels combustion
What are the properties of Sulfur Oxide?
Sharp irritant to mucous membranes
rotten egg odor
What does Sulfur Oxide cause on contact with water?
Sulfurous and sulfuric acids
What is the mechanism of action for Sulfur Oxide Toxicosis?
Direct irritation of the mucous membranes and reflex bronchoconstriction
Lung damage
What is the cause of death with Sulfur Oxide Poisoning?
Hypoxia
What are the clinical signs of Sulfur Oxide Poisoning?
irritation to mucous membranes
effects on respiration
What is the treatment for Sulfur Oxide Poisoning?
Fresh air
ventilation
oxygen
ointment for mucous membranes
What is the cause of toxicity of Smoke inhalation?
Mixture of substances burning/combusting Temperature of the fire Length of exposure Availability of oxygen Size of the animal
What enhances toxicity of smoke inhalation?
Burns in the respiratory tissue
Simple asphyxiants
iner (CO2) gases or vapors that displace oxygen in air and have low concentrations and low physiological effect
Chemical asphyxiants
prevent uptake of oxygen and produce toxic local and systemic effects
Irritants
chemically reactive on contact with MM to cause local effects
What are examples of Simple asphyxiants?
CO2
Methane
What are examples of Chemicals
CO
HCN
HSH
NO
What are clinical signs of smoke inhalation?
Cough
dyspnea
tachypnea
Lung Auscultation: Rales, Wheezes, decreased breaths sounds, crackles
tachycardia
hypoxemia
Hypotension
dysrhythmias
Signs of irritation: conjunctivitis, pharyngitis, rhinitis. drooling, dysphagia
CNS signs: agitation, confusion, ataxia, abnormal posturing, loss of consciousness. seizures
What are the lesions associated with Smoke inhalation?
Burns
Pulmonary changes
cerebral edema
lesions associated with CO poisoning
What is the treatment for smoke inhalation?
Removal of smoke Beta 2 adrenergic agonists for bronchoconstriction NO STEROIDS! AVOID Cough suppressants Maintain patent airway and oxygenation NSAIDs IV fluids
Soot
Finely divided carbonaceous particulate matter suspended in the gases and hot air of smoke
What adheres to soot?
Sulfur dioxide
What is the most important determinant of respiratory injury?
Solubility
What do highly soluble particles cause?
Injury to mucosa, inflammatory mediators, and free radicals leading to increased permeability and edema
