Unit 1 - Toxic Gases Flashcards
What are the types of exposure that toxic gases can have?
Respiratory, dermal, and other
What local effects can toxic gases have?
Irritation, inflammation, edema, necrosis, fibrosis, and emphysema
What toxic gases are more common in large animal?
Nitrogen dioxide, hydrogen sulfide, ammonia, methane, carbon dioxide, and anhydrous
What toxic gases are more common in small animals?
carbon monoxide
What toxic gases are more common in avian species?
polytetrafluoroethylene
What is the most common gas in animal facilities?
ammonia (NH3)
What are the characteristics of ammonia?
colorless, lighter than air, and a shar pungent odor
Why is the ammonia odor worse in the winter months?
Because there is not a lot of air flow, it is very dry, and the areas are confined
What are the sources of ammonia?
Manure/slurry pits
Fertilizers
What clinical signs occur at 50 ppm of ammonia?
Decreased feed intake and decreased ciliary clearance
Why is decreased ciliary clearance bad?
It can increase the chance of respiratory disease because they are what work to get crap out of the lungs
What ocular clinical signs does ammonia cause?
Keratoconjunctivitis and lacrimation
What respiratory clinical signs does ammonia cause?
Increased nasal discharge, sneezing and coughing, pulmonary congestion, and dyspnea
What reproductive clinical signs does ammonia cause?
Decreased egg production
What terminal clinical signs are associated with ammonia?
Hypoxia, cyanosis, and violent seizures
What diagnostic tests are used to diagnose ammonia toxicosis?
There are really no reliable diagnostic tests - history of exposure and odor is all we’ve got
How is ammonia toxicosis treated?
Remove the source
Supportive care - eye ointment and abx
How is ammonia toxicosis prevented?
Provide adequate ventilation
What are the characteristics of anhydrous ammonia (Gas-NH3)?
Colorless (white vapor when spread), pungent odor, lighter than air, and water soluble
What are the sources of anhydrous ammonia?
Agricultural fertilizer, commercial refrigerant, and meth labs
What is the prime target for anhydrous ammonia?
mucous membranes
When anhydrous ammonia interacts with the water at the mucous membranes, what happens?
It creates ammonium hydroxide which is extremely caustic. This causes very strong alkali burns resulting in necrosis of the dermis, epithelium, and the muzzle
What clinical effects are associated with anhydrous ammonia?
Fluid accumulation in the lungs, respiratory distress
Sloughing of the respiratory tract epithelium
Corneal damage leading to blindness
Acute death
How is anhydrous ammonia toxicosis treated?
Supportive care, but the best option is euthanasia
How is anhydrous ammonia toxicosis prevented?
Ensure that equipment is functioning properly and DO NOT park anhydrous tanks near livestock or the house
What is the impact of anhydrous ammonia on human health?
It is extremely hazardous so you need to make sure that you have a self contained breathing apparatus and protective clothing
What should you do if you get exposed to anhydrous ammonia?
Remove your contaminated clothes and flush with water for 5 minutes
Why should you beware of the wind if there is an anhydrous ammonia leak, or a tank breaks, or something like that?
The gas could originally be blowing one way, but it can change direction and all of a sudden be blowing right in your face
What are the characteristics of carbon monoxide?
It is colorless, lighter than air, and odorless
What are the sources of carbon monoxide?
Inefficient combustion of carbon fuels in combination with inadequate ventilation
It can be acute or chronic
What can lead to inefficient combustion of carbon fuels?
Space heaters, grills, furnaces
Old/out of date heaters
Automobile exhaust
Fires
What can cause inadequate ventilation that leads to carbon monoxide poisoning?
Small space - farrowing room, chicken coop, and house garage
Clogged exhaust pipe/vent
Curtains that are ‘up’ in livestock facilities
What is the MOA of carbon monoxide?
CO binds to hemoglobin creating COHb. Oxygen cannot bind because CO is bound so there is less oxygen to the tissues causing anoxia
Fetal hemoglobin is more susceptible to CO. What clinical affects might you expect due to this?
Spontaneous abortions and still births
What acute clinical signs are associated with CO toxicity?
These are based on the degree of hypoxia: drowsiness, lethargy, incoordination, decreased heart excitability, cherry-red skin and mucous membranes
Dyspnea then coma then spasms then death
Abortions and stillbirths
What chronic clinical signs are associated with CO toxicosis?
Low exercise tolerance, abnormal posture, gait, and reflexes, and ECG abnormalities
What testing needs to be done ASAP in cases of suspected CO toxicosis?
Carboxyhemoglobin testing
What samples can be taken ante-mortem for carboxyhemoglobin testing? Post mortem?
ante-mortem - whole blood
Post-mortem - ‘lung juice’ and fetal thoracic fluid
What samples can be taken for histopath examination in CO cases?
the brain and the heart
COHb may return to normal after _______.
3-6 hours
What gross lesions are associated with CO toxicosis?
Bright cherry-red skin, blood, and mucous membranes