Toxic gases 1 Flashcards
T/F: Ammonia is heavier than air
True
it is also soluble in water and readily reacts with hydroxyl ions in MM - forming ammonium hydroxide which is a caustic irritant
what are the forms of ammonium exposure animals may experience?
inhalation from..
decomposing manure in a confined area
burning nylon/plastic
Anhydrous ammonia used in fertilizer - broken hoses or values during transport
At what dose does ammonia cause burning of the eyes?
25-35 ppm
*in enclosed animal houses ammonia levels may reach up to 50ppm
Exposure of ammonia at _____ ppm can cause acute death?
5000 ppm
what livestock are most susceptible to ammonia poisoning?
Swine and poultry
what are the MOA of ammonia?
Direct irritation of the mm
Increased susceptibility to Resp. infection due to continuous exposure and inflammation
Decreased growth in young animals
What happens pathologically when ammonia is inhaled at high concentrations?
Pulmonary edema and lung congestion due to increased permeability of lung capillaries
alkalosis and compensatory acidosis
May inhibit the TCA cycle = decreased cellular respiration
Death due to electrolyte and cellular metabolic effects –> asphyxia
Hydrogen sulfide is colorless and has the odor of ____
rotten eggs
What happens when hydrogen sulfide comes into contact with mm?
It is an irritant bc it concerts to sulfuric acid in solution and forms sulfide when it comes into contact with moist mm
What occurs when sulfides mix with silver, iron, lead, or other metals?
forms a black or dark colored compounds - occurs with iron in the GIT and tissues
How/when are animals exposed to hydrogen sulfide?
Exposure from decomposition of urine and feces in underfloor waste pits, manure packs, sewage and other organic matter containing sulfur
(normal H2S levels in one of these wastes pits is around 10ppm)
Deadly levels of H2S may reach 1000ppm
What is the most dangerous sewage gas?
Hydrogen sulfide
sudden exposure at 400ppm may be fatal
200ppm is a dangerous level
1000ppm causes rapid unconsciousness and death in an hour
greater than 2000ppm will cause paralysis after just 1-2 breaths
(humans)
What is considered acute toxic levels of hydrogen sulfide in mammals?
500 - 800 ppm
poultry did not result in immediate death at 4000ppm
What is H2S converted to in the blood?
alkali sulfides
What is the MOA of H2S?
Inhibition of cellular respiration - decreased cytochrome oxidase
What is a differential diagnosis for H2S poisoning?
Ammonia
What is used for H2S treatment?
Sodium nitrate - forms methemoglobin and binds sulfide radicals and reactivates cytochrome oxidase
supportive care
What is the MOST effective treatment of H2S poisoning?
PREVENTION - H2S monitors should be used
T/F: H2S could delay rigor mortis
TRUE
Is carbon monoxide soluble?
NO
it is also colorless and odorless
How do exposures to CO occur?
Accidental exposures from fires, propane powered equipment, space heaters, etc and automobile exhaust
What concentration of CO can cause clinical signs and death with a 1 hour exposure?
Greater than 1000 ppm (0.1%)
What is the MOA of CO?
CO combines with hemoglobin to form carboxyhemoglobin which can NOT carry oxygen
death is from hypoxia
Animals with CO poisoning may have bright red blood and healthy pink mm.. why?
Carboxyhemoglobin is bright red due to hyperventilation
this is not noted in all cases
