Toxic gases 1

Question 1

T/F: Ammonia is heavier than air

Answer 1

True

it is also soluble in water and readily reacts with hydroxyl ions in MM - forming ammonium hydroxide which is a caustic irritant

Question 2

what are the forms of ammonium exposure animals may experience?

Answer 2

inhalation from..

decomposing manure in a confined area
burning nylon/plastic
Anhydrous ammonia used in fertilizer - broken hoses or values during transport

Question 3

At what dose does ammonia cause burning of the eyes?

Answer 3

25-35 ppm

*in enclosed animal houses ammonia levels may reach up to 50ppm

Question 4

Exposure of ammonia at _____ ppm can cause acute death?

Answer 4

5000 ppm

Question 5

what livestock are most susceptible to ammonia poisoning?

Answer 5

Swine and poultry

Question 6

what are the MOA of ammonia?

Answer 6

Direct irritation of the mm
Increased susceptibility to Resp. infection due to continuous exposure and inflammation
Decreased growth in young animals

Question 7

What happens pathologically when ammonia is inhaled at high concentrations?

Answer 7

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

Question 8

Hydrogen sulfide is colorless and has the odor of ____

Answer 8

rotten eggs

Question 9

What happens when hydrogen sulfide comes into contact with mm?

Answer 9

It is an irritant bc it concerts to sulfuric acid in solution and forms sulfide when it comes into contact with moist mm

Question 10

What occurs when sulfides mix with silver, iron, lead, or other metals?

Answer 10

forms a black or dark colored compounds - occurs with iron in the GIT and tissues

Question 11

How/when are animals exposed to hydrogen sulfide?

Answer 11

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

Question 12

What is the most dangerous sewage gas?

Answer 12

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)

Question 13

What is considered acute toxic levels of hydrogen sulfide in mammals?

Answer 13

500 - 800 ppm

poultry did not result in immediate death at 4000ppm

Question 14

What is H2S converted to in the blood?

Answer 14

alkali sulfides

Question 15

What is the MOA of H2S?

Answer 15

Inhibition of cellular respiration - decreased cytochrome oxidase

Question 16

What is a differential diagnosis for H2S poisoning?

Answer 16

Ammonia

Question 17

What is used for H2S treatment?

Answer 17

Sodium nitrate - forms methemoglobin and binds sulfide radicals and reactivates cytochrome oxidase

supportive care

Question 18

What is the MOST effective treatment of H2S poisoning?

Answer 18

PREVENTION - H2S monitors should be used

Question 19

T/F: H2S could delay rigor mortis

Answer 19

TRUE

Question 20

Is carbon monoxide soluble?

Answer 20

NO

it is also colorless and odorless

Question 21

How do exposures to CO occur?

Answer 21

Accidental exposures from fires, propane powered equipment, space heaters, etc and automobile exhaust

Question 22

What concentration of CO can cause clinical signs and death with a 1 hour exposure?

Answer 22

Greater than 1000 ppm (0.1%)

Question 23

What is the MOA of CO?

Answer 23

CO combines with hemoglobin to form carboxyhemoglobin which can NOT carry oxygen

death is from hypoxia

Question 24

Animals with CO poisoning may have bright red blood and healthy pink mm.. why?

Answer 24

Carboxyhemoglobin is bright red due to hyperventilation

this is not noted in all cases