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Simple asphyxiants 單純窒息劑
carbon dioxide 二氧化碳, hydrogen 氫氣, nitrogen 氮氣,
the noble gases 惰性氣體 (helium 氦, neon 氖, argon 氬, krypton 氪, xenon 氙, radon 氡),
and simple hydrocarbons such as methane 甲烷, butane 丁烷, and propane 丙烷.
 
Displace oxygen from air 使氧氣濃度下降
 

Irritant Gases or Droplets 呼吸道刺激
 
高水溶性
Highly water-soluble agents react with water in the upper respiratory tract and produce immediate irritation and discomfort.
The most common agent released in chemical events is the highly soluble pulmonary irritant ammonia.
sulfur dioxide 二氧化硫 and hydrogen chloride 氯化氫, Hydrogen fluoride 氟化氫
 
significant eye irritation and edema, burning in the throat,
and, at higher concentrations, constriction of the upper airway
 
Hydrogen fluoride : 補鈣 serum ionized calcium level and administration of supplemental calcium IV
 
Intermediate in solubility are chlorine 氯 and hydrogen sulfide 硫化氫
Chlorine : the second most common hazardous material released.
Chlorine reacts with water in the upper airways to produce hydrochloric 鹽酸 and hydrochlorous acids 次氯酸
Symptoms include burning of the conjunctiva, throat, and the bronchial tree.
Because of its acrid odor, chlorine has good warning properties.
Higher concentrations can produce bronchospasm, lower pulmonary injury, and delayed pulmonary edema.
 
Minimally soluble agents : Phosgene 光氣
 
It produces only minimal irritation to the eyes and upper airways and,
in fact, has a pleasant odor of new-mown hay. 新割干草
it slowly hydrolyzes to hydrochloric acid and reacts in the alveoli to cause the delayed onset of severe acute lung injury
Noncardiogenic pulmonary edema
 

Interrupt the delivery of oxygen transport by altering hemoglobin 氧氣攜帶
 
Carbon monoxide 一氧化碳 and methylene chloride 二氯甲烷
一氧化碳的來源有兩種,一為二氯甲烷,是去除油污或油漆的一種溶劑,常發生於蠟筆工廠
另一種大家較為熟知,為燃燒不完全所致
carboxyhemoglobin
 
Nitrites : divalent Fe2+ to trivalent Fe3+. Hemoglobin with trivalent iron is called methemoglobin
Treated initially with high concentrations of oxygen.
Methemoglobinemia may be treated with methylene blue.
 
 

Chemical asphyxiants 電子傳遞鍊
interfere with oxygen utilization at the electron transport chain in the mitochondria
cyanide 氰化物, hydrogen sulfide 硫化氫, phosphine 磷化氫, and sodium azide 疊氮化鈉
headache, alteration of consciousness, seizures, and severe acidosis
Hydroxocobalamin
 
 

Nerve agents 神經毒劑
sarin (GB), soman (GD), tabun (GA) and VX
They bind to acetylcholinesterase in a two-stage process.
The first stage is reversible if the antidote pralidoxime is given.
The second stage (aging process) makes the enzyme unavailable to be regenerated by pralidoxime.
“DUMBELS” syndrome :
defecation, urination, miosis, bradycardia/bronchospasm/bronchorrhea, emesis, lacrimation, and salivation.
 
Excess cholinergic stimulation here causes the progression from
muscular fasciculation to profound muscular weakness to complete paralysis in a dose-dependent fashion.
 
Brain : excessive stimulation produces coma and seizures.
Many organophosphates cross the blood–brain barrier freely, and the nerve agents in particular have potent CNS effects.
 
Atropine counteracts only the muscarinic effects.
Pralidoxime counteracts the nicotinic effects.
Benzodiazepines treat seizures.
 
Administer IV atropine to anyone experiencing hypersalivation, bronchial secretions, or bradycardia
High doses of atropine were not needed in the lower concentration exposures
Titrate atropine administration to clearing of the excess secretions.
Pupil size and heart rate response are poor indicators of adequate atropinization in organophosphate exposure.
 
pralidoxime is 1 - 2 grams IV slowly over 20 to 30 minutes.
In a large event with multiple casualties, half this may be given to spread the antidote to the maximal number of patients.
continuous infusion of pralidoxime at 500 milligrams/h
or intermittent bolus dosages of 1 to 2 grams every 6 hours
 
Succinylcholine should not be used !!
The onset of action of succinylcholine will be the same (usually <90 seconds),
but the duration of action of this drug will be prolonged to several hours !
 

incapacitating agents 失能劑
mace 辣椒水, tear gas 雖然不是傳統這個分類的, 但也能被列入
Narcotic vapors
 

Vesicant 糜爛發泡毒劑
芥子毒氣 (Mustard gas)
光氣肟 (Phosgene oxime) - severe skin erythema
Lewisite 路易氏劑
 
Vesicants cause damage to eyes, skin, mucous membranes,
and potentially the lungs if exposed to high concentrations
 
Both lewisite and phosgene oxime produce symptoms on immediate contact.
Sulfur mustard skin symptoms are delayed in onset for 4 to 8 hours,
leading to blistering similar to second-degree burns within 2 to 18 hours of initial exposure.
Ocular damage, Corneal vesicle - copious irrigation
 
The mustard agents may produce a systemic toxicity,
with marrow suppression as a delayed component presenting with a falling WBC count
and increased risk of infection 3 to 5 days after exposure
 
 
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