Phosgene: Difference between revisions
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==Background== | ==Background== | ||
[[File:Phosgene poster ww2.jpg|thumb]] | [[File:Phosgene poster ww2.jpg|thumb]] | ||
* phosgene (COCl2) is a highly toxic, colorless gas or liquid | *phosgene (COCl2) is a highly toxic, colorless gas or liquid | ||
*Classified as a [[pulmonary chemical agent]], [[chemical weapon]] | *Classified as a [[pulmonary chemical agent]], [[chemical weapon]] | ||
* gained infamy in WWI - responsible for 85% of deaths due to chemical weapons | *gained infamy in WWI - responsible for 85% of deaths due to chemical weapons | ||
* pulmonary irritant | *pulmonary irritant | ||
* major complication is non-cardiogenic pulmonary edema | *major complication is non-cardiogenic pulmonary edema | ||
* used in chemical reactions - large scale exposures usually 2/2 industrial accidents | *used in chemical reactions - large scale exposures usually 2/2 industrial accidents | ||
** manufacturers of dyes, resins, coal tar, pesticides | **manufacturers of dyes, resins, coal tar, pesticides | ||
*Denser than air, settles in low-lying places – trenches/basements | *Denser than air, settles in low-lying places – trenches/basements | ||
*Rapid olfactory fatigue can occur leading to prolonged exposure | *Rapid olfactory fatigue can occur leading to prolonged exposure | ||
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===Pathophysiology=== | ===Pathophysiology=== | ||
* acrylation reaction with amino, hydroxyl, and sulfhydryl goups | *acrylation reaction with amino, hydroxyl, and sulfhydryl goups | ||
* membrane structural changes, protein denaturation, depletion of glutathione | *membrane structural changes, protein denaturation, depletion of glutathione | ||
* increased vascular permeability leads to noncardiogenic pulmonary edema | *increased vascular permeability leads to noncardiogenic pulmonary edema | ||
==Clinical Features== | ==Clinical Features== | ||
* some people may note a smell of freshly cut hay or grass | *some people may note a smell of freshly cut hay or grass | ||
* eye and throat symptoms may occur at very low concentrations | *eye and throat symptoms may occur at very low concentrations | ||
* unpredictable latent phase | *unpredictable latent phase | ||
* development of noncardiogenic pulmonary edema | *development of noncardiogenic pulmonary edema | ||
*Symptoms may take 2-24 hours to develop | *Symptoms may take 2-24 hours to develop | ||
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==Evaluation== | ==Evaluation== | ||
* high index of suspicion, ask about work history/exposures | *high index of suspicion, ask about work history/exposures | ||
* no combination of labs/xrays can predict whether pt will develop pulmonary edema | *no combination of labs/xrays can predict whether pt will develop pulmonary edema | ||
* latent phase can be 30 min - 72hrs but significant exposures usually developed pulmonary symptoms within 24 hrs | *latent phase can be 30 min - 72hrs but significant exposures usually developed pulmonary symptoms within 24 hrs | ||
==Management== | ==Management== | ||
* supportive care | *supportive care | ||
* with [[pulmonary edema]] patients may require [[intubation]] with high PEEP | *with [[pulmonary edema]] patients may require [[intubation]] with high PEEP | ||
* [[albuterol]] for bronchospasm | *[[albuterol]] for bronchospasm | ||
* [[steroid]]s recommended but no solid evidence for efficacy | *[[steroid]]s recommended but no solid evidence for efficacy | ||
* no specific antidote exists | *no specific antidote exists | ||
==Disposition== | ==Disposition== | ||
Revision as of 01:12, 24 July 2017
Not to be confused with phosgene oxime (CX)
Background
- phosgene (COCl2) is a highly toxic, colorless gas or liquid
- Classified as a pulmonary chemical agent, chemical weapon
- gained infamy in WWI - responsible for 85% of deaths due to chemical weapons
- pulmonary irritant
- major complication is non-cardiogenic pulmonary edema
- used in chemical reactions - large scale exposures usually 2/2 industrial accidents
- manufacturers of dyes, resins, coal tar, pesticides
- Denser than air, settles in low-lying places – trenches/basements
- Rapid olfactory fatigue can occur leading to prolonged exposure
- Exposure may be secondary to fire at textile factory/house, metalwork, or burning Freon
Pathophysiology
- acrylation reaction with amino, hydroxyl, and sulfhydryl goups
- membrane structural changes, protein denaturation, depletion of glutathione
- increased vascular permeability leads to noncardiogenic pulmonary edema
Clinical Features
- some people may note a smell of freshly cut hay or grass
- eye and throat symptoms may occur at very low concentrations
- unpredictable latent phase
- development of noncardiogenic pulmonary edema
- Symptoms may take 2-24 hours to develop
Symptoms by Concentration
- Low: mild cough, chest tightness, shortness of breath
- Moderate: Lacrimation
- High: Non-cardiogenic pulmonary edema within 2 to 6 hours after exposure with death within 24-48 hours
Differential Diagnosis
Chemical weapons
- Blister chemical agents (Vesicants)
- Lewisite (L)
- Sulfur mustard (H)
- Phosgene oxime (CX)
- Pulmonary chemical agents (Choking agents)
- Incendiary agents
- Cyanide chemical weapon agents (Blood agents)
- Prussic acid (AKA hydrogen cyanide, hydrocyanic acid, or formonitrile)
- Nerve Agents (organophosphates)
- Acetylcholinesterase inhibitors
- Household and commercial pesticides (diazinon and parathion)
- G-series (sarin, tabun, soman)
- V-series (VX)
- Lacrimating or riot-control agents
- Pepper spray
- Chloroacetophenone
- CS
Evaluation
- high index of suspicion, ask about work history/exposures
- no combination of labs/xrays can predict whether pt will develop pulmonary edema
- latent phase can be 30 min - 72hrs but significant exposures usually developed pulmonary symptoms within 24 hrs
Management
- supportive care
- with pulmonary edema patients may require intubation with high PEEP
- albuterol for bronchospasm
- steroids recommended but no solid evidence for efficacy
- no specific antidote exists