Friday, 6 February 2015

Inhalation

The CEM syllabus says knows the rarer causes of breathless-ness including "inhalational injury from chemical and physical irritants, foreign body inhalation". A search for that came up with cyanide poisoning and methaemoglobinaemia - so have written a bit about them too on further blog posts. I also think that carbon monoxide poisoning is important - blog post to follow.

History
The following key points should be taken in a focused history
            Exactly what exposed to and how much (ie volume and concentration)?
            What route?
            What protective measures were taken?

            What treatment was given?

PPE
Some chemicals do not cause secondary contamination e.g. chlorine.

Smoke Inhalation
- Monitor for 4-6 hours in the ED.
- Observe for longer if high risk items in their history:
History of closed-space exposure for longer than 10 minutes
Carbonaceous sputum production
Arterial PO2 less than 60 mm Hg
Metabolic acidosis
Carboxyhemoglobin levels above 15%
Arteriovenous oxygen difference (on 100% oxygen) greater than 100 mm Hg
Bronchospasm
Odynophagia
Central facial burns
Pulmonary injury from smoke inhalation causes hyperinflation and atelectasis. Debris from cellular necrosis, inflammatory exudate, and shed epithelium combine with carbonaceous material to narrow airways that are already compromised by oedema. Reflex bronchoconstriction further worsens the obstruction.


Metals
Metal fume fever (MFF) is an acute disease induced by intense inhalation of metal oxides- mostly zinc. It is a self-limited syndrome characterized by fever, myalgias, headache, and nausea. Symptoms develop 4-12 hours after exposure and typically last several hours; severe cases generally resolve in 1-2 days. Observation is usually all that is necessary.

The exact pathology of MFF is not well understood but likely involves the deposition of fine metal particulates in the alveoli.



http://www.enlightenme.org/knowledge-bank/cempaedia/industrial-chemical-incidents
http://www.toxlearning.co.uk/course/view.php?id=21
http://emedicine.medscape.com/article/771194-overview
http://emedicine.medscape.com/article/814287-overview
http://emedicine.medscape.com/article/1005903-overview
http://emedicine.medscape.com/article/204178-overview#a0101
http://www.annemergmed.com/article/S0196-0644(05)80424-X/abstract
http://lifeinthefastlane.com/ccc/smoke-inhalation/
http://lifeinthefastlane.com/condom-inhalation/
http://lifeinthefastlane.com/toxicology-conundrum-038/


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