Respiratory system/respiration breathing

Dust masks, or particulate filter respirators, protect the respiratory system against any kind of inhaled particles. The simplest type, in the form of a cone-shaped fibrous filter that fits over the nose and mouth, is held in place by an elastic band around the back of the head. It is disposable, relatively comfortable to wear, and is useful when the dust is neither excessive nor toxic. It becomes readily clogged and should be discarded and replaced whenever breathing becomes restricted. Its use should not be carried over from day to day. 

Many, perhaps most, chemical agents exert their lethal effects because of effects on the respiratory system and thus the provision of breathing support is essential. This is because toxic agents produce effects that cause blockage of the air passages, depression and failure of the respiratory control centres in the brain or paralysis of the muscles of respiration. To overcome these combined effects, the emergency medical response must include the ability to be able to clear and support the airway and also to be able to ventilate the lungs artificially when there is respiratory deficiency or arrest. This support is now part of a standard response for advanced life support in both conventional and toxic trauma and is termed TOXALS (Baker, 1996 Department of Health, 2003) (see Box 3). 

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