Subcutaneous emphysema due to compressed air.

Compressed-air tools are of interest by reason of their vibratory action which affects the peripheral circulation of the fingers. Raynaud's syndrome in riveters, pneumatic chisellers and drillers is well known. The harmful effect is almost certainly due to vibration, although cooling of the hands may occur with some pneumatic tools and may be a contributory factor.* Apart from using compressed air for riveting, burring and drilling operations, there are, however, two other widespread and simpler uses of compressed air in industry, associated with a totally different hazard. It is used as a coolant, i.e. to cool the tool on a lathe or other machine; and, more commonly, to blow away metal chips during machining so that the operator can see the work. A flexible rubber tube with a nozzle is used, rather like a small hosepipe, which most workers sling near their machine. The air pressure is about 70 lb. per square inch, which is capable of dimpling the back of the clenched fist quite deeply even when the nozzle is held several inches away. Considering its widespread use it is surprising that accidents are not more frequent; they are common enough, however, and are known to experienced industrial nurses. Several cases have come to my notice where there was skin trauma through which air entry caused subcutaneous emphysema.