PIN-INDEX SYSTEM

Typical Number in Hospital:

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References: 2

Delivery of the wrong anaesthetic gases may cause death or permanent injury. One precaution taken to prevent this has been the introduction of an international standard system to provide non-interchangeable mating between the gas cylinder and the cylinder yokes on anaesthetic machines. This takes the form (set out in British Standard BS 1319 of 1976) of one or two pins protruding from the yoke which mate with holes in the cylinders. Pin-indexing is not used on larger cylinders or free standing cylinders for oxygen therapy.

Another precaution against the connection of incorrect cylinders is the colour coding of cylinders. Unfortunately this is not yet standardized internationally.

A similar idea has been employed to prevent the filling of anaesthetic vaporizers with the wrong agent. Examples are the Fraser Sweatman pin safety system, and the Cyprane keyed filler system which utilize non-interchangeable filling bottles and nozzles for topping up the reservoirs of anaesthetic vaporizers.