Editor, Australian Prescriber Vol. 17 No. 4 1994 includes as an insert, the wall chart 'Medical management of severe anaphylactoid and anaphylactic reactions'. Step 4 advises that one, or preferably two, widebore intravenous lines be established. It is regrettable that wide bore is followed by '(16 gauge or larger)'. Many practitioners would not need to be told what widebore means; those who do are presumably also likely to be less skilled in inserting such cannulae. The flow of a watery solution and even of the colloid Haemaccel through an 18 gauge cannula is only a little slower than through a 16 gauge cannula under the same circumstances, but this might be compensated for by raising the infusion flask as much as possible. In any case, an 18 gauge cannula is much easier to insert and the subsequent infusion is far superior to failing to insert a larger cannula, often involving several attempts and the destruction of invaluable venous sites! For many years in anaesthetic practice, I have stressed to my trainees that 16 gauge or larger cannulae need not be used unless there is a significant risk that rapid transfusion of blood or packed cells might be required.
Herbert C. Newman
Anaesthetist
Camberwell, Vic.
