Cannula. A plastic tube designed for insertion into a body cavity. We use cannulae for the nasal-delivery of oxygen. Paramedics also use venous cannulae, incorporating a sheathed needle which is inserted into a vein (cannulation) so that fluids and drugs may be delivered. Paramedics will decide on an appropriate size (IV cannula sizing is all about bore width, in other words, how wide the hollow part of the needle is) depending on: the age and size of the patient; the size and condition of their veins; the amount of fluid that will be given, or if no fluids are to be given, the amount and type of drug that will be given.
Larger bore cannulae are chosen for trauma and cardiac arrest, simply because fluids will almost always be given. It is common for paramedics to choose a middle-sized cannula (18g) for most patients requiring IV access because this will enable a choice of drugs and fluids if required.
Larger bore cannulae are chosen for trauma and cardiac arrest, simply because fluids will almost always be given. It is common for paramedics to choose a middle-sized cannula (18g) for most patients requiring IV access because this will enable a choice of drugs and fluids if required.
Paramedics may also decide to cannulate a patient so that a vein is made patent, in case the patient's condition deteriorates and finding an appropriate vein becomes difficult later on. This technique is known as 'Keep Vein Open' (KVO).
