Knowmedical introduced among its products kits for epidural and spinal anaesthesia. Epidural anaesthesia is the anaesthesia of rachis though an injection of local anaesthetic drug in the extra-dural space. The introduction in the epidural space could be made in the cervical, thoracic, lumbar or sacral area.

The epidural space extends from the magnum foramen, where the dura pleura arrives, to the sacral coccyx ligament, which includes the sacral iatum. This is an open space, because it is crossed by 31 pairs of spinal nerves and it communicates with the para-vertebral spaces. The epidural space in lumbar region, in the introduction point of the needle, on the median line is about 4-6mm deep. The distance of the epidural space from the skin varies from 2,5 to 9cm, with a medium value of 4-5cm.

Tuohy needle is the most used one for puncture in the epidural space. The size changes between 16G to 20G. The edge is curved towards the height to allow the exit of the catheter and to determine its direction. Moreover, it is less cutting, to reduce risks of dura puncture. The needle has to be graduated in cm to guarantee the measurement of the reached depth. Each needle has a mandrin that runs easy, in order to avoid the obstruction of the needle lumen by little pieces of skin and tissue. This element is taken away before the introduction of the yellow ligament to allow the application of techniques to identify the epidural space (Loss of resistance and pending drop techniques).

The catheter is in nylon to allow obtaining a product neither too soft (clinking risk) nor too rigid (wounds risk). Moreover, the BaSO₄ line has the function to make the catheter radiopaque and to let it be seen in case of breaking. The epidural catheter must have the following characteristics:

• Not to be either too soft or too rigid;
• be resistant not to break during extraction, and not to clink during puncture;
• iameter must be reduced in order to allow passage into the Tuohy needle;
• inner diameter must allow the injection of anaesthetic drug without too high resistance;
• length must be sufficient to fix it easily in the thoracic region;
• edge must be soft and regular to avoid venous and dura mater puncture;
• have cm graduation to allow exact identification of the length of catheter which is in the epidural space;
• can only have one hole, distal or on side.

It is possible to use a stylet inside the catheter in order to make it more rigid and to make its introduction easier. The stylet has a blue coloured grip, in order to let the doctor see it more easily and take it away.

The syringe is a device that allows identification of the good position of the needle in the epidural space. Syringes come in two different models:

• L.O.R. syringes (loss of resistance);
• Standard syringes, with better sensibility.

In order to better identify the epidural space it is necessary that the plunger moves easily into the syringe body.

The adaptor has a male Luer lock cap that allows both maintaining inside sterility until use, even if the package is open, and correct position of the catheter.

The filter is specific for the administration of anaesthetics in the epidural space, with the aim to lowen the risks of particles and/or contamination. It has an exact filtration surface of 4,3 cm² with a porosity of 0,2 μm. It has a male Luer Lock cap and a vented cap that keeps the inside sterility until the use even if the package is open.