Inserting the needle. The woman's back is washed down with cool antiseptic solution and covered with green sterile drapes. The anaesthetist then feels the bones in the woman's lower spine with their fingers, to locate the best position to insert the needle. Once this is found they then inject a small amount of local anaesthetic at this point, just under the surface of the woman's skin (this may sting for a few seconds). After a few minutes (waiting for the local to take effect) a long, hollow epidural needle is inserted between two of the lower backbones until the tip reaches the firm interspinous ligament, which lies just before the epidural space. The insertion of the needle will usually feel like strong pressure and pushing in the area.
Inserting the epidural needle can be made a little more difficult for the anaesthetist if the woman is not very tall (making the spaces between the backbones smaller), is overweight for her height (fat tissue can make the location more difficult to determine), or has twins or more (making it more difficult for the woman to curl up into position).
 |
Image 8-15 shows an actual epidural needle being inserted. If you wish to look at this image you can click here:  Image 8-15. |
Testing for the location. Once the anaesthetist feels they have reached the ligament tissue they attach a syringe to the end of the epidural needle. The syringe will either have a small amount of air or sterile salt water (saline) in it. A small amount of pressure is placed on the syringe plunger as the needle is advanced slightly further. Once the epidural space is located the anaesthetist feels a 'loss of resistance' as the air or salt water is released into the epidural space.
The plunger on the syringe is then gently pulled back to see if any blood or spinal fluid can be seen.