the bloody tap
Generally defined as blood in the epidural catheter, the risk being that the catheter has threaded into an epidural vein. If not recognised and managed correctly, could cause local anaesthetic toxicity.
The commonest reason to get a bloody tap is threading the catheter during contractions, when the veins are at their most engorged.
Flush catheter free of blood, with 2-5ml saline, and then aspirate. If blood is easy to aspirate, pull catheter back 1-2cm, whilst leaving adequate catheter (3-4cm) in space.
NB do not withdraw catheter whilst tuohy needle in situ, risk of shearing catheter tip.
If blood no longer aspirates, cautiously give test dose, being mindful of signs of local anaesthetic toxicity.
If blood still aspirates, abandon that epidural attempt and reinsert. There is lots of discussion surrounding level of next attempt. This may be dictated by ease of insertion at another level. Same level may be reattempted, particularly if difficult to palpate next level.
If a second tap occurs, may be that there is anatomical variation in epidural vein plexus, and consideration of abandoning epidural altogether.