[Unexpected intravenous penetration of an epidural catheter]

The tip of an epidural catheter inserted by the lumbar route, penetrated into the inner vertebral venous plexus. After the position of the catheter tip had been corrected, blood neither returned spontaneously nor could any be aspirated, suggesting that it was in the correct position. A low dose (3.5 ml) of 0.75% bupivacaine was given as a test injection whereupon no signs of a systemic reaction were observed. When the entire initial dose of 10 ml was given, the patient developed tonic clonic seizures. The fit could be controlled by giving oxygen and thiobarbital. The patient was given succinylcholine and then intubated and ventilated. As no signs of cardiac depression were noted, the operation (open mobilisation of a joint) was performed under general anaesthesia. The patient recovered normally. If the position of an epidural catheter which has penetrated an epidural vein has been corrected, this does not ensure that the tip has been removed from the vein, even if blood cannot be aspirated. This incorrect position can be detected by injection of a small volume of epinephrine-containing local anaesthetic, but this procedure cannot be recommended in cases of coronary insufficiency. The anaesthesist is best advised to remove the catheter completely and place a fresh epidural at a different level.