Use of imaging agent to determine postoperative indwelling epidural catheter position

Abstract

Background: Epidural anesthesia is widely used to provide pain relief, whether for surgical anesthesia, postoperative analgesia, treatment of chronic pain, or to facilitate painless childbirth. In many cases, however, the epidural catheter is inserted blindly and the indwelling catheter position is almost always uncertain.

Methods: In this study, the loss-of-resistance technique was used and an imaging agent was injected through the indwelling epidural anesthesia catheter to confirm the position of its tip and examine the migration rate. Study subjects were patients scheduled to undergo surgery using general anesthesia combined with epidural anesthesia. Placement of the epidural catheter was confirmed postoperatively by injection of an imaging agent and X-ray imaging.

Results: The indwelling epidural catheter was placed between upper thoracic vertebrae (n = 83; incorrect placement, n = 5), lower thoracic vertebrae (n = 123; incorrect placement, n = 5), and lower thoracic vertebra-lumbar vertebra (n = 46; incorrect placement, n = 7). In this study, a relatively high frequency of incorrectly placed epidural catheters using the loss-of-resistance technique was observed, and it was found that incorrect catheter placement resulted in inadequate analgesia during surgery.

Conclusions: Although the loss-of-resistance technique is easy and convenient as a method for epidural catheter placement, it frequently results in inadequate placement of epidural catheters. Care should be taken when performing this procedure.

Keywords: epidural anesthesia; iotrolan; pain; postoperative; radiography.

Fig. 1

Study flow. From a pool of 654 patients, we explained the objective of this study to 513 patients and obtained informed consent from 268 patients.

Fig. 2

Typical imaging views. Typical imaging views of the (A) upper thoracic area, (B) lower thoracic area, and (C) lumbar vertebrae. Arrows indicate regions imaged.

Fig. 3

Incorrect epidural catheter placement in the imaged upper thoracic area. Incorrect epidural catheter placement was observed by imaging of the upper thoracic vertebrae. Arrow indicates subcutaneous leakage of imaging agent.

Fig. 4

Incorrect epidural catheter placement of the imaged lower thoracic area. Incorrect epidural catheter placement was observed by imaging of the lower thoracic vertebrae. (A) Administered imaging agent is leaking subcutaneously. (B) Administered imaging agent is highlighting the intercostal nerve.

Fig. 5

Incorrect epidural catheter placement in the imaged lumbar area. Incorrect epidural catheter placement was observed by imaging of the lumbar area. Administered imaging agent is highlighting the psoas compartment.