[Reliability of the epidural test dose].

Complications associated with epidural anaesthesia include accidental intravascular or subarachnoid epidural catheter misplacement resulting in systemic toxicity and total spinal block, respectively. Epidural test doses are used routinely to prevent these events. It is not known whether the use of test doses improves the safety of epidural anaesthesia. The reliability of the epinephrine test dose in terms of detecting intravascular injection is impaired in elderly patients, patients receiving beta-blockers, patients undergoing vascular surgery, patients under general anaesthesia, and in women in labour. The ability of the epidural test dose to detect subarachnoid injection remains unknown. Studies are needed to determine 1) the reliability of the epidural test dose among different groups of patients, 2) the safety of the test dose, and 3) the incidence of epidural catheter misplacements.