Failed epidural: causes and management

Abstract

Failed epidural anaesthesia or analgesia is more frequent than generally recognized. We review the factors known to influence the success rate of epidural anaesthesia. Reasons for an inadequate epidural block include incorrect primary placement, secondary migration of a catheter after correct placement, and suboptimal dosing of local anaesthetic drugs. For catheter placement, the loss of resistance using saline has become the most widely used method. Patient positioning, the use of a midline or paramedian approach, and the method used for catheter fixation can all influence the success rate. When using equipotent doses, the difference in clinical effect between bupivacaine and the newer isoforms levobupivacaine and ropivacaine appears minimal. With continuous infusion, dose is the primary determinant of epidural anaesthesia quality, with volume and concentration playing a lesser role. Addition of adjuvants, especially opioids and epinephrine, may substantially increase the success rate of epidural analgesia. Adjuvant opioids may have a spinal or supraspinal action. The use of patient-controlled epidural analgesia with background infusion appears to be the best method for postoperative analgesia.

The epidural electric stimulation test does not predict local anesthetic spread or consumption in labour epidural analgesia

“…Nevertheless, it may be associated with complications, such as intrathecal, intravascular or subdural catheter placement, as well as the inappropriate positioning of the latter in the epidural space, leading to failed or inadequate blocks. 1 In a large cohort study in non-obstetric subjects, up to a 27% failure rate for lumbar epidural has been described, 2 while in labour epidural analgesia, a 1.5-23% failure rate has been reported. 3,4 The correct placement of the epidural catheter therefore remains a clinical concern.…”

Preparing Drugs for Infusion Via Syringe Pump: A Key Step to Ensure Homogeneous Concentration

“…Failure to reach the analgesic concentration is one of the causes of ineffectiveness of an epidural analgesic. 29 It is important to note that all of the drug solutions were shaken with (1) an air bubble and (2) mixing by turning the syringe top-to-bottom in a 180° shaking movement 5 consecutive times. To our knowledge, these 2 measures have never been recommended.…”

Utility of transesophageal echocardiography in identifying spinal canal structures and epidural catheter position: a prospective observational study of intraoperative hemodynamics and postoperative analgesia

“…4 Precise positioning of the epidural catheter is thought to be an important requirement for optimal analgesia using minimal drug doses and fewer related complications. 5,6 One of the major concerns with using epidural anesthesia is the relatively high incidence (up to 30% in some reports) 7 of inadequate block, 8 which is thought most likely to be caused by misplacement of the epidural catheter. 9 Although surface ultrasonography is a non-invasive tool that can be used in awake patients, its usefulness for thoracic epidural imaging is limited because of the narrow thoracic intervertebral spaces and the oblique trajectory needed for ultrasound imaging in this region.…”