Low-dose intrathecal local anesthetic does not increase the threshold current for the epidural stimulation test: a prospective observational trial of neuraxial analgesia in labouring women

Electrical stimulation test for epidural catheter placement after receiving intrathecal local anesthetic during a combined spinal-epidural technique for Cesarean delivery: confirmation of the spinal nerve root as epidural site of action

“…The current threshold to elicit the motor response was comparable with the reported range of 2-10 mA (mean, 4.2 mA) after low-dose intrathecal injection with labour CSE. 3 This observation supports the notion that the site of action of the EST is primarily at the nerve roots within the epidural compartment rather than the spinal cord itself. Unrecognized epidural catheter failures after CSE procedures are an ongoing concern as a result of clinicians not being able to test or utilize the epidural catheters until after the initial spinal dose portion of the CSE has dissipated.…”

“…1,2 In obstetrical patients, this test can confirm the proper epidural catheter placement in labouring women receiving low-dose combined spinal epidural (CSE). 3 Confirmation of epidural catheter placement after a full surgical spinal dose CSE for Cesarean delivery is important as epidural failure (1.7%) is a known complication of the CSE procedure. 4 We share our experience of applying an EST via the epidural catheter following full surgical spinal dose of CSE for Cesarean delivery.…”

Failed caudal block due to physiologic changes associated with a cerebrospinal fluid leak: a case report

“…Current thinking suggests that early nerve block occurs as an extradural radicular block, with a subdural spinal block occurring later. 6,7 We speculate that the etiology of the failed caudal block could have been multifactorial in this patient. We considered one of the most likely mechanisms to be high systemic absorption of the injected anesthetic due to significant epidural venous plexus engorgement.…”