A series of truly failed spinal anesthetics

Bupivacaine concentrations in lumbar cerebrospinal fluid in patients with failed spinal anaesthesia

“…4 Proposed mechanisms for inadequate block despite correct dosing and injection technique are maldistribution, 5 variability in the anatomy of the lumbar subarachnoid space, 6 inadvertent subdural 7 or epidural injection, 8 and resistance to the effects of LA. 9 Confronted with FSA, the anaesthesiologist can either administer general anaesthesia or repeat the subarachnoid injection with an identical or smaller dose of LA. However, choosing an adequate dose of LA for a second subarachnoid injection is difficult because the amount of LA already present in the subarachnoid space is unknown.…”

Efficacy and safety of three ophthalmic inserts for topical anaesthesia of the cornea. An exploratory comparative dose‐ranging, double‐blind, randomized trial in healthy volunteers

“…Considering each element of the primary end‐point, it should be noted that only one patient did not reach complete anaesthesia with inserts A and B, while all patients achieved complete anaesthesia with insert C. The data obtained in this patient were surprising: no anaesthesia was provided by treatment A, only one stimulation time revealed corneal anaesthesia with treatment B (anaesthesia < 5 min), and anaesthesia of 5 min was induced by treatment C. This profile suggests a possible resistance to anaesthesia, already described in the literature, rather than a lack of efficacy of the products investigated [7–9].…”

Large intrathecal volume: a cause of true failed spinal anesthesia

“…Physiologic resistance to an intrathecal local anesthetic as an explanation for failed spinal anesthesia has been included among the etiologies for a true failed spinal [2,4]; however, as "resistant" sodium channel conformations to local anesthetics have yet to be discovered in the Caucasian population, it should not be seriously considered in the etiology of failed spinal anesthesia. One case of true failed spinal anesthesia in 2004 describes failed spinal anesthesia in a parturient following an intrathecal bupivacaine injection.…”

“…Reports of true failures of intrathecal analgesia have been largely associated with spinal catheter use rather than with single-injection spinals; the catheter-related failures are believed to be secondary to malposition of the catheter (caudad placement) with maldistribution of local anesthetic. Although there are different theories to explain true failures of spinal anesthesia, most failures are actually due to technical mishaps with failure to actually introduce the local anesthetic into the cerebrospinal fl uid (CSF) [2][3][4][5]. Anatomic malformations and enlarged thecal volumes, that lead to sacral restriction and spinal failure, are rarely observed or reported.…”