Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1983
Evaluation of neurotoxicity after subarachnoid injection of large volumes of local anesthetic solutions.
Recent case reports describing prolonged neurologic deficit after accidental spinal anesthesia with large volumes of 2-chloroprocaine have led to the suggestion that chloroprocaine may be more likely to cause such complications than other local anesthetics. We evaluated the neurologic effects of lumbar puncture alone and of large-volume subarachnoid administration of 2-chloroprocaine (3%), bupivacaine (0.75%), lidocaine (2%), Elliott's solution B (which is similar to CSF), or the carrier solution of 2-chloroprocaine (Nesacaine) in 48 sheep and 8 monkeys. Cerebrospinal fluid of sheep was collected on days 1 and 7 for biochemical and biological analyses, and CSF pressures of monkeys were recorded before and after injection. ⋯ Three of the eight monkeys had lumbar subpial demyelination with macrophage invasion; two had received bupivacaine, and one received 2-chloroprocaine. No solution produced significant abnormalities in sheep CSF composition. We conclude that no local anesthetic or solution was more neurotoxic than another when injected in large volumes into the subarachnoid space of sheep or monkeys.
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Paraplegia is the major risk involved in reconstructive surgery for scoliosis with fusion. To detect spinal cord dysfunction intraoperatively, somatosensory cortical-evoked potential (SCEP) monitoring and a wake-up test or a combination of the two is generally used. Our pilot studies indicated that a balanced anesthesia technique consisting of nitrous oxide, narcotics, and a muscle relaxant is well-suited both for SCEP monitoring as well as for wake-up tests. ⋯ Wake-up tests were smooth and repeatable. Patients who received fentanyl infusions fared better than those receiving MS in that they did not require postoperative respiratory support. Continuous infusions of fentanyl are useful in reconstructive spinal surgery for scoliosis with monitoring.