Anesthesia and analgesia
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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.
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Anesthesia and analgesia · Aug 1983
Comparative StudyLidocaine and bupivacaine differential blockade of isolated canine nerves.
In vitro studies of pharmacologic actions of local anesthetics are usually performed at room temperature using amphibian nerves exposed to local anesthetics for substantial periods of time. We performed in vitro studies of pharmacologic responses of motor A fibers and sensory C fibers to lidocaine and bupivacaine in clinically effective concentrations using a canine nerve preparation at body temperature with short exposure times to evaluate responses under clinically relevant conditions. Differential blockade of isolated, desheathed phrenic and vagus nerves was achieved with bupivacaine (0.58 mM), C fibers being blocked before A fibers (P less than 0.05). Lidocaine (2.8 mM) did not block A and C fibers differentially.
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Anesthesia and analgesia · Aug 1983
Thymidine and methionine syntheses in pregnant rats exposed to nitrous oxide.
The dose-dependent effects of nitrous oxide on thymidine and methionine syntheses were investigated in pregnant rats. Female Sprague-Dawley rats were exposed on day 9 of gestation to 0.75%, 7.5%, or 75% nitrous oxide for 24 h. Immediately and 72 h after exposure, a deoxyuridine-suppression test was performed on maternal bone marrow and a methionine synthetase assay was performed on maternal liver to assess thymidine and methionine syntheses, respectively. ⋯ Recovery was complete 72 h after exposure. Methionine synthetase activity was abolished at all concentrations of nitrous oxide tested and did not return to control values 72 h after exposure. Fetal weight and gross appearance were not affected by exposure to nitrous oxide; however, the observed decrease in thymidine and methionine syntheses after nitrous oxide exposure may account for its teratogenic effects.
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Anesthesia and analgesia · Jul 1983
Randomized Controlled Trial Clinical TrialEpidural morphine for the relief of postoperative pain after cesarean delivery.
To determine the safety, efficacy, and dose response of epidurally administered morphine for analgesia after cesarean delivery, 40 healthy women who underwent cesarean delivery with epidural anesthesia were randomly assigned to receive one of four regimens for relief of postoperative pain: intramuscular administration of morphine, 7.5 mg (N = 10); or epidural administration of morphine, 2 mg (N = 10), 5 mg (N = 10), or 7.5 mg (N = 10). Evaluations were made of intensity and relief of pain, time to administration of additional analgesic medications, changes in vital signs and blood-gas tensions, and adverse effects. Intramuscular administration of 7.5 mg of morphine effectively relieved pain for only a short time. ⋯ There were no significant changes in vital signs or blood-gas tensions. Side effects included pruritus and nausea, which occurred frequently but were usually mild and easily treated. We concluded that either 5 mg or 7.5 mg of morphine epidurally administered was effective and safe in providing prolonged analgesia after cesarean delivery.