Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1999
Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: implications for regional anesthesia. Mayo Perioperative Outcomes Group.
Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. ⋯ The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.
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Anesthesia and analgesia · Feb 1999
Comparative StudyCraniotomy procedures are associated with less analgesic requirements than other surgical procedures.
The conventional wisdom that neurosurgical patients experience minimal postoperative pain and require little analgesia has been challenged. To address this, we reviewed our anesthesia and postanesthesia care unit (PACU) records for 1995 and compared pain management in patients undergoing major intracranial and selected extracranial procedures. We recorded patient weight, operative time, time in the PACU, intraoperative and postoperative opioid use, PACU pain scores, and level of consciousness in patients who had undergone open fixation of mandible or maxilla (Group E), clipping of aneurysms or excision of tumors (Group I), or lumbar laminectomy (Group L). Group I (n = 78) patients received less fentanyl in the operating room (0.016 microg x kg(-1) x min(-1) versus 0.023 microg x kg(-1) x min(-1) for Group E [n = 134] and 0.023 microg x kg(-1) x min(-1) for Group L [n = 21]; P < 0.05), received less morphine in the PACU (0.0004 vs 0.0013 vs 0.0015 mg kg(-1) x min(-1); P < 0.005), reported lower pain scores (0.76 vs 2.5 vs 2.4; P < 0.05), and spent less time in the PACU (89.5 vs 109 vs 105 min; P < 0.05) than Group E or L patients. Our results were similar when only patients with Glasgow Coma Scale scores > or = 14 were used in a subset analysis. We conclude that patients suffer less pain and use fewer opioids in the PACU after intracranial surgery than after facial reconstruction or lumbar laminectomy. Our results confirm that the average craniotomy patient has less postoperative pain than patients who undergo other surgical procedures, although patients who undergo frontal craniotomy may require more aggressive pain management. ⋯ This study compares the pain report and analgesic use in patients after intracranial versus extracranial surgery. The results confirm the commonly held but recently challenged belief that neurosurgery patients suffer less pain postoperatively than other patients. In this study, we found that most patients report minimal pain after intracranial surgery but that a small subset of patients, many of whom have undergone frontal craniotomies, require aggressive treatment of postoperative pain.
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Anesthesia and analgesia · Feb 1999
The risk of persistent paresthesia is not increased with repeated axillary block.
Neurologic deficits are noted on physical examination in approximately 0.2%-19% of patients after regional anesthetic techniques. Laboratory and clinical studies suggest that a subclinical neuropathy occurs much more often. Performing a regional anesthetic technique during this period may result in additional nerve trauma. We evaluated the frequency of neurologic complications in patients undergoing repeated axillary block. A total of 1614 blocks were performed on 607 patients. The median number of blocks per patient was two (range 2-10 blocks). The median interval between blocks was 12.6 wk, including 188 (31%) patients who received multiple blocks within 1 wk. Sixty-two neurologic complications occurred in 51 patients for an overall frequency of 8.4%. Of the 62 nerve injuries, 7 (11.3%) were related to the anesthetic technique; the remaining 55 (88.7%) were a result of the surgical procedure. Patient age and gender, the presence of preexisting neurologic conditions, a surgical procedure to a nerve, and total number of blocks did not increase the risk of neurologic complications. No regional anesthetic technique risk factors, including elicitation of a paresthesia, selection of local anesthetic, or addition of epinephrine, were identified. The success rate was higher with the paresthesia technique than with nerve stimulator technique or transarterial injection, and with use of mepivacaine versus bupivacaine. We conclude that the frequency of neurologic complications in patients undergoing repeated axillary block is similar to that in patients receiving a single regional technique. These patients are not likely to be at increased risk of neurologic complications. ⋯ The risk of neurologic complications was not increased in patients who underwent multiple axillary blocks, even within a 1-wk interval. No risk factors for anesthetic-related complications were identified. However, block success rate was increased with the paresthesia technique and the injection of mepivacaine versus bupivacaine.
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Anesthesia and analgesia · Feb 1999
Comparative StudyPre- versus postinjury effects of intravenous GABAergic anesthetics on formalin-induced Fos immunoreactivity in the rat spinal cord.
We evaluated the suppression of spinal Fos-like immunoreactivity (FLI) by i.v. anesthetics in the rat formalin model. Preformalin injection (1.5% subcutaneously) treatment groups included i.v. saline controls and three i.v. GABAergic anesthetic groups (pentobarbital 20 mg/kg, propofol 10 mg/kg, or alphaxalone 1.5 mg/kg; n = 12 per group). After perfusion 2 h postformalin, spinal cords were dissected, sliced at 30 microm, and processed by immunoperoxidase staining with an antibody against the Fos protein. Quantification and determination of the laminar distribution of Fos-labeled nuclei were performed at the L4-5 spinal level ipsilateral to formalin injection. Drug groups demonstrating FLI suppression were comparatively studied in a 5-min postformalin treatment group. Pentobarbital pretreatment failed to suppress FLI. However, significant reductions (percent decrease) of FLI were observed with propofol (63%) and alphaxalone (30%) compared with saline controls. Pre- versus postformalin comparison studies showed that propofol, but not alphaxalone, suppressed FLI more effectively when given preformalin. Given the observed inconsistencies between this study of Fos expression and our previous behavioral study, it is questionable whether anesthetic modulation of noxious stimulus-induced FLI parallels that of behavioral responses. ⋯ In this study, we examined whether i.v. general anesthetics (propofol, alphaxalone, and pentobarbital) prevent injury-induced spinal cord changes. We measured spinal Fos protein after rats received anesthetics before versus after a formalin injection. Fos inhibition patterns were inconsistent with behavioral studies of these anesthetics, suggesting that Fos inhibition does not always correlate with behavioral analgesia.