Teaching an old pain medicine society new tweets: integrating social media into continuing medical education.

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Preoperative Screening and Case Cancellation in Cocaine-Abusing Veterans Scheduled for Elective Surgery

Background. Perioperative management of cocaine-abusing patients scheduled for elective surgery varies widely based on individual anecdotes and personal experience. Methods. Chiefs of the anesthesia departments in the Veterans Affairs (VA) health system were surveyed to estimate how often they encounter surgical patients with cocaine use. Respondents were asked about their screening criteria, timing of screening, action resulting from positive screening, and if they have a formal policy for management of these patients. Interest in the development of VA guidelines for the perioperative management of patients with a history of cocaine use was also queried. Results. 172 VA anesthesia departments’ chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Results. 172 VA anesthesia departments’ chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Conclusions. There is a general consensus that formal guidelines would be helpful. Further studies are needed to help formulate evidence-based guidelines for managing patients screening positive for cocaine prior to elective surgery

Standardizing Nomenclature in Regional Anesthesia: an ASRA-ESRA Delphi Consensus Study of Abdominal Wall, Paraspinal, and Chest Wall Blocks

BACKGROUND: There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques. METHODS: We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement. RESULTS: Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified. CONCLUSIONS: Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice

Dexamethasone as Adjuvant to Bupivacaine Prolongs the Duration of Thermal Antinociception and Prevents Bupivacaine-Induced Rebound Hyperalgesia via Regional Mechanism in a Mouse Sciatic Nerve Block Model

<div><p>Background</p><p>Dexamethasone has been studied as an effective adjuvant to prolong the analgesia duration of local anesthetics in peripheral nerve block. However, the route of action for dexamethasone and its potential neurotoxicity are still unclear.</p><p>Methods</p><p>A mouse sciatic nerve block model was used. The sciatic nerve was injected with 60ul of combinations of various medications, including dexamethasone and/or bupivacaine. Neurobehavioral changes were observed for 2 days prior to injection, and then continuously for up to 7 days after injection. In addition, the sciatic nerves were harvested at either 2 days or 7 days after injection. Toluidine blue dyeing and immunohistochemistry test were performed to study the short-term and long-term histopathological changes of the sciatic nerves. There were six study groups: normal saline control, bupivacaine (10mg/kg) only, dexamethasone (0.5mg/kg) only, bupivacaine (10mg/kg) combined with low-dose (0.14mg/kg) dexamethasone, bupivacaine (10mg/kg) combined with high-dose (0.5mg/kg) dexamethasone, and bupivacaine (10mg/kg) combined with intramuscular dexamethasone (0.5mg/kg).</p><p>Results</p><p>High-dose perineural dexamethasone, but not systemic dexamethasone, combined with bupivacaine prolonged the duration of both sensory and motor block of mouse sciatic nerve. There was no significant difference on the onset time of the sciatic nerve block. There was “rebound hyperalgesia” to thermal stimulus after the resolution of plain bupivacaine sciatic nerve block. Interestingly, both low and high dose perineural dexamethasone prevented bupivacaine-induced hyperalgesia. There was an early phase of axon degeneration and Schwann cell response as represented by S-100 expression as well as the percentage of demyelinated axon and nucleus in the plain bupivacaine group compared with the bupivacaine plus dexamethasone groups on post-injection day 2, which resolved on post-injection day 7. Furthermore, we demonstrated that perineural dexamethasone, but not systemic dexamethasone, could prevent axon degeneration and demyelination. There was no significant caspase-dependent apoptosis process in the mouse sciatic nerve among all study groups during our study period.</p><p>Conclusions</p><p>Perineural, not systemic, dexamethasone added to a clinical concentration of bupivacaine may not only prolong the duration of sensory and motor blockade of sciatic nerve, but also prevent the bupivacaine-induced reversible neurotoxicity and short-term “rebound hyperalgesia” after the resolution of nerve block.</p></div

Motor recovery of mouse sciatic nerve block with various medication.

<p>* indicates P<0.05 when compared with other groups. # indicates P<0.05 when compared with baseline control. The data were reported as mean ± SEM. NS, normal saline; Bup, bupivacaine; Dexa, dexamethasone; i.m., intramuscularly.</p

S-100 expression in sciatic nerves.

<p>5A. S-100 protein immunostaining in sciatic nerves (200×); 5B. Immunoreactivity of S-100 expression in different treatment groups on day 2 and day 7. Bupivacaine with or without intramuscular dexamethasone treatment group showed significantly lower S-100 expression on day 2 (red box) than that on day 7 (*<i>P</i><0.05), while S-100 was expressed significantly higher when treated with perineural bupivacaine and high-dose dexamethasone than treated with perineural bupivacaine and low-dose of dexamethasone (^#<i>P</i><0.05); 5C. Immunohistochemical assay for S-100 protein staining (deep brown, black arrows) in each group was primarily localized in the myelin sheath (400×, counterstained with hematoxylin). NS, normal saline; Bup, bupivacaine; Dexa, dexamethasone. Scale bar: 45 μm (black color),10 μm (red color).</p

Caspase-3 expression in sciatic nerves.

<p>4A. Immunohistochemical assays for cleaved caspase-3 staining (200×, nucleus counterstained with hematoxylin). There was no significant caspase expression in sciatic nerve axoplasm in all groups; 4B. Caspase-3 expression in positive control tissue (red arrows) (hippocampal neurons, 200×); 4C. Percentage of nucleus in sciatic nerves. The percentage of nucleus staining (blue arrows) in sciatic nerve was significant higher in bupivacaine treated mice on day 2 than day 7 (red box, *<i>P</i><0.05), while no significant difference was found in other groups. 4D. Caspase-3 expression in mouse sciatic nerve after bupivacaine and high-dose dexamethasone block (400×). NS, normal saline; Bup, bupivacaine; Dexa, dexamethasone. Scale bar: 45 μm (black color),10 μm (red color).</p

Paw withdrawal latency behavioral changes in response to thermal stimulation after sciatic nerve block with various medications.

<p>* indicates P<0.05 when compared with other groups. # indicates P<0.05 when compared with baseline control. The data were reported as mean ± SEM. NS, normal saline; Bup, bupivacaine; Dexa, dexamethasone; i.m., intramuscularly.</p

Microscopic changes of sciatic nerves after sciatic nerve block.

<p>3A. istomorphological changes of paraffin-embedded sciatic nerves on day 2 and day 7 after injection (400×, toluidine blue staining). Nerves appeared normal on day 2 and day 7 after injection in most groups, while nerves in the bupivacaine treated group (red box) showed fiber degeneration with vague myelin sheath appearance (arrows) at 2 days after injection; 3B. Percentage of demyelinated axons in sections (n = 5 per group). The percentage of unmyelinated axons in bupivacaine group was significant higher on post-injection day 2 than on day 7 (*<i>P</i><0.05), while no significant difference was observed in other groups. NS, normal saline; Bup, bupivacaine; Dexa, dexamethasone. Sale bar is at 10μm.</p