The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: clinical signs, severity, and therapeutic agents.

BACKGROUND: Diagnosis of perioperative anaphylaxis is difficult because of its non-specific and variable signs and symptoms. Therapeutic agents used to treat anaphylaxis and anaesthesiologist responses also vary depending on the case, which might affect outcomes; however, only a few studies have focused on these factors. METHODS: This prospective study of perioperative anaphylaxis, a part of the Japanese Epidemiologic Study for Perioperative Anaphylaxis, investigated the clinical signs, its severity, therapeutic drugs, epinephrine administration, and anaesthesiologist responses in cases of perioperative anaphylaxis to assess trends and variability. Shock index was used to assess severity of cardiovascular collapse. RESULTS: In 43 patients analysed in this study, cardiovascular signs (88.4%) were the most frequent, followed by skin (81.4%) and respiratory signs (60.5%). The presence of signs increased during the clinical course. The median time from the first signs to diagnosis of anaphylaxis was 10 (5.0-17.8) min. The rates of epinephrine use were 30.2% (unused), 48.8% (i.v.), and 20.9% (i.m.). The median time from diagnosis of anaphylaxis to epinephrine administration was 7 (inter-quartile range: 1.5-8.0) min. Antihistamines and corticosteroids were each used in 69.8% of cases. The worst shock index was higher in patients who received i.v. epinephrine (2.77 [0.90] mean [standard deviation]) than in both no epinephrine use cases (1.35 [0.41]) and i.m. epinephrine cases (1.89 [0.77] (P<0.001]). CONCLUSIONS: The clinical signs and treatments of perioperative anaphylaxis are variable, and the choice regarding epinephrine administration is based on symptom severity. CLINICAL TRIAL REGISTRATION: UMIN000035350.

Local anesthetic toxicity: acute and chronic management.

Local anesthetics are commonly used medicines in clinical settings. They are used for pain management during minor interventional treatments, and for postoperative care after major surgeries. Cocaine is the well-known origin of local anesthetics, and the drug and related derivatives have long history of clinical usage for more than several centuries. Although illegal use of cocaine and its abuse are social problem in some countries, other local anesthetics are safely and effectively used in clinics and hospitals all over the world. However, still this drug category has several side-effects and possibilities of rare but serious complications. Acute neurotoxicity and cardiac toxicity are derived from unexpected high serum concentration. Allergic reactions are observed in some cases, especially following the use of ester structure drugs. Chronic toxicity is provoked when nerve fibers are exposed to local anesthetics at a high concentration for a long duration. Adequate treatments for acute toxic reactions can secure complete recovery of patients, and careful use of drugs prevents long-lasting neurological complications. In addition to respiratory and circulatory management, effectiveness of lipid rescue in the acute toxicity treatment has been certified in many clinical guidelines. Prevention of the use of high concentration of local anesthetics is also validated to be effective to decrease the possibility of nerve fiber damage.

Technical communication: percutaneous radiofrequency mandibular nerve rhizotomy guided by high-speed real-time computed tomography fluoroscopy.

We present a new method of percutaneous radiofrequency mandibular nerve rhizotomy for pain relief in the mandibular region, in which needle placement is guided by high-speed real-time computed tomography (CT) fluoroscopy. Eleven patients (13 procedures) with idiopathic trigeminal neuralgia underwent the procedure. CT fluoroscopy simultaneously provided 3 slices (1-mm interval series, craniocaudally) in 1 fluoroscopic view, allowing for accurate needle placement. Trigeminal neuralgia improved in all patients without severe complications. The mean numerical rating scales of pain intensity (+ or - sd) decreased from 6.5 (+ or - 1.8, pretreatment) to 1.8 (+ or - 1.7, 1 month after treatment) and to 0.9 (+ or - 1.0, 3 months after treatment). Our limited-case series suggests potential advantages for the new CT fluoroscopy guidance, but these findings await confirmation from randomized controlled trials and large-case series.

Fibroblast growth factor and insulin-like growth factor rescue growth cones of sensory neurites from collapse after tetracaine-induced injury.

BACKGROUND: Basic fibroblast growth factor (bFGF) and insulin-like growth factor (IGF)-1 have multiple effects on cells, including proliferation, differentiation, and survival. In this study, we investigated the effects of different concentrations of IGF and bFGF on the morphology of growth cones of the developing sensory neurons after tetracaine-induced injury in vitro. METHODS: Dorsal root ganglia were isolated from chick embryos on embryonic day 7 or 8 and cultured for 24 hours. Tissues were then exposed to 100 mumol/L tetracaine for 60 minutes. The media were replaced by tetracaine-free media containing different concentrations of IGF, bFGF, or combination of IGF 50 ng/mL and bFGF 5 ng/mL and incubated for a further 24 hours. Growth cone collapse assays were then performed to assess regeneration of neurons. RESULTS: Exposure of dorsal root ganglia explants to tetracaine 100 mumol/L for 1 hour caused significant growth cone collapse 24 hours after washing out tetracaine (P < 0.01). It was found that adding bFGF (5, 10, 20, and 50 ng/mL) or IGF (50 and 100 ng/mL) to the replacement media significantly decreased growth cone collapse percentage at 24 hours after washout (P < 0.01); however, the low concentrations of bFGF (2 ng/mL) or IGF (25 ng/mL) did not cause significant change. Growth cone collapse after simultaneous addition of 5 ng/mL bFGF and 50 ng/mL IGF was statistically lower than the values after adding 5 ng/mL bFGF (P < 0.01), and it was marginally lower than 50 ng/mL IGF. CONCLUSION: bFGF and bIGF decreased growth cone collapse after tetracaine-induced injury in vitro.

Percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy.

INTRODUCTION: Although Gasserian ganglion block is an established treatment for trigeminal neuralgia, the foramen ovale cannot always be clearly visualized by classical X-ray radiography. We present a new method for percutaneous radio-frequency thermocoagulation of the Gasserian ganglion, in which computed tomography (CT) fluoroscopy is used to guide needle placement. METHODS: In the present study, 15 patients with trigeminal neuralgia underwent percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy. RESULTS: Trigeminal neuralgia was improved in all patients after treatment without any severe complications. Moderate dysesthesia occurred in only one case. CONCLUSION: CT fluoroscopy-guided percutaneous radio-frequency thermocoagulation of the Gasserian ganglion was safe, quick, and effective for patients with intractable idiopathic trigeminal neuralgia.

Tetracaine at a small concentration delayed nerve growth without destroying neurites and growth cones.

Local anesthetics have direct neurotoxicity and induce growth cone collapse when applied to neurons at large concentrations. However, the effects of prolonged exposure to local anesthetics at a small concentration have never been studied. We examined whether neurite growth was slowed by tetracaine at small concentrations in chick embryo dorsal root ganglions. The effects of tetracaine were examined microscopically and by a neurite growth rate assay, quantitative morphologic assay, growth cone collapse assay, and Western blot assay. Neurite growth 24 and 48 h after application was delayed significantly when tetracaine was applied at a concentration larger than 5 microM. Filopodia of growth cones retracted, and their number was significantly decreased 24 and 48 h after the application of 10 and 20 microM of tetracaine. The quantity of actin in cell bodies increased, contrary to the effect on neurites and growth cones, where actin decreased 48 h after the application of 5, 10, and 20 microM of tetracaine. In conclusion, continuous exposure to tetracaine at small concentrations delayed neurite growth, reduced the number of filopodia, and decreased actin content.

The effects of volatile anesthetics on intraoperative monitoring of myogenic motor-evoked potentials to transcranial electrical stimulation and on partial neuromuscular blockade during propofol/fentanyl/nitrous oxide anesthesia in humans.

The aim of the present study was to compare the influence of volatile anesthetics on transcranial motor-evoked potentials (tcMEP) in humans anesthetized with propofol/fentanyl/nitrous oxide and on partial neuromuscular blockade (NMB). The authors studied 35 ASA I and II patients who were undergoing elective craniotomy and brain tumor resection. The patients were randomized to one of three groups to receive halothane (HAL), isoflurane (ISO), or sevoflurane (SEV). Anesthetic depth was initially adjusted using the bispectral index to 40+/-5, and NMB was adjusted to 40%-50% of one twitch of train of four (T1) after recovery from intubation. MEPs with train of five square-wave pulses were elicited using screw electrodes placed in the skull over C3-C4. After craniotomy, the inhalational agent was introduced at 0.5 MAC and then 1.0 MAC (20 minutes each), and the effects on MEPs, NMB, and hemodynamic variables were studied. A decrease in BIS and systolic blood pressure was observed with all agents. Both SEV and ISO at 1.0 MAC significantly decreased train-of-four ratio from 38.4+/-18.1 at control to 19.0+/-9.7 and from 35.3+/-12.4 to 26.1+/-13.7, respectively (P<0.001), but not HAL at 1.0 MAC. The amplitudes of tcMEPs were significantly reduced by all agents at 1.0 MAC, with the effect being less in HAL at 0.5 MAC. We have shown that HAL had a lesser suppressive effect on MEPs than either ISO or SEV at 0.5 MAC, which was partially due to a lesser degree of NMB.

Thermogangliolysis of the Gasserian ganglion under computed tomography fluoroscopy.

Gasserian ganglion block is an established treatment for trigeminal neuralgia. A landmark approach assisted by X-ray fluoroscopy is the most common method; however, visualization of the foramen ovale is difficult in some cases. Here we report two cases in which a novel technique using modern computed tomography (CT) fluoroscopy was employed. A 63-year-old woman suffering pain in the maxillary nerve area was treated by thermogangliolysis under CT fluoroscopy. The patient was positioned on a CT stage with the head in an overhanging position. The CT gantry was set at an oblique angle to obtain a coronal view of the foramen ovale. The safest and shortest route to the foramen was designed using the CT image and a 22-gauge insulated needle was advanced following the designed route under CT fluoroscopy. The effect of the nerve block was estimated by injection of a test dose of mepivacaine, after which the ganglion was thermally coagulated at 90 degrees C. Satisfactory analgesia was obtained in this case without any complications. Another patient (65 years old) was also treated by the same technique, and satisfactory pain relief was obtained. In conclusion, CT fluoroscopy-guided Gasserian ganglion thermolysis is considered a safe, quick, and effective treatment for trigeminal neuralgia.