Kenta Furutani

Bupivacaine inhibits glutamatergic transmission in spinal dorsal horn neurons.

Background:The local anesthetic bupivacaine is thought not only to block sodium channels but also to interact with various receptors. Here, the authors focus on excitatory glutamatergic transmission in the superficial dorsal horn of the spinal cord with respect to its importance for nociceptive processing. Methods:The effects of bupivacaine on the response to exogenous administration of N-methyl-d-aspartate (NMDA) receptor agonists were examined in lamina II neurons of adult rat spinal cord slices using the whole-cell patch-clamp technique. Results:Bupivacaine (0.5, 2 mm) dose-dependently reduced the peak amplitudes of exogenous NMDA-induced currents. However, this inhibitory effect of bupivacaine (2 mm) was not blocked by the presence of tetrodotoxin, a sodium channel blocker, or La3+, a voltage-gated Ca2+ channel blocker, and was unaffected by changes in pH conditions. Moreover, intrapipette guanosine-5′-O-(2-thiodiphosphate) (1 mm), a G-protein inhibitor, did not block the reduction of NMDA current amplitudes by bupivacaine. Similarly, lidocaine, ropivacaine, and mepivacaine also reduced the amplitudes of NMDA-induced currents. Conclusions:These findings raise the possibility that the antinociceptive effect of bupivacaine may be due to direct modulation of NMDA receptors in the superficial dorsal horn. In addition to voltage-gated sodium channels, glutamate NMDA receptors are also important for analgesia induced by local anesthetics.

Effects of ropivacaine concentration on the spread of sensory block produced by continuous thoracic paravertebral block: a prospective, randomised, controlled, double-blind study

Factors affecting the distribution of continuous thoracic paravertebral block have never been examined. We designed this prospective, double‐blind study to check whether continuous thoracic paravertebral block with a higher ropivacaine concentration would provide a wider segmental sensory block spread. Sixty consecutive patients undergoing pulmonary lobectomy or segmentectomy were randomly allocated to receive continuous paravertebral infusion of either 0.2% or 0.5% ropivacaine (6 ml.h−1). The primary outcome was the number of anaesthetised dermatomes as determined by loss of cold sensation 24 h after surgery. Twenty‐seven patients per group were included in the final analysis. The median (IQR [range]) number of anaesthetised dermatomes 24 h after surgery was 4 (3–6 [1–9]) with ropivacaine 0.2% and 4 (3–6 [2–11]) with ropivacaine 0.5% (p = 0.66). Contrary to our expectation, the segmental spread of sensory block produced by continuous thoracic paravertebral block does not depend on ropivacaine concentration.

A new ultrasound-guided pubic approach for proximal obturator nerve block: clinical study and cadaver evaluation

We evaluated an alternative technique for ultrasound‐guided proximal level obturator nerve block that might facilitate needle visualisation using in‐plane ultrasound guidance. Twenty patients undergoing transurethral bladder tumour resection requiring an obturator nerve block were enrolled into a prospective observational study. With the patient in the lithotomy position, the transducer was placed on the medial thigh along the extended line of the inguinal crease, and aimed cephalad to view a thick fascia between the pectineus and obturator externus muscles that contains the obturator nerve. A stimulating nerve block needle was inserted at the pubic region and advanced in‐plane with the transducer in an anterior‐to‐posterior direction. Eight ml levobupivacaine 0.75% was injected within the fascia. The median (IQR [range]) duration for ultrasound identification of the target and injection were 8.5 (7–12 [5–24]) s and 62 (44.5–78.25 [39–383]) s, respectively. All blocks were successful. A cadaver evaluation demonstrated that the dye injected into the target fascia using our technique travelled retrogradely through the obturator canal, and surrounded the anterior and posterior branches of the obturator nerve both proximally and distally to the obturator canal. We believe that this is a promising new technique for ultrasound‐guided proximal level obturator nerve block.

Free radical scavenger edaravone produces robust neuroprotection in a rat model of spinal cord injury

We used a multimodal approach to evaluate the effects of edaravone in a rat model of spinal cord injury (SCI). SCI was induced by extradural compression of thoracic spinal cord. In experiment 1, 30 min prior to compression, rats received a 3 mg/kg intravenous bolus of edaravone followed by a maintenance infusion of 1 (low-dose), 3 (moderate-dose), or 10 (high-dose) mg/kg/h edaravone. Although both moderate- and high-dose edaravone regimens promoted recovery of spinal motor-evoked potentials (MEPs) at 2 h post-SCI, the effect of the moderate dose was more pronounced. In experiment 2, moderate-dose edaravone was administered 30 min prior to compression, at the start of compression, or 10 min after decompression. Although both preemptive and coincident administration resulted in significantly improved spinal MEPs at 2 h post-SCI, the effect of preemptive administration was more pronounced. A moderate dose of edaravone resulted in significant attenuation of lipid peroxidation, as evidenced by lower concentrations of the free radical malonyldialdehyde in the spinal cord 3 h post-SCI. Malonyldialdehyde levels in the high-dose edaravone group were not reduced. Both moderate- and high-dose edaravone resulted in significant functional improvements, evidenced by better Basso-Beattie-Bresnahan (BBB) scores and better performance on an inclined plane during an 8 week period post-SCI. Both moderate- and high-dose edaravone significantly attenuated neuronal loss in the spinal cord at 8 weeks post-SCI, as evidenced by quantitative immunohistochemical analysis of NeuN-positive cells. In conclusion, early administration of a moderate dose of edaravone minimized the negative consequences of SCI and facilitated functional recovery.

Anaesthesia and orphan disease: marked attenuation of motor evoked potentials by high-dose dexmedetomidine in a child with Angelman syndrome undergoing scoliosis surgery: A case report with pharmacokinetic analysis.

References 1 Spies CD, Kip M, Lau A, et al. Influence of vaccination and surgery on HLADR expression in patients with upper aerodigestive tract cancer. J Int Med Res 2008; 36:296–307. 2 Haining WN, Evans JW, Seth NP, et al. Measuring T cell immunity to influenza vaccination in children after haemopoietic stem cell transplantation. Br J Haematol 2004; 127:322–325. 3 Holvast A, van Assen S, de Haan A, et al. Studies of cell-mediated immune responses to influenza vaccination in systemic lupus erythematosus. Arthritis Rheum 2009; 60:2438–2447. 4 Xiao W, Mindrinos MN, Seok J, et al. A genomic storm in critically injured humans. J Exp Med 2011; 208:2581–2590.

Proximal approach for ultrasound-guided infraclavicular brachial plexus block

Infraclavicular brachial plexus block (ICB) is performed between the clavicle and axilla and can be used for surgical procedures performed below the midhumerus. Various ultrasound-guided ICB approaches have been reported.1e3 In Japanese regional anesthesia textbooks issued during the last decade, these approaches have commonly been classified as “distal” and “proximal.”4 In English literature, references to ultrasound-guided ICB generally indicate the distal approach. In this approach, an ultrasound transducer is placed near the coracoid process in the sagittal plane, and the distinct lateral, posterior, and medial brachial plexus cords, which surround the axillary artery, are visualized.1,2 Multiple injections are recommended to ensure a block in all cords. However, controversy exists because a single injection posterior to the axillary artery has been demonstrated to provide a more reliable blockade in comparison with multiple injections into the three distinct cords.5 All three cords are not always identifiable by ultrasonography in the distal approach because of their variable and relatively deeper locations. We presume that this difficulty in identification may affect the manner of insertion in the distal approach. Furthermore, the appropriate catheter tip position for a continuous block is also controversial, although tip placement near the posterior cord is suggested.2 In the proximal approach, which is frequently described in Japanese literature, the linear transducer is placed adjacent to the inferior border of the clavicle, parallel to the clavicle, and lateral to

Comparison of a curved forceps with a conventional straight forceps for nasogastric tube insertion under videolaryngoscopic guidance: A randomized, crossover manikin study

Background: Nasogastric tube (NGT) insertion is an easy procedure that can be routinely performed under general anesthesia. However, for difficult cases, there are limited insertion techniques available in routine clinical practice, considering the flexibility of NGTs. The SUZY curved forceps are designed for the removal of pharyngolaryngeal foreign bodies under guidance of the McGRATH MAC (McG) videolaryngoscope. Because McG enables clear visualization of the esophageal inlet, we hypothesized that the SUZY forceps can facilitate easier NGT insertion compared with the conventional Magill forceps under McG guidance and designed a randomized, crossover manikin study to test this hypothesis. Materials and Methods: Ten anesthesiologists participated in this study. Each participant was instructed to insert an NGT using either the SUZY or the Magill forceps under McG guidance. Both types of forceps were used by each participant in a computer-generated random order. The primary outcome measure was the number of “strokes” (1 stroke was defined by a specific sequence of participant actions) required to advance the NGT 30 cm from the starting point. Data are expressed as medians (interquartile ranges [ranges]). Results: The number of strokes required for NGT insertion was fewer in the SUZY group than in the Magill group {7 [7.0–12.5 (5–14)] vs 16.5 [13.5–20.3 (7–22)]; P <.05}. The time required for NGT insertion was also lesser in the SUZY group than in the Magill group {15.4 [13.7–20.0 (7.0–38.3)] seconds vs 30.3 [22.0–42.3 (12.8–47.5) seconds]; P <.05}. Conclusions: The SUZY curved forceps facilitated NGT insertion more effectively than the Magill straight forceps under McG guidance. Our results suggest that NGT insertion using the SUZY forceps under McG guidance is a secure and easy procedure.

Difficult tracheal intubation in a patient with maternal uniparental disomy 14

BackgroundMaternal uniparental disomy 14 (UPD(14)mat) is an imprinting disorder. It is a rare disease, but there is the possibility that more undiagnosed patients might exist because the clinical features of UPD(14)mat resemble those of the Prader-Willi syndrome or other congenital diseases. We performed anesthetic management for an 8-year-old girl with UPD(14)mat.Case presentationsShe was admitted to undergo correction surgery due to symptomatic scoliosis. Preoperative examination revealed that she had a restricted mouth opening and retrognathia, as well as some typical characteristics of UPD(14)mat, such as small hands, growth retardation, and precocious puberty. We induced general anesthesia using sevoflurane without any problems. However, the tracheal intubation was difficult because of the restricted mouth opening. We used the McGRATHR MAC videolaryngoscope to overcome this problem.ConclusionsWe speculate that the craniofacial deformity in case of UPD(14)mat patients may lead to difficulty in tracheal intubation.

More solid evidence is required to validate a hypergravity-induced increase in sensitivity to propofol.

November 2014 • Volume 119 • Number 5 Copyright