Background Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks. Methods We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as >= 75% agreement and weak consensus as 50%-74% agreement. Results A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research. Conclusions We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.

Background and objectives Documentation is important for quality improvement, education, and research. There is currently a lack of recommendations regarding key aspects of documentation in regional anesthesia. The aim of this study was to establish recommendations for documentation in regional anesthesia. Methods Following the formation of the executive committee and a directed literature review, a long list of potential documentation components was created. A modified Delphi process was then employed to achieve consensus amongst a group of international experts in regional anesthesia. This consisted of 2 rounds of anonymous electronic voting and a final virtual round table discussion with live polling on items not yet excluded or accepted from previous rounds. Progression or exclusion of potential components through the rounds was based on the achievement of strong consensus. Strong consensus was defined as ≥75% agreement and weak consensus as 50%–74% agreement. Results Seventy-seven collaborators participated in both rounds 1 and 2, while 50 collaborators took part in round 3. In total, experts voted on 83 items and achieved a strong consensus on 51 items, weak consensus on 3 and rejected 29. Conclusion By means of a modified Delphi process, we have established expert consensus on documentation in regional anesthesia.

BackgroundThere 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.MethodsWe 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.ResultsSixty 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.ConclusionsHarmonization 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.

This report reviews the topographical and functional anatomy relevant for assessing whether or not the obturator nerve (ON) can be anesthetized using a fascia iliaca compartment (FIC) block. The ON does not cross the FIC. This means that the ON would only be blocked by an FIC block if the injectate spreads to the ON outside of the FIC. Such a phenomena would require the creation of one or more artificial passageways to the ON in the retro-psoas compartment or the retroperitoneal compartment by disrupting the normal anatomical integrity of the FI. Due to this requirement for an artificial pathway, an FIC block probably does not block the ON.

We report 166 microinvasive ultrasound-guided carpal tunnel releases using the MICROi-Blade (Summit Medical Products, Inc, Sandy, UT), a needle-based tool for cutting under ultrasound guidance. The 6-month follow-up of the first 21 cases, including 5 bilateral releases, showed a progressive reduction in median pain scores, Boston Carpal Tunnel Questionnaire (BCTQ) Symptom Severity Scale scores, and BCTQ Functional Status Scale scores. The median return to work was 7 days. The 3-month follow-up of 62 subsequent cases showed similar improvement in the BCTQ scores and return to work. There were no complications. This report supports the effectiveness of the technique.

Ultrasound (US)‐guided microinvasive procedures are defined as those performed via needles without notable scarring. Ten cadaver hands underwent US‐guided microinvasive carpal tunnel release using a novel needle‐based tool, the micro i‐Blade (Summit Medical Products, Inc, Sandy, UT). A US‐imaged landmark, the inflexion point of the ligaments distal to the hook of the hamate, was used to position the distal extent of the cut. The transverse carpal ligament was successfully released in all hands without damage to nerves or arteries. In 3 specimens, the fascia between the thenar and hypothenar muscles was partly preserved, whereas the palmar aponeurosis was partly cut in 1 specimen. The micro i‐Blade with the cutting knife retracted was also useful as a probe palpated through the palm of the cadaver hand, to test the release of the transverse carpal ligament and to guide the procedure.

Peripheral intravenous and intra-arterial catheters often block with movement of the limb in which they are inserted. Although the cause of this blockage is commonly attributed to a valve or other structure within the vein, evidence for this is lacking. We used ultrasound to assess the cause of blockage on movement, and degree of tip movement, of 62 venous and 21 radial arterial catheters. In both venous and arterial catheters, blockage was predominantly caused by impingement of the catheter on the vessel wall, with catheter kinking and spasm of the vessel also seen. Mean potential tip movement was 12.3 mm and 5.7 mm in hand and forearm venous catheters respectively and 9.5 mm in radial artery catheters. There was a significantly lower rate of blockage for forearm (20%) compared to dorsal hand venous catheters (83%, P <0.001) and 52% of radial artery catheters showed damping and blockage on wrist flexion. This study emphasises the advantages of placement of venous catheters in the straight veins of the forearm.

American Journal of Physical Medicine & Rehabilitation 96(12):p e217, December 2017. | DOI: 10.1097/PHM.0000000000000772

FIGURE 1. Composite picture of block extent derived from Støving et al. A, Area of reduced block in the midclavicular line. B, Area of reduced block in the L1 nerve distribution. S tøving and colleagues 1 have improved our understanding of the effect of local anaesthetic in the lateral transversus abdominis plane (TAP) with their volunteer study. They are also to be congratulated on the presentation of their images showing the extent of cutaneous sensory block produced. The block was performed with the needle tip reaching the TAP in the midaxillary line midway between the iliac crest and the costal margin. Subsequent sensory mapping was performed, and photographs presented. Støving et al noted a nondermatomal distribution of the cutaneous block with extensive and reliable block of the lateral cutaneous branches of the abdominal nerves and a much more restricted sensory block of the medial skin. The presentation of their data has enabled me to reinterpret and explain of the cutaneous sensory block based on the known anatomy of the peripheral nerves in the abdominal wall. Using the pictures and block outlines from the front of the volunteers, I created a composite picture of the block extent. The 16 individual pictures were extracted and placed into imaging software (Adobe Photoshop; Adobe Systems Inc, San Jose, California). The block extent was outlined in each picture, filled with solid color, and flipped horizontally if needed (Fig. 1 inset). The position of the umbilicus, pubic symphysis, and the lateral wall, as derived from the image, were then used to resize and move each image in the vertical and horizontal axis to line them up in a standard position. The solid color of the block areas was then made transparent so that the density of color of the composite image of the 16 adjusted block areas reflected the chance of block in a particular area (Fig. 1). The composite image highlights 2 significant areas that show nondermatomal block distribution as noted by Støving et al. This distribution, however, is consistent with the known anatomy. In the area marked A in Figure 1, there is a scalloping out of the upper extent of the block and reduction in block intensity along the midclavicular line, superior to the anterior superior iliac spine (ASIS). Rozen et al described a nerve

Emergency catheter cricothyroidotomy often fails. Case reports have concentrated on kinking and displacement of the catheter as the major causes. We investigated catheter tip penetration of the trachea. Using insertion angles of 90°, 75°, 60°, 45° and 30° we advanced 14 G intravenous catheters into fresh isolated sheep tracheas during high pressure oxygen insufflation. At all angles, the catheter tip became blocked by pushing into the mucosa with submucosal gas injection on one or more attempts. Full thickness rupture with extratracheal gas also occurred on insertions at 90° and 60°. We then tested a Luer-mounted prototype wire stylet which remains in situ during insufflation. Using the same methodology, the stylet was able to be placed and prevented blockage at all angles of insertion. Mucosal trauma and submucosal gas injection occurred on insertions at 90° and 75°. Our results should guide further stylet design.

AnaesthesiaVolume 70, Issue 1 p. 112-113 CorrespondenceFree Access TAP block nomenclature P. Hebbard, P. Hebbard p.hebbard@bigpond.com North East Health, Wangaratta, AustraliaSearch for more papers by this author P. Hebbard, P. Hebbard p.hebbard@bigpond.com North East Health, Wangaratta, AustraliaSearch for more papers by this author First published: 09 December 2014 https://doi.org/10.1111/anae.12970Citations: 29 No external funding and no competing interests declared. Previously posted on the Anaesthesia correspondence website: www.anaesthesiacorrespondence.com. AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Børglum et al. propose a division of transversus abdominis plexus (TAP) block nomenclature into 'upper' and 'lateral' zones with 'dual' TAP blocks being injections into both zones 1. The use of 'posterior' in this scheme is reserved for the injection through the triangle of Petit. Nomenclature involving the triangle of Petit in relation to abdominal wall blockade has been confused from the start. In their landmark 2007 paper, McDonnell et al. described a block via the triangle of Petit using illustra-tions, computed tomography (CT) and magnetic resonance images 2. Unfortunately, the triangle was incorrectly illustrated in the lateral rather than posterior abdominal wall. The injection sites were also positioned laterally, particular for the subject in the CT image who received an injection centred anteriorly to the mid-axillary line. Jankovic et al. showed the anterior and middle parts of the triangle of Petit to be on average 5.8 cm and 9.3 cm posterior to the mid-axillary line, respectively 3. As originally described, therefore, it is not possible to inject perpendicular to the triangle of Petit without rolling the patient onto his/her side. In many patients, the skin over the lumbar triangle of Petit is in contact with the mattress when positioned supine. I co-authored the first description of ultrasound-guided TAP block in 2007 4, and was aware of McDonnell et al.'s detailed description of the triangle of Petit landmark technique at the time of writing. When it became apparent that posterior block did not spread well above the umbilicus, I described a 'subcostal' approach to improve spread 5, the term being used in the surgical sense as in subcostal (Kocher's) incision, rather than in reference to the subcostal nerve. 'Subcostal oblique' was used to define the passage of the needle along the costal margin, enabling a catheter to be placed, producing a more extensive block across the line of the nerves. Børglum and colleagues propose that we should drop the use of 'subcostal' to avoid confusion with the subcostal nerve, but I do not think this a strong argument as the term has been in use in the literature for six years and correlates with the surgical anatomy. 'Intercostal' has also been used to refer to the subcostal location, which makes less sense since intercostal block already exists, and almost all blocks into the TAP block the intercostal nerves even though the block is not in the intercostal space. Lee at al. first used 'posterior' to define a separate TAP location in 2010 when comparing the lateral site with a subcostal injection 6, more clearly locating 'lateral' as 'posterior' in this context. It is clear that location of injection into the TAP alters the spread and effect of TAP blocks. I propose the range of TAP injections should be classified as follows (Fig. 4): Figure 4Open in figure viewerPowerPoint Diagram of proposed TAP zones. USC, upper subcostal; LSC, lower subcostal; LAT, lateral; POST, posterior; II, ilio-inguinal. Upper subcostal TAP (deep to the rectus, mainly covering T7 and T8) Lower subcostal TAP (lateral to rectus. mainly covering T-11) Lateral TAP (midway between costal margin and iliac crest in the mid-clavicular line, mainly covering T11 and T12) Ilio-inguinal TAP (near the iliac crest lateral to the anterior superior iliac spine, mainly covering T12 and L1) Posterior TAP (injections in the TAP in the area of the triangle of Petit) This proposed scheme describes five distinct areas that have a different distribution of blockade. Within this scheme terms such as 'dual' or 'four quadrant' TAP blocks may refer to injection into the upper subcostal and lateral areas, and 'subcostal oblique' to a single injection passing through the upper and lower subcostal TAP to the ilio-inguinal TAP area. References 1Børglum J, Abdallah FW, McDonnell JG, Moriggl B, Bendtsen TF. TAP block terminology. Anaesthesia 2014; 69: 1055– 6. 2McDonnell JG, O'Donnell BD, Farrell T, et al. Transversus abdominis plane block: a cadaveric and radiological evaluation. Regional Anesthesia and Pain Medicine 2007; 32: 399– 404. 3Jankovic ZB, du Feu FM, McConnell P. An anatomical study of the transversus abdominis plane block: location of the lumbar triangle of Petit and adjacent nerves. Anesthesia and Analgesia 2009; 109: 981– 5. 4Hebbard P, Fujiwara Y, Shibata Y, Royse C. Ultrasound-guided transversus abdominis plane (TAP) block. Anaesthesia and Intensive Care 2007; 35: 616– 7. 5Hebbard P. Subcostal transversus abdominis plane block under ultrasound guidance. Anesthesia and Analgesia 2008; 106: 674– 5. 6Lee TH, Barrington MJ, Tran TM, Wong D, Hebbard PD. Comparison of extent of sensory block following posterior and subcostal approaches to ultrasound-guided transversus abdominis plane block. Anaesthesia and Intensive Care 2010; 38: 452– 60. Citing Literature Volume70, Issue1January 2015Pages 112-113 FiguresReferencesRelatedInformation

BACKGROUND:The transversus abdominis plane (TAP) block involves injecting a large volume of local anaesthetic between the muscles of the abdominal wall. Plasma concentrations of ropivacaine after gynaecological laparotomy are potentially high enough to result in systemic toxicity, and there are pharmacokinetic reasons why pregnancy may increase susceptibility to local anaesthetic toxicity.METHODS:Adult female patients (n=30) undergoing elective Caesarean section under spinal anaesthesia received bilateral ultrasound-guided TAP blocks after wound closure (2.5 mg kg(-1) of ropivacaine diluted to 40 ml). Venous blood samples were collected at 10, 20, 30, 45, 60, 90, 120, 180 and 240 min following the block. Blood samples were assayed for total and free ropivacaine concentrations. Patients were assessed for symptoms of local anaesthetic toxicity.RESULTS:The mean [standard deviation (SD)] peak total concentration of ropivacaine occurred at 30 min post-injection and was 1.82 (0.69) μg ml(-1). The maximum detected concentration in any patient was 3.76 μg ml(-1) (at 10 min post-injection). Three patients reported symptoms of mild neurotoxicity, and the mean (SD) peak levels were elevated in these patients, 2.70 (0.46) µg ml(-1).CONCLUSIONS:TAP blocks can result in elevated plasma ropivacaine concentrations in patients undergoing Caesarean section, which may be associated with neurotoxicity.

Editor—We thank Dr Landy and colleagues for their interest in our paper.1Griffiths JD Barron FA Grant S Bjorksten AR Hebbard P Royse CF Plasma ropivacaine concentrations after ultrasound-guided transversus abdominis plane block.Br J Anaesth. 2010; 105: 853-856doi:10.1093/bja/aeq255Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar The case they describe appears to support our hypothesis that the transversus abdominis plane (TAP) block has the potential to result in clinical neurotoxicity as a result of local anaesthetic absorption. We would like to comment on a number of interesting features of this case. First, it is noteworthy that the onset of symptoms is at 15 min post-injection. This corresponds approximately to the peak plasma levels detected in our study. As Dr Landy and colleagues suggest, this is more consistent with absorption of local anaesthetic from the TAP plane rather than inadvertent intravascular injection. Secondly, it seems likely that the patient’s significant liver impairment will have contributed to the manifestation of clinical toxicity. This supports the proposal that total doses of local anaesthetic should be reduced in ‘at risk’ patient groups. It would be useful to know the unbound level, given that it is the free ropivacaine level that is responsible for clinical manifestations of toxicity and also, because their patient is likely to have had decreased levels of α-1 acid glycoprotein, decreased protein binding and therefore, an increased concentration of free ropivacaine for a given total concentration of drug. We also note that a relatively high concentration of ropivacaine was used (0.75%), presumably in order to obtain surgical anaesthesia rather than postoperative analgesia. While it is clear that for a given regional technique, a higher dose of local anaesthetic results in higher plasma concentrations,2Wulf H Worthmann F Behnke H Böhle AS Pharmacokinetics and pharmacodynamics of ropivacaine 2 mg/mL, 5 mg/mL, or 7.5 mg/mL after ilioinguinal blockade for inguinal hernia repair in adults.Anesth Analg. 1999; 89: 1471-1474Crossref PubMed Google Scholar it is unknown to what extent the concentration of injectate directly contributes to the rate or extent of plasma uptake. However, 0.5% ropivacaine is effective for ilioinguinal block and infiltration for inguinal hernia repair.3Wulf H Behnke H Vogel I Schroder J Clinical usefulness, safety, and plasma concentration of ropivacaine 0.5% for inguinal hernia repair in regional anesthesia.Reg Anesth Pain Med. 2001; 26: 348-351Crossref PubMed Google Scholar It has also been shown that there is no additional benefit to using 0.75% ropivacaine compared with 0.5% ropivacaine for interscalene block.4Klein SM Greengrass R Steele SM et al.A comparison of 0.5% bupivacaine, 0.5% ropivacaine, and 0.75% ropivacaine for interscalene brachial plexus block.Anesth Analg. 1998; 87: 1316-1319PubMed Google Scholar The anatomical location of the injection in this case is not described, but it seems likely that the total volume of 30 ml was used on one side only (for a unilateral procedure), and presumably only in the posterior (anterior axillary line) rather than spread over a larger area of the TAP (e.g. the subcostal approach).5Hebbard P Subcostal transversus abdominis plane block under ultrasound guidance.Anesth Analg. 2008; 106 (author reply 675): 674-675doi:10.1213/ane.0b013e318161a88fCrossref PubMed Scopus (195) Google Scholar This larger volume in a smaller plane may also result in a larger ‘hydrostatic’ pressure, facilitating leak into the surrounding tissues. Practitioners using the TAP block will be aware that a proportion of injectate can occasionally be observed leaking from the TAP plane into the surrounding musculature. It is unknown the extent (if any) to which this ‘leak’ may correlate with the degree of systemic absorption and contribute to variability in absorption between blocks. Again we thank Dr Landy and colleagues for reinforcing that in patients at increased risk of local anaesthetic toxicity either from pharmacokinetic or pharmacodynamics reasons, the total dose should be reduced. None declared.

cannot support specific recommendations. The cardiovascular profile of pancuronium suggests that it can produce cardiovascular stimulation possibly by a direct action and an increased release/decreased reuptake of catecholamines at the adrenergic nerve terminals. b-Adrenoreceptors and M2 muscarinic receptors possibly play a significant role in pancuronium-induced cardiac responses. 6 Pancuronium has been found to have a higher potency for interaction with cardiac muscarinic receptors compared with newer neuromuscular blockers. On the other hand, as shown in Supplementary Table S1 of our review, there is sufficient evidence supporting the lack of significant cardiac effects of newer neuromuscular blockers, such as atracurium, cisatracurium, and rocuronium. Based on the above, we consider that pancuronium is probably not the first-choice neuromuscular blocker for patients with arrhythmogenic syndromes (as ARVD), even though serious adverse effects have not been observed in the authors’ clinical practice, or confirmed in relevant clinical reports. In conclusion, pancuronium seems to have a less favourable cardiovascular profile compared with newer neuromuscular blockers according to electrophysiological studies. Regarding neuromuscular blockers and ARVD, relevant literature is inadequate to support specific recommendations. On the other hand, as it is prudent for the physicians always to be on the safe side, we consider that neuromuscular blockers with minimal cardiovascular effects should be preferred over pancuronium in patients who are at risk of arrhythmias, as are patients with ARVD.