[Peripheral truncal blocks-Overview and assessment]. / Periphere Rumpfwandblockaden ­ Übersicht und Bewertung.

By implementation of sonography for regional anesthesia, truncal blocks became more relevant in the daily practice of anesthesia and pain therapy. Due to visualized needle guidance ultrasound supports more safety and helps to avoid complications during needle placement. Additionally, complex punctures are possible that were associated with higher risk using landmarks alone. Next to the blocking of specific nerve structures, interfascial and compartment blocks have also become established, whereby the visualization of individual nerves and plexus structures is not of relevance. The present review article describes published and clinically established puncture techniques with respect to the indications and procedures. The clinical value is reported according to the scientific evidence and the analgesic profile. Moreover, the authors explain potential risks, complications and dosing of local anesthetic agents.

Epidural needle insertion : A large registry analysis.

BACKGROUND: Dural puncture, paraesthesia and vascular puncture are the most common complications of epidural catheter insertion. Their association with variation in midline needle insertion depth is unknown. OBJECTIVE: This study evaluated the risk of dural and vascular punctures and the unwanted events paraesthesia and multiple skin punctures related to midline needle insertion depth. MATERIAL AND METHODS: A total of 14,503 epidural catheter insertions including lumbar (L1-L5; n = 5367), low thoracic (T7-T12, n = 8234) and upper thoracic (T1-T6, n = 902) insertions, were extracted from the German Network for Regional Anaesthesia registry between 2007 and 2015. The primary outcomes were compared with logistic regression and adjusted (adj) for confounders to determine the risk of complications/events. Results are presented as odds ratios (OR, [95% confidence interval]). MAIN RESULTS: Midline insertion depth depended on body mass index, sex, and spinal level. After adjusting for confounders increased puncture depth (cm) remained an independent risk factor for vascular puncture (adjOR 1.27 [1.09-1.47], p = 0.002) and multiple skin punctures (adjOR 1.25 [1.21-1.29], p < 0.001). In contrast, dural punctures occurred at significantly shallower depths (adjOR 0.73 [0.60-0.89], p = 0.002). Paraesthesia was unrelated to insertion depth. Body mass index and sex had no influence on paraesthesia, dural and vascular punctures. Thoracic epidural insertion was associated with a lower risk of vascular puncture than at lumbar sites (adjOR 0.39 [0.18-0.84], p = 0.02). CONCLUSION: Variation in midline insertion depth is an independent risk factor for epidural complications; however, variability precludes use of depth as a reliable guide to insertion in individual patients.

[Sciatic nerve block "out-of-plane" distal to the bifurcation: effective and safe]. / Ischiadikusblockade "out-of-plane" distal der Bifurkation: effektiv und sicher.

BACKGROUND: Ultrasound guided distal sciatic nerve block (DSB) at bifurcation level shows fast onset and provides excellent success rates. However, its safe performance might be difficult for the unexperienced physician. Just slightly distal to the bifurcation, the tibial nerve (TN) and common fibular nerve (CFN) can be shown clearly separated from each other. Therefore, we investigated if a block done here would provide similar quality results compared to the DSB proximally to the division, with a potentially lower risk of nerve damage. METHODS: In this randomized, prospective trial, 56 patients per group received either a DSB distal to the bifurcation "out-of-plane" (dist.) or proximally "in-plane" (prox.) with 30 ml of Mepivacaine 1% each. Success was tested by a blinded examiner after 15 and 30 min respectively (sensory and motor block of TN and CFN: 0 = none, 2 = complete, change of skin temperature). Videos of the blocks were inspected by an independent expert retrospectively with regard to the spread of the local anesthetic (LA) and accidental intraneural injection. RESULTS: Cumulative single nerve measurements and temperature changes revealed significant shorter onset and better efficacy (dist/prox: 15 min: 3.13 ± 1.86/1.82 ± 1.62; 30 min: 5.73 ± 1.92/3.21 ± 1.88; T15 min: 30.3 ± 3.48/28.0 ± 3.67, T30 min. 33.0 ± 2.46/30.6 ± 3.86; MV/SD; ANOVA; p < 0.01) combined with a higher rate of subparaneural spread in the dist. group (41/51 vs.12/53; χ2; p < 0,01). Procedure times were similar. There were no complications in either group. DISCUSSION: The subparaneural spread of the LA turned out to be crucial for better results in the distal group. The steep angle using the out-of-plane approach favors needle penetration through the paraneural sheath. The distance between the branches allows the safe application of the LA, so an effective block can be done with just one injection. CONCLUSION: DSB slightly distal to the bifurcation, in an out-of-plane technique between the TN and CFN, can be done fast, effectively and safe.

Peripheral nerve blocks on the upper extremity: Technique of landmark-based and ultrasound-guided approaches.

The German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) established an expert panel to develop preliminary recommendations for the application of peripheral nerve blocks on the upper extremity. The present recommendations state in different variations how ultrasound and/or electrical nerve stimulation guided nerve blocks should be performed. The description of each procedure is rather a recommendation than a guideline. The anaesthesiologist should select the variation of block which provides the highest grade of safety according to his individual opportunities. The first section comprises recommendations regarding dosages of local anaesthetics, general indications and contraindications for peripheral nerve blocks and informations about complications. In the following sections most common blocks techniques on the upper extremity are described.

Early pharmacokinetic of ropivacaine without epinephrine after injection into the psoas compartment.

BACKGROUND: Large amounts of local anaesthetics (LA) are used during psoas compartment block (PCB), especially if combined with sciatic nerve block. Data regarding early pharmacokinetics of ropivacaine for PCB are lacking, notably when a vasoconstrictive agent has not been added. METHODS: PCB was established in 11 patients using 150 mg ropivacaine without epinephrine. Free and total arterial plasma concentrations of ropivacaine were measured at nine time points during the following 30 min. Also total protein, albumin, and α1-acid glycoprotein concentrations were analysed. RESULTS: Ropivacaine plasma concentrations were found in all patients within 30 s after injections. Maximum measured plasma concentrations were measured in all but two patients within the first 10 min. One patient experienced partial intravascular injection. Plasma concentrations showed wide inter-individual variability. Ranges of maximum measured plasma concentrations of total and free ropivacaine were 422-3905 and 5-186 ng ml(-1), respectively. The Pearson correlation between total and free concentrations was 0.96. No obvious relationship between concentrations of different plasma proteins (total protein, albumin, α1-acid glycoprotein) and ropivacaine concentrations was found. Maximal 5% of the measured ropivacaine was unbound. All blocks were successful and no signs of toxicity were observed. CONCLUSIONS: Maximum measured plasma concentrations of ropivacaine after PCB must be expected within 10 min. Although plasma concentrations stayed below toxic thresholds, our study demonstrates the risk of this regional anaesthesia technique. CLINICAL TRIAL REGISTRATION: The clinical study was not registered because enrolment of study patients occurred in 2006.

Nerve localization for peripheral regional anesthesia. Recommendations of the German Society of Anaesthesiology and Intensive Care Medicine.

The German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) established an expert panel to develop preliminary recommendations for nerve localization in peripheral regional anesthesia. Based on expert knowledge and the relatively limited data, the recommendations state how ultrasound and/or electrical nerve stimulation should be used in daily practice, and where and when local anesthetics should be injected. Moreover, it was defined under which conditions a peripheral nerve block under general anesthesia or deep sedation is applicable.Regarding the use of ultrasound the expert opinion was that out-of-plane and in-plane-techniques can be considered equal with respect to patient safety. Nevertheless, the direct or indirect visualization of the needle tip has to be assured. The injection of local anesthetics has to be visualized. Injections into nerves or those requiring an injection pressure should be avoided. The sole use of electrical nerve stimulation or ultrasound for nerve localization is still a suitable option as well as their combined use. To avoid accidental intraneural needle placement, an electrical current threshold ≥ 0.5 mA should be used. Moreover, it was stated that peripheral nerve blocks or continuous nerve block techniques under sedation or general anesthesia are applicable in adult patients who are unable to tolerate the block being performed in an awake state or have difficulty cooperating.This article is published in English.

[Incidence of infection from catheter procedures for regional anesthesia: first results from the network of DGAI and BDA]. / Infektionsinzidenz von Katheterverfahren zur Regionalanästhesie : Erste Ergebnisse aus dem Netzwerk von DGAI und BDA.

BACKGROUND: To analyze safety issues of regional anaesthesia and analgesia in Germany only a few single center studies are available. Therefore, the German Society for Anaesthesiology and Intensive Care Medicine (Deutschen Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) and the Professional Association of German Anaesthetists (Berufsverband Deutscher Anästhesisten, BDA) initiated a network for safety in regional anaesthesia. From this the first results on infectious complications will be reported. MATERIALS AND METHODS: In a Delphi process the documentation of the setup and maintenance of regional anaesthesia and analgesia was agreed with the participants in a working group from the DGAI. After approval by the officially authorized representative for patient data privacy protection a registry was programmed to collect anonymous data. Up to October 2008 data from 6 centers could be analyzed. RESULTS: After testing for plausibility 8,781 regional anaesthesia procedures (22,112 catheter days) could be analyzed. The 5,057 neuraxial and 3,724 peripheral catheter-based procedures were in place for a median of 2.48 days (range 1.0-3.0 days) and 4 severe, 15 moderate and 128 mild infections were recorded. Diabetics were not found to show a statistically significant increase in risk (2.6% compared to 1.9% for non-diabetics: n.s.). Neuraxial procedures seem to have a higher rate of infections than peripheral procedures (2.7% vs. 1.3%, p<0.0001). Multiple punctures of the skin also seem to be associated with a higher infection rate than single skin punctures (4.1% vs. 1.6%, p<0.0001). CONCLUSIONS: Infectious complications of catheter-based regional anaesthesia are common. Strict hygienic standards must therefore be complied with. More data are necessary to calculate risk factors. The registry provided can also be used as a benchmark to reduce these rates further.

[The value of regional and general anaesthesia in orthopaedic surgery]. / Stellenwert von Regional- und Allgemeinanästhesie in der Orthopädie.

Adequate postoperative pain management is of major importance for a short rehabilitation time after painful orthopaedic surgery. Multimodal pathways have been established to achieve a surgical patient free of pain and complications. Peripheral and central nerve blocks are a fundamental part of these interdisciplinary strategies and are already implemented in orthopaedic surgical care. This article summarises the value of special anaesthetic techniques, especially regional anaesthesia, in orthopaedic surgery and discusses their impact on several postoperative outcome goals.

[Reduction in the aggressiveness of ventilation by inhalation of perfluorohexane after therapy of oleic acid-induced respiratory failure]. / Reduktion der Aggressivität der Beatmung nach Therapie eines Olsäure-induzierten Lungenversagens durch Inhalation von Perfluorhexan.

INTRODUCTION: The application of perfluorohexane (PFH) vapor led to an improvement of oxygenation and mechanical lung function in a model of oleic acid-induced ARDS in sheep. The aim of this study was to investigate the effects of PFH on gas exchange over an extended time period and to reduce the invasiveness of ventilation. METHOD: ARDS was induced in sheep ( n=12) by injecting 0.1 ml/kg body weight oleic acid intravenously. Six sheep were treated for 30 min with 18 vol.% PFH (PFH-Tx) and followed up over a time period of 240 min while untreated sheep ( n=6) served as controls. Subsequently the F(I)O(2) was reduced to generate a p(a)O(2) between 100-140 mmHg. Gas exchange, respiratory and hemodynamic data were collected at regular intervals. Data were analysed using covariance analysis. RESULTS: PFH treatment led to an improvement in oxygenation ( p<0.01) and in mechanical lung function ( p<0.01). Furthermore, mean pulmonary artery pressure ( p<0.01) and shunt ( p<0.01) were lower in PFH-Tx. F(I)O(2) could be reduced in all PFH-treated animals ( p<0.01). CONCLUSION: Treatment of oleic acid-induced lung injury with PFH vapor improved oxygenation and mechanical lung function over a extended time period allowing a reduction in the invasiveness of ventilation.

[Secondary cranial extension after spinal anesthesia with isobaric 0.5% bupivacaine following postural change]. / Hohe sekundäre Ausbreitung einer Spinalanästhesie mit isobarem 0,5%igem Bupivacain nach spätem Lagewechsel.

Inadvertent cranial extension of sympathetic and sensory block following posture change during spinal anaesthesia has been reported for isobaric as well as for hyperbaric local anaesthetics. We present the case of a patient who underwent surgical repair of a refracture of the tibia under spinal anaesthesia with 17.5 mg of isobaric 0.5% bupivacaine. The maximum level of sensory block (MLSB) reached T8 after 15 min. Following posture change into a 15 degrees anti-Trendelenburg position 35 min after lumbar puncture, the MLSB increased cranially for 10 segments and reached the C6 level after 10 min of anti-Trendelenburg position. The patient suffered from severe bradycardia and arterial hypotension which were treated with 6% hydroxyethyl starch, atropine and Akrinor. In addition, the patient developed respiratory insufficiency and was therefore intubated and the lungs were mechanically ventilated. The operation was performed uneventfully with the patient under general anaesthesia. At the end of surgery the trachea was extubated, and the patient was awake with stable hemodynamics, sufficient spontaneous ventilation and free of pain. MLSB reached the second lumbar dermatome. This case shows that after assumed fixation of the local anaesthetic an inadvertent extension of the MLSB following posture change is possible. Close surveillance is recommended for patients with central neuraxial blocks until the block is in complete remission. The mechanisms for inadvertent high extension of the MLSB following posture change are discussed.