Convolutional neural network for brachial plexus segmentation at the interscalene level.

BACKGROUND: Regional anesthesia with ultrasound-guided brachial plexus block is widely used for patients undergoing shoulder and upper limb surgery, but needle misplacement can result in complications. The purpose of this study was to develop and validate a convolutional neural network (CNN) model for segmentation of the brachial plexus at the interscalene level. METHODS: This prospective study included patients who underwent ultrasound-guided brachial plexus block in the Anesthesiology Department of Beijing Jishuitan Hospital between October 2019 and June 2022. A Unet semantic segmentation model was developed to train the CNN to identify the brachial plexus features in the ultrasound images. The degree of overlap between the predicted segmentation and ground truth segmentation (manually drawn by experienced clinicians) was evaluated by calculation of the Dice index and Jaccard index. RESULTS: The final analysis included 502 images from 127 patients aged 41 ± 14 years-old (72 men, 56.7%). The mean Dice index was 0.748 ± 0.190, which was extremely close to the threshold level of 0.75 for good overlap between the predicted and ground truth segregations. The Jaccard index was 0.630 ± 0.213, which exceeded the threshold value of 0.5 for a good overlap. CONCLUSION: The CNN performed well at segregating the brachial plexus at the interscalene level. Further development could allow the CNN to be used to facilitate real-time identification of the brachial plexus during interscalene block administration. CLINICAL TRIAL REGISTRATION: The trial was registered prior to patient enrollment at the Chinese Clinical Trial Registry (ChiCTR2200055591), the site url is https://www.chictr.org.cn/ . The date of trial registration and patient enrollment is 14/01/2022.

Influence of Regional Analgesia on Self-Reported Quality of Sleep After Gynecological Abdominal Surgery: A Secondary Analysis of a Randomized Trial.

OBJECTIVES: To determine whether intrathecal morphine (ITM) analgesia in abdominal surgery for presumed gynecological malignancy was associated with better self-reported sleep quality postoperatively compared with epidural analgesia (EDA), and to evaluate risk factors for bad sleep quality. METHODS: A secondary analysis of a randomized open controlled trial, comparing ITM and EDA as postoperative analgesia in 80 women undergoing laparotomy under general anaesthesia in an enhanced recovery after surgery framework. A total of 38 women allocated to ITM and 39 to EDA completed the study. The Swedish Postoperative Symptoms Questionnaire assessed symptoms and sleep quality during the first postoperative week. Multiple logistic regression models evaluated risk factors. The results are presented as adjusted odds ratios with 95% CIs. RESULTS: The sleep quality night-by-night did not differ significantly between the women who had ITM or EDA. Risk factors for bad sleep quality for night 1 were age (0.91; 0.84-0.99), operation time (1.02; 1.00-1.03), and opioid consumption (0.96; 0.91-0.99). For night 2, regular use of hypnotics preoperatively (15.81; 1.52-164.27) and opioid consumption (1.07; 1.00-1.14) were independent risk factors for bad sleep. After the second night, no risk factors were disclosed. CONCLUSIONS: ITM and EDA did not appear to affect the sleep quality postoperatively differently in women undergoing laparotomy for presumed gynecological malignancy. Risk factors for self-reported bad sleep quality varied during the first 3 days after surgery. Younger age, longer operation time, and preoperative use of hypnotics were associated with bad sleep quality, whereas the effect of opioid consumption on sleep quality varied depending on the time since surgery. These findings merit further studies.

AMBULATORY EYE SURGERY AND ANTITHROMBOTIC THERAPY - NEW APPROACHES.

One of the most common surgeries in elderly patients is eye surgery. An increasing number of patients undergoing ambulatory eye surgery are on antithrombotic therapy. These drugs may increase the risk of perioperative bleeding associated with ophthalmic needle blocks and/or eye surgery. Intraoperative bleeding and postoperative hemorrhagic complications may lead to the loss of vision or even eyes. On the other hand, stopping anticoagulants and antiplatelets before the surgery may increase the risk of thrombotic events with potentially life-threatening complications. The aim of this narrative review is to provide a systematic review of the published evidence for the perioperative antithrombotic management of patients undergoing different types of eye surgery in ambulatory settings. A comprehensive review of the English-language medical literature search utilizing PubMed, Ovid Medline® and Google Scholar from January 2015 to December 2018 was performed. The database searches included studies providing evidence relevant to ambulatory eye surgery and perioperative antiplatelet medications and anticoagulants. Updated recommendations will be given for continuation, discontinuation, and modification of antithrombotic agents in order to optimize the management of antithrombotic therapies in outpatients scheduled for eye surgery.

Cognitive function after surgery with regional or general anesthesia: A population-based study.

INTRODUCTION: Our aim was to examine whether surgery with regional anesthesia (RA) is associated with accelerated long-term cognitive decline comparable with that previously reported after general anesthesia (GA). METHODS: Longitudinal cognitive function was analyzed in a cohort of 1819 older adults. Models assessed the rate of change in global and domain-specific cognition over time in participants exposed to RA or GA. RESULTS: When compared with those unexposed to anesthesia, the postoperative rate of change of the cognitive global z-score was greater in those exposed to both RA (difference in annual decline of -0.041, P = .011) and GA (-0.061, P < .001); these rates did not differ. In analysis of the domain-specific scores, an accelerated decline in memory was observed after GA (-0.065, P < .001) but not RA (-0.011, P = .565). CONCLUSIONS: Older adults undergoing surgery with RA experience decline of global cognition similar to those receiving GA; however, memory was not affected.

Fascial layers influence the spread of injectate during ultrasound-guided infraclavicular brachial plexus block: a cadaver study.

BACKGROUND: Fascial layers of the neurovascular sheath containing the brachial plexus influence distribution of local anaesthetic, hence increasing the risk of block failure when performing infraclavicular brachial plexus block (ICB). METHODS: Ultrasound-guided infraclavicular brachial plexus block was performed on cadavers using a single injection technique with dye (20-30 ml). After injection, we carried out consecutive dissection of the neurovascular bundle to study dye injectate spread and identify the presence of fascial layers. Ultrasound video images (scout scan and injection) and recordings of dissections were evaluated by independent experts (regional anaesthetists and anatomists). RESULTS: Well defined fascial layers were identified at dissection in seven out of 12 infraclavicular spaces studied. These fascial layers impeded the spread of dye injectate substantially in six cases and partially in one case. No fascial layers were identified at dissection in five cases, in each of which the spread of injectate was complete throughout the neurovascular bundle. The sensitivity and specificity of ultrasonography and haptic sensation for detection of fascial layers were poor. CONCLUSIONS: When fascial layers are present in the neurovascular sheath, they impede the spread of injectate during infraclavicular brachial plexus block. Ultrasound detection of these fascial layers is unreliable in cadavers. These findings support the use of greater volumes of injectate or a multiple injection technique when performing this block.

Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet.

BACKGROUND: Placement of local anaesthetic within the adductor canal using ultrasonography is an alternative to femoral nerve blocks for postoperative pain relief after knee joint replacement surgery. However, the effect of an inflated thigh tourniquet on the distribution of local anaesthetic within the adductor canal is unknown. The aim of this cadaveric study was to compare the distribution of radio-opaque dye within the adductor canal in the presence or absence of an inflated thigh tourniquet. METHODS: Bilateral ultrasound-guided adductor canal blocks were performed on the thawed lower limbs of five fresh frozen human cadavers. The left and right lower cadaver limbs were randomised to receive or not receive a thigh tourniquet inflated to 300 mm Hg for 1 h. X-rays with iohexol radio-opaque dye were obtained in four views, and fiducial markers inserted as reference points. Virtual editing technology was used to recreate outlines representing the distribution of the radio-opaque dye and superimpose these on anatomical images. RESULTS: Radio-opaque dye was distributed on the medial aspect of the thighs with entire and well circumscribed margins. The majority of the radio-opaque dye was confined within the adductor canal. Superior-inferior dye distribution was 315 mm [95% confidence intervals (CI) 289-342] and 264 mm (95% CI 239-289) in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -80.46 to -22.22, P=0.0081). Image analysis using the recreated radio-opaque outlines suggested that the most proximal point of the radio-opaque dye was 100 mm (95% CI 82-117) or 117 mm (95% CI 62-171) below the inguinal ligament in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -38 to 72, P=0.456). CONCLUSIONS: Application and inflation of thigh tourniquets significantly increased the combined superior-inferior dye distribution within the adductor canal of cadaveric limbs. There was insufficient evidence to suggest significant proximal spread of 25 ml of local anaesthetic to involve the motor branches of the femoral nerve. In some patients, the local anaesthetic may reach the popliteal fossa in close approximation to the sciatic nerve.

Ultrasound-guided serratus anterior plane block combined with the two-incision technique for subcutaneous ICD implantation.

BACKGROUND: The standard technique for implanting a subcutaneous implantable cardioverter defibrillator (S-ICD) requires three incisions and the pocket of the device is created in the subcutaneous tissue of the left lateral thoracic wall. However, a two-incision technique may be adopted, in which the cranial parasternal region is avoided and the device is positioned more deeply, completely under the latissimus dorsi muscle. This can also be combined with ultrasound-guided serratus anterior plane block (US-SAPB) for intraoperative anesthesia and perioperative analgesia. We describe our preliminary experience of US-SAPB combined with the two-incision intermuscular technique. METHODS: We performed US-SAPB 40 minutes before starting the procedure, while the patient was in the supine position. The devices were implanted under the latissimus dorsi muscle. All patients were followed-up after hospital discharge. RESULTS: Twelve patients (male 50%, 53 ± 16 years, body mass index 23 ± 4) underwent the S-ICD implantation with the combined technique. The mean procedure duration was 47 ± 11 minutes. The procedure was successful and a shock energy of 65 J was successful in converting the induced ventricular fibrillation in all patients. The US-SAPB was successful in 92% of cases and only one patient required convertion into general anesthesia due to pain during the procedure. In the postoperative period, patients did not report major discomfort and analgesics were not required. During a median follow-up of 12 months, no complications were reported. CONCLUSIONS: Serratus anterior plane block combined with the intermuscular and two-incision technique proved to be safe and effective during the S-ICD implantation procedure.

Ultrasound-guided intermediate cervical plexus and additional peripheral facial nerve block for carotid endarterectomy : A prospective pilot study.

BACKGROUND AND OBJECTIVES: Ultrasound-guided intermediate cervical plexus block with perivascular local anesthetic infiltration is an established anesthetic procedure for carotid endarterectomy. In this prospective pilot study an additional subplatysmal block of the superficial ansa cervicalis is presented for the first time. The target structures are the anastomoses between the facial nerve (cervical and marginal mandibular branches) and cervical plexus. METHODS: An ultrasound-guided intermediate cervical plexus block (20 ml of ropivacaine 0.75%) was performed (n = 28). Then, depending on the individual sonoanatomy, 5 ml of prilocaine 1% was injected into the carotid sheath (group 1: no perivascular infiltration, n = 14, group 2: perivascular infiltration, n = 14). The third step was subplatysmal injection of 5 ml of prilocaine 1% between the medial edge of the sternocleidomastoid muscle and the submandibular gland (n = 28). The investigated parameters included the need for supplementation and block-related side effects. RESULTS: The requirement for supplemental local anesthetic infiltration in the skin incision area was minimal at mean (M) 1.1 ml (standard deviation (SD) ±2.4 ml). Perivascular infiltration in group 2 significantly decreased the total amount of local anesthetic supplemented: group 1 M = 4.2 ml (SD = ±3.1 ml), group 2 M = 1.7 ml (SD = ±2.0 ml) (p = 0.018). The incidence of block-related side effects was not significantly different between the two groups. CONCLUSION: This study presents an ultrasound-guided subplatysmal block of the superficial ansa cervicalis for the first time, with the aim of optimizing anesthesia quality during surgical interventions in the carotid triangle.

Chloroprocaine for epidural anesthesia in infants and children.

Continuous epidural infusions are an effective and safe method of providing anesthesia and postoperative analgesia in infants and children with multiple advantages over systemic medications, including earlier tracheal extubation, decreased perioperative stress response, earlier return of bowel function, and decreased exposure to volatile anesthetic agents with uncertain long-term neurocognitive effects. Despite these benefits, local anesthetic toxicity remains a concern in neonates and infants because of their decreased metabolic capacity for amide local anesthetics. Chloroprocaine, an ester local anesthetic agent, which is rapidly metabolized in plasma at all ages, is an attractive alternative for this special population, particularly in the presence of superimposed liver impairment or when higher infusion rates are needed for surgical incisions stretching many dermatomes. The current manuscript reviews the literature pertaining to the use of 2-chloroprocaine for regional anesthesia in infants and children. Dosing regimens are presented and the applications of 2-chloroprocaine in this population are discussed.

Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children.

BACKGROUND: Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children. METHODS: A total of 141 children under 12 years old who had undergone lumbar-sacral magnetic resonance imaging were included. The T2 sagittal image that provided the best view of the sacrococcygeal membrane and the dural sac was chosen. We used Picture Achieving and Communication System (Centricity® PACS, GE Healthcare Co.) to measure the distance between the sacrococcygeal ligament and the dural sac, the length of the sacrococcygeal ligament, and the maximum depth of the caudal space. RESULTS: There were strong correlations between age, weight, height, and BSA, and the distance between the sacrococcygeal ligament and dural sac, as well as the length of the sacrococcygeal ligament. Based on these findings, a simple formula to calculate the distance between the sacrococcygeal ligament and dural sac was developed: 25 × BSA (mm). CONCLUSION: This simple formula can accurately calculate the safe depth of the caudal epidural space to prevent unintended dural puncture during caudal block in children. However, further clinical studies based on this formula are needed to substantiate its utility.

Extrafascial injection for interscalene brachial plexus block reduces respiratory complications compared with a conventional intrafascial injection: a randomized, controlled, double-blind trial.

BACKGROUND: Hemidiaphragmatic paresis after ultrasound-guided interscalene brachial plexus block is reported to occur in up to 100% of patients. We tested the hypothesis that an injection lateral to the brachial plexus sheath reduces the incidence of hemidiaphragmatic paresis compared with a conventional intrafascial injection, while providing similar analgesia. METHODS: Forty ASA I-III patients undergoing elective shoulder and clavicle surgery under general anaesthesia were randomized to receive an ultrasound-guided interscalene brachial plexus block for analgesia, using 20 ml bupivacaine 0.5% with epinephrine 1:200 000 injected either between C5 and C6 within the interscalene groove (conventional intrafascial injection), or 4 mm lateral to the brachial plexus sheath (extrafascial injection). The primary outcome was incidence of hemidiaphragmatic paresis (diaphragmatic excursion reduction >75%), measured by M-mode ultrasonography, before and 30 min after the procedure. Secondary outcomes were forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow. Additional outcomes included time to first opioid request and pain scores at 24 h postoperatively (numeric rating scale, 0-10). RESULTS: The incidences of hemidiaphragmatic paresis were 90% (95% CI: 68-99%) and 21% (95% CI: 6-46%) in the conventional and extrafascial injection groups, respectively (P<0.0001). Other respiratory outcomes were significantly better preserved in the extrafascial injection group. The mean time to first opioid request was similar between groups (conventional: 802 min [95% CI: 620-984 min]; extrafascial: 973 min [95% CI: 791-1155 min]; P=0.19) as were pain scores at 24 h postoperatively (conventional: 1.6 [95% CI: 0.9-2.2]; extrafascial: 1.6 [95% CI: 0.8-2.4]; P=0.97). CONCLUSIONS: Ultrasound-guided interscalene brachial plexus block with an extrafascial injection reduces the incidence of hemidiaphragmatic paresis and impact on respiratory function while providing similar analgesia, when compared with a conventional injection. CLINICAL TRIAL REGISTRATION: NCT02074397.

[Hygiene aspects in ultrasound-guided regional anesthesia]. / Hygieneaspekte in der ultraschallgestützten Regionalanästhesie.

BACKGROUND: Sterile and clean working conditions are one of the keystones of medical practice and this is also true for ultrasound-guided regional anesthesia. The routine clinical practice in ultrasound-guided regional anesthesia does not always comply with the principles of sterile and clean working conditions in medicine: therefore, patients are exposed to potential hazards regarding the transmission of pathogens via the ultrasound equipment. OBJECTIVE: This article deals with the question of whether sterile working conditions in ultrasound-guided regional anesthesia are a relevant topic with medical and economic implications. Is it possible to implement the general recommendations for sterile working conditions in ultrasonography for the specific application of ultrasound-guided regional anesthesia? MATERIAL AND METHODS: A search of the available literature and published guidelines in the field of sterile working conditions with ultrasound was carried out. RESULTS: The association between cross-infections and ultrasound equipment is undeniable. Many methods for cleansing and disinfection of ultrasound equipment have been published. All these methods are associated with advantages and disadvantages. The direct sterilization of ultrasound probes with high-percentage alcohol can damage ultrasound probes (especially linear). The use of self-adhesive sterile ultrasound probe covers is a practical method to achieve sterile working conditions in ultrasound-guided regional anesthesia. CONCLUSION: The use of sterile ultrasound probe covers and sterile ultrasound contact media is an important prerequisite to avoid cross-infection between patients. An appropriate scientific evaluation should serve as evidence in this field.

Ultrasound-guided intermediate cervical plexus block and perivascular local anesthetic infiltration for carotid endarterectomy : A randomized controlled trial.

BACKGROUND AND OBJECTIVE: Ultrasound-guided blocks of the cervical plexus are established anesthetic procedures for carotid endarterectomy. This randomized, double-blind, placebo-controlled study tested the hypothesis that an additional ultrasound-guided periarterial injection of local anesthetic leads to a lower frequency of periarterial supplementation by the surgeon. METHODS: A total of 40 patients were randomly assigned to 1 of 2 groups. In both groups an ultrasound-guided intermediate cervical plexus block (20 ml of 0.75 % ropivacaine) at the level of the fourth cervical vertebra was performed. In a second step, the needle was inserted from posterolateral to anteromedial (in-plane technique) relative to the internal carotid artery and then, depending on the randomized group assignment, 5 ml of 0.75 % ropivacaine (group 2) or 5 ml of 0.9 % saline (group 1) was injected. The parameters investigated included the need for supplementation, patient comfort, the incidence of side effects and circulatory changes. RESULTS: The two groups did not significantly differ (p = 0.459) in terms of the need for intraoperative supplementation with 1 % prilocaine with a mean (range) in group 2 of 4.9 ml (0-20 ml), in group 1 of 3.7 ml (0-16 ml) and patient comfort (p = 0.144). In addition, a trend towards a higher complication rate was observed in group 2. CONCLUSION: For ultrasound-guided intermediate blocks of the cervical plexus, an additional periarterial infiltration showed no advantage. Abandoning this technique leads to a relevant simplification of the blocking technique and tends to reduce block-related side effects.

Defining competence in obstetric epidural anaesthesia for inexperienced trainees.

BACKGROUND: Cumulative sum (CUSUM) analysis has been used for assessing competence of trainees learning new technical skills. One of its disadvantages is the required definition of acceptable and unacceptable success rates. We therefore monitored the development of competence amongst trainees new to obstetric epidural anaesthesia in a large public hospital. METHODS: Obstetric epidural data were collected prospectively between January 1996 and December 2011. Success rates for inexperienced trainees were calculated retrospectively for (1) the whole database, (2) for each consecutive attempt and (3) each trainee's individual overall success rate. Acceptable and unacceptable success rates were defined and CUSUM graphs generated for each trainee. Competence was assessed for each trainee and the number of attempts to reach competence recorded. RESULTS: Mean (sd) success rate for all inexperienced trainees was 76.8 (0.1%), range 63-90%. Consecutive attempt success rate produced a learning curve with a mean success rate commencing at 58% on attempt 1. After attempt 10 the attempt number had no effect on subsequent success rates. From these results, the acceptable and unacceptable success rates were set at 65 and 55% respectively. CUSUM graphs demonstrated 76 out of 81 trainees competent after a mean of 46 (22) attempts. CONCLUSIONS: CUSUM is useful for assessing trainee epidural competence. Trainees require approximately 50 attempts, as defined by CUSUM, to reach competence.

Randomized trial of anaesthetic interventions in external cephalic version for breech presentation.

BACKGROUND: Successful external cephalic version (ECV) for breech presenting fetus reduces the need for Caesarean section (CS). We aimed to compare the success rate of ECV with either spinal anaesthesia (SA) or i.v. analgesia using remifentanil. METHODS: In a double-phased, stratified randomized blinded controlled study we compared the success rates of ECV, performed under spinal anaesthesia (SA), i.v. analgesia (IVA) using remifentanil or no anaesthetic interventions. In phase I, 189 patients were stratified by parity before randomization to ECV, performed by blinded operators, under SA using either hyperbaric bupivacaine 9 mg with fentanyl 15 µg, i.v. remifentanil infusion 0.1 µg kg min(-1), or Control (no anaesthetic intervention). Operators performing ECV were blinded to the treatment allocation. In phase 2, patients in the Control group in whom the initial ECV failed were further randomized to receive either SA (n=9) or IVA (n=9) for a re-attempt. The primary outcome was the incidence of successful ECV. RESULTS: The success rate in Phase 1 was greatest using SA [52/63 (83%)], compared with IVA [40/63 (64%)] and Control [40/63 (64%)], (P=0.027). Median [IQR] pain scores on a visual analogue scale (range 0-100), were 0 [0-0] with SA, 35 [0-60] with IVA and 50 [30-75] in the Control group (P<0.001). Median [IQR] VAS sedation scores were highest with IVA [75 (50-80)], followed by SA, [0 (0-50)] and Control [0 (0-0)]. In phase 2, 7/9 (78%) of ECV re-attempts were successful with SA, whereas all re-attempts using IVA failed (P=0.0007). The incidence of fetal bradycardia necessitating emergency CS within 30 min, was similar among groups; 1.6% (1/63) in the SA and IVA groups and 3.2% (2/63) in the Control group. CONCLUSIONS: SA increased the success rate and reduced pain for both primary and re-attempts of ECV, whereas IVA using remifentanil infusion only reduced the pain. There was no significant increase in the incidence of fetal bradycardia or emergency CS, with ECV performed under anaesthetic interventions. Relaxation of the abdominal muscles from SA appears to underlie the improved outcomes for ECV.

Analgesic effect of ultrasound-guided transversus abdominis plane block after total abdominal hysterectomy: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To assess the effect of bilateral ultrasound-guided transversus abdominis plane block with ropivacaine compared with placebo as part of a multimodal analgesic regimen. DESIGN: A randomized, double-blind, placebo-controlled trial following the CONSORT criteria. SETTING: Hvidovre University Hospital. PATIENTS: Forty-six women scheduled for total abdominal hysterectomy. INTERVENTION: Women received either ropivacaine 0.75%, 20 mL (n = 24) or 0.9% saline, 20 mL (n = 24) in the transversus abdominis plane on each side. MAIN OUTCOME MEASURES: Primary outcome was the 24-h postoperative morphine consumption. Secondary outcomes were pain scores at rest and during coughing, postoperative nausea and vomiting at 1, 2, 4, 6, 8, and 24 h, and time to first mobilization. RESULTS: There was no difference in the mean 24-h postoperative morphine consumption between the two groups (p = 0.733). The ropivacaine group had significantly lower median pain scores at 1 h (p = 0.008) and 2 h (p = 0.027) postoperatively at rest and at 8 h (p = 0.028) during coughing. There was no significant difference in other secondary outcomes. CONCLUSION: There was no reduction in 24-h morphine consumption when using an ultrasound-guided transversus abdominis plane block in women undergoing total abdominal hysterectomy. As part of a multimodal regimen the transversus abdominis plane block showed some effect on pain scores at rest only in the early postoperative period.

[Postoperative pain therapy in Germany. Status quo]. / Therapie postoperativer Schmerzen in Deutschland. Aktueller Stand.

A great deal of progress has been made in the field of postoperative pain therapy in the last 20 years. Beginning from clinical trials on the effectiveness of individual procedures, such as epidural anesthesia and patient-controlled analgesia, a wide range of healthcare services research as well as basic research with human and animal experiments has been established. Whereas health services research in the 1980s and 1990s focused more on the implementation of acute pain services, outcome-oriented research approaches are nowadays the center of attention. Acute pain registries and pain certification projects initiated in Germany have to be mentioned particularly in this respect. Basic research papers from recent years increasingly address specific aspects of acute postoperative pain and have provided translational approaches that are applied around the world for studying neurobiological mechanisms of postoperative pain. At the same time, interdisciplinary cooperation in research projects has led to a better understanding of complex correlations regarding predictors and mechanisms (including psychosocial aspects) of acute and in recent times also chronic pain after surgery. In parallel, evidence-based medicine has found its way into acute pain medicine in Germany. In 2007, clinical acute pain therapy in Germany was enhanced by S3 level guidelines for the first time; however, the implementation is still incomplete. In future, questions concerning mechanism-based therapy of acute pain need to be equally in the center of attention of research, such as prevention of persisting pain after surgery and acute pain of different origins.

[Improvement of sonographic visualization of cannula needle tips by alignment of the needle lumen : In vitro investigation of established needle tip forms]. / Verbesserung der sonographischen Sichtbarkeit von Kanülenspitzen durch Ausrichtung der Öffnungsfläche : In-vitro-Untersuchung etablierter Schliffformen.

BACKGROUND: In the context of ultrasound-guided peripheral nerve blocks (regional anesthesia), clear visualization of the needle tip and the target structure are mandatory for the performance of a safe puncture and injection. The purpose of this in vitro study was to analyze the visualization of different forms of needle tips and calibers of cannulas in a phantom simulating human tissue, with the help of a standardized image analysis system. Different depths and angles of the puncture needle in relation to the ultrasound probe were tested. MATERIAL AND METHODS: Cannula needles established for use in regional anesthesia with different surfaces, diameters and needle tip form in 23 different combinations were analyzed. A gelatine-based phantom was used to simulate human tissue. The standardized visualization of the needle tip with the ultrasound probe was performed in plane at different angles (30°, 45° and 60°), depths of penetration (1 cm, 2 cm and 3 cm) and two different alignments of the cannula needle lumen to the ultrasound probe (0° and 180°). The screenshots of the ultrasound pictures were analyzed by quantifying the pixel brightness around the needle tip (region of interest) with a standardized software (score 0-255). RESULTS: In this study 1104 ultrasound images of cannula needles were analyzed. Diminished scores (reduced pixel brightness) of the needle tips were documented with increasing distance from the ultrasound probe. Comparison of punctures at angles of 30° and 45° showed no differences in needle tip visibility (same scores) but punctures at an angle of 60° were poorly visualized compared with 30° and 45° (mean scores 87.90 ± 11.60 vs. 78.40 ± 12.07, p < 0.001 and 81.85 ± 11.79 vs. 78.40 ± 12.07, p < 0.001, respectively). The direct alignment of the cannula lumen towards the ultrasound probe (0°) was significantly more easily visualized when compared with the reverse alignment of 180° (mean scores 86.90 ± 12.74 vs. 84.80 ± 11.66, p = 0.003, respectively). No differences in visibility were detected between the different cannula needle diameters examined. The Sprotte cannula showed the best visibility score with respect to the cut of the needle tip (mean score 89.40 ± 11.72). CONCLUSION: The visibility of cannulas in ultrasound scans depends on the ultrasound frequency, angle of the puncture in relation to the ultrasound probe and the depth of penetration. The results of this study showed that direct alignment of the cannula needle lumen towards the ultrasound probe (0°) independently improved needle tip visualization. This simple measure allows a significant improvement in the safe performance of ultrasound-guided peripheral nerve blocks.

Is Jedi Grip efficient and effective in ultrasound-guided peripheral nerve blocking? A prospective, randomized, observer-blinded study.

BACKGROUND: In this prospective, randomized, controlled observer-blinded study, we aimed to compare the efficacy of a single-operator technique called the Jedi Grip and a conventional technique requiring a double operator in ultrasound-guided axillary brachial plexus blocking. METHODS: Ninety-two patients (ASA I-II; aged 18-65 years old) who underwent elective hand, wrist and forearm surgery were randomly assigned to Group Conventional (C) or Group Jedi (J). In both groups, axillary plexus blockade was performed by applying 5 cc of a mixture of 10 cc of 0.5% bupivacaine and 10 cc of 2% prilocaine to the ulnar, radial, median, and musculocutaneous nerves. Parameters such as the performance time and number of needle passes were recorded during the procedure. Subsequently, a blinded observer evaluated and recorded parameters related to the blockade success. The main outcome variables were the performance time and success rate (surgical anesthesia). RESULTS: The block performance time of the Jedi technique was slightly longer than that of the conventional technique (220 (50), 202 (78) s, respectively) (median (IQR); p = 0.05). No significant difference was found between groups in terms of blocking success; 9 (20%) from the conventional group and 3 (6.4%) from the Jedi group were unsuccessful (p = 0.053). No differences were found in terms of arterial puncture, and no other complications occurred in either group. The motor-sensory block onset and termination times and initial analgesia requirements were similar. CONCLUSION: The Jedi technique may be applied safely with similar block success and performance results as the conventional technique.

[Principles of the perioperative management of direct oral anticoagulants]. / Grundlagen des perioperativen Umgangs mit direkten oralen Antikoagulanzien.

Within the approved indications direct oral anticoagulants (DOAC) are increasingly gaining acceptance instead of vitamin K antagonists (VKA). In the last 12 months 5 guidelines relevant to the perioperative management of DOACs have been updated. This article summarizes the current recommendations for the perioperative management of treatment with DOACs. The available substances and their pharmacological properties as well as the possibilities for specific laboratory diagnostics of the effect of DOAC are explained. Special focus is placed on anesthesiologically important aspects of substance-specific preoperative and postoperative intermission intervals, the procedure for neuraxial regional anesthesia and antagonization with specific antidotes in cases of life-threatening bleeding.