Besonderheiten des Antithrombotikaeinsatzes bei verschiedenen chirurgischen Eingriffen

Neuraxial blockade has been shown to provide essential benefits in terms of reduced perioperative morbidity and mortality. Case series from recent years indicate that spinal epidural hematoma is more common than previously estimated, with incidences of 1:200,000 in obstetric patients and as high as 1:3,600 in female orthopedic patients. To lower this risk, societies worldwide have issued guidelines establishing recommended time intervals between administration of antithrombotic drugs and performance of neuraxial blockade. If adherence to these intervals imposes a high risk of theomboembolic complications, neuraxial blockade should be withheld in favor of continued antithrombotic therapy. In such patients an alternative plan for postoperative pain management such as patient-controlled intravenous analgesia or peripheral nerve blocks should be established. In patients on continued acetylsalicylic acid therapy, neuraxial blockade may be performed if thromboembolism prophylaxis is not administered concurrently.     

Empfehlungen für die Anwendung konventioneller und neuer Antithrombotika aus anästhesiologischer Sicht

Neuraxial blockade confers benefits to surgical patients not only due to the high analgesic quality but also through a reduction in postoperative complications, such as respiratory insufficiency and a shortening of postoperative paralytic ileus. In orthopedic surgery peripheral and neuraxial blockades are extensively used to enhance postoperative mobilization. The most serious complication of neuraxial blockade is spinal epidural hematoma, which may lead to permanent paraplegia if left untreated. The risk is enhanced in patients receiving thromboembolism prophylaxis. Most national societies have issued guidelines with specific time intervals between application of antithrombotic drugs and subsequent neuraxial blockade to minimize this risk. From the viewpoint of an anesthesiologist it is preferable to start with chemical thromboembolism prophylaxis postoperatively as opposed to preoperatively, to administer all drugs in the evening and to limit the number of available drugs at each site. The safety of neuraxial blockade in the presence of the new oral anticoagulant rivaroxaban is currently unknown due to limited experience and dabigatran is considered contraindicated with indwelling epidural catheters according to the manufacturer.     

Removal of an epidural catheter under ongoing antithrombotic therapy

A rare though extremely harmful complication in neuraxial anaesthesia is an epidural hematoma which can be associated with deleterious consequences for the patient, e. g. persistent paraplegia. The risk of epidural haematomas after neuraxial blockade is dependent on abnormal anatomy of the spine, difficult and multiple punctures and coagulation disorders. Especially when patients undergo therapy with anticoagulants like low molecular heparin or platelet inhibitors (tyclopidine) or a combination of them, the indication for neuraxial blockade must strictly outweigh risk of spinal bleeding. In this context, the precautions and contraindications are the same for spinal puncture and catheter insertion as for catheter removal. We describe the case of a patient who underwent emergency coronary angioplasty in combination with coronary stent implantation due to acute postoperative myocardial infarction following knee replacement in continuous epidural anaesthesia. Under the symptoms of a beginning local infection at the puncture site the epidural catheter had to be removed in spite of ongoing antithrombotic therapy. A possible management of such cases is discussed with regard to risk minimization.     

L’anesthésie loco-régionale neuraxiale ne devrait plus être utilisée en chirurgie vasculaire

OBJECTIVES: Neuraxial blockade (spinal or epidural anesthesia) is still widely used in patients undergoing vascular surgery. However, the combined administration of anticoagulants and antiplatelet agents may compromise the safety of this technique with regards to the potential occurrence of a spinal or of an epidural hematoma. We review the benefits and risks of neuraxial blockade in light of the evolution of anticoagulation for vascular surgery. MAIN FINDINGS: Vascular surgery generally requires a high level of intraoperative anticoagulation. An increasing number of patients are also treated pre and post-operatively with antiplatelet agents. Their administration cannot be interrupted without serious risks to the patients' cardiovascular system and, further their continued use during surgery may improve graft permeability. Recent reports have emphasized the danger of neuraxial anesthesia in patients receiving low dose anticoagulation. So, high doses of heparins should carry an ever higher risk of serious complications in patients undergoing neuraxial blockade. Furthermore, no published data has ever demonstrated convincingly the benefit of either epidural or spinal anesthesia over general anesthesia. No differences have ever been documented in terms of cardio-vascular morbidity, graft patency, and mortality. CONCLUSION: Routine neuraxial blockade cannot be recommended in patients undergoing vascular surgery. The decision to perform a neuraxial block in such a patient may only be taken on a case by case basis, after careful consideration of expected benefits and potential risks.     

R��ckenmarknahe Regionalan?sthesie bei Patienten mit h?morrhagischen Diathesen

Neuraxial anesthesia is an established and safe procedure in perioperative pain therapy which can help to minimize complications and to improve perioperative outcome. In patients with acquired bleeding disorders by comorbidities or concomitant antithrombotic medication an individual decision should be made based on risks and benefits. A large number of literature references and guidelines help making a decision, for example the recently updated evidence-based guidelines of the American Society of Regional Anesthesia and Pain Medicine for patients receiving antithrombotic or thrombolytic therapy. However, no explicit recommendations or guidelines exist for patients with hemorrhagic diatheses, such as von Willebrand disease (vWD), hemophilia A and B and idiopathic thrombocytopenic purpura (ITP). Published data regarding the safety of neuraxial techniques in these patients is scarce. Neuraxial anesthesia in patients with vWD is only acceptable when coagulation is optimized (substitution of factor concentrates or hemostatic agents depending on the type of vWD) and monitored frequently during the procedure. The only exception might be obstetric patients with vWD type I as coagulation frequently normalizes at the end of pregnancy. In these patients neuraxial anesthesia can often be performed without supplementation of clotting factors.Neuraxial techniques in patients with hemophilia A or B are usually contraindicated. The procedure may only be acceptable if serious reasons exist against general anesthesia. Supplementation of the missing factor to normal levels and monitoring during procedure is essential if neuraxial block is performed.Patients with ITP often present with low platelet counts. Normally, spinal or epidural anesthesia is considered safe if the platelet count is over 80,000/μl. However, the consistently low platelet counts in ITP seem to be less problematic than rapidly falling values due to other diseases, because this is often accompanied by platelet dysfunction or coagulopathy. In several studies neuraxial anesthesia was successfully performed with platelet counts between 50,000 and 80,000/μl. Nevertheless, the minimum safe platelet count for neuraxial blockade remains undefined in these patients.Evidence-based recommendations for neuraxial anaesthesia in patients with hemophilia, vWD or ITP cannot be offered. Each patient has to be treated individually with appropriate caution. This overview is intended to assist in the decision for or against neuraxial anesthesia in these patients, with emphasis on the pathophysiological background, blood investigations and case reports from the literature.     

Regional anaesthesia in the patient receiving antithrombotic and antiplatelet therapy

The actual incidence of neurological dysfunction resulting from haemorrhagic complications associated with neuraxial block is unknown. Although the incidence cited in the literature is estimated to be <1 in 150,000 epidural and <1 in 220,000 spinal anaesthetics, recent surveys suggest that the frequency is increasing and may be as high as 1 in 3000 in some patient populations. Overall, the risk of clinically significant bleeding increases with age, associated abnormalities of the spinal cord or vertebral column, the presence of an underlying coagulopathy, difficulty during needle placement, and an indwelling neuraxial catheter during sustained anticoagulation (particularly with standard unfractionated heparin or low molecular weight heparin). The decision to perform spinal or epidural anaesthesia/analgesia and the timing of catheter removal in a patient receiving antithrombotic therapy is made on an individual basis, weighing the small, although definite risk of spinal haematoma with the benefits of regional anaesthesia for a specific patient. Coagulation status should be optimized at the time of spinal or epidural needle/catheter placement, and the level of anticoagulation must be carefully monitored during the period of neuraxial catheterization. Indwelling catheters should not be removed in the presence of therapeutic anticoagulation, as this appears to significantly increase the risk of spinal haematoma. Vigilance in monitoring is critical to allow early evaluation of neurological dysfunction and prompt intervention. An understanding of the complexity of this issue is essential to patient management.     

Lumbar Plexus Block Using High-pressure Injection Leads to Contralateral and Epidural Spread

Background: The main advantage of lumbar plexus block over neuraxial anesthesia is unilateral blockade; however, the relatively common occurrence of bilateral spread (up to 27%) makes this advantage unpredictable. The authors hypothesized that high injection pressures during lumbar plexus block carry a higher risk of bilateral or neuraxial anesthesia.

Methods: Eighty patients undergoing knee arthroscopy (age 18-65 yr; American Society of Anesthesiologists physical status I or II) during a standard, nerve stimulator-guided lumbar plexus block using 35 ml mepivacaine, 1.5%, were scheduled to be studied. Patients were randomly assigned to receive either a low-pressure (< 15 psi) or a high-pressure (> 20 psi) injection, as assessed by an inline injection pressure monitor (BSmart(R); Concert Medical LLC, Norwell, MA). The block success rate and the presence of bilateral sensory and/or motor blockade were assessed.

Results: An interim analysis was performed at n = 20 after an unexpectedly high number of patients had neuraxial spread, necessitating early termination of the study. Five of 10 patients (50%) in the high-pressure group had a neuraxial block with a dermatomal sensory level T10 or higher. In contrast, no patient in the low-pressure group (n = 10) had evidence of neuraxial spread. Moreover, 6 patients (60%) in the high-pressure group demonstrated bilateral sensory blockade in the femoral distribution, whereas no patient in the low-pressure group had evidence of a bilateral femoral block.     

Spinal anaesthesia despite combined clopidogrel and aspirin therapy in a patient awaiting lung transplantation: effects of platelet transfusion on clotting tests

The risk of central neuraxial blockade in patients treated with newer antiplatelet drugs is unclear. We report the case of a woman awaiting lung transplantation who presented for emergency groin surgery. She had recently undergone a coronary artery stent implantation and was treated with both clopidogrel and aspirin. Despite this dual antiplatelet therapy, uneventful spinal anaesthesia was administered following platelet transfusion. While thromboelastography was of no help in assessing the degree of anticoagulation, the effects of platelet transfusion were reflected by adenosine diphosphate and epinephrine aggregometry. Thus, in selected patients, platelet transfusion may be appropriate to enable central neuraxial blockade when deemed necessary.     

Central neuraxial blocks and anticoagulation: a review of current trends

Patients receiving anticoagulants offer a challenge to anaesthesiologists. The issue of spinal haematoma following central neuraxial block in such patients is a contentious issue. Although rare, with an estimated incidence of < 1:150,000 for epidural blocks and 1:220,000 for spinal anaesthetics in patients with normal coagulation status, this is an emergency situation with a potentially grave prognosis. The review presents cases of spinal haematomata that have occurred in the last 5 years, both spontaneously and after central neuraxial blockade. Of the 60 cases reported in the literature, 33% occurred following central neuraxial block and, of these, 55% were associated with concomitant use of anticoagulants. The pharmacology of the newer and older anticoagulants is also described. The variety of risk factors and diverse recommendations that have been described in these patients are reviewed.     

再谈围术期服用阿司匹林对手术和椎管内麻醉的影响

背景 对患有心血管疾病(cardiovascular disease,CVD)正在进行抗血小板治疗的患者,目前不仅无具体的、可被接受的围术期管理建议,而且对该类患者行椎管内麻醉存在争议,因接受抗血小板治疗可增加硬膜外血肿的风险. 目的 对阿司匹林的作用机制及其剂量、临床疗效与安全性关系进行综述. 内容 随着CVD患病率的不断增加,对接受阿司匹林治疗的高风险患者给予恰当的围手术期管理,是外科医师和麻醉医师共同面对的一个临床问题.为此,对需要行心血管或非心血管手术的CVD患者,必须在临床作出诸多治疗决策. 趋向 围术期抗凝治疗是以对血栓和出血事件的风险评估为依据的,应通过多学科协作来实现简化患者管理和最小化临床不良结局的治疗目标.     

Severe neurological complications after central neuraxial blockades in Sweden 1990-1999

BACKGROUND: Central neuraxial blockades find widespread applications. Severe complications are believed to be extremely rare, but the incidence is probably underestimated. METHODS: A retrospective study of severe neurologic complications after central neuraxial blockades in Sweden 1990-1999 was performed. Information was obtained from a postal survey and administrative files in the health care system. During the study period approximately 1,260,000 spinal blockades and 450,000 epidural blockades were administered, including 200,000 epidural blockades for pain relief in labor. RESULTS:: The 127 complications found included spinal hematoma (33), cauda equina syndrome (32), meningitis (29), epidural abscess (13), and miscellaneous (20). Permanent neurologic damage was observed in 85 patients. Incidence of complications after spinal blockade was within 1:20-30,000 in all patient groups. Incidence after obstetric epidural blockade was 1:25,000; in the remaining patients it was 1:3600 (P < 0.0001). Spinal hematoma after obstetric epidural blockade carried the incidence 1:200,000, significantly lower than the incidence 1:3,600 females subject to knee arthroplasty (P < 0.0001). CONCLUSIONS:: More complications than expected were found, probably as a result of the comprehensive study design. Half of the complications were retrieved exclusively from administrative files. Complications occur significantly more often after epidural blockade than after spinal blockade, and the complications are different. Obstetric patients carry significantly lower incidence of complications. Osteoporosis is proposed as a previously neglected risk factor. Close surveillance after central neuraxial blockade is mandatory for safe practice.     

SBA 2020: Atualização na diretriz da anestesia regional em uso de anticoagulantes

The development of protocols to prevent perioperative Venous Thromboembolism (VTE) and the introduction of increasingly potent antithrombotic drugs have resulted in concerns of increased risk of neuraxial bleeding. Since the Brazilian Society of Anesthesiology (SBA) 2014 guideline, new oral anticoagulant drugs were approved by international regulating agencies, and by ANVISA. Societies and organizations that try to approach concerns through guidelines have presented conflicting perioperative management recommendations. As a response to these issues and to the need for a more rational approach, managements were updated in the present narrative revision, and guideline statements made. They were projected to encourage safe and quality patient care, but cannot assure specific results. Like any clinical guide recommendation, they are subject to review as knowledge grows, on specific complications, for example. The objective was to assess safety aspects of regional analgesia and anesthesia in patients using antithrombotic drugs, such as: possible technique‐associated complications; spinal hematoma‐associated risk factors, prevention strategies, diagnosis and treatment; safe interval for discontinuing and reinitiating medication after regional blockade.     

Neuraxial blockade using image intensifier in patients after spinal instrumentation

There is scant information in the literature regarding central neuraxial blockade in patients with previous back surgery or severe kyphoscoliosis. This report describes a 58-year-old female and an 84-year-old female with spinal instrumentation who presented for orthopedic surgery under neuraxial blockade. In both cases, multiple attempts of needle insertion using standard technique were unsuccessful, whereas spinal combined with epidural anesthesia was performed successfully using image intensifier. The anatomical considerations and difficulties in achieving reliable neuraxial blockade after spinal instrumentation are reviewed. Neuraxial blockade using image intensifier may provide less technical difficulty and a more reliable result in such patients.     

Ultrasound-guided rectus sheath blockade is a safe and accurate method for emergency ileostomy for patients with coagulopathy

Obstructive ileus is a life-threatening gastrointestinal condition that requires emergency operation. Patients with obstructive ileus sometimes develop coagulopathy. In such cases, central neuraxial blockade should be avoided. Rectus sheath blockade (RSB) is one of the popular methods for abdominal wall surgery. Ultrasound imaging of the rectus sheath may facilitate successful RSB by indicating the presence and location of rectus abdominis. Two patients presented with ileus secondary to rectal or sigmoid cancer and underwent emergency ileostomy. The patients had mild coagulopathy [platelet count, 77,000 microl(-1) in case 1, and platelet count, 98,000 microl(-1) in case 2]. Each patient underwent general anesthesia using propofol and remifentanil. They were given 0.5% ropivacaine 20ml for RSB under ultrasound-guidance. Their hemodynamics was stable and they did not need another muscle relaxant during operation, except succinylcholine during induction. RSB is useful for abdominal operations. In addition, ultrasonogrhaphy facilitates the prediction of depth of the posterior rectus sheath and improves the accuracy of local anesthetic placement. We conclude that RSB is effective for improving postoperative pain and intraoperative muscle relaxation of the abdominal wall. Ultrasound-guided RSB is an alternative method to central neuraxial blockade.     

Inhibition of platelet function by hydroxyethyl starch solutions in chronic pain patients undergoing peridural anesthesia

The use of hydroxyethyl starch (HES) solutions as a fluid replacement before peridural blockade may compromise blood coagulation, thus increasing the risk of neuraxial bleeding. In this prospective, double-blind, placebo-controlled, crossover study, we compared the influence of HES 130 (molecular weight in kilodalton), HES 200, and lactated Ringer's solution on platelet function and hemodynamics in chronic low back pain patients scheduled for peridural blockades. Patients received 3 test infusions of 10 mL/kg each administered IV for 30 min. Collagen/epinephrine and collagen/adenosine diphosphate were used as agonists for assessment of platelet function analyzer-closure times. Arterial blood pressure, heart rate, platelet counts, and hemoglobin levels were documented. Platelet function analyzer-closure times remained stable after lactated Ringer's solution but were significantly prolonged after HES. The platelet-inhibiting effect of HES 200 was more than that of HES 130. Hemodynamic stability was sufficiently maintained by all test infusions. In contrast to previous observations, a relevant antiplatelet effect of both low and medium molecular weight HES solutions was found in this study in chronic pain patients undergoing peridural anesthesia. Because hemostasiological competence is a prerequisite for safe neuraxial blockade, the decision of HES for intravascular fluid administration before blockade should be critically made.     

Spinal anaesthesia for caesarean section in the presence of respiratory failure and spinal metastases from a soft tissue clear cell sarcoma

Spinal metastases occur in up to 70% of all patients with cancer. However, only 10% are symptomatic. Before considering central neuraxial blockade in patients with malignancy, a history of back pain should be excluded. Anaesthetists should be aware that intrathecal and epidural injections could cause paraplegia if metastases are impinging on the spinal cord. Failure to achieve adequate sensory anaesthesia after central neuraxial blockade or presentation with postoperative paraplegia may indicate the presence of asymptomatic vertebral canal metastases. In this report, the anaesthetic management of a patient with respiratory failure and spinal metastases from a soft tissue sarcoma, requiring caesarean section is described. Sensory anaesthesia extending above a level of imminent cord compression was achieved despite loss of cerebrospinal fluid signal on magnetic resonance imaging.     

Infectious complications of regional anesthesia

Although individual cases have been reported in the literature, serious infections of the central nervous system (CNS) such as arachnoiditis, meningitis, and abscess following spinal or epidural anesthesia are rare. However, recent epidemiologic series from Europe suggest that the frequency of infectious complications associated with neuraxial techniques may be increasing. Importantly, while meningitis and epidural abscess are both complications of neuraxial block, the risk factors and causative organisms are disparate. For example, staphylococcus is the organism most commonly associated epidural abscess; often these infections occurred in patients with impaired immunity. Conversely, meningitis follows dural puncture, and is typically caused by alpha-hemolytic streptococci, with the source of the organism the nasopharynx of the proceduralist. In order to reduce the risk of serious infection following neuraxial blockade, the clinician must be knowledgeable in the pathogenesis of CNS infections, patient selection, and use of meticulous aseptic technique. Finally, since delay in the diagnosis may result in morbidity and even death, it is crucial to be aware of the presenting signs and symptoms of meningitis and epidural abscess.     

Regional anaesthesia for labour,operative vaginal delivery and caesarean delivery: a narrative review

This narrative review discusses recent evidence surrounding the use of regional anaesthesia in the obstetric setting, including intrapartum techniques for labour and operative vaginal delivery, and caesarean delivery. Pudendal nerve blockade, ideally administered by an obstetrician, should be considered for operative vaginal delivery if neuraxial analgesia is contraindicated. Regional techniques are increasingly utilised in clinical practice for caesarean delivery to minimise opioid consumption, reduce pain, improve postpartum recovery and facilitate earlier discharge as part of enhanced recovery protocols. The evidence surrounding transversus abdominis plane and quadratus lumborum blockade supports their use when: long-acting neuraxial opioids cannot be administered due to contraindications; if emergency delivery necessitates general anaesthesia; or as a postoperative rescue technique. Current data suggest quadratus lumborum blockade is no more effective than transversus abdominis plane blockade after caesarean delivery. Transversus abdominis plane blockade, wound catheter insertion and single shot wound infiltration are all effective techniques for reducing postoperative opioid consumption, with transversus abdominis plane blockade favoured, followed by wound catheters and then wound infiltration. Ilio-inguinal and iliohypogastric, erector spinae plane and rectus sheath blockade all require further studies to determine their efficacy for caesarean delivery in the presence or absence of long-acting neuraxial opioids. Future studies are needed to: compare approaches for individual techniques; determine which combinations of techniques and dosing regimens result in optimal analgesic and recovery outcomes following delivery; and elucidate the populations that benefit most from regional anaesthesia in the obstetric setting.     

Der Patient mit Koronarstent

Nowadays stents are implanted in over 90% of percutaneous coronary interventions. Depending on the type of stent implanted, dual antiplatelet therapy combining a cyclooxygenase inhibitor such as acetylsalicylic acid and an adenosine diphosphate receptor antagonist (thienopyridine) such as clopidogrel is required for 1–12 months. Premature termination of antiplatelet therapy during non-cardiac surgery significantly increases the risk of stent thrombosis and consequently myocardial infarction, whereas continuation of dual antiplatelet therapy during surgery increases the risk of severe bleeding. Accordingly, treatment recommendations have to be based on the individual relative risk. In cases with a high risk for major bleeding during surgery, interruption of antiplatelet therapy may be required, whereas in cases of a high risk of stent thrombosis, both antiplatelet drugs should be continued throughout surgery. Patients on dual antiplatelet therapy should be counseled by a team of anesthesiologists, surgeons and cardiologists, to devise the right point in time for the operation, the best perioperative antiplatelet therapy and the appropriate perioperative monitoring.     

Conventional landmark palpation vs. preprocedural ultrasound for neuraxial analgesia and anaesthesia in obstetrics – a systematic review and meta-analysis with trial sequential analyses

The aim of this systematic review and meta-analysis was to examine the efficacy, time taken and the safety of neuraxial blockade performed for obstetric patients with the assistance of preprocedural ultrasound, in comparison with the landmark palpation method. The bibliographic databases Central, CINAHL, EMBASE, Global Health, MEDLINE, Scopus and Web of Science were searched from inception to 13 February 2020 for randomised controlled trials that included pregnant women having neuraxial procedures with preprocedural ultrasound as the intervention and conventional landmark palpation as the comparator. For continuous and dichotomous outcomes, respectively, we calculated the mean difference using the inverse-variance method and the risk ratio with the Mantel–Haenszel method. In all, 22 trials with 2462 patients were included. Confirmed by trial sequential analysis, preprocedural ultrasound increased the first-pass success rate by a risk ratio (95%CI) of 1.46 (1.16–1.82), p = 0.001 in 13 trials with 1253 patients. No evidence of a difference was found in the total time taken between preprocedural ultrasound and landmark palpation, with a mean difference (95%CI) of 50.1 (−13.7 to 113.94) s, p = 0.12 in eight trials with 709 patients. The quality of evidence was graded as low and very low, respectively, for these co-primary outcomes. Sub-group analysis underlined the increased benefit of preprocedural ultrasound for those in whom the neuraxial procedure was predicted to be difficult. Complications, including postpartum back pain and headache, were decreased with preprocedural ultrasound. The adoption of preprocedural ultrasound for neuraxial procedures in obstetrics is recommended and, in the opinion of the authors, should be considered as a standard of care, in view of its potential to increase efficacy and reduce complications without significant prolongation of the total time required.